Full text of "The conquest of the air; aeronautics, aviation; history, theory, practice"

See other formats

Google

This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project

to make the world's books discoverable online.

It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject

to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books

are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover.

Marks, notations and other maiginalia present in the original volume will appear in this file - a reminder of this book's long journey from the

publisher to a library and finally to you.

Usage guidelines

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the
public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing tliis resource, we liave taken steps to
prevent abuse by commercial parties, including placing technical restrictions on automated querying.
We also ask that you:

+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for
personal, non-commercial purposes.

+ Refrain fivm automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine
translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the
use of public domain materials for these purposes and may be able to help.

+ Maintain attributionTht GoogXt "watermark" you see on each file is essential for in forming people about this project and helping them find
additional materials through Google Book Search. Please do not remove it.

+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just
because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other
countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of
any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner
anywhere in the world. Copyright infringement liabili^ can be quite severe.

About Google Book Search

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers
discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web

at |http: //books .google .com/I

PREFACE TO ENGLISH EDITION

Thb year 1908 was one of experiments ia aerial
navigation ; 1909 is the year of the most brilliant
achievementa.

In 1908 the magnificent experiments of the Wright
Brothers excited the admiration of all to a supreme
degree ; and in the month of October of the same year
two audadous aviators, Farman and BMriot, leaving
their experimenting grounds, boldly set out into the
realm of practice. On October 30 Farman accomplished
the first '* aerial voyage," by travelling from Ch^ons to
Bheims, passing over villages, forests, and hills ; and
the next day Blfiriot achieved the first " cross-country "
journey in a closed circle between Toury and Artenay,
making two descents en rottte, and restarting under his
own effort, without any launching apparatiu, finally
returning to his starting-point.

The "Conquest of the Air," commenced in 1885 by
the first dirigible, La France, built by Colonel Benard,
is to-day asserted in the new development — aviation.

But now, in 1909, our human birds have excelled.
By a remarkable flight, Bleriot, more fortunate than his
rival Latham, who came to grief off his destination, sue.
ceeded in crossing the Channel on July 25, thus realising
through the atmosphere that entente cordiale made

> • * i

vtti rUXTACt. TO latfGLfiB

"^M; ^AHUt ^ JMIStflOT'. Ufflr WlfHIlg S. 'SBC*

iMM«tl^' tClK Utt tiClBL TifiirC iJl USA JWi

v^^iM. f'tiulitfix. tn#(iL fc iioiiuifr tnuk n

v^irti^^anK l^i^UUl IcMxausfsvk ^iosSunii & sop:
j'^ir^HiMi., ki 1^ trxunotfiuii ginrLinuuBE i^ht,

w JH AMn^^w; uid Conk, liisr

^ {^ MiMiidb — tbut is Uip 9kT. hew « 7S

if <M^ 4j«r> rwtJk Utf: £m!1 tittt it
t^ MMi^ y^iAr, ISKfS^, that the two
if^rfn^m wte$^. iiisnmiAkhed by dirigible hillnnni^ wbieh
^#4rr^ 44ditjix^y nMertod the pfWBhiHtj of tlieir far4ar» l
nf^y^Aii/^, <«!« will QndenUnd that the lugfawmy of
il^ Miu0/Hf0t0fn m mm open, and that the "O ouim eatof
il^ Air*' Utm htoome aa aocomjdiahed tut.

T(i^ frirxflaot 10 therafinre c^portane to ezpfaun how
Uik e^/u/|ii«0t baa been eflfoeted, to describe the principleii
//f Um9 er/natnictioii and control of aerial ▼ o a po h, dirigible
indUM^mt or aviation apparatus ; that is my reaaoo ftr
writing this bo^ik*

f tiavi^ written it as lucidly as possiUe, so that it can
im ruarl by alL It has no pretensions to being an ** aero-
fiauiiiMi^l encyclopflddia/' but rather an '' introduction to
tti4» ttiuily of aeronautics/' that those who read and
iifiiierstand it may be able to follow accordingly and
with advantage the whole progress of the new science

THE CONQUEST OF
THE AIR

NAVIGATING THE AIR

A 8CISNTIFIC 8TATEMSNT OF

THE PBOGBE88 OF AEBO-

NAUTICAL 8CISNCS

UP TO THE

PBE8SNT

TIME

In One Volume, Crown 8to. Ulnstrated
Priee 6t.

Lokdok: William HmrxMAHH

THE CONQUEST OF
* T H E X I E ^

AERONAUTICS
AVIATION

HISTORY : THBOBY : PBACnCE

ALPHONSE BEEGET

T rSEHIDEDT LA BOCISTE rKAN^IlE D

WITH EXPLANATOET DIA0BAM8
ANi) FHOTOQBAPHS

LONDON : WILLIAM HEINEMANN

NEW YORK :G. P. PUTNAM'S SONS

1909

xvi CONTENTS

CHAPTER VII : THE FUTURE OF AERIAL
NAVIGATION

Dirigible* or aeroplanet. MiStary appKcaUoma. App
to civil ttfe, SdmUfk appKeatioiu : exfloraHtm of%
couniriet. The nuhtririal movemml created ^ oeho/i
tion. What remamt to he done t Pjp. SS

APPENDIX Pp. %

INDEX Pp. S8

ILLUSTRATIONS

PLATES

PACIHO
PLATE PAGB

I. Flight of ''La France" over Paris (Sept. 25, 1885);
voyage of the " B16riot ** aeroplane from Toury to
Arteulay and back with two descents (Oct. 31,
1908) FronHspUce

Ia. M. Farman and his biplane on which he flew 180 kilo-
metres (112^ miles) in 3 hours ; M. Paulhan finishing
his morning flight of 50 kilometres (31^ miles) in 50
minutes on his Voisin biplane viii

II. The dirigible balloon '' R^pubUque " 10

III. The screw-propeller of the " Ville de Paris " ; the screw-

propeller of the " Bayard-C16ment " 22

IV. The dirigible " Bayard-Clement " 24

V. Screw-propeller and car of the German airship '' Par-
seval " ; Col. Lowther, M. Capazza, M. Clement (car
of the " Bayard-C16ment ") 32

VI. Front part of the '' Bayard-Clement " car showing pro-
peller shaft 36

VII. The '' Bayard-Clement " returning to its garage (showing

the details of the pneumatic empennage) 40

VIII. The '' Bayard-Ciement " over the Madeleine ; the Place
Venddme, the Madeleine (as seen from the '^ Bayard-
Ciement") 46

IX. The car of the dirigible '' Republique " 54

X. The dirigible ^^Patrie" seen from below. The horizontal
stabilisating empennage can be distinguished as well
as the elevating rudder in front 70

XI. The little detachable '' Zodiac " dirigible ; transporting
a '' Zodiac " ; assembling a ^* Zodiac " ; dissembling
a « Zodiac " car 78

xvU b

ift..

xviii ILLUSTRATIONS

rLATB

XI !• Santot-Dumont's aeroplane winning the Deotidi prae;
a '* Santos-Dumont " aeroplane ; a *' Santoa-Damont'
dirigible ; an accident ; the little *' Santoa-DamoBt'
aeroplane

XIII. The '' Ville-de-Paris " in ite garage

XIV. The German dirigible ''Zeppelin*' nuuioeaTring over

Lake Constance

XV. The meUl skeleton of the dirigible ** Zeppelin " ; Sevm
d' Albuquerque's rigid dirigible '' Pkz/' destroyed bj
fire in Paris (1902)

XVI. The Italian military dirigible manoeuvring over Btm-
ciano ; the German dirigible ** Groas "

XVII. M. Ader's ''Avion "; the "Avion " with wings folded;
Wright making an aerial glide; OttoLilienthal glidiof;

XVIII. M, Santos-Dumont's first trial (aeroplane without motor
towed by the "Rapiere"); M. Santos-Dumont's
floating aeroplane ; the Gastambide-Mangin mono-
plane in full flight

XIX. Henri Farman at the wheel of his aeroplane (the prow

of the machine is to the right) U

XX. Ck)nstructing an aeroplane wing (Ferber) 1!

XXI. The Joanneton apparatus for recording the speed of
airships; carrying 100 horse-power aviation motor
(Antoinette) I

XXII. Ciobron light motor; Esnault-Pelterie light motor;
M. Kapf(6rer, M. Sabathier; bridge and eontrolling
mechanism of " Bayard-Clement " I

XXIII. H. Farman's aeroplane (Voisin, constructor); H. Far-
man, M. Henri Deutsch ; £. Archdeacon, H. Far-
man ; H. Farman winning the Deutsch prize ]

XXI I Ia. Mr. Glenn Curtis, winner of the Gordon-Bennett Cup,

Rheims, 1909 1

XXIV. Wilbur Wright at the helm of his aeroplane (the two
steering levers may be distinctly seen) ; the Wright
aeroplane issuing from its garage at Auvours Camp
(the prow is to the right) 1

XXV. The Wright aeroplane flying ; the Wright aeroplane
at the moment of launching by the drop of a weight
falling from its " pylon " S

XXVI. Louis Bleriot's monoplane in full flight (the Foster-
chassis and the " Aileron " at the tip of each wing
are plainly shown) S

ILLUSTRATIONS xix

VACIVQ

PLATE PAGE

XXVIa. The B16riot aeroplane preparing to leave the French
coast (the aviator standing on his bird^ and the
wooden propeller and motor can be plainly seen) ;

Bl6riot crossing the Channel^ July 28, 1909 212

XXVII. The Esnault-Pelterie monoplane 21 6

XXVIIa. Mr. Latham, winner of the height competition at

Rheims, 1909 222

XXVIII. Monoplane " Antoinette IV " ; motor and skate of the

'' Antoinette " aeroplane 226

XXIX. De la Hault's omithopt^re ; Ck)mu's h^licopt^re 232

XXX. Henri Farman's voyage from Chalons to Rheims 24.4

XXXI. The Br6guet; light h61icopt^re (the propellers) ; light

h^licopt^re (motor and steering) 264

XXXII. Chalais-Meudon Park; the Eiffel Tower; the Place

Vend6me 266

DIAGRAMS IN TEXT

no. PAGE

1 Resistance of the air upon a normally moving surface 15

2 Influence of the front shape 15

3 Different shapes of dirigibles 1 7

4 Eddying action resulting from flat shape of stem 17

5 Triangular connection suspension (indeformable) 25

6 Air-ballonnet 27

7 Action of the elevating rudder 31

8 Route sUbility 38

9 Longitudinal stability 33

10 Instability produced by parallel connections 35

1 1 Deformation of shape of transverse section 35

12 Action of the ballonnet 36

13 Imperfect equilibrium 37

14 Cruciform empennage of the Palrie and Reptiblique 40

15 Pneumatic empennages ^

16 Application point of the propelling force 43

17 Rational arrangement of the screw 44

XX ILLUSTRATIONS

no. PACK

18 Compass card 47

19 Example of relative wind 50

20 Combined efiects of wind and independent speed 53

21 Instance where the independent speed is less than the

wind 53

22 Case where the independent speed equals the wind 54

23 The balloon speed is greater than the wind, so it can go

an3rwhere 54

24 The dirigible balloon Bayard'CUmenl 63

25 Constructor Surcours method of '^ mooring " a dirigible 73

26 Voyage of the BmfardClimefU (November 19O8) (iSO kilo-

metres in a closed circle in 6ve hours^ without descent) 76

27 A little Z<N/tac dirigible 78

28 Design for the first dirigible by General Meusnier (1784) %5

29 Henry Giflfard's steam driven balloon (1852) 87

30 Captains Renard and Krebs' balloon La France (1884) 91

31 The first two aerial voyages in a closed circle made by

La France over Paris in 1885 93

32 Route and altitude map of Santos-Dumont's journey (the

Deutsch prize, October 1901) 95

33 The dirigible balloon Lehaudy (side elevation) 97

34 The dirigible balloon Lehaudy (under-side plan) 97

35 The dirigible ViUe-de-ParU, offered by M. Henry Deutsch to

the French Minister of War 101

36 Journey of the yille-de-Paris from Sartrouville to Verdun

(January 15, 19O8) 103

37 The German dirigible Zeppelin 105

38 Voyage of the Zeppelin August 4 and 5, 19O8 (606 kilometres,

ending in the destruction of the idrship) 107

39 Voyage of Zeppelin IIL in a closed circle (April 1909) 109

40 The German dirigible Parseval 109

41 The dirigible Belgique, with two propellers and twin screws 111

42 Equilibrium of the kite 125

43 Equilibrium of the theoretical aeroplane 128

44 Resistance of the air upon a slanting surface 1 30

45 Influence of the angle of attack 1 30

ILLUSTRATIONS xxi

no. PAGE

46 Flat surface advancing normally through the air (the air

molecules gliding symmetrically round the ends) 181

47 The surface advancing obliquely through the air (the gaseous

molecules gliding past in a dissymmetrical maunei") 131

48 Equilibrium of the actual aeroplane 13^

49 Action of the empennage 133

50 Action of a vertical '' fringe " at the stern 133

51 A long and narrow surface 136

52 A short and wide surface 1 36

53 Spread of a bird's wings 1 37

54 Evolution of the cellular^ from the multiple^ kite 141

55 An aeroplane turning 143

56 Principle of warping the planes (Wilbur and Orville Wright) 145

57 The correcting ailerons (Bl^riot) 147

58 Partitioning (MM. Voisin) 147

59 The steering rudder 151

60 Pisciform section of the wings 159

61 Propulsion of an aeroplane by two screws (A^ with the two

propellers — B^ with one only) l65

62 Combined action of wind and propulsion speeds 171

63 Wind and the aeroplane : actual and relative routes respec-

tively 172

64 Effect of inequalities of the ground surface upon the move-

ment of the air 174

65 Principle of the L^ger h^licopt^re 1 82

66 Side elevation of the Capazza lenticular balloon ] 84

67 Front view of the lenticular balloon 184

68 Plan of Capazza's lenticular balloon 185

69 The Voisin aeroplane (H. Farman's type) 189

70 The Voisin aeroplane (Delagrange type) 191

71 The W^right Brothers' aeroplane 193

72 Details of the wing- warping action in the Wright aeroplane 197

73 Maurice Farman's aeroplane 203

74 L. B16riot's monoplane 209

75 The rolling chassis of the Bl^riot aeroplane 211

x> ^^ L^:iT?^i:z y<

22
23

24
25
26

27
28

29 -

30 (

32 ]

33 1

34 1

35 1

36 J

37 T

39 V

40 T

"4t

riG.

18 " »- "J^^rx 1 ■wjU'JiiiAtitz

• ^ ■«

.--■»■

19 '■« '■Im' •

20 ''» Kma^ : • --• -i r.:-

21 "" Pic *JUBir..: ■■j'-':i t^:-:::

•cw iL It-;- :.

■ ■lurv iiiu 'irn*'. . . -^ - ■" - ■' ;*er
*i Hie ••\lMuniu«Jii ■■: ' c:i-f '^n . - t -:

^*^-

It-

xxiv INTRODUCTION

experiment the poeaibility of steering balloons, a possi-
bility which was triumphantly realised by Colonel
Henard twenty-five years ago, in 1884.

It is now therefore possible to direct a balloon floating
in the air by virtue of the principle formulated by
Archimedes, because its weight is less than that of the
air it displacea This first solution of aerial navigation
has the merit of complete novelty ; Nature has nothing
comparable to show us; it difiers as much from the
flight of birds as the action of a railway-train fi:om that
of the most agile of our quadrupeds.

But the example of birds was always present, inciting
the human brain to seek a further solution ; the prob-
lem was to rise into the air mechanically, without the
cumbersome intermediary of a volume of light gas en-
closed in an impermeable envelope ; in a word, to
navigate the air after the manner of birds with an
apparatus heavier than air.

The first essays were made a long time ago, but it
WM not until 1895 that the solution already presaged
began to be tangible. Now at last aerial navigation
without an aerostat, mechanical sustentation, aviation^
in short, is an accomplished fact ; its practical application
is merely a question of minor improvements.

There are then two quite distinct forms of aerial
navigation, that of the dirigible balloon, and that of
aviation. We have therefore a natural division for
this book, in the first part of which we shall deal with
dirigible balloons.

PART I

DIRIGIBLE BALLOONS

CHAPTER I

PRINCIPLES

How THE AERIAL VESSEL FLOATS AND MOVES : WhY DIRIOIBILITY

MUST DEPEND ON A MOTOR AND A PROPELLER: A COMPARISON

BETWEEN MARINE AND AERIAL NAVIGATION

THE PRINCIPLE OF ARCHIMEDES

A DIRIGIBLE balloon is an apparatus which is supported
in the air by making use of the pressure exercised by
this on all bodies plunged into it ; thanks to a propeller
revolved by a motors it can and must move in this
element at the will of the aeronaut.

I may state the fundamental principle of aerostation
in a very few words.

Archimedes discovered it, and formulated it as follows :

Every body plunged into a fluid is subjected by this
fluid to a ^^ pressure ^^ from below to above, which is equal
to the weight of the fluid displaced by the body.

It is in virtue of this principle that ships float on the

water and fish swim in it. When a body, the exterior

volume of which is a cubic metre, is plunged into water,

this body also displaces a cubic metre of water, or, in

other words, 1000 litres. Now 1000 litres of water

weigh 1000 kilogrammes. Three possibilities may then

arise : the weight of the body immersed may be less than

1000 kilogrammes, and it will then rise and float on

the surface ; or it may be exactly 1000 kilogrammes, in

4 THE CONQUEST OF THE AIR

which case it wiU remain in equilibrium in the water at
a certain level; or, finally, it may weigh more than
1000 kilogrammes,, and then it will sink to the bottom.

These three factors are realised by fish, which are able
at will to rise to the surface, to suspend themselves in
the water, and to go down to the bottom ; to carry out
these operations they vary their specific gravity by the
help of their natatory gland, a bag containing air which
they can dilate or compress as they please; we shall
find later, in dealing with dirigible balloons, a similar
organ in the " air-ballonnet."

HOW DOES A DIRIGIBLE BALLOON RISE ?
THE ASCENDING EFFORT

The principle being laid down, we may make use of it
to raise an object into the atmosphere ; we have only to
produce a body, the total weight of which shall be less
than that of the volume of air it displaces.

Now the weight of the air is known : a cubic metre of
it weighs 1*293 kilogrammes, that is to say, about 1300
grammes, when the temperature is at zero and the
barometer indicates 760 millimetres. On the other hand,
there are ^* light " gases, such as the gas used for illumi-
nating purposes and hydrogen. A cubic metre of lighting
gas, at zero, weighs about 500 grammes, and a cubic
metre of hydrogen, under the same conditions, weighs
only 110 grammes.

Let us take this latter, the most suitable for the object
we have in view. Let us make a huge receptacle of some
supple and impermeable material — a " balloon " — ^and let
us fill this " envelope " with hydrogen gas. Let us sup-
pose that the interior volume of this receptacle is 1000

PRINCIPLES 5

cubic metres ; when filled with hydrogen it will weigh
110 kilogrammes ; but the 1000 cubic metres of air that
it displaces will weigh 1293 kilogrammes.

The difference, i.e.^ 1183 kilogrammes, will be the
Yeirticel pressure from below to above on the receptacle
by virtue of Archimedes' principle. The envelope thus
inflated with hydrogen would therefore be capable of
lifting 1183 kilogrammes, that is to say, 1 kilogramme
183 grammes per cubic metra. A balloon thus con-
structed is called an aerostcU. The point where the
pressure which supports it is exerted is called the
centre of pressure^ and its position coincides more or less
with that of the centre of gravity of the inflated envelope.

If, then, the weight of the envelope itself, plus the
weight of a support affixed to it to carry the motor and
propeller, and the weight of the travellers, does not
exceed 1180 kilogrammes, the apparatus will rise ; the
difference will be its ascensional effort. If the total
weight of the envelope and of the system it supports
exceeds 1180 kilogrammes, the apparatus will remain
fixed to the ground.

If, instead of inflating our envelope with hydrogen,
we had used lighting gas, it would only have been able
to raise 690 kilogrammes instead of 1180; obviously
therefore, there is an advantage in using hydrogen.

The very existence of the ascensional efibrt produced
by the pressure of the ambient air provides the aeronaut
with the simple means of making his balloon rise or sink
at wilL If he wishes to rise, he has only to throw out
of his car a portion of the weight it contains ; ballast^
in the form of bags of sand, is always carried for this
purpose. If, on the other hand, he wishes to descend.

8 THE CONQUEST OF THE AIR

ting these, gives a certain speed to the boat ; we shall
see that so long as this speed is appreciable^ the rudder
acts efiSciently, and that the steersman has only to move
it to the right or to the left at will to procure the evolution
of the vessel. But let the rower rest on his oars, the
boat, deprived of speed, will float " like a buoy," and it
will be useless for the helmsman to work the rudder, as
the latter will have no effect upon the boat, which will
be the sport of the water on which it floats ; in order
to steer it, we must propel it.

In the same way we must " propel " an aerostat if we
want to " steer " it. But to propel it we must have a
motor, and every motor is necessarily heavy. Let us
now inquire into the respective weights of the motors it
would be possible to use.

In the first place, there is the ^' human motor," that is
to say, the muscular energy of the passengers in the car.
It is hardly necessary to say that this was the first motor
to be taken into account in the earliest days of aerosta-
tion, for at that period it was the only one known. But
though such a dream was possible then, it is so no longer,
for the more precise data concerning mechanical experi-
ments have established the weight-conditions of each
category of motors.

The practical unit of energy is steam horse-power, that
is to say, a force capable of raising 75 kilogrammes one
metre from the ground in one second. This power is
very much greater than that of the animal horse. A
man represents but a fraction of it. Now mechanicians
have established by experiment, independently of all
theory, that the weight of the steam horse-power
translated into human muscular power, is about 1000

PRINCIPLES 9

kilogrammes ; in other words, it takes 1000 kilo-
grammes of men to produce an effort equal to that of
the steam horse ! It was therefore obviously futile to
attempt to steer balloons by utilising the muscular power
of the few aeronauts who controlled them.

In the early days of steam power, motors were of con-
siderable weight. The engine of the Sphinx^ the first
steamship in the French Navy, weighed more than 1000
kilogrammes per horse-power, and even thirty years ago
steam motors weighed some 100 kilogrammes per horse-
power. Hence the first steam engines were no more
suitable for the propulsion of aerostats than human effort,
to say nothing of the danger of installing a boiler heated
by coal beneath an envelope inflated with hydrogen, an
eminently inflammable gas.

Nevertheless, steam was the power used in the first
motor employed in a balloon. Its application was essayed
in 1852 by the engineer, Henry Giffard. Instead of
using the steam motors already in existence, he had
one of 3 horse-power, expressly built for his experi-
ment ; he succeeded in reducing the weight per horse-
power to 53 kilogrammes; this was a remarkable
achievement at the time and an enterprise of extra-
or^nary audacity, taking its dangers into account. But
the steam engine was very soon abandoned, owing to
the risk of fire, and aeronauts adopted the electric motor,
which, from 1880, was the recognised motor of the future.
Colonel Benard succeeded in obtaining an electric motor
of 8 horse-power, weighing only 40 kilogrammes per
horse-power, and capable of prolonged action ; this made
recU aerial navigation a possibility, and he had the glory
of first accomplishing it in 1886.

10 THE CONQUEST OP THE AIR

But about 1890 a new engine made its appearance;
rude and clumsy at first, it was very soon improved and
perfected ; thanks to this invention, a new industry was
bom — ^the automobile — ^which has revolutionised all our
habits. The engine was the ** explosion motor. **

The explosion motor is the lightest of any of equal
power. To-day mechanicians have succeeded in reducing
motors especially designed for aviation to the almost
incredible weight of 2 kilogrammes per horse-power.
Moreover, its action has been perfected ; it can start in
an instant without any preparation. The volume has
been reduced proportionately to the weight, so the engine
10 not cumbersome. It is due to this invention that
aeronautics have become what we see, and that aviation
has been made possible in its turn. The explosion motor
is the only one now used for aerial navigation.

WRIGHT PER HORSE-POWER, AND PER HORSE-
POWER HOUR

If we consider a machine able to give 100 horse-power
for a weight of 1000 kilogrammes, we shall say that the
** weight per horse-power "is 10 kilogrammes. But such
data is insufficient for the aeronaut in working out his
plans of construction.

For we have not only to raise our machine, but to use
it, to make it go, and for this we require a com-
bustible, which in our particular case is petrol. Then
we must have water to cool the motor, oil to grease
its mechanism, and the accessories necessary for the
working of the engine. In a word, if our 100 horse-
power engine consumes 1 kilogramme of various materials
per horse- power, it will use 100 kilogrammes of provisions

]\ t-

.j:;:^v^51f^

PRINCIPLES 11

per hour. If we want to make it go for ten hours, it will
require 1000 kilogrammes of provisions, the weight of
which must be added to that of the machine itself.

Thus, in the example we have taken, we shall have
1000 kilogrammes, the net weight of the engine, and
1000 kilogranmies of provisions, to enable it to run for
ten hours, making a total of 2000 kilogrammea But for
these 2000 kilogrammes we shall get 100 horse-power for
ten hours — ^that is, 1000 horse-power hours. The weight
per horse-power hour is, therefore, to be obtained by
dividing 2000 by 1000; that is to say, it will be 2
kilogrammes.

It is essential that we should not confound these two
terms ; the weight per horse-power hour depends on a
proper use of the combustible by the engine, whereas the
weight per horse-power only depends solely on the con-
struction of the engine. As Colonel Benard has already
pointed out, it is possible to have the same number of kilo-
grammes for the weight per horse-power hour with a light
engine that consumes a great deal, as with a heavy engine
that consumes very little ; but with too heavy an engine
the balloon would not perhaps rise at all ; and the first
duty of a balloon, even of a dirigible, is to rise into the air :
ptimum vivere^ deinde phUosophcm^ said the philosophers.

To conclude what we have been saying, we may lay
down this principle : the motor should, above all things,
be as light as possible; that is to say, the point of
primary importance is to keep down the weight per horse-
power. As to the diminution of the horse-power hour,
this would merely enable us to prolong the duration of
^e voyage, or, to use a phrase proper to naval warfare,
to extend the '' radius of action " of the airship.

12 THE CONQUEST OF THE AIR

MARINE AND AERIAL NAVIGATION

THE DIRIGIBLE, THE STEAMSHIP, AND THE

SUBMARINE

The airship has often been compared to the steamship,
the aerial ocean to the marine ocean ; is this a legitimate
comparison ? We will briefly examine this question.

We must first note the essential and absolute difference
between an airship and a vessel. The latter floats
upon an element of great density, the water, in which its
propellers find an appreciable fulcrum, by virtue of its
great resistance ; only a part of its hull is immersed, and
it is upon this part only that the resistance which the
surrounding liquid offers to the advance of the vessel is
exercised. The balloon, on the other hand, is completely
immersed in the liquid which sustains it by its vertical
thrust, and this, due to the weight of a gas the thermal
expansion of which is very great, varies every instant in
accordance with the slightest vicissitudes of temperature
or of barometric pressure, whereas the "hydrostatic
pressure " which causes the ship to float upon the water
does not vary appreciably when the temperature changes.

But no floating vehicle, be it balloon or vessel, is ever
required to float in a perfectly immobile element ; the sea
is agitated by marine currents, such as the Gulf Stream,
which circulates across the Atlantic, or the tidal currents
at certain places on our coasts ; on the other hand, the
atmosphere is in perpetual motion under the action of the
" winds," which are aerial currents. There is, however,
an essential difference between these two kinds of currents.
Whereas the most rapid of the marine currents, such as
the !^az de Sein and the Raz Blanchard do not exceed

PRINCIPLES 18

a speed of 9 knots (16*500 km. per hour), the aerial
currents have often very considerable speeds. Directly
the wind *' freshens," as sailors say, its speed is very soon
increased from 10 to 15 metres a second, that is, from 36
to 56 kilometres an hour. A ship, to which its engines
give a speed which is very considerable in the most
modem types (20, 25, and even 30 knots, or 37, 46, and
55 kilometres an hour), will very soon overcome the ocean
currents, the speed of which need only be deducted from
that of the ship ; whereas the dirigible balloons are
obliged to struggle against currents of air the violence of
which condemn it to immobility-— or to retreat.

In short, the ship and the dirigible balloon are not
comparable. The only exact parallel of this kind which
we could draw is that of the airship and the submarine,
which is also completely immersed in the fluid which
supports it. But the advantage is still on the side of the
submarine, which never has to overcome the rapid currents
with which its aerial counterpart has to contend. A
juster comparison might be made between a dirigible
balloon and a submarine which had to advance, not against
a current, but against a torrent.

We see how difficult a problem the propulsion and
steering of aerostats is, and we can readily understand
why it has taken a century to discover how to guide the
machine which the brothers Montgolfier launched in the
air for the first time in 1783.

THE RESISTANCS OF THE AIR

-nift ytiiiiigfHi <Hr mot ^Mmmsiiat:: T

THE UESGSTAXCE CMT TBE JOK

Wk m« ii&B«e^Hfoc« $<i^tt2|^ ttf» itdb^ tia aMOsta t» mud provide
it Ytdli ;& «Ek><twr W^^n^ tit ;iai "^ taiiqp«nidMik qpeed ** which
Yil^ iHttiiaiW itis p«v>|MdyMtt^)iaiil<iM^^ its directioiL

Gttil vty«H^ wi^ ti&w^ pe^^pid Qwr jftnantrt^ it wiQ ex-
pemoEii^f' m ntnttiteytM^ iEram i^ nrriNrndSng atmosphere
lid ilb^ (K^rmo^l ttk^^wtt^^ mHMiS'vw we mttoB^ to dis-
pibcie % Kvtr v^T^MJ^xrynil £dl ;ti ottiteraJ: ftni — fcr instance,
ii wi^ ^rrt ^ m^^x^ % IS^uicvE w^iAdk w^ bdi ia our hand in
tW >«rti^lMr — «^ )i^ ^ c>M«$Q;ttiiM ti^ ItW neyTHBait we are
l»nH«^ |v^ f«v«i^NK '1^ o^^noiteiti^iiMi luA dqpeod upon
kl^ >(v£wM vr 1^ lv^Qdt wks$^ ^^£ i{&a# Wdjr iftsplaced, for
w^ ^Wit i^tr ^tl x^mtW ^NVi^iSuEi;^ 3ft t^;^ w&nHdbar we farj to
t^vW tiW KwN^ ^JJ v*ir 9Kt^w W. Wd^ ^Jfe^ QK«e that the
^rvw^^A!;^\V w^ je:t^«^5^^ iiC ^ ^/Qaj«^ sX^ood^QQiniii^ b«»ng equal,
wv tint t^^ w.*x^ i;;i fl^w^^i^^.

vHilS^. >»A^^ ;j^'4t^fw,y^x^,x 5v^ vWQ:^!h)i^ ^^d^ ■Wiwtj: vsf this ** air-
^rwif^^nfc^K^ ' Vtii> ^x >rtCik^iH3t«w^ **i; t^:t^«tiit»»Lli. They
i*A>n<^ *»:;:r;>twx 4i; '4*W i^.V^'jtr^^L sN"<nK)wtv«r^, W&K& is exact
-.T ^i^ ^iJ^K,7> ^<5!i;^ tA^^> ;^^^.vw«ii5^ 'if wi^ demand

THE RESISTANCE OF THE AIR 15

precision : '* the resistance offered by the air to a surface
element which is moving on a line perpendicular to its
plane is proportional to the extent of this surface, to the
square of the speed which animates it, and to a nimierical
co-efficient, the mean value of which is 0125. The
resistance is, thus, expressed in kilogrammes, if ihe
surface of the moving element
is measured in square metres,
and if the speed is expressed
in metres per second (Fig. 1)/
For instance, let us con-
sider a panel, a board of 4
square metres surface, moving
normally to its plane at a
speed of 10 metres per second; the resistance, in kilo-
grammes, will be obtained by multiplying the surfitce,
4, by the square of the speed, that is to say by 10 x 10,
or 100, and by multiplying the sum by the co-efficient

Fio. 1. BesiBtance of the air upon
a normally moving surface

Fio. 3. Influenoe of front shape

0*125. It will therefore be the product of 4 x 100 x
0*125, that is to say, 50 kilogrames. If the speed of
movement be doubled, the resistance of the air will be
quadrupled ; it would become nine times greater if the
resistance were tripled — and so on.

When the moving body is preceded by a " prow," that

^ The reader who wishes to know the formula of the resistanoe 61
the air, is referred to the Appendix at the end of the hook.

16 THE CONQUEST OF THE AIR

is, a surface having tapering sides, which separate the
molecules of air without striking them sharply as would
a flat surface confronting them, the resistance is dimin-
ished. Thus, if we take the panel of Fig. 1 , but cause it
to be preceded by surfaces which will divide and thrust
aside the molecules of air, as would be the case if we
made use of the hemisphere or the cone (Fig. 2) with
a base of the same superficies as the panel, the resistance
of the air to the speed of 10 metres per second, which
was 50 kilogrammes for the flat panel moving ortho-
gonally, will be but 25 kilogrammes for the hemisphere,
and only 9 kilogrammes for the acute-angled cone.

Experience has shown that not only is the shape of
the '' bow " of the moving body important, but also that
of its " stern," that is to say of the " poop," for the
profile of the latter may either permit an easy reunion of
the molecules of air separated by the prow, and gliding
along the sides to rejoin each other, or, on the other
hand, its abrupt line may cause the molecules separated
by the prow to re-unite tumultuously, clashing one with
another and producing eddies behind the moving body.

THE SHAPE OF DIRIGIBLE BALLOONS: SPINDLE,
FISH, AND CYLINDER

The points we have just considered must be taken into
account in determining the shape of dirigible balloons.

In the first place, there can be no question of attempt-
ing to propel a spherical balloon ; the surface on which
the resistance of the air iwould be exercised during the
progress of the balloon would be enormous. With an equal
volume of envelope, it is necessary to choose a shape that
presents as small a surface as possible to the air as it

be that of a mrmmisaxa^ tgnrift^, u. ri'nif ':ofj. uid. rf
so, should k adracee -w^niL -dui acr^ :r I2« smfc'ier flsi
foremost ? or KxsaJd h "ts » rrlniar '

Hie fins stc^iqxz. ^::ee teG^5fcri £z. :?5i, rf I>3j«m-
de LAme in iS72. azri |
of TiflBSodier in 1S^4.
were made with ^fimr
foiin"(s|HDdle-6haped I
balloons; in other
words, th«r shape,
equally pointed at
^ther end, was sym-
metrical in relation
to the central plan

flmi ik«p« of tK^ra

(¥ig. 3). Bat all this was chaoged when that man of
genius appeared who was indisputably the real creator
of aerial navigation. Colonel Charles Eenanl, whoiH*
premature death in 1905 was an irreparable I088 to
science and to France.

18 THE CONQUEST OF THE AIR

Renard demonstrated by his calculations that the
most advantageous shape is that of a dissymmetrical fisb
(B), with the largest end at the front. So long ago as
the beginning of the nineteenth century, Marey-Monge
had presaged the necessity of adopting this form if an
attempt should be made to propel aerostats : " They
must have the head of a cod and the tail of a mackerel ''
was his dictum.

This, indeed, is the shape of all birds and of all swiftly
moving fishes : whales, cachalots, and porpoises. At
present all dirigible balloons which have proved really
capable of progression are all constructed in the shape
worked out by Renard.

We must now point out that if the conditions of pn^res-
sion and of the resistance of the air are to be normal, the
balloon must preserve its shape during its course, either
ascending or descending ; we sl^all see later how this
condition is fulfilled by the " air ballonnet."

As to the cylindrical form (C), adopted in Germany by
Count Zeppelin, it seems less advantageous ; the mole-
cules of air thrust apart by the point in front exercise an
exaggerated friction on the sides before they re-unite,
thus retarding the progress of the airship. The other
•German aeronauts are therefore gradually returning to
\the pisciform shape.

In any case, the pointed end behind is indispensable,
Tor without it there would be an eddy of the molecules
of air, and consequently a partial vacuum which would
cause antagonistic prow thrust ; this pressure, exercised
against the forward movement, would retard the speed of
the airship (Fig. 4) ; it is therefore necessary at all costs
to avoid it by tapering the rear end of the balloon.

THE RESISTANCE OF THE AIR 19

RESULT OF AIR RESISTANCE : ADVANTAGE
OF BALLOONS OF LARGE CAPACITY,
STRENGTH AND SPEED

The resistance of the air to the movement being pro-
portionate to the square of the speed of the moving
body, will lead us to a most important conclusion. It is,
that balloons of large size have an advantage over those
of smaller dimensions. Let me explain.

To start with a clear idea, let us consider an airship in
the shape of an oblong box with a square base, the latter
being, for instance, 1 metre each side, by 5 metres long.
Its volume will be 5 cubic metres, and its ascensional
effort, taking this at 1 kUogramme per cubic metre, will
be 5 kilogrammes. This balloon, if inflated with
hydrogen, will, in round numbers, lift a motor the power
of which will be limited by this weight of 5 kilogrammes ;
and if we suppose that a motor weighing exactly 5 kilo-
grammes per horse-power has been constructed, the
motor this balloon can lift will be of one horse-power.

Having demonstrated this, let us construct a second
airship, exactly similar to the first, and also inflated
with hydrogen, but with all the dimensions doubled;
that is to say, having a squared base of 2 metres, by a
length of 10 metres instead of 5. The volume of this
balloon will not be double that of the first, it will be
2 X 2 X 10, in other words 40 cubic metres ; that is, eight
times larger, while its surface of resistance to progression
will be that of its base, i.e., 4 square metres.

Thus, as we have doubled all the dimensions, the
resistance of the air will be four times greater, whereas
the volume, that is to say the lifting power, will be txghX

20 THE CONQUEST OF THE AIR

tixnea as much. Now, with a lifting power eight times
greater, it will be possible to lift a motor eight times
more powerful, and even mpre, for the weight per
horse-power diminishes in proportion as the power of the
motor increases. The balloon whose dimensions have
been doubled will therefore have a motor of at least
40 hors6-p6wer to meet a resistance of the air bearing
upon four square metres, that is to say, 10 horse-power
per one square metre of the transverse section, whereas
the balloon of half this size will have only a 5 horse-
power per one square metre of the section. The advan-
tage is consequently all on the side of large balloons, and
aeronauts who wish to undertake important journeys,
and carry large stores of combustibles and numerous
passengers, will find it profitable to construct dirigible
balloons of large dimensions. The largest dirigible
balloon yet constructed is the Zeppelin^ of 12,000 cubic
metres, while the smallest is the Santos Dumont, No. 1,
which gauged but 180 cubic metres; it is true that its
only passenger, M. Santos Dumont, weighed only 52
kilogrammes, and that the whole car weighed only 10
kilogranmies !

To sum up, we may say that the volume, on which the
power of the motor that can be carried depends, varies
according to the cubic dimensions of the airship, whereas
its surface, on which the resistance offered by the air to its
progress depends, varies only according to the square.

Finally, it is necessary to point out that the power
necessary to communicate increasing speeds to the same
airship increases proportionately to the cube of the speed.
This law has been demonstrated by calculation and
verified by experience. It is of vital importance, for it

THE RESISTANCE OF THE AIR 21

leads to various conclusions of the utmost moment.
rhus, to double the speed of a dirigible balloon, we must
^ve it a motor power not tvnce, but eight times greater
(8 is the cube of 2 ; 8 » 2 x 2 x 2). We see therefore
that great care is necessary in calculating the elements
of a dirigible balloon, when it is destined to undertake
journeys of any length.

THE « RADIUS OF ACTION " OF AN AIRSHIP

A dirigible balloon ought not, indeed, to be a mere
object of scientific curiosity, or an instrument of sport ; it
should have a useful application; it should be able to
accomplish journeys. The longer these can be made to
last, the greater will be the utility of the engine.
Therefore it will be necessary, first and foremost, to
ensure long-sustained flight in the ascents of this dirigible
balloon.

Here the question of speed plays a very important
part, as does also that of the motor power it will be
necessary to apply to the airship to give it the desired
speed. This power, as we have just seen, is proportional
to the cube of the speed. And this must be taken into
account if travelling velocity is not the sole desideratum,
and if the total distance the aerial vessel can travel is also
an important factor.

Let us consider a balloon of 3000 cubic metres,
travelling at the rate of 60 kilometres an hour, with two
engines of 60 horse-power each. These two engines
would consume a total quantity of 60 kilogrammes of
petrol an hour. The balloon, carrying six passengers,
can take 600 kilogrammes of petrol, which will make it
possible for it to travel for ten hours ; if we take into

22 THE CONQUEST OF THE AIR

consideration that it has to retam to its mooring-ground,
its pilot will have five hours of progress at his disposal,
or, i*eckoning 60 kilometres to the hoar, 300 kilometres.
We should say under these conditions that the radius of
caelum of this diriffihle baUoan is 300 kUametres.

Let us now suppose that only one of the motors is
used ; the propelling power then will be only 60 horse-
power ; the speed will be divided by the cubic root of 2,
that is, in round numbers, 1*25 ; it will therefore be
48 kilometres an hour. But the single motor will only
consume 30 kilogrammes of petrol, and there are 600 on
board ; the airship would therefore have twenty hours of
trawl before it, instead of ten, that is, ten to go and ten
to return ; it will therefore be able to travel 10 times 48
kilometres, and still have the means of returning to its
starting-point. We should therefore say that under
these altered conditions^ the radius of action of the
dirigible is 480 kilometres.

Thus, by demanding a speed of 48 kilometres only per
hour instead of 60, we extend the radius of action of the
same dirigible from 300 to 480 kilometre& We have
consequently increased it very considerably.

This shows us how important this consideration of the
radius of action is, especially in the application of aerial
navigation to military or geographical matters. One
thing should be clearly understood : speed is costly on an
airship as on a transatlantic liner ; to double it, the
motor power must be multiplied by 8 ; the balloon naust
therefore carry eight times more fuel; whereas, by
diminishing the motor-power by one-half, the speed is
only reduced by one-fifth. When, therefore, airships
attempt to perform long aerial voyages, the problem that

THE RESISTANCE OF THE AIR 28

confronts them will be, how to reconcile the minimum
speed which will enable them to make way effectually
against the prevailing winds, with a reduction of the
motor power, which, by diminishing the amount of fuel
consumed, will enable the store of petrol to hold out
sufficiently to reach the most distant points! The
wisest solution would obviously be to furnish the
dirigible balloon with two independent motors ; when a
** special effort " was required, the two engines could be
used; but in favourable atmospheric conditions, the
travellers would be content with the propulsion furnished
by a single motor. Though the speed would be some-
what diminished, it would be possible to travel a good
deal farther.

All we have just said of the " radius of action " of a
dirigible applies of course to aeroplanes, for which this
consideration is also of the greatest importance.

CONDITIONS OF EQUILIBRIUM OF DIRIGIBLES

The first condition to be fulfilled by our dirigible
balloon, whether stationary or in motion, is that it
should always be '' in equilibrium."

When stationary, the airship should always maintain
such a position that the geometrical axis of the solid
body formed by its envelope is horizontal. Now when
a dirigible balloon is suspended motionless in calm air, it
is subjected to the action of two forces; one is its
weighty P (Fig. 5), which is applied to the centre of
gravity C of the system formed by the envelope and all
it supports ; the other is the thrust of the air, applied to
a point B called the centre of thrust. If the envelope
contained only its inflating gas, and had neither car nor

24 THE CONQUEST OF THE AIR

cargo to carry, and even if the weight of this envelope
were negligible, the centre of thrust and the centre of
gravity would coincide. But the addition of the weights
that the envelope has to lift into the atmosphere causes
this result : these two forces are not a continuation of
one another.

As they must necessarily be equal if the balloon
neither ascends nor descends, it follows that they will
make the balloon turn until they are a continuation
of one another, and our airship will then take the
position indicated by Fig. 5 (No. 2).

To avoid this position, which would be incompatible
with rapid propulsion, the weight must be properly
distributed along the car fi*om M to N, in such a
manner that, when the balloon is horizontal, the two
forces, the pressure BQ and the weight CP, are upon
the same vertical line. " Static equilibrium '* will then be
ensured. We see therefore that the connections between
the car and the envelope must never vary, though
at the same time they must be allowed a certain flexi-
bility, indispensable in aerial navigation. We shall return
to this point when we deal with longitudinal stability.

But this is not all ; the balloon, as it advances under
the combined action of its motor, its rudder and the
resistance of the air, must preserve a general stability ;
it must remain perceptibly horizontal, and must not
execute violent or extensive movements, either from fore
to aft, or from right to left ; in other words, there must
be neither ** pitching " nor " rolling."

Every one knows what are the classic methods of
aeronauts who go up in spherical non-dirigible balloons.
To ascend, they diminish the total weight of their balloon

THE RESISTANCE OF THE AIR 25

by throwing out ballast, that is, part of a supplementary
weight, composed of sandbags, which they take with
them at starting. When, on the other hand, they want
to descendf as they have no means of increasing their
weight, they diminish the thrust of the air on the

Fio. 6. Triangular connection suspension (indeformable)

balloon by letting some of the light gas of the envelope
(the specific lightness of which constitutes the lifting
force of the balloon) escape from a valve. This ascen-
sional efibrt diminishes in proportion to the amount of gas
allowed to escape. The aeronaut is therefore able to ascend
or descend at will by the dual means of ballast and valve.
But this simple method cannot be applied to the
conduct of a dirigible balloon. Dynamic equilibrium,
that is to say the equilibrium of the airship in
motion, must take into account not only its weight
and the sustaining pressure of the air, but also
the resistance of the air exercised upon its envelope,
which resistance depends on ' the dimensions and the
shape of that envelope ; in calculations, this shape is
assumed to be invariable. Now what will happen if we
allow a portion of the gas enclosed in the envelope to

26 THE CONQUEST OF THE AIR

escape? When the balloon descends firom the atmo-
spheric stratum from which the aeronaut wishes to
approach the earth, it will find itself in masses of air, the
pressure of which will increase as he comes nearer to the
ground ; this will be easily understood, since theee
lower strata bear the weight of the upper strata. The
confined gas, now insufficient to fill the balloon, as a
certain portion has been allowed to escape, will contract ;
the balloon, no longer full, will become flaccid, and will
not retain its original shape. The centre of resistance of
the air will consequently have changed, as well as the
centre of thrust, and the initial conditions will no longer
be in force. As these conditions were used as the basis
of calculations dealing with the equilibrium of the airship,
that equilibrium can be no longer maintained.

THE AIR BALLONNET : RIGID BALLOONS

All these inconveniences are obviated by an ingenious
contrivance, the idea of which originated with General
Meusnier, who formulated it in 1784, only a year after
the brilliant experiments of the Montgolfier brothers.
Like all remarkable developments prematurely evolved,
General Meusnier's idea was forgotten, and it was not
until 1872 that the famous naval engineer, Dupuy de
L6me, the inventor of the ironclad, resuscitated it in
connection with his attempts to make balloons dirigible.

We have seen above that it is absolutely essential to
keep the balloon always perfectly inflated ; on the other
hand, in order to descend, it is necessary to let out gas,
which partially empties the envelope. To maintain the
volume of this, it would therefore be necessary to take a
stock of hydrogen to introduce into the envelope by

Area of
compartment

Ballonnet

Air Pipe.

THE RESISTANCE OF THE AIR 27

means of a pump worked from the car. But when we
consider that it would be necessary to carry this hydrogen
compressed in very strong steel cylinders, we see, as a
simple calculation will sufficiently prove, that the weight
of the necessary number of cylinders would be prohibitive.
Consequently, the
aeronaut is obliged to
reject this method,
which is perfect from
the theoretical point
of view, but impracti-
cable in fact. He will Fio. e. Air-Ballonnet

rely, not upon a supplementary stock of hydrogen, but
on air drawn from the ambient atmosphere, to restore
the original volume, and he will replace the volume of
hydrogen lost in the descent by an equal volume of air
which he will introduce into the envelope by means of
a pump.

At the same time, the danger that would be incurred
by sending this air directly into the envelope of the
balloon must not be overlooked ; it would mingle with
the remaining hydrogen, and we should thus have a gas
not only as inflammable as hydrogen, but an explosive
el^nent infinitely more dangerous. Here the ingenious
artifice of the ballonnet comes into play.

Instead of making the interior of the balloon a single
capacity, constituting the whole interior, it is divided in
two by a fribric partition liable to deformation (Fig. 6).
This partition occupies the lower part of the balloon, and
there forms a space called the air-haUonnet, terminating
in a tube that descends into the car, whence a pump can
charge air into it.

28 THE CONQUEST OF THE AIR

When the balloon, at the beginning of its ascent, b
completely inflated with hydrogen, this fisibric partition
lies against the lower part of the envelope, exactly like a
lining. If the balloon rises, the interior gas dilates,
because the outer air becomes less dense, and a portion of
this gas escapes through automatic valves ; the ballooii
therefore remains fully inflated so long as it rises. If the
descent begins, the gas, diminished by the quantity whidi
has escaped during the ascent, no longer suffices to fill
the envelope, which would then become flaccid, lose its
original shape, and compromise the general equilibrimn.

The ballonnet now comes into play ; by means of a
pump installed in the car, the aeronauts force air into
it, until the sum of the new volume it acquires and that
of the remaining hydrogen gas, reconstitute the total
original volume of the aerostat. In this way the mitial
conditions of equilibrium are always maintained, in con-
formity with the calculations of the constructors.

There is obviously another way of ensuring this per-
manence of form so necessary to the dirigible balloon ;
it is to make the balloon rigid ; this last heroic solution
has been adopted by Count Zeppelin for his gigantic
balloon of 12,000 cubic metres, the Zeppdin.

To ensure this invariability of form, the balloon is
furnished with an absolutely rigid metallic skeleton,
made of aluminium tubes. This framing is divided into
several compartments, and a very strong yet light fisibric
is stretched over the whole. This is the outer envelope,
on which the resistance of the air is exercised during the
progress of the balloon. In addition, there is, in the
interior of each compartment, a balloon of air-tight
rubber fabric, which is inflated with hydrogen. Thus

THE RESISTANCE OF THE AIR 29

the airship contains a certain number of balloons, the sum
of whose lifting power constitutes the total ascensional
effort. The external form is invariable, thanks to the
material of the envelope and the framework on which it
is BtretchecL

We see at a glance, what colossal difficulties such an
arrangement presents, the difficulty of constructing a
trellised cylinder 120 metres long and 11 metres wide
to say nothing of its expense ; the difficulty of fixing the
external envelope, and finally, the complication of inflat-
ing the elementary balloons contained in each of the
compartments. Experience has shown the difficulty of
managing such masses both at starting and landing : we
shall return to this question later on. In any case it is
difficult, and also very perilous, to give the body of an
airship a rigid substructure.

ALTITUDE STABILITY : ELEVATING RUDDERS

This question of stability is therefore of the utmost
importance ; it is the basis of aerial navigation.

Every one knows that the aerostat, whether dirigible
or not, can rise or sink at will by the double action of
the ballast and the escape- valve ; the skill of the aeronaut
lies in economising the expenditure of these two essential
elements ; the ballonnet, in these conditions, ensures the
permanence of the exterior form.

But this double action, expenditure of ballast and
expenditure of gas, soon puts the aerostat hors de
combat : it must therefore carefully preserve a sufficient
stock of ballast to guard against the always possible
dangers of a difficult or unexpected landing ; it must also
preserve enough gas to be able at the last moment, to

80 THE CONQUEST OF THE AIR

let out a portion of it and descend abruptly. Thus it
has been found necessary to invent something else for
dirigible aerostats destined to undertake long voyages,
and this new appliance is the '' elevating rudder."

A dirigible balloon, indeed, requires a motive power,
which, through the intermediary of a propeller (generally
a screw) communicates to it the independent speed
without which it is impossible to steer it. But of this
motive power, employed for horizontal propulsion, a small
portion may be diverted which will serve for vertical
propulsion ; that is to say, in the particular case we are
considering, it will be used to make the aerostat rise or
sink slightly, without any expenditure either of gas or
ballast.

The arrangement consists in providing the dirigible
balloon with planes which can be inclined at will, known
as "elevating rudders." These planes move about a
horizontal axis, placed transversely to the axis of the
balloon (Fig. 7), and may be placed in the middle, or
fore or aft of the apparatus. In our figure, we have
supposed that they are placed at the'back of the pisciform
envelope ; a glance at these two figures will convince us
of their controlling action; they raise or depress the
** nose " of the balloon at will, just as the ordinary
rudder turns it to the right or left. The same thing
happens if they are placed in front. Generally speaking,
it is difficult to fix them on the envelope itself, and they
are placed on the car, as in the case of the ClSment-
Bayard (Fig. 24), where we see this rudder, in the form
of three parallel planes, fixed in front of the long car,
immediately behind the screw propeller ; the apparatus
is also called a " stabilisator."

THE RESISTANCE OF THE AIR 81

3Yating rudders may also be placed towards the

le either of the envelope or of the car ; they then,

rtue of the resistance they offer to the air, no longer

to raise or depress the stern or the bow, that is to

rection of Travel.

ction of air resistance
vpan the
plane.

Elevating rudder
(ascending

ElevaiinjJ rudder
(aescendin|)

resistance

Fio. 7. Action of the elevating rudder

to incline the balloon, but to raise or depress the
e body.

has been proposed to get the same result by means
rews with vertical axes, which would, of course, turn
ontally ; their action, in this case, would have the
J of raising or lowering the airship by exercising
(ure on it either from above or below, according to
direction in which they were worked. A more
nal proposition is to joint the shaft of the screw, so
it could be inclined either upwards or downwards,
neither of these expedients is as simple or more
cious than the elevating rudder, which is now in
ral use.

IILITY OF DIRECTION : LONGITUDINAL
ILITY

iloute Stability," or " Stability of Direction," consists
16 following condition which the balloon ought to

82 THE CONQUEST OF THE AIR

fulfil : its axis must always be at a tangent to the curve it
describes if its course be curvilinear, and steered in
accordance with the direction of this course itself if the
latter be straight (Fig. 8). This stability is a quality
which is exercised in the horizontal plane ; we must there-
fore suppose that in Fig. 8 the dirigible balloon is seen
from above and is travelling parallel with the ground.

How is this stability to be ensured ? In the following
manner : as soon as the balloon shows a disposition to
diverge from the direction it ought to follow TT, a
direction which is tangent to its trajectory, it must be
brought back by the resistance of the air itself. For this
purpose, constant use may be made of the " steering
rudder," which, like the rudder of boats, serves to direct
the airship from right to left. But this method would be
fatiguing to the pilot, and not sufficiently efficacious to
prevent unforeseen divergencies. Aeronauts, therefore,
prefer to ensure stability of direction by the construction
of the balloon itself, and this is the chief reason for con-
structing our modern dirigible on the lines of the fish,
with the larger end in front ; the centre of gravity of the
balloon is thus brought to the front, and the "leverage''
of the stabilisating elements formed by the stern of the
envelope is very efficaciously augmented.

However, the envelope of the balloon itself would not
suffice, so just astern of the latter *' stabilisating surfaces,"
have been disposed, formed of vertical planes fixed to the
envelope, the sum of which form, as it were, the keel of
th6 dirigible analogous to the keel of a ship. By this
means, stability of direction is obtained naturally, without
having recourse to the ordinary rudder, which is only
used to obtain change of direction.

THE RESISTANCE OF THE AIR 83

We have still to consider "longitudinal stability."
What is this third stability ? It is the property of
remaining always
horizontal or nearly
80, which the balloon
ought to retain, what-
ever evolutions its
pilot may cause it to
make. In other
words, it is the
property of not

" pitching. " J^io- 8- Rottte stability

This longitudinal stability is much more important
even than stability of direction. For should this latter
be imperfect, the aeronaut corrects it readily by working
his steering apparatus more frequently. But if longitu-

ii Q tKrust

P weigkt.

The two forces
BQ ct CP
tending to
secure
^SQuilibrium
of the balloon.

Fio. 9. Longitudinal stability

dinal stability is defective, the balloon may incline in a
dangerous manner, and here the necessity of an unvary-
ing connection between the car and the envelope appears
more important than ever.

If, in fact, the balloon and the car are united by un-
yarying attachments, the suspension being triangular

84 THE CONQUEST OF THE AIR

when in a state of equilibrium, the thrust and the weight
are in the extension of one another ; if the balloon
inclines, the car retaining its relative position, the weight
is no longer in the prolongation of thrust ; but then the
two forces tend to " trim " the airship. If, on the con-
trary, the suspension is liable to displacement (Fig. 10),
we see that if the dirigible inclin^ for some reason, its
equilibrium would not be restored by the action of the
weight of its car and cargo.

The suspension must, therefore, be incapable of die*
placement, and for this reason the idea of making the
balloon rigid, and of uniting it to its car by rigid attach-
ments has often presented itself {Zeppelin, Pax, for
instance). But absolute rigidity involves terrible draw-
backs ; all rigid balloons have hitherto ended by accidents.
Aeronauts in general have decided in favour of triangular
suspension (Fig. 9) ; these are sufficiently unvarying, as
long experience has shown.

One of the most serious causes of longitudinal instabi-
lity lies in the gas which fills the balloon ; its tendency
is to augment any inclination accidentally produced.
This gas, by the very fact of its gaseous nature, is com-
pressible, and on the other hand, the envelope of supple
material, is essentially deformable. A transverse section
of an inflated balloon would not therefore be a circle, but
an ovoid figure (Fig. 11), the larger end of which would
be uppermost. There are two causes for this : in the first
place, the traction of the suspensory ropes of the car
compresses the envelope laterally from A to B and from A'
to B', making it almost flat ; in the second place, the
interior gas, being lighter than air, tends to accumulate
in the upper part, and this force obviously acts in the

THE RESISTANCE OF THE AIR 85

same manner as the preceding one, deforming the trans-
verse section of the balloon.

At a first glance, this deformation wotild not appear to

/ /////////////////

Fio. 10. Instability prodaoed hy parallel conneotioni

have any injurious influence on longitudinal stabiKty ;
nevertheless, the last cause we have put forward may be
adverse to this stability.
Let OS suppose, for example,
that the balloon is inclined,
as in Fig. 12 ; the interior
gas, which is lighter than
air, will immediately rush
to the upper part, leaving
the lowered end. The latter
will be insufficiently in-
flated, whereas the former
will be inflated to excess.
The centre of thrust B
will be displaced towards
the right and as the two
forces which would tend to restore the equilibrium of the
balloon, BP and CP will be less and less distant one
from another, this restoration will not take place. Such a

ression
elope-

Ak—

\ *"

^•s

bV-

Effect

upon form

sdl

Fio. 11. Deformation of shape of
transverse section

86 THE CONQUEST OF THE AIR

contingency would be especially serious if the balloon were
imperfectly inflated, for with a perfectly full balloon, this
accident is less redoubtable. Thus the function of the
ballonnet is doubly important, because it ensures per-
manent inflation, and consequently persistent stability,

. , .-.^. - ^^ - Destroy sc

^ J^ //^ _\jzi longitudinal

^,2 Division 4fi.. -■■^V'Oiil!^^**^'^'^ owin^ to

t>l of ' ballonnet B >^ ^[n^^. displacement

into 3 ballonnets ^w^l oF gas.

bl b2 b3.
bo prevent accumnlation
oF air in B

Fio. 13. Action of the ballonnet

for the gas of the ballonnet, imprisoned in its special
envelope, cannot accumulate in the lower part of the
dirigible's envelope. Colonel Benard even di\'ided the
ballonnet into several flexible compartments without
any intercommunication in such a manner that the air
contained in it could in no possible case accumulate
by its own weight or inclination at either end of it
(Fig. 12 B).

Aeronauts have every reason to dread the inclination of
airships, and to avoid them by every possible device.
For the resistance of the material and of the suspension,
&c., is calculated on the assumption that the airship will
be horizontal, or very nearly so, in which case the strain is
equally distributed throughout the suspension and on all
the material. If, on the contrary, the airship should
incline in an exaggerated and unforeseen fashion, there
would be elements which take no strain at all, and others

*>' ■ • ^-

NrV.- V

THE RESISTANCE OF THE Am 87

which would be loaded to excess ; grave accidents have
resulted from such a cause.

The operation of filling the ballonnet is consequently a
most important mancBuvre in aeronautica Many con-
structors now make it automatic : a pump is continually
sending air into the ballonnet, and a valve in the latter
opens as soon as the pressure of the air exceeds a given
value ; the air it contains then escapes into the atmo-
sphere, and the pressure resumes its normal value, ensuring
the preservation of the form automatically.

Axis of suspension.

REALISATION OF DYNAMIC EQUILIBRIUM : THE
CRITICAL SPEED : THE « EMPENNAGE "

It was in 1904 that Colonel Charles Eenard first
formulated the exact laws concerning the dynamic equi-
librium of dirigible
balloons, discovered
the causes which ren-
der this equilibrium
precarious, and at the
same time indicated
bywhatmeansitmight
be completely ob-
Let us now

Axis of suspension

Fig. is. Imperfect equilibrium

briefly summarise the results
achieved by this distinguished officer.

We will begin by noting that if we took a symmetrical
fusiform balloon^ tapering equally at each end and sus-
pended in a horizontal axis passing through its centre of
gravity, this balloon would be in a state of ** indifferent "
longitudinal equilibrium (Fig. 13). If the axis of the
balloon is horizontal, and if a horizontal current of air
bears upon it, the balloon will be in equilibrium, but an

88 THE CONQUEST OF THE AIR

equilibriiun essentially *' unstable/' for calculation shows,
and experience has proved, that so soon as the envelope
thus suspended inclines ever so slightly, this inclination
will increase until the axis of the balloon is perpendicular
to the current of air ; in other words, till it assumes a
vertical position ; this position is inadmissible, for it
would amount in an airship to absolute instability.

If, instead of a symmetrical fusiform balloon, we take a
pisciform balloon, with the larger end in front, the insta-
bility would still persist, though it would be considerably
diminished, and here we are not in the domain of theory
but of experience, for it was by dint of innumerable ex-
periments, instituted with admirable method, that Colonel
Benard obtained all the results we are now discussing.
In the case of a pisciform balloon the disturbing effect is
due, in unequal degrees, to the diameter of the balloon, its
inclination and speed, whereas the stabilisating effect
depends on the inclination and diameter of the balloon,
but not upon the speed. The disturbing effect in the
equilibrium therefore depends solely on the speed, atid
augments very swiftly as the speed itself increases.

It will, therefore, be easily understood that there is a
certain speed for which the two effects are equal, and
beyond which the disturbing effect, depending on speed
will overpower the the stabilisating effect. To this speed
Colonel Renard gave the name "critical speed" ; if this
is exceeded, the equilibrium of the balloon becomes un-
stable. The most remarkable feature of Colonel Renard's
brilliant labours in this field is, that they are the expres-
sion, no doubt, of learned calculations, but, above all, of
experiments built up and conducted on a highly scientific
method, experiments in which the gifted aeronaut sub-

THE RESISTANCE OF THE AIR 89

mitted keels of various shapes and dimensions to the action
of a current of air which he could modify at will.

We shall naturally ask if this ** critical speed " is very
oonsiderable. We shall find that it is relatively slight,
as the following numbers will show. Let us take, for
instance, a dirigible pisciform balloon of the type La
France ; its critical speed is 10 metres a second, or 36
kilometres an hour, and a 24 hoi'se-power motor suffices to
supply this speed. Now the lightness of contemporary
motors is such, that a balloon of this type could easily
lift a motor of from 80 to 100 horse-power. With this
motor it might theoretically have a speed of 1 5 metres a
second, or 55 kilometres per hour, but it could not
accomplish this in practice ; for, its critical speed being
36 kilometres, its equilibrium would become unstable if
this were exceeded ; long before this speed was attained,
in fact, the stability of an airship would become pre*
carious and totally inadequate.

It would therefore be useless to essay the lightening of
the motor, that is to say the augmentation of the speed
of balloons, unless we had a means of ensuring its
stability, for, as Colonel Renard wittily observed in the
case we have quoted : '^ If the balloon were provided with
a motor of 100 horse-power, the first 24 would make it
go, and the other 76 break our necks."

This means of stabilisating is the '' empennage," that
is to say, the systematic use of rigid planes, both
vertical and horizontal, passing through the axis of the
balloon, and placed very much behind the centre of
gravity ; the resemblance of a balloon thus armed to a
leathered arrow is obvious, hence the name of the
apparatus.

40 THE CONQUEST OF THE AIR

With a balloon of the size of La France (60 metres
long and 10 metres in diameter), the surface necessary
to achieve strict emp^nation^ i.e., to annul the disturb-
ing effect, is 40 square
metres, lying 25 metres
behind the centre of
gravity. By slightly
augmenting the surface
and the distance, a degree
of security higher still is
secured.

But how is this " em-

Fio. 14. Crucifonn ^empennage of the
Patrie and lUpuhliqut

pennation " to be carried out ? In the Lehaudy balloon
it was fulfilled by means of surfaces afiixed to the
framework between the balloon and the car; in La

Vaie de Paris

Bayard-Climent

Fia. 15. Pneumatic empennages

Patrie^ a still better plan was adopted; the feathered
arrow has been literally realised by fitting four sur-
faces in the form of a cross to the stern of the
envelope, as shown in Fig. 14. Colonel Renard pointed
out another method of obtaining the effect of the em-
pennage without the use of rigid planes, difficult to fix
to the envelope of the airship and tending to overload

V - r

-«»»'(r*#

THE RESISTANCE OF THE AIR 41

the prow ; this was to affix to the extremity of the enve-
lope elongated ballonnets projecting from the body of the
balloon. This miethod was adopted by M. Surcouf in two
different forms : cylindrical ballonnets for M. Deutsch's
Ville de Paris (Fig. 15), and conical ballonnets for M.
Clement's Bayard. Inflated with hydrogen, these bal-
lonnets exercise a pressure which compensates for their
weight, and they no longer constitute a useless and
unsymmetrical supplementary load to the airship.

There are obviously other means by which instability
in motion may be counteracted ; the use, for instance, of
a very elongated car, which allows a considerable weight
to be displaced from stem to stem; this method was
EMlopted in the Zeppelin ; but such an arrangement is
difficult to work, and the '' empennage " is at once simpler
and very much safer.

POINT OF APPLICATION OF THE PROPULSIVE
FORCE : " DEVIATION "

Where should the motive power which is to propel the
dirigible balloon be applied ? At what point of the com-
plex system formed by the envelope and its accessories
should the propulsive force act? We have still to
examine this question.

As the essential sustaining part of the airship is the
envelope, it is this which offers the maximum resistance to
the air. Theoretically, therefore, the propulsive effort
should be applied to the axis of the balloon itself, and so
Qoany inventors have thought ; several have attempted to
(naterialise this theory, notably the unfortunate Brazilian
Severe d' Albuquerque in his balloon Paa^^ which ended in
\ catastrophe, and the constructor Rose, who produced a

42 THE CONQUEST OF THE AIR

twin airship, the axis of the screw being between the two
balloons which constituted his system.

This conception would be a perfectly just one if the car
and the rigging offered no resistance to the air ; but their
resistance is far from negligible. The car has a transverse
section of several square metres, and the sum of the sur-
faces presented by the suspensory ropes is enormous. To
give an idea of this, let us take these to be steel cords of
three strands, each of three threads, that is, nine threads
to the cord ; their diameter is about three millimetres,
their length between the car and the balloon about ten
metres. One of these ropes would therefore offer a
resisting surface of about 300 square centimetres or three
square decimetres ; ten of these cords would thus represent
a surface resistance of about one-third of a square metre,
and sixty cords would equal two square metres. Add to
this the sum of the sections of the knots, splices, pulleys,
ropes used in the working of the vessel, transverse membei'S
which serve to send compressed air into the ballonnet by
the special pump, the surfaces of the rigging, guide-ropes,
&c., and finally, the surfaces of the passengers, and you
will soon arrive at a sum of resisting surfaces, exterior to
the sustaining envelope, and equal to a quarter, a third,
and even more of a transverse section thereof. K, there-
fore, we represent the resistance offered by the envelope as
BR (Fig* 16), and that offered by the car and its acces-
sories as CR', the motor-power AF must be applied at
the point A, between B and C, and nearer to B than to C,
to ensure the permanently horizontal position of the system
under the combined action of motor and resisting effort.
But, on the other hand, it is difficult, at least in the present
state of aeronautic construction, to fix the shaft of the

Fio. 16. Application point of tho
propelling force

THE RESISTANCE OF THE AIR 48

¥ to the envelope itself, without using rigid envelopes
those of the Zeppelin or the Pax. Perforce, therefore,
leronaut has to be content with an application of the
>r power to the car itself. Hence a tendency in the
;ible balloon to tip up at the nose, because the force
lot exercised directly
he point of applica-
A, the resultant of
^wo forces R and R^
constant use of the
iting rudder becomes
3sary, and we find
thistiltingisthe more
ounced the farther
»r is from the envelope. The term " deviation " is
to describe this tilting effect produced by the action
le propeller.

will be readily understood that this " deviation " will
lodified in proportion as the car is brought closer to
balloon ; but this approximation is limited by the
:er of installing a combustion engine too close to an
lope containing an inflammable gas. The golden
1 must therefore be observed. If the car were too far
the balloon, the tilting effect would be very great,
the balloon would incline without advancing,
le Comte de la Yaulx has found a very ingenious solu-
of this difBculty. It consists in fixing the screw H
17) to a shaft HK placed at a height between the
lope and the car. The latter contains the motor
h works the shaft HK through a transmission system.
is a very rational solution, and it is probable that it
be widely followed in airship construction.

44 THE CONQUEST OF THE AIR

As to the position of the screw, this may vary consider-
ably : Colonel Benard and M. Surcouf, the constructor of
the balloons Bayard-ClSment and Ville de Paris, place

it at the prow of the car ;
under these conditions it
draws the balloon. Other
constructors place it at
the stern ; this was the
plan adopted by Gifl&rd,
Dupuy de L6me, and the
brothers Tissandier. M.
Julliot, the engineer, to whom we owe the Lebaudy
and the Patrie, introduced two screws, which he fixed
outside the car, on either side and almost at its
centre. We see then that various arrangements are
in use. But on the whole there seems to be a preference
for the screw at the prow of the car.

Fio. 17. Rational arrangement of
the screw

CHAPTER III

THE WIND AND DIRIGIBLE BALLOONS

The chief enemy of the aeronaut : How the wind inter-

TSNE8 IN the PROBLEM OF AERIAL NAVIGATION : RELATION BE-
TWEEN THE 8PEED OF THE WIND AND THAT OF THE AIRSHIP : ThE
" APPROACHABLE ANGLE " : ACCESSIBLE AND INACCESSIBLE REGIONS

WHAT IS THE WIND ?

Thb wind is easy to define : it is the movement of
atmospheric masses in a* horizontal direction, the dis-
placement of air parallel to the surface of the earth. The
study of the winds is one of the principal objects of that
branch of physics called meteorology.

Meteorology, or at least the study of atmospheric
phenomena over continents, otherwise called *' Con-
tinental meteorology," is relatively backward, com-
pared with nautical meteorology. The reason is that
above oceans the immense and uniform surface of
the waters allows molecules of air to obey the laws ot
equilibrium and the movement of fluids freely, whereas
the surface of the land, bristling with an infinite variety
of obstacles, ofiers much greater di£Bculty to the estab-
lishment of clearly defined rules. Moreover, the waters
of the sea cover nearly three-quarters of the surface of
the terrestrial globe ; it is above them, therefore, that
the great laws of the movements of the atmosphere are
demonstrated ; finally, all sailors are meteorologists,
whereas keen observers are rare on land ; this fact has

46 THE CONQUEST OF THE AIR

given rise to the sarcastic definition of meteorology as a
science which consists in knowing what kind of weather
it was yesterday.

Yet it is with the winds that blow over continents
that aeronauts will have to reckon, at least, in their early
days, for the moment has not yet come (though, indeed,
it may not be far distant) when, launching themselves
audaciously over the waters, they will have to struggle
with oceanic winds, and consequently to experience
personally the laws of nautical meteorology.

The wind is differentiated by its direction and its
velocity, or its force. Its direction is indicated by naming
the point of the horizon whence it blows : a north-east
wind is a wind which blows from the point of the horizon
situated in the north-east, &c. ; the so-called ^* compass-
card " of the mariner gives all directions of wind by their
initials (Fig. 18).

The velocity of the wind is reckoned by metres per
second. We should say, for instance, a wind of 7*50 m.
per second. By multiplying the speed in metres per
second by the factor 3600, the number of seconds in an*
hour, we get the speed of the wind in kilometres pof
hour. A wind of 10 metres a second is, therefore, 86
kilometres an hour ; the wind of 7*50 m. corresponds tD
26 kilometres an hour.

The force of the wind may be measured by the pressme
it exercises upon a motionless obstacle normally opposed:
to it. Sailors have deduced from centuries of navigatum.
in sailing-vessels that the pressure of a wind making a
metre per second upon a surface of one square metre
perpendicular to its direction is 0*125 m., or, in correct
language, 125 grammes to the square metre. This pressure

(AS lEES FtOH Tim ~ BArARD-CLiUKK

ITHF ^ ■

iFLBUC

. r

won Llhi** '

WIND AND DIRIGIBLE BALLOONS 47

increases in proportion to the surface of resistance, and in
proportion to the square of the wind's speed. For a wind
of 2 metres per second, it vould therefore amount to
4 X 0*125 kg., or 500 grunmes per square metre ; for
a wind traveUing at a speed of 4 metres, it would be
16 X 0-125, or 2 kilo-
grammes per square
metre, and so on.

When the speed of
the wind becomes
considerable, the pres-
sure it exercises upon
fixed obstacles be-
comes in its turn
enormous ; a wind of
25 metres per second,
or 90 kilometres an

hour, would esercise FI°- IS- Compasx-card

a pressure of 25 x 25 x 0-125, or nearly 80 kilogrammes
per square metre. The accident which resulted in the
loss of the dirigible balloon La Pafrie was due to this
formidable pressure.

I i

5%*^"^

THE WIND AND THE AERONAUT

Let UB now deBue this idea of the wind rather more
pTecieely, for, in the special case we are studying, an
uiaccurate idea of it is often formed, and it must not be
iwgotten that it is in the very bosom of the atmosphere
th&t we encounter it with our dirigible balloons. * Let us
fterefore study the wind, not in its relation to the ground,
^t in its relation to the airship.

If we were in a spherical balloon, it would be bus*

48 THE CONQUEST OF THE AIR

ceptiUe to iins pr eaB ure ao long as, mpnx»8B of inflation,
it were held to the grooiid by mooriiig ropea; this
" force of the wind " would tend to beat it down upon
the groond or to tear it firom the hands of those who
were holding and keeping it stationary. Bat so soon as
its moorings are cast off, so soon as the balloon rises into
the air without any propelling mechanism, the aeronaut
is conscious of afasolate calm: the wind, in &ct, is
imperceptible to him, because the wind is a relcUive
movement of the molecules of air in respect of an
observer stationed upon the ground. Once in the air, a
spherical balloon forms part of the atmosphere. It is
carried along by the wind itself, and moves with it; ib
not displaced in relcUian to it. So long as the ballocm
neither rises nor sinks, a little banderole £BU»tened to the
rigging hangs vertically, without fluttering as it would do
under the action of the wind if it were fixed to the ground.
Thus, for the (Aeronaut who belongs^ not to the earthy
hut to the atmosphere^ ivind does not exist ; these are the
very words used by Colonel Renard the first time he
described in public his definitive experiments upon the
steering of balloons. If then we were to take an airship,
dirigible or otherwise, everything in connection with it
would happen as if the air were motionless. If the
balloon is dirigible, that is to say, if it is furnished with
a motor and a propeller, and if these forms have been
duly studied, the aeronaut could move in this atmosphere
in every direction, as if the wind did not exist ; as his
balloon* advanced, he would have the same sensations as
if he were passing through an absolutely calm atmo-
sphere. He would have an impression of wind, but this
wind would have no relation to that which blows over the

WIND AND DIRIGIBLE BALLOONS 49

surface of the earth ; it would be a current of air from
the stem to the stem of the balloon, and this wind would
he created by the aeronaut himself in his progress ; it
would be the result of the displacement of the balloon
under the action of its screw. Should he stop this, calm
would be at once established, and the aerial navigator
would no longer feel the slightest current of air.

To sum up, then, we may say with Colonel Renard that
<< the balloon belongs to the air and has nothing to fear
firom it If it is furnished with a propeller and a motor,
in a word, if it is dirigible, the wind changes nothing,
either in the nature of the efforts it has to undergo
during the voyage or in the speed of its displacement in
relation to the aerial ocean in which it floats : and every-
thing goes on as if, the air being perfectly motionless,
the earth were flying beneath it with a speed equal and
contrary to that of the wind." *

In the case of the aerostat, as of the airship, the wind
therefore means, from the point of view of a final result,
a relative displacement of the ground, exactly as if the
aerial swimmer being motionless, the earth were carried
along by the current of air. From this we shall note
interesting results, which will show us the limitations
of the efficacious action of dirigible balloons.

INDEPENDENT SPEED AND WIND VELOCITY : THE
APPROACHABLE ANGLE

Let us imagine an "aerial fleet"" (Fig. 19) hovering
over Paris, composed of a central balloon, playing the

^ GoIoDel Oh. Benard : La Nfmgaium ahiennef a lecture delivered
•ft a meeiiiig of the Sooi6t^ dee Amis de la Science^ April 8, 1886.
s IKd.

50 THE CONQUEST OF THE AIR

part of flagship, and six " aerial cruisers " ; the admiral's
baUoon occupies the centre of the circle formed by the
Btx cruisers ; all the engines have stopped, and the flottlk
is for the moment motionless in relation to the air. The
wind is west, blowing at a speed of 8 metres per second,
that is to say, 29 kilometres an hour.

FiQ. IS. Biainple of nlatlvs wiod

At this moment the admiral's balloon issues an order :
the six cruisers are to effect a reconnaissance, each going
off in a different direction, while the balloon in command
will remain motionless to await their return. Let qb
imagine all these cruisers travelling at the same speed
of 6*50 metres a second, for instance, or 22 kilometres an
hour : this is the independent speed of each in calm air.
At the end of an hour they would all be 22 kilometres
from the admiral's balloon ; in other words, they would
be distributed on the circumference of a circle with a
radius of 22 kilometres, the geometrical centre of which
would be occupied by the balloon in command. This is
what would be happening tn the air. Now let us see

WIND AND DIRIGIBLE BALLOONS 51

how our seven balloons have been disposed above the
ground^ taking into account the wind, which is blowing
at the rate of 7 metres a second, or 29 kilometres an
hour.

The earth will appear to have fled towards the west
precisely at the speed of the wind, that is, 29 kilometres
an hour. Thus Paris, which was just now immediately
under the admiral's balloon, will be removed 29 kilometres
west of the airship, which, having stopped its engine,
has remained motionless in the air. Below this balloon
will stretch a new region, that of the Marne, and Lagny
is now the centre of the circle with a radius of 22 kilo-
metres, on the circumference of which the six aerial
cruisers are symmetrically distributed. Consequently
the west wind has really had no effect but that of dis-
placing the whole aerial fleet en bloc towards the west
by a distance of 29 kilometres under the wind. It has
therefore made no change in the relative positions of the
airships.

Armed with this result, we may now determine the
points which the dirigible balloon could attempt to reach,
taking into account its independent speed and the
velocity of the wind.

Let us imagine our balloon furnished, by means of its
motor and its screw, with an independent speed of
6*50 metres per second; this, as we have already
explained, amounts to saying that in absolutely calm air
this balloon would travel 22 kilometres to the hour.
Let us suppose that this independent speed differs from
that of the wind, which we will take to be 8 metres a
second (29 kilometres an hour). The balloon starts from
the point P (Fig. 20), in the direction PA, at an inde-

52 THE CONQUEST OF THE AIR

pendent speed represented by the length, PB : this
would mean that, if there were no wind, at the end of
an hour it would have arrived at B. But the wind is
blowing in the direction PS at a speed represented by
PV : the balloon will therefore travel along the route
indicated in length and in direction by the diagonal PR
of the parallelogram BPVR, and at the end of an hour,
under the combined action of its own speed BP and that
of the wind, PV, it will have arrived at the point R,
having throughout preserved the direction represented
by the silhouettes (1) and (2). Consequently, should
the speed of the wind be greater than its own, and
should it be directly opposed to this, there would
be regions in the atmosphere access to which would
be impossible to the balloon, which could only by
using its motor deviate from the direction of the wind,
as is shown in Fig. 20. We will now inquire more
closely into this question. Three cases might present
themselves :

1. The independent speed of the balloon is less than
that of the vnnd. (Fig. 21.) Let P be the starting-point
of the balloon, and let us take the line PA to represent
its actual speed. This means that if the air were calm,
at the end of an hour it would find itself somewhere on
the circumference of the circle C, the centre of which is P,
and the radius of which corresponds to this speed PA.
But the wind is blowing with a speed V, greater than v :
accordingly, all the circle, C, finds itself at the end of an
hour transported to C, and the balloon will find itself
somewhere on this new circle C, which is, from this very
fact, the circle of points approachable in the space of an
hour, the distance, PP', being equal to the speed of the

b/*„„

•/^

V s

Fifl. 3Q. Combined effaoU o( wind and
Independent ipaed

WIND AND DIRIGIBLE BALLOONS S8

wind. The otUy points of the ^xtce which the balloon could
reach would therefore he those which woiUd be comprised
within the angle
formed by the tan-
gents leading from
the point V to the
circle C, that is to
say, comprised in
the r^on which is
iAiaded in the figure.
All the rest would be space iaaccessible to the balloon.
The accessible angle will consequently be greater, the less
difference there is between the speed of the wind and that
of the balloon. This space would be nil if the speed of the
balloon were itself
nU; this is the case
with free balloons,
which can only
move along the
line PF.

2. The indepen-
dent speed of the
balloon is equal to
that of the wind
(fig. 22). — The balloon is at the point p, its actual
speed is PA, equal to the speed of the wind ; if the
wind were not blowing, at the end of an hour the
balloon would be somewhere on the circumference of the
drcle ', but the wind is blowing with the speed PP',
exactly equal to that of the airship itself; the circle is
therefore transported to C, and it is on the circumference
of C that the balloon finds itself at the end of an hour.

/Actual

' I"

■

^yyZ^,

■'

Fio. U Ou« whan tho indapNideiit ipaed
equkli tha wind

5i THE CONQUEST OF THE AIR

The shaded angle of the former example, which has
become more and more obtuse as the values of the
two speeds approxi-
mated, becomes equal
to two right angles,
and tba aooessible
r^on oom[uisee tiie
entire half of the
space, thatwhiob is to
the right of the tan-
gent leads from the
point Pto theoiroIeC.
S. Themd^iendent
speed of the baUom
is greater than that of the wind (Fig. 23). — In this ease
there is oo special anglewhich limits the acoeasible runona;
the whole apace is acces-
sible to the airship, even
in the direction contrary
to that of the wind, and
if the balloon goes
straight against the
current of air, it will
advance in respect to
the ground with a Bpeed
equal to the difference
between its own apeed
and that of the wind :
all space is there/ore accessible to a dirigible balloon
whose indepejvient speed is greater than that of the wind.
This last condition is the essential and sufficient condi-
tion of perfect dirigibility.

Fia. 2). The balloon ipeed !■ gntiM Uiu
the wind, ao it can go anrwhera

PUBLK" ll-%,A. .

WIND AND DIRIGIBLE BALLOONS 65

RESENT CONDITIONS OF DIRIGIBILITY IN RELATION
O THE WIND

We know now under what conditions an aeronaut
ould hope to reach any given point. Are these con-
itions compatible with the average state of the atmo-
phere, in other words, with the average speed of the
rinds that prevail in our regions ? Here we must rely
n observation alone for a satisfactory answer.

Our official meteorologists are silent on this point in
beir treatises, as on many others ; so it has been requisite
)r our aeronauts to make the experiments necessary to
btain the results indispensable to them. Such experi-
lents have been carried out for many years at the
iilitary establishment of Chalais-Meudon. The very
iteresting results are summarised in the following Table.
a this Table, the first column gives the speed of the
'ind in metres per second ; the second, the correspond-
ig speed in kilometres per hour ; the third, in fractions
P a thousand, the possibilities of encountering a wind of
le velocity denoted. Thus, for instance, if we take a
ind of 5 metres a second, or 18 kilometres an hour,
le possibility of having a lighter wind will be 323
lousandths, in other words, there will be 323 chances
> 1000 that the wind will be blowing at a rate of less
lan 18 kilometres an hour. The fourth column indi-
itee the number of days in the year when, on an
i^erage, a wind of less velocity than those indicated in
le first two columns will be prevailing. These final
gures are therefore those which will throw most light on
le present conditions of dirigibility for the aeronaut.

We must remember that these figures apply to the

66 THE CONQUEST OF THE AIR

vicinity of Paris, where the obserratioos on which Uiej
are based were carried out.

Speed of the wind

fi|*ed of th< wind

FoMibiUtiM (in
pKrU of a UiouuDd)

Uist the wind

relocitj will ba loa

than tbat of the

first two ooluaiu.

Kombwofdan
Id the jew what
there would Ua

"■=.'"

in kilometre*
PM bour.

relocitj Sebg Urn
than tbat of tbt
fint two oolonna.

HatriM.

EilometrM,

Dajfc

250

109

5-00

S2S

117

7- BO

5t3

197

1000

708

258

12-50

615

297

ISOO

886

S23

17-50

987

34S

20-00

963

350

22-60

978

354

25 00

986

358

27 50

991

361

8000

108

996

363

3250

117

996

364

85-00

12G

998

864

37-50

135

999

364

40-00

144

1000

365

4250

153

1000

365

4500

162

1000

565

The importaDce of these results is at once apparent,
especially if we translate the average chances of the
wind into " numbers of days per year," as I have done
here.

Thus, let us take the speed of 10 metres a second, or
36 kilometres an hour ; accordiog to the probabilitiee
arrived at by these long series of observations, there are
258 days In the year when the speed of the wind in the
neighbourhood of Paris is, generally speaking, less than
36 kilometres an hour. Therefore a dirigible ballooD

WIND AND DIRIGIBLE BALLOONS 67

with a speed of 10 metres a second could make way
against the wind, on an average, 258 days out of 365 ;
if the balloon has a speed of 12*50 per second at least,
that is to say 45 kilometres an hour (which is the speed
of the Bayanrd-CUment^ the Repuhligue and the Vxlle de
Paris), we see that it would be dirigible on an average
297 days out of 365, that is to say, about ten months
out of the twelve. Now, as I have already stated, this
is the speed actually maintained by all modern airships.

We may therefore affirm, figures in hand, that the
problem of aerial navigation hy dirigible balloons is
completely solved.

Of course there are exceptional cases: thus, the
average probability of winds travelling faster than
35 metres a second, that is to say, hurricanes blowing at
a rate of 125 kilometres an hour and even more, is nil^
or almost nil; in other words, 999 times out of a
thousand the chances would be in favour of a less violent
wind. Such winds, however, do occur occasionally, but
they are accidents ; they devastate gardens, and damage
buildings, and are, I repeat, exceptional eventualities.

There is, nevertheless, one important remark still to
make on the velocity of the wind ; this is that the speed
of atmospheric currents augments very rapidly as we
rise in the air. In Paris, for instance, owing to the
Eiffel Tower making it possible to observe these effects,
whereas the average speed of the wind in the course of
the year is about 2 metres per second on the level of
the houses (7*200 km. per hour), it is over 8 metres at
the top of the tower (about 29 kilometres an hour).
Aeronauts must therefore take this circumstance very
carefully into account, if they wish to form an accurate

68 THE CONQUEST OF THE AIR

idea of the power of the wind against which their
balloons will have to struggle when the voyage is to
take place, not just above the earth, but at a certain
height in the atmosphera

We see, too, that if constructors accomplish the short
stage connoted by the next advance in aeronautics, that
is to say, if they achieve a speed of 20 metres per second
or 72 kilometres an hour for the '* independent " speed
of airships, these will be able in our regions to travel
350 days a year; this would be absolute solution, for
the days when the speed of the wind is higher than
20 metres a second are days of clearly defined bad
weather, and are fortunately not very frequent.

Progress will therefore consist in augmenting the
power and the output of the motor and in improving the
quality of envelopes, which must be made capable of
resisting the increased pressures of the air caused by the
greater speed of flight in the future.

CHAPTER IV

CONSTRUCTION AND MANAGEMENT
OF A DIRIGIBLE BALLOON

Appucation of the prxccdino principles : How to construct
an airship : how to arrange the motor and propeller :
The two rudders : What are the travelung sensations in

A dirigible ?

THE ENVELOPE AND ITC OUTLINE

Ws have just shown what are the fundamental prin-
ciples of aerial navigation by dirigible balloons. We
must now see how these principles are applied in the
construction of those airships from which practical results
may be expected.

The construction of the envelope is the first thing to

be done. We have already said that it must be light,

strong, and impervious to hydrogen. All, or practically

all, modem dirigible balloons have envelopes of rubbered

material, consisting of two layers of fabric with a layer of

robber between them. This material weighs 300 grammes

per square metre, and will bear a strain of 1800 grammes

per metre. Very often, after the envelope is constructed,

it Is coated with a layer of chromate of lead, to arrest those

Bolar rays which, by their actinic action, might affect

the rubber ; it was this colouring matter which gave

M. Lebaudy's balloon the ^^ yellow " tint, and suggested

Its popular nickname.

60 THE CONQUEST OF THE AIR

The outline of the envelope is important, for the
exterior form of the airship ought to correspond to the
minimum of effort required for propulsion in the air,
while ensuring longitudinal stability. Thus the curved
outlines of modern airships have been studied ¥rith the
utmost mathematical precision.

The modem balloon should, following the indications
given by Renard, be pisciform, with the larger end
forward, after the manner of fishes and birds, otherwise
there will be a risk of low efficiency (examples of which
will be given in the following chapter). But the profile
and the elongation have still to be considered.

The envelopes constitute what is known in geometry
as '' surfaces of revolution," in the sense that they may
be considered as engendered by the rotation round thttr
longitudinal axes, of the curve which defines their profila
The constructor begins by fixing the length of the
balloon, its maximum diameter, and the position of the
latter in the length of the envelope ; after this he calcu-
lates the profile, generally formed since Renard's time, of
two parabolas united ; these parabolas are either simple
or of the superior degree ; but these are mathematical
details which I need only indicate. WKen the envelope
is calculated, it is drawn, and the diagrams necessary for
cutting out the pieces of material are made ; these
pieces, sewn together, constitute the body of the
balloon.

We will take as our type of a dirigible balloon the
Clement-Bayard^ which Parisians have so often seen
floating above their city, and which is familiar to me firom
the fact that I have made various ascents and voyages
therein ; the perfection of its construction and the

CONSTRUCTION AND MANAGEMENT 61

accuracy of its evolutions give it a right to be cited as a
sample of French aeronautics.

THE CONSTRUCTION OF THE ENVELOPE : THE GAS

The silhouette of the envelope (Fig. 24) is formed by
two parabolas of the third degree. The envelope is
made of panels sewn together ; its total volume is 3500
cubic metres.

Its surface is 2250 square metres. It is 56*25 metres
in length and the maximum diameter at its largest
section is 10*58 metres. This envelope is inflated with
pure hydrogen gas ; in spite of the high price of this gas,
which costs 1 franc and sometimes more per cubic metre,
it is preferred to illuminating gas, no matter how cheap
this may be, on account of its great lifting power ; and
balloon-material has become so perfect that it reduces
the loss of gas by exudation through the rubbered fabric
to an insignificant percentage.

In the middle of the envelope there is a ripping valve,
this is an aperture in the upper part of the envelope
covered by a band of fabric which can be torn ofl* in an
instant by pulling a cord, should a rapid descent become
necessary ; this manoeuvre can be carried out from the
ear. At the end is the pneumatic empenruigef consisting
of four spherico-conical ballonnets, tangent to the back
part of the envelope and communicating therewith
through holes. The air-ballonnet proper is divided into
two parts ; it is 23 metres long, and has a volume o^
1100 cubic metres.

The balloon is furnished with four automatic valves ;
two for the hydrogen gas, which automatically open as soon

62 THE CONQUEST OF THE AIR

as the preesure equals 40 millimetres of water, and two
for the air, opening when the pressure equals 30 milU-
metres. These two pressures are indicated by two
manometers fixed under the eyes of the pilot, on the
firont of the bridge. If a valve were not working
automatically, he would therefore be warned, and could
work it himself by pulling a cord. The air is continually
pumped into the ballonnet by a fan which can pump 1800
litres per minute, and this is actuated through trans-
mission from the motor. When this stops, the &n can be
worked by hand.

The suspensions are thin steel cables of three strands,
each of three threads. Some of them are 3, others
4 millimetres in diameter, and they can bear respectively
a strain of 400 and 600 kilogrammes. They terminate
in " goose's-feet " of hemp fastened to boxwood
stakes, and the latter are encased in a "girth'' sewn
into the fabric, which forms the envelope of the balloon ;
the net is thus rendered unnecessary, and this facilitates
the passage of the molecules of air along the envelope, by
dispensing with the resistance offered by the asperities of
loops and knots.

Beneath the " suspension girth " is placed the liftbg
girth, also sewn to the fabric. The "lifts" are steel
ropes, which are oblique in relation to the length of the
balloon, and ensure the indispensable triangular suspen-
sion that secures the solidity of the car and the envelope,
both in longitudinal and lateral directions. These lifts
connect together by four " knots," which also constitute
the fixed points of the suspension. These knots may be
distinctly seen in the diagram.

3NSTRUCTI0N AND MANAGEMENT 68

64 THE CONQUEST OF THE AIR

THE CAR, RUDDER, AND MOTOR

The car is built up of a series of cubes of steel tubes of
30 and 40 millimetres diameter. The sides of the cubes
measure 1*50 metres, and their contiguity forms the car.
The sides of these cubes are made rigid by steel wire
diagonals fitted with stretchers. The central part of the
car has a height of 2 metres; its total length is 28
metres.

The steering rudder is carried at the stem; it is
double, and its surfitce is about 1 5 square metres. It is
composed of rubber fabric stretched upon a steel tube
framework having its axis connected to the car by means
of a cardan joint. The fourth knot of the lifting ropes
(that of the stern) and two stretchers serve to hold it.

The '' stabilisator," or elevating rudder, fitted to the
front of the car, is in reality a " triplane " turning about
a horizontal axis and able to be inclined from 16 to 17
degrees above or below the horizontal. Its efficiency is
considerable, inasmuch as in accordance with specific
calculations, when the machine is at full speed, the
effect of the stabilisator is more or less equivalent to
100 kilogrammes of ballast, according to the degree of
upward or downward inclination. This rudder, and that
at the stern, are controlled through steel wires and
chains, by two wheels placed upon the bridge on the
right and left respectively; like those of motor-can
these wheels are " irreversible."

In the centre of the car is the passengers' acconunodft-
tion as well as the pilot's position. The latter, hj
raising the floor of the car, is elevated about 50 cent!*
metres. The pilot, standing on the left, has the steering

CONSTRUCTION AND MANAGEMENT 65

wheel under his hand ; on his right is his assistant
holding the elevating rudder-wheel. In front is the
motor room, and the pilot can communicate direct with
the engineer. A vertical panel on the front of the
bridge x^urries the whole of the controlling instruments.
These are the manometer of the halloon and air-
ballonnet; the barometer to indicate continuously the
altitude, as well as a barograph ; the dynamometer which
permanently records the tractive effort of the screw;
and lastly, the speedometer registering the number of
revolutions per minute made by the motor. In addition
to this is a shelf carrying the chart and a compass,
well compensated owing to the masses of iron and steel
in the balloon, to set forth the coiu^se to be followed.
Through the passengers' space extends a large suspended
table carrying the road maps, indispensable to the voyage
and for guidance by comparison with the country
spread immediately below. Lastly under the car are
the '^ skates " which enable the airship to alight without
the car being injured by rubbing against the ground.

The engine is an explosion motor, such as are used in
automobiles. It is multicylindrical, works with a
mixture of air and petrol gas, and is of 105 horse-power.
The special materials of which it is constructed ensures
at one and the same time great soHdity and a remarkable
regularity in running, without forfeiting that lightness
indispensable to an aeronautical motor. It weighs 352
kilogrammes aU told. The weight of the petrol tanks is
64 kilogrammes, that of the oil reservoirs 10 kilo-
grammes ; the motor is water-cooled ; 65 litres of water
being carried in a radiator and a circulating system
which complete weighs 83 kilogrammes. In "working

66 THE CONQUEST OF THE AIR

order " the total weight, everything included, represents
5 kilogrammes per horse-power.

The engine nms at 1050 revolutions per minute, but
by means of a reducing-system of two gear wheels, the
propeller shaft does not turn at more than a third of this
speed — 350 revolutions. The fuel consumption is from
38 to 40 litres per hour; of oil about 5 litres. The
whole of the motor is mounted upon a chassis, fixed to
the car by springs in such a manner that vibration is
reduced to the minimum, being no greater than in a well-
built motor-car standing still with the motor running.
The connection by circular segments is fitted. with
springs which can be easily regulated by means of a
worm wheel so as to obtain a constant and absolutely
certain tightening. Lastly, we may add that the motor
is fitted with two ignitions, magneto and accumulators,
and that by means of decompression cocks it can be
started up with the greatest ease.

THE SCREW, " SLIP," DIMENSIONS, AND POSITION

The screw is the propeller exclusively used to-day in
aerial navigation, both upon dirigibles and aeroplanes.
As a matter of fact, the screw essentially presents to the
fullest degree the first and most important acquisition ;
simple, and when its design, dimensions, and its operation
are well thought out, its performance is excellent.

It is scarcely necessary to explain what a propeller is :
It is a screw y or rather, there are two elements of the
threads of this screw which we call the vniigs or blades
which screw into the air. If the screw penetrates wood
or a metal nut, with each revolution it will advance a

CONSTRUCTION AND MANAGEMENT 67

lertain distance, which is always the same, known as
he *' pitch," and which is no more than the distance
leparating two consecutive threads, this distance being
imputed parallel to the axis. But the screw of an
kirship screws into the air, and the latter is, for a screw,
\n essentially unsteady nut, so that at each revolution
;he aerial vessel, instead of advancing a distance equal to
he "pitch," only moves forward a part thereof The
iifFerence between the "pitch" of the screw and the
idvance of the airship itself for each of these revolutions,
8 defined as the slip of the screw, that is the proportion
)f this difference and the " pitch " itself Thus a screw
may have a slip of ^ if, when it makes a revolution,
the airship which it drives does not move forward more
bhan ^ of its pitch.

This knowledge of slip enables us to consider the
controversial question of large screws turning slowly, or
3f small screws revolving very rapidly, and we may easily
imderstand that it is necessary, a priori, to reject the
Skarews which are too small : turning very rapidly they
would begin to drive away the air from around them
without forcing the airship forward ; their enormous slip
would not enable it to advance. It is what Colonel
Renard expressed in a picturesque manner by saying
"We cannot propel an Atlantic liner by rowing, even
very rapidly, with a penholder." Let us therefore take
screws of large diameter. However, one is limited in
their dimensions by their weight. As they turn power-
fulfy but slowly, it is necessary to add to their weight
that of the speed-reducing gear, which transmits the
always very rapid revolutions of the light motors used in
aerostation. There will be consequently an absolute

68 THE CONQUEST OF THE AIR

limit to bear in mind, because it is necessary to choose
between the efficiency of the propeller, that is to say the
portion of motor effort which is transformed into useful
tractive effort, and the engine-power. By augmenting
the weight of the screws the efficiency of the propeller
may be improved ; but then it becomes necessary to
increase the weight of the motor, and it must not be
forgotten that in aeronautics the question of weight is
always vital, and that in an airship only a total given
weight is available for the whole of its mechanical equip-
ment, motor and propeller.

One other question now remains — ^the position of the
propeller ; should it be placed at the prow, at the stem,
or in the centre? We have already discussed this
question (p. 43) as well as that of determining the level
at which it must be driven between the axes of the
balloon and the car respectively.

These principles being disposed of we will consider the
propeller of the CUment-Bayard.

Hitherto the screws of dirigibles have been made
of sheets of light metal, or bent upon metal frames;
sometimes they were even made of fabric stretched over
a clumsy skeleton. The screw of the ClSment-Bayard is
of wood, and is a striking piece of work by Chauvi^re the
engineer.

It has only two blades ; as a matter of fact if the
number of the latter were increased too greatly, each
would move upon the air already displaced by its neigh-
bour, and efficiency would be decreased. M. Chauvifere
thought it possible, by special arrangements, to balance
the efforts of propulsion and the effects of centrifugal
force arising from the rotary movement, efforts and

CONSTRUCTION AND MANAGEMENT 69

effects which increase in a general manner pretty well
in accordance with the same laws.

The Clement-Bayard screw is 5 metres in diameter.
The pitch is variable and increases from the axis to the
extremity of the blades. It is built up of countersunk
ribs assembled and superposed in the form of a fan,
similar to the steps of a ^* winding staircase." Revolving
at 350 revolutions per minute, each of the tips of the
blades describes, in a circular path, 100 metres per
second, This enormous "peripheral speed" is the
maximum that has as yet been attained with screws of
this design. At this speed it produces stabilisating effects,
called gyroscopic, recalling to mind those of the small
device used as a toy known as the gyroscope, the stability
of which, occasionally, is disconcerting ; it seems to defy
the laws of balance by simultaneously maintaining its
rotating speed and the mass disposed around its circum-
ference. In the case of the actual screw its gyroscopic
effects strongly oppose the pitching of the balloon, and
produce a stabilisating effect. This was the reason why
the constructor did not strive too much after lightness in
the screw, which weighs 90 kilogrammes.

At speeds of 350 revolutions per minute the Clement-
Bayard propeUer sustains with its blades a centrifugal
effort exceeding 19,000 kilogrammes, and yet so perfect
is its construction that it is not submitted to more than
one-twentieth of its breaking strain.

The independent speed of the balloon, driven by its
motor and propeller, is 50 kilometres per hour; i.e., 14
metres per second. To complete our description let us
add that the dirigible is always berthed in a *' hangar,"
which enables it to await, sheltered from heavy weather,

70 THE CONQUEST OF THE AIR

favourable conditions for the pending journeys. This
shed is at Sartrouville, but a new shelter is being built
on the manoeuvring ground at Issy-les-Moulineaux.

HANDLING THE AIRSHIP: STARTING OUT:
EN ROUTE: THE DESCENT

The handling of a dirigible balloon is not so simple as
that of a spherical balloon owing to the elongated form
of the envelope containing the gas, and upon which
depends the ascensional effort.

The dirigible must at first be brought out of its
" hangar," wherein it is held upon the ground by a con-
siderable, imposed weight, comprising bags of ballast. A
number of men draw up in two lines on each side of the
balloon, in which the pilot and his assistant take their
places. The men detach the ballast-bags carefully until
the balloon evinces a very slight tendency to lift itself;
hauling with all their might they bring it out of its
dock, so holding it that it almost touches the ground.
Arriving in the open air it is hauled to as level an area
of ground as possible, and then again surcharged with
the bags of ballast, so that it rests naturally upon the
earth.

The pilot assures himself that all is in good order;
that the valves work, that the cords which control them
are to hand, are not twisted or swollen; that the
recording instruments work properly ; that the wheels of
the steering rudder and stabilisator efficiently govern
those two mechanisms; that his compass, his charts,
his ballast are all to hand, as well as the cord which
operates the ripping valve. Meantime the engineer has
passed as minutely over his motor, seeing to the lubrica-

i«

H I

■t

tT^«

CONSTRUCTION AND MANAGEMENT 71

tion of all parts, the propeller shaft and screw bearings ;

tests his indicators and recording instruments, and when

all is ready informs the pilot.

The latter now instructs the men to swing the balloon
rouod in such a way that it starts out "to leeward."
The passengers are embarked, and the ballast little by
little discharged, until the balloon slightly rises; this
operation is called " weighing " the balloon. The pilot
CDmmapds the engineer to start up the motor, but
without coupling the propeller- When the engine is
under way and all is ready he throws out the last bags
of ballast so as to give the balloon the requisite lifting
effort. "Hands off," he shouts. At this word the
workmen let go the sides of the car to which they have
been clinging, and the balloon is now held by two ropes
Oily, attached to the under side of the car by a " goose-
foot" at front and rear. These cords are then " paid
out" equally, in such a manner as to keep the airship
horizontal, and when at last the pilot cries "let go," the
men drop these ropes and the vessel rises. The pilot
orders the engineer to let in the propeller ; the balloon
obtains its independent speed, and with a turn to make
wre the steering mechanism is working properly, sets
the course it is proposed to take.

En route, if the weather is clear, the pilot always
keeps bis eye upon the chart, so as to assure himself
^t he is following the right course by comparison with
the actual topography of the country unrolled beneath
the feet of the travellers. If he ventures out at night
or in a fog he will fix his attention upon the compass,
*hile his assistant at the wheel of the elevating rudder
*ill not let his eye leave the barometer, so as to preserve

72 THE CONQUEST OF THE AHl

by the manipulation of the rudder, the desired altitude
of the balloon, without throwing out ballast or letting
out ga&

With regard to the sensation of *^wind'' felt by
travellers, this is only that due to the independent
speed of the balloon, 45 to 50 kilometres per hour;
whether it be a following or a head wind it will always
be the same, neither more nor less intense, because the
^* surrounding ** wind does nothing but carry the whole
of the atmosphere, of which the balloon is a part, from
one point of the earth to another, and travellers in the
car are under the same condition as if they ran very
quickly to and fro through the interior of a large ship.
The speed of their movement would cause them to feel
an impression of wind which would be the same, irre-
spective of the direction and force of the wind, which
blowing over the surface of the sea transports, in a com-
bined movement, both them and the vessel in which
they were sheltered.

So far as concerns ascent and descent, this is effected
within a small limit of about 100 metres by the manipu-
lation of the stabilisator. It must be pointed out that,
unlike the free balloon, the ascensional effort of an
airship is constantly increasing. Unballasting is con-
tinuously taking place by the consumption of the petrol
by the motor, and in this manner it loses about 40 kilo-
grammes per hour. This is where the charging of the
air ballonnet fortunately intervenes to secure the con-
stancy of the external shape and consequently also the
constancy of the air pressure.

It is hardly necessary to urge passengers in a dirigible
to exercise the greatest prudence. Nothing mv^t be

CONSTRUCTION AND MANAGEMENT 78

iroim overboard, be it a bottle, an empty box, or even

chicken boae, without the pilot's permission : the

iatic sensibility of these airships is extreme, and it is

no. 36. Oomtrootor Snraonfi DWtbod of "mooring" a dlrlfible

r to avoid any action which might vary it acci-
antally.

As to the descent of an airship, at least in the majority
r cases, it must take place only in a locality where a
Dcking " hangar " can be obtained, descent in open
nm^ being always hazardous. This was only too well
lown in the accidents to the Patrie and the Zeppelin.
Atifltng ia made in a manner just opposite to that of
soent. But care must be observed that the men who

74 THE CONQUEST OF THE AIR

seize the two guide-ropes to bring the balloon gently to
earthy at first grasp the " windward " rope so as to hold
the balloon with its nose to the wind ; negligence of this
precaution, the balloon^ held only by the stem rope^
would rear up, owing to the wind driving against the
prow, and thus imperil it. Once the balloon has landed
the workmen seize it by the car, keep it down by attach-
ing numerous bags of ballast, and then bear it gently
into its hangar.

It might however reach, and be compelled to descend,
in open country, and to " moor " by fixing the airship
with its anchors. In this case there is an arrangement
conceived by M. Surcouf which appears to offer the
greatest security to the airship forced to make a *^ halt "
at a place unprovided with a special shelter.

Beneath the body, and towards the front of the
balloon leading to the ballonnet, is an automatic valve
(Fig. 25) which can open itself like a purse. During
the journey a spring keeps it closed, and the ballonnet
works as usual by means of its charging fan. But if
the vessel is compelled to stop, it is fixed to the ground
by anchors, or by stakes, with the cable, which by
means of a " goose foot " is attached to the prow of the
car, the balloon thus being held stationary, with its motor
stopped, swinging in the wind. But under the influence
of temperature changes the gas will contract or expand,
and with the motor no longer running, the ballonnet
will not be able to maintain the invariable form of the
envelope.

Then, under the pulling action of the same restraining
cords, the " mooring " valve opens, always to the wind,
since it is to the front of the balloon, the latter adapting

CONSTRUCTION AND MANAGEMENT 75

itself like a weather vane, nose to the wind. Under
these conditions the air so caught in the pocket hlows it
open, and keeps the ballonnet inflated to assure the
permanency of its shape. One can, for greater security,
attach bags of ballast to the stern rope. If the stern of
the balloon should descend this ballast would strike the
ground, and the envelope, released of a considerable
weight, would rise again before it could come into con-
tact with the earth and thereby be damaged.

VOYAGES OF THE " CLfiMENT-BAYARD "

The dirigible balloon which we will describe in detail
has completed more than thirty trips, with uniform
success. During the Aeronautical] Show held at the
Grand Palais in the month of December 1908, it
repeatedly came and hovered above the Champs- Elysees.
Its evolutions above Paris have rendered it popular,
acquainting the whole population with the appearance
and travel of an airship. It has made numerous cruises
around the capital, some very long, all brilliant, first
under the direction of M. Kapf(Srer, collaborator of
IL Surcouf ; later of M. Gapazza, the eminent Corsican
aeronaut, who so far has been the ,only one to accom-
plish the crossing of the Mediterranean in a balloon.

The most remarkable of these excursions was that
when M. Clement resolved to set out from the airship
** hangar'' to visit his seat at Pierrefonds (Fig. 26). The
vessel left Sartrouville on November 1 at 11.15 a.m. in a
east-south-east wind blowing at a velocity of 20
kilometres per hour. M. Clement, the owner of the
balloon, was accompanied by a passenger ; MM. Capazza

76 THE CONQUEST OF THE AIR

and Kapf^rer were on the bridge ; Sabatier the rai^eer,
and a mechauician, were at the motor. The balloon
passed successively over Maisons-Lafitte, Pierrelaye,
I'isle-Adam, Beaumont, Crell (at 12.30), Font S^ta-
Max^nce, Compifegne (at 1.30). It then wore round to

FlO. 26. Vojage of the " CWmeot- Bayard " (Novsmlwr 1908), (S60 k
in a ctoeed circle in five houn without dewwat)

the east and arrived at Pierrefonds at two o'clock ; tboD
it resumed its journey to Paris, by Rocquemont,
Ermenonville, Chennevi^res, Bourget (passed at 3.30),
Pantin ; then described a large circular sweep overParia,
and regained Sartrouville at eight minutes past four.
The total distance was 200 kilometres, and it was

CONSTRUCTION AND MANAGEMENT 77

covered in 4 hours 50 minutes. It was the " world's
lecord" for a round trip accomplished by a dirigible
without descent during its journey, and returning to its
starting-point. The great journey of the Zeppelin^ of
which we shall speak in the following chapter, was not
completed by return to the point of departure, inasmuch
M the MTship was unfortunately destroyed in the course
of its homeward journey.
Here is the airship's official ^' bill off lading " : 6

psSBongers, 300 litres of fuel, 20 litres of oil, 65 litres of
water, 250 kilogrammes of ballast (sand in bags), and 59
kilogrammes of manoeuvring ropes.

« AERIAL YACHTS"

A dirigible such as we have described is, in the field of
aerial navigation, the equivalent of a warship, or of a
large mercantile steamship; it is the "ocean liner."
Bat its great cost (about £12,000) the absolute necessity
j> of maintaining an immense and expensive hangar in
* which to dock it, renders it a vessel of pleasure inacces-
riUe to many amateurs for aerial trips. There had to
be devised the ** little dirigible," the ^' aerial yacht " at
a more popular price, and more simple to control. This
very convenient type of small balloon is available to-day,
and is known under the generic name of the '^ Zodiac/'

ThiSy to hazard a comparison borrowed from auto-

mobilism, is the " aerial voiturette." It is designed to

/ eoahle one or two passengers to make easy trips into the

mr, and without the necessity of maintaining a sheltering

For this purpose the gas bag, of 700 cubic metres, is

78 THE CONQUEST OF THE AIR

iuflated not with pure hjdrogen, which is expensive and
not always obtainable, but with coal ^s which is avail-
able at all towns and can be purchased cheaply. Inflated
therewith it will lift one pereon, but by combining about
100 cubic metres of hydrogen, it will lift two. It is

PiO. 27. A little "Zodiu" dlrigtblo

pisciform in shape, with stabilisating planes, and Has two
rudders.

The car is detachable into three pieces ; each of than
is formed of wooden trellis, light, flexible, and yet at the
same time solid, being fixed together by bronze Bockets,
nuts, and bolts. A water-cooled, four-cylinder, 16 honft-
power motor drives through cardan shafting a stern
screw, which runs at about 600 revolutions per minute;
the latter is of 2*30 metres diameter. The motor
actuates also a fen which may be seen inthephotograjdt;
this keeps, through the medium of an ajr-ballonnet, the
permanent external form of the envelope.

The whole balloon dismantled, car and envelope,
packed in canvas cloth, can be transported by horse and
cart. One inflates the balloon at the spot where the

THE N-/ __

PUBLIC UbKART

CONSTRUCTION AND MANAGEMENT 79

gas is obtainable, and it can be prepared for an ascent
in an hour and a half. The little airship can travel at
a speed ranging from 25 to 28 kilometres per hour ; can
remain aloft for three hours with 75 kilogrammes of
ballast, and costs ready for use £1000. Truly therefore
it is the aerial "auto/' enabling trips to be made in
the air without being compelled to return to a stationary
hanganr^ because the balloon coming to earth at the end
of its journey can be deflated like a simple '' spherical " and
loaded upon a cart for conveyance to the nearest station.
This handy type of little dirigible certainly fulfils in
every respect the " airship for alL" On Easter Sunday,
April 11, 1909, it made a remarkable journey. With
MM. Henry de la Vaulx and Clerget on board, it
mancBuvred above the Bois de Boulogne for three hours
with the greatest ease, before the eyes of crowds of
Parisians, which the beautiful weather had caused to
flock upon their favourite promenade.

IMPRESSIONS IN A DIRIGIBLE : DIZZINESS : SAFETY

And now, a question which will naturally arise in the
mind of the reader, a question which is prompted to all
those who have travelled in a dirigible. What are one's
sensations ? Does one sufier from giddiness ? Has one
8ea-sicknes8 ? Has one fear ?
I will endeavour to reply to these interrogations.
On board one has a feeling of complete security.
Before entering the car there is time to take a walk
tt)iind the balloon, for it is still berthed in its dock ; to
examine with care every part, feel the lifting and sus-
pension system. The whole is so solid ; is made of

80 THE CONQUEST OF THE AIR

material of such perfect quality ; the total reBistance is
80 well calculated and tested to twenty times what the
whole will have to withstand, that in an instant every
qualm of disquietude slips from the mind : the only
hesitation one has is that of actually embarking. But
the catastrophes of the Pax and the Bradsky balloon
have been instructive. To-day the general utilisation of
the air ballonnet secures stability ; the motor is placed
well away from the balloon ; the suspension system
is indeformable and distributes the weight equally over
the envelope ; all parts of the motor capable of giving
off either sparks or leakages of gas are boxed m
or covered with metallic sheathing : lastly, trained
and experienced aeronauts always conduct the ascentB,
for no owner of an airship would be mad enough to
attempt a trip without the indispensable assistance of
one of those ** captains of the air " such as, for example,
the Count de la Yaulx, Capazza, or Eapf($rer.

Mal'de-mer is unknown aboard these airships, for the
simple reason that the longitudinal stability being so
very great there is neither pitching nor rolling. Many
are the ladies who have already received the baptism of
the air ; not one of them has suffered from this terrible
malady of which ocean vessels preserve, alas ! the un-
enviable monopoly.

With regard to dizziness this is unknown in a balloon
when the latter is not held to the earth by a rope.
Dizziness, when looking from the height of a tower or
from the edge of a precipice, is produced by the view of
the vertical wall which drops below one's self, and which
" conducting the eye " right down to the bottom, enables
one to calculate the depth of the chasm. In the captive

CONSTRUCTION AND MANAGEMENT 81

balloon the sight of the cable may Bometimes produce
the same effect; but in a dirigible, there being no
material connection, one cannot estimate one's altitude :
one believes, and one actually is, above a magnificent
plan in relief, with the feeling of beatitude which is
grand, with the impression of mdeed being independent
of aU, to have broken away firom one's bonds and to be
the master of space.

One can now consequently accomplish by dirigible
and with absolute safety, voyages in the strictest sense
of the word. I have made many myself, which I will
never forget, on board the CUment-Bayard. The time
is not far distant when airships, in addition to their
military utilisation, of which we will speak after we have
described aviation apparatuses, will have applications to
everyday life, without speaking of their employment,
which will arise, for those geographical explorations
which yet remain to be made.

CHAPTER V

HISTORY AND DESCRIPTION OF THE
PRINCIPAL DIRIGIBLES

Early days of aeronautics: From General Mbusnier to
Colonel Renard^ Giffard^ Dupuy de L^me, Tusandier : M.
Henry Deutsch^ Count Zeppelin, M. Santos-Dumont and

M. Lebaudy

THE PIONEER : GENERAL MEUSNIER, INVENTOR
OF THE AERIAL SCREW

The history of dirigible balloons, up to recent times, has
been somewhat devoid of results. If the importance of
what has been done is unquestionable, it can at least be
asserted that the quality in this case substitutes quantity,
since it was no farther back than 1852 that the first
serious attempt in this direction was made by Henry
Oiffard. Before him there may have been some ideas
more or less vague, but nothing tangible.

However, it is one of these projects which it is neces-
sary to describe, and that v^ith some detail, because of
its importance, its far-reaching value, and the date of its
conception. It is that made in 1784, scarcely one year
after the discovery of the brothers Montgolfier, by an
engineering officer — Lieutenant, subsequently, General
Meusnier.

Meusnier was an extraordinary intellect. He aston-
ished his masters by his precocity, by the confidence of
his reasoning, by the perspicacity of his views. He was

HISTORY AND DESCRIPTION 88

a member of the Acad^mie des Sciences at twenty-nine,
after his work in aerostation, which however was only
one of his accomplishments, and he was the collaborator
of Lavoisier in several experiments. He was killed at
the siege of Mayence in 1793 ; he was then General.

Meusnier was the true inventor of aerial navigation,
and was a ** scientific " initiator. Through not following
the lines which he laid down, aerial navigation lost a
century in futile groping about ; in experiments abso-
lutely without method. In fact, at a time when
relatively nothing was known concerning the science of
the atniosphere, Meusniei: had the distinction of finding
in one stroke all the laws governing the stability of an
airship, and calculating the conditions of equilibrium for
an elongated balloon, after having strikingly demon-
strated the necessity of this elongation. Meusnier's
designs and calculations are preserved in the technical
engineering section at the French War Office in the form
of drawings and numerical tables .

His airship designs relate to two balloons, one very
large, the other much smaller, and it is in these projects
that one finds distinctly described two absolutely new
arrangements which are in universal use to-day : the
cUr-bcdlonnet to secure stability and the screw for aerial
propulsion. With regard to the motive power, owing
to the absence of suitable motors in his day, he contented
himself with the use of the muscular power of the men
carried on board.

The dimensions of his largest balloon (which however
was never constructed) were 260 feet in length, and 130
feet in diameter ; that is to say 85 and i2*50 metres
respectively. The shape was that of an ellipse, and as

84 THE CONQUEST OF THE AIR

one may see, the elongation was equal to twice the
diameter. The cubical contents were to be 60,000 cubic
metre&

The balloon (Fig. 28) would thus have followed the
form of a perfect ellipsoid, which was the paramount
development to be realised as compared with the sphe-
rical form. It was to be a double envelope, comprising
two skins, each of which was to fulfil a different
purpose. The first, the " envelope of strength," very
resistant, was consolidated by bands. The second,
placed within the former, was to be impermeable to the
light gas which was to sustain it. This inner balloon
was never to be completely inflated and the space
between the two envelopes was to receive, in varying
quantities, the air to be forced therein through pipes by
two pumps carried in the car. This was in very truth the
air-ballonnetf and its use was certainly to maintain invari-
ability of the exterior form.

The car was attached to the envelopes by a triangular
suspension system. This was the '* indeformable sus-
pension " which is to-day considered imperative, and
which is universally adopted. The lifting system was
to be attached not to a net, but to a girth sewn to the
fabric. Moreover, at three points where the lifting
rope members met, forming " suspension knots," were
fitted the axes of the three propellers, that Meusnier
described as " revolving oars " (rames toumantes) and
which were no other than screw propellers. Conse-
quently this remarkable system, which is universally
used to-day for driving steamships, was invented in
1784 for aerial navigation and by a Frenchman at that.
But that was not all. Meusnier not only recomimended

HISTORY AND DESCRIPTION 85

the elongated form ; not only conceived the girth fasten-
ing ; the triangular suspension ; the air ballonnet ; and
screw propeller ; but moreover indicated the point the
latter should be installed. It may be observed in the

^,„^) 1 '

:^??->^

-XV /' '^""i »

■Cr^\\

/: yj^^"""^^^^^^^^ \ \ II

\^:>-%pe tarfd from which

car is suspendWL^i^/

^4==H^

■^=#^ j^/

Stern \^ \|\^ ^l/")^^ J* // ■"""

mf#Air pipes.

Rudder ^^^^^^^
Car

Arpxmp

Pie. S8. Dedffn for the flnt dirigible b; Oenenl Uetunler (17S4)

diagram that the motor shaft is not connected to the
car, but is placed between this latter and the balloon.
In this way the illustrious and accomplished officer
Bet forth in one stroke everything requisite for aerial
navigation. For this reason he justly deserves the
distinction of being the forerunner, the initiator, of
aeronautics.

We are indebted for this information to a remarkable

86 THE CONQUEST OF THE AHl

memoir of the engineering lieutenant Ldtoum^, which
was presented to the Acad^mie des Sciences by General
Perrier in 1886, wherein these details are set forth in a
very scientific manner.

THE FIRST MOTOR BALLOON : GIFFARD'S
AIRSHIP (1852)

It was some sixty years later that the solution was first
practically resolved, by an eminent engineer whose name
is justly celebrated — Henry GiffiBuxl, the inventor of the
*' Oiffitrd injector," used throughout the world in con-
nection with the boilers of locomotives. Giffiird was
convinced of the impotency of the '* human motor/' and its
excessive weight, and he conceived the audacious project
of carrying under an elongated balloon, a steam-engine
complete with boiler and propeller. One shudders in
thinking of the courage of this man in venturing to carry
an incandescent fire inunediately beneath his balloon
inflated with hydrogen. But the many precautions which
he adopted ensured him of safety.

The shape of his balloon was of a symmetrical cigar,
pointed at both ends (Fig. 29). Its length was 44 metres,
diameter 12 metres, the elongation thus being in the
proportion of 3 '5. Its volume was 2500 cubic metres,
and it was inflated with coal-gas which gave him a lifting
power of 1200 kilogrammes. The steam-engine, including
boiler, weighed 159 kilogrammes, and developed 3 horse-
power,giving a weight of 53 kilogrammes per horse-power.
It was at that time a noteworthy achievement. The
engine was inverted, to reduce the risks from fire, and
was mounted on a platform attached by six ropes to a
" strengthened beam " supported by slings connected to

HISTORY AND DESCRIPTION

a net which corered the whole of the balloon except on
its under side. This suspension, one can see, had the
drawback of being possible of displacement. Moreover,
the absence of the ballonnet did not secure permanence
of the envelope's exterior form. On the other hand, the

Fro. 39. Btnij aiBard't atsam-driTen tMlloon (ISS2)

use of the long pole had the advantage of distributing, in
a pretty uniform manner, the strain upon the whole of
the aerostatic envelope. At the stern a triangular Bail,
mancBUvred firom the car, formed the rudder.

With this balloon Giffard carried out eome experiments
of the greatest value. True, the low independent speed
(3 metres per second) which he obtained, in conformity
with his calculations, did not permit him to navigate in
the air in a circle : that is to iulfit an " aerial voyage " ;

88 THE CONQUEST OF THE AIR

but he was able to make some very neat evolutions,
deviating at his desire from the direction of the vrind,
thereby testifying to the efficiency of his rudder. In a
word, he succeeded in demonstrating, in an experimental
and unquestionable manner, the possibility of aerial navi-
gation by the aid of an airship furnished with a motor
and a screw. His efforts justly belong, consequently, to
the history of aeronautics.

DUPUY DE LOME'S DIRIGIBLE (1872)

It is necessary to wait another twenty years to see a
second rational effort in aerial navigation. This was that
made by the illustrious marine engineer, Dupuy de Ldme,
the inventor of the ironclad. Struck with the value of
balloons during the siege of Paris, Dupuy de Ldme
thought that this usefulness could be doubled if one
were able, not only to leave the besieged capital as did
the free balloons, but to return again at will ! So he set
to work to perfect a dirigible free from the disadvajitages
of Giffard's.

Notwithstanding the excessive weight of the human
motor, he decided to rely upon the muscular energy
of the passengers to move his screw, so as to avoid
the dangers of the steam-engine. The balloon was
fusiform, symmetrical, and pointed at both ends. Its
length was 36*50 metres, diameter 14*84 metres, giving
an elongation equivalent to 2*5. The volume of the
envelope was 3450 cubic metres.

In the interior of the latter was placed an air-hallonnet ;
this, in short, was the first time that Meusnier's concep-
tion was realised. The volume of this ballonnet was a

HISTORY AND DESCRIPTION 89

tenth of that of the ballooD. Dupuy de L6m6 did not
pin his faith, in the use of the ballonnet, to the lines
set forth by Greneral Meusnier: he adopted the inde-
formable triangular network suspension. The screw
weighed 75 kilogrammes, was 9 metres in diameter, and
was driven by eight men. Under these conditions the
stability was perfect/and in still air the balloon was able
to travel at a speed of 2*25 metres per second — very
nearly 8 kilometres per hour.

Conceived and calculated during the siege of Paris, the
balloon was not built until 1872. It did no more than
start at Vincennes, on February 2, 1872. Notwithstand-
ing a violent wind, the stability was perfect, owing to the
triangular suspension, and the airship was able to deviate
12 degrees from the wind's direction. This test had
the merit of defining the essential points for the con-
struction of dirigibles, and to show the possibility of
obtaining, while travelling, an absolutely perfect stability.

DI&IOIBLE BALLOON OF THE BROTHERS
nSSANDIER (1883)

Impressed by the qualities and regular working of
the electric motor, and the absence of danger which
attended its use, MM. Albert and Gaston Tissandier
built, in 1883, a dirigible airship driven by an electric
motor, for which the energy was supplied from a
bichromate of potash pile battery.

The balloon, properly so-called, was fusiform, sym-
metrical, with the two ends pointed, and having an
elongation equal to 3 ; its length was 28 metres,
greatest diameter 9*2 metres, and its volume 1060
cubic metres. The netting, the cords and the knots

90 THE CONQUEST OF THE AIR

of which, by their projection, offered such resistance
to movement, was replaced by a suspension*' cover."
The very light screw weighed no more than 7 kilogrammes,
and was set 10 metres firom the balloon.

The motor (a Siemens dynamo) weighed 55 kilogrammes
for a motive effort of 1^ horse-power ; the electricity was
furnished by four batteries, of which each comprised ox
compartments, each forming a pile element. The reser-
voirs, raised or lowered at will by a sjrstem of pulleys,
connected or disconnected the liquid exciter, which was
an acid solution of bichromate of potash.

After a preliminary trip in October 1883, the balkmi,
in September 1884, sailed for so long as two hours at an
independent speed of 4 metres per second : it was not
able to go against the wind, but was able to complete
numerous evolutions to the right or lefl of the direction
of the latter. Stability was defective, owing to the
absence of the ballonnet.

Be that as it may, the Tissandier balloon was the first
dirigible driven by electricity ; it opened a way which
could be followed, and which might lead towards the
definite solution of the problem of aerial navigation.

CAPTAINS RENARD AND KREBS* BALLOON
"LA FRANCE" (1884 AND 1885)

It was at this time that Captain Renard, director of the
military aeronautictvl establishment at Chalais-Meudon, in
collaboration with Captain Krebs, and his brother, Captain
Paul Kenard, built a vessel which combined in its un-
precedented type all indispensable features, and which
realised all necessary requirements as much in the
aerostatical as in the mechanical parts. This balloon is

HISTORY AND DESCRIPTION 91

indisputably the starting-point of practical aerial navi-
gation, and it has served aa a model to all that have
Ebllowed. Moreover, those who have digressed from the
leasoDB furnished thereby have coimted nothing else but
bulure.
This pisciform ballooQ (Fig. 30), with its larger end in

Fia. so. "fff'T B«iiard ftod Erebt' ImIIooii La Fnttut (ISM)

froat, was 51 metres long and 8 '40 metres in maximum
diameter, which represents an elongation equal to 6. Its
Tolome was 1864 cubic melres. The envelope, of varnished
Chinese silk, was built up of longitudinal gores converging
tanmids the two points. The network was replaced by a
" cover " formed of bands of transversal widths of silk
Mini tt^ther at their edges, and so cut out as to follow
the " geodesical lines " of the surface. The triangular
■D^iension advocated by Dupuy de L6me was discarded
is &vour of two oblique " cross-pieces " connecting with
tke frtmt and rear of the car, and with the balloon cover
SDi^wDfflOn ; those in the centre were parallel with them,
and directly carried the car.

92 THE CONQUEST OF THE AIR

The vertical steering rudder was placed at the stem.
It was a lath framework strengthened by two diagonals,
and covered with a double sheathing of silk stretched to
form its surface. At the rear of the car, moving about a
horizontal axis, was an ** elevating rudder " which inclined
to the front or to the rear, enabling the balloon to be given
an ascending or descending movement.

The design of the car was a completely new idea ; its
great length recalled the oar-propelled yawls used in
regattas. It was built up of bamboo trellis, had a length
of 32 metres by 1 '30 metres broad, and a maximum depth
of 1*80 metres. Its great length is copied to-day in the
most successful dirigibles, such as the FiUe de Paris and
the CUment'Baya/rd. A " cabin,** coni^aining the motor
and all necessary control, was placed forward*

The motor, built by M. Granune, weighed 96 kilo-
grammes, and developed 9 horse-power. The energy was
transmitted through a hollow shaft, the bearings of
which were fixed to two flexible suspensions, to a screw
placed at the prow of the vessel. This arrangement is
likewise copied to-day in our most modern dirigibles.
The screw was 7 metres in diameter, with a pitch of 8*50
metres, and weighed 40 kilogrammes : it made 50
revolutions per minute.

The electrical generator comprised a "chromium
chloride " battery invented by Colonel Benard and was
of extreme lightness. Each element was formed of a
glass tube in which was a very thin platinum-silver ^
electrode, in the centre of which was a zinc rod. '
The total weight of this accumulator was 400 kilo- j
grammes, which represented 44 kilogrammes per horse- i
power.

HISTORY AND DESCRIPTION 98

e independent speed of the airship with this motive
m was 6'50 metres per second,
e first ascent took place at Chalais on September 1 2,
. The balloon manoeuvred with the greatest ease
"etumed under its own power to the starting-point.

St Cloud //

Boulogne /

a/k I s

M //"

•♦^

^n/Ff^

«/

^-.^

Sevres \

ir^^

lasy

t^jBuratpr nia^e

•7

CUmapt

Srpl S3 1885

jf ^Meudon

oil

m mJeuney laade

iS? *

►^

Sfs/>i.P3.ja85

>. SI. The Bnt two Mrial TOjagM in • doMd circle mmde by La Frane»,
OT«r PiHi, in 1B8S

was a decided triumph, which echoed throughout
rwld. Three further ascents were made in the same
to tune up the apparatus. Then in September 1885
listorical ascents were held in the presence of General
lenon, Minister of War. La France lef% Chalais,
ibed several evolutions over Paris, and returned
B hangar under its own power : the Jirxt round

94 THE CONQUEST OF THE AIR

'' aerial voyage " there and hack was accompLxAd
(Fig. 31) : aerial navigation became an acoomplifihed
fact, the '* highway of the air " was opened and aeicnaotB
had only to fly.

THE ERA OF THE "EXPLOSION" MOTOR: M. HENRY
DEUTSCH: M. SANTOS-DUMONTS EXPERIMENTS

The Chalais-Meudon balloon was consequently tfae
marvel of its day and undoubtedly with electric moton
it was difficult to go &rther in this direction ; but a new
mechanical engine had appeared creating a new industry
and revolutionising the art of transportation : this wai
the '' petrol motor." One man contributed as much bf
his eflbrts and his personal action as by his genero»
encouragements to popularising its exclusive use for
aerial navigation. This was M. Henry Deutsch de la ^
Meurthe.

So soon as it appeared he undertook the important
task of showing the part the explosion motor was destined
to fulfil ; it comprised that marvellous accumulator of
energy — petroleum spirit. From his youth he had been
consumed by one obsession — the solution of aerial navi-
gation. When he saw what Colonel Renard had done
by the use of the electrical motor, he conceived the idea
of using the petrol engine for aeronautical purposes, and
as far back as 1887 demonstrated to the officers of
Meudon the possibilities there were in extending their
efforts towards this end. At the same time he ordered
the constructors Mignon and Rouart to build an explosion
motor upon the new lines, and in 1889, showed President
Carnot the first petrol motor-driven carriage. Always
reverting to his idea of steering balloons, he accordingly

HISTORY AND DESCRIPTION 95

'Undertook to furniEh the financial and materia) means to
Remonstrate its possibilities, in connection with hie first
idea : after expending considerable sums in actual
arch, he unhesitatingly offered numerous prizes to
IteHcourage the efforts of aeronauts and aviators. The

Tia. SS. Bonto knd altitude map of Santoa-DumoQt'i jouroej (the OeutMli
PrUe, Oclolwr 1901)

** Deutach prize " of £4000 certainly contributed much to

fttamalate their enthusiasm, and it is only an act of

Jnetice and acknowledgment to place the name of

I- "Mi. Henry Deutsch at the forefront of contemporary

t Aeronautical history, the many conquests in which are

^ tUkdoubtedlydueto the exclusive use of explosion motors.

r It was M. Santos-Dumont who, on October 19, 1901,

L '^voa the Deutsch prize, the conditions of which consisted

F in setting out from St. Cloud, doubling the Eiffel Tower,

i And returning to the starting-point within half an hour

(Fig. 32). With an indomitable perseverance, an unheard-

' of audacity carried to intrepidity, the young Brazilian

' aeronaut built dirigible upon diri^ble. some large, some

96 THE CONQUEST OF THE AIR

small, some medium, and at last, after ten times escaping
death, he succeeded in carrjring off the much-coveted prize.
His name became deservedly well known, more especially
as a little later he lifted the first "Deutsch prize" for avia-
tion. The airship with which he carried off these trophies,
the Santos-Dumont No. 6, had an elliptical envelope d
33 metres length by 6 metres in diameter, and a volume of
622 cubic metres ; there was an air-ballonnet of 60 cubic
metres capacity, and his motor developed 16 horse-
power.

Once the movement in favour of aerial navigation vm
started, it extended rapidly ; on all sides surged inventors,
not always alas ! sufficiently proficient in theory ex
practice ; not always prudent enough ; not always pro-
fiting by the lessons given by their illustrious predecessora
The Brazilian Severo d' Albuquerque met his death in 1902
through his balloon exploding owing to the lack of fore-
sight in the installation of his motor ; in the course of
the same year 1902, the engineer Bradsky was killed,
together with his companion Paul Morin, owing to the
defective character of the suspension of his dirigible,
which, notwithstanding Colonel Renard's reconunenda-
tions, did not include the ballormet.

THE " LEBAUDY " BALLOON. " LA PATRIE "

These catastrophes did not damp the ardour of the
aeronauts. But they made them more careful, and led
them to realise the necessity there was for them to be
thoroughly grounded in all questions touching aeronautics,
if they desired to venture to build and test a dirigible. So
in 1902, when MM. Lebaudy decided upon the construc-
tion of a huge airship, they secured the collaboration of a

HISTORY AND DESCRIPTION 97

distinguished engineer, M. JuiUot, and entrusted its erec-
tion to one of the most skilful " builders " M. Surcouf

Budder.

Vertical plane

Slabihsator frame

Car a. IVm screws;

VsrUcal keel,
stabilisator

Fzo. 8S. The dirigible balloon L$l>audy (side elevation)

The Lehaudy balloon (Figs. 33 and 34), which the
Parifiians promptly christened the "Jaune" (yellow)

Rudiler -

iVaine of stabilisator

1 ^rz^T'^m y/yyyyyy^^;:7,'yyyy. 'yyy^

— ,^^^»^-^ —

burtace p^
horizjonbal tail An.

oupporiuig lM^al^.

FlO. 34. The dirigible balloon Zebaudy (under-side plan)

owing to the colour produced by the varnish upon the
eoctemal sm&ce of its envelope, measured 58 metres long
by 9.80 metres greater diameter : its elongation is conse-
quently 5.6, and its total volume was 2300 cubic metres.
It is dissymmetrical, the greatest diameter being forwards
and is pointed at both ends. The body of the balloon is

98 THE CONQUEST OF THE AIR

not completely ** round/' the lower part being cut by a
section thereby fonning a flat plane resting upon sjram
serving as the suspension medium for the envelope and the
car. At the same time, the flat form of this firaming acts is
a " stabilisating plane/' which is efficient in use. Under
this frame is a "strengthened girder," which, covered
with &bric, forms a vertical stabilisating plane extended
into a veritable bird's tail, a stabilisator in itself, and whidi
is terminated by the steering rudder properly called.

The car is short, and the motor which is fitted therein
transmits its power to two screws of 2*44 metres diameter,
one being three, the other two, bladed. The propelling
force is exerted therefore not at the extreme front, as in
the La France, or at the rear as in the Santas DumorU,
but about amidships. The short length of this car renders
difficult the uniform distribution of its weight upon the
envelope : also the latter has a peculiar '* saddle form ; " it
is hollowed towards its centre in the manner of a saddle,
due to the weight of the car imposed upon the central
part of the envelope. This arrangement has its disad-
vantage in this sense, that the general form of the balloon
is altered, and does not in practice conform to the princi-
ples which have served in determining the theoretical
conditions of equilibrium and of propulsion. It is just to
add that the efficiency of this balloon is remarkable. The
air-ballonnet is divided into three compartments, to pre-
vent the air surging towards the base in case the airship
becomes tilted, and has a capacity of 500 cubic metres.
The motor is of the Mercedes pattern, and develops 40
horse-power when running at 1200 revolutions per minute.
An acetylene searchlight of 100,000 candle-power,
mounted with a projector, facilitates landing at night.

• ■ «

HISTORY AND DESCRIPTION 99

After a magnificent series of triumphant flights made
in 1904, MM. Lebaudy in 1905 offered this magnificent
dirigible to the Minister of War, who sent it to Toul.
The State then decided to order a dirigible of the same
" semi-rigid " type ; this was La Patrie.

Save in some details, La Patrie was identical with the
Lebaudy : its volume was increased by 200 cubic metres
through extending the length by 2 metres ; the ballonnet
was 650 cubic metres instead of 500, and the motor
built by Panhard and Levassor developed 70 as against
40 horse-power. Lastly, instead of ending in a point the
stem was rounded and fitted with a cruciform '' empen-
nage " for the purpose of securing still greater stability.
An elevating governor of two projecting planes was fixed
to the front of the horizontal stabilisating framework.
Otherwise it was a sister airship to the Lebaudy.

The life of the Patrie was brilliant but short. After
it had proved its exceptional qualities such as no other
airship had shown up to that time, after it had travelled
under its own power from Paris to Verdun in seven hours
without any incident on November 23, 1907, this magni-
ficent dirigible some days after was caught in a gale
which forced a descent. Despite the efforts of 200
soldiers the wind catching its enormous broadside surface
tore the balloon from their hands, and bore it away in the
storm. It passed over France and England, dropping
pieces of its motor at different points on English terri-
tory, and disappeared into the North Sea, where it was
perceived, still inflated, some days after the accident.

A new balloon of the same type, the Repuhlique was
ordered by the Government from MM. Lebaudy for the
national defence. The JRSpuhlique presents some remark-

480910

100 THE CONQUEST OF THE AIR

able features : the impennealiilily of ite e tt icl mie per
mite it to Fomain ixiflated 110 daya inA one cAmge of
gaa. Ite fint flight, made in September 1908, ksted
six and a half hoursy and it covered over 200 IdkmetraB
in a doeed cirda After the CZfaiait-JBoyanI this k
the moet striking record of a comfJeto tzip without
descent, and with return to the startii^-pcHnt. The
characteristics of the Bfyublique are the same as those
of La Patrie as well as the arrangement of the motor
and '' empennage." The BSpubUque has been ''mili-
tarised/' and without a doubt will be employed finr the
defence of the eastern frontier. Lastly, a new militaiy
balloon, the LiberU^ mora powerful still, is under oonstnie-
tion : it will be 67 metres long, of 2400 cuUc metreB
capacity, and will be'fitted with a 100 horse-power motor.

BALLOONS WFTH HOLLOW STABIUSATOBS :
M. DEUTSCH'S ''VILLE DE PARIS":
M. CL^MENPS » BAYARD"

All this time M. H. Deutsch de la Meurthe had not
remained idle. Not content with merely having en-
couraged aeronautics, he wished to become a militant
himself: he thereforo had an airship constructed after
the designs of M. Tatin. This vessel, not giving the
expected results, he ordered a second in 1906, and for
this secured M. Surcouf, who had become instilled with
the ideas of Colonel Renard. For the first time he
conceived an '' empennage " of inflated ballonnets, which
we have already described in discussing longitudinal
stability. The body of the balloon (Fig. 35) is pisciform,
with the master-diameter towards the front. The stem
is connected to a cylinder carrying the stabilisating

HISTORY AND DESCRIPTION

lot THE COXQUEST OF THE AIR

hancumrte. Its len^itii k 60*50 we^xes; maximiim
dkaeter, 10'50 metres; Tofamie, 3200 cubic metres.
Tike CU-, lftttio&-wark of metal tabmi^ is 30 metres long,
a&d of tbe " stref^^tbened girder* fiscm. The baUoimet,
dirided into three fompartmcgta^ las a ridiiiiie of 500
cable metroB, and t«t> rodders are attached to the car,
ooe for staering latenllj, and the other fix* aaooit and
deBoent. The 70 hone-power motor driveB a two-bladed
propeDer 6 metzee in diameter, ranning at 900 revolu-
tiona. The aoefw, fdaoed at the prow in oonformity with
the ideas of Coknd Benard, makes, through a reducing
gear, 180 rerolntioDS per minute. Tliis huge airship has
aooomidished soceessfbl flights, and it was cm board this
vessel that the Prince rf Monaco, the eminent and learned
navigator, who has surveyed and sounded the ocean, re-
ceived the ** baptism erf* the air," the highest altitudes of
which he had previously scientifically explored in mid-
Atlantic by means of '' sounding balloons.''

After the catastrophe which destroyed the Pdtrie^ M.
Henry Deutsch made a patriotic, generous offer; his
balloon was ready ; he submitted it to the Minister of
War to take the place of the lost airship, and the Ville-
de-Paris set out from Paris to Verdun, under its own
power, to replace the wrecked dirigible. This voyage
was made on January 15, 1908 (Fig. 36).

During the exploits of M. Deutsch's balloon, M.
Clement, one of our best known automobile builders,
ordered from M. Surcouf a dirigible of the same type,
but a little larger — the Bayard. We have already de-
scribed it in detail, so there is no need to do so again.
Let us simply say that a new airship, the Ville-de-
Bordeaux, has recently issued from the Surcouf works,

^^B

^^^M

i ' ^9

B) : ,,M

H' ' '^1^1

I^V *'( 3^^^^H

1 - •

HISTORY AND DESCRIPTION 108

and that its features appear to be in no way inferior to
i its contemporaries. Finally, another airship of the same
type, the Colonel Menard, has been ordered by the Govern-
ment for the national defence.
Count H. de la Yaulx has built some excellent small

f^o. 36. Joomey of the VUU-de-Parii from Bartrouyille to Verdun

(January 16» 1908)

dirigibles of less cubical capacity with a very ingenious
arrangement, consisting as we have already explained
(page 43) in placing the screw between the balloon and
the car, on a level with an intermediate beam. His
dirigible, of small volume (720 cubic metres), is very
ooanageable and has given ezceUent results.

FOREIGN DIRIGIBLES : COUNT ZEPPELIN'S AIRSHIPS

The attention of our neighbours across the Bhine was
quickly drawn to the gigantic progress effected in France
in aeronautical traveL They at once foresaw its military
applications, and desirous of not being left behind, re-
solved to excel the French constructors in the building
of a gigantic airship— ^^ colossal " as it is colloquially called
in Gennany. It was Count Zeppelin who, with a dogged
perseverance, an ardent patriotism, which one cannot
bat admire, concentrated his knowledge, his life, and his

104 THE CONQUEST OF THE AIR

fortune, to the fulfilment of this idea. Moreover, it was
shared and sustained not only by H.I.M. Emperor
William H. and by H.LM. the Eang of Wurtemberg,
but also by national enthusiasnL He was advised by
those admirable meteorological aeronauts who grace
German science, and among whom figure Hergesell,
Assmann, Berson, kc

Conceiving an immense dirigible, he sought to secure
indeformability or rigidity by construction : he designed
a gigantic airship 130 metres in length by 1170 metres
in diameter, and with a capacity of about 12,000 cubic
metres. Its form was of a cylinder having coned ^ds,
the elongation being equal to 11 (Fig. 37).

Rigidity was secured by means of a metallic frame-
work, in aluminium, which not only gave to the system
the rigidity much sought after by its inventor, but he
also divided the huge cigaf into numerous compartments :
17 in all. Each of these is 8 metres long, except those
5 and 13, which corresponded to the two cars, and which
are not more than 4 metres in length. The rigidity of
the skeleton is secured by transverse partitions formed
of cross-bracing covered with fabric. It may be seen
that this balloon is not provided with a ballonnet.

Each compartment contains a balloon of india-rubber
fabric partially inflated (nine-tenths only) ; the inflation
of these 17 balloons is a lengthy and difficult operation.

The whole of the skeleton is covered with stretched
fabric. The two cars are attached to the balloon in a
rigid manner, and connected by a bridge, along which
slides a counterweight. The two motors are of 170
horse-power, and drive four propellers of 1*30 metres
diameter, running at 800 revolutions.

HISTORY AND DESCRIPTION

106 THE CONQUEST OF THE AIR

Such a mass is difficult, if not impossihle, to handle
upon the ground ; so its sheltering hangar is a floating
shed, anchored upon Lake Constance. This *'dock,''
held only at one end hy a powerful hawser, swings itself
round under the action of the wind, so that the entrance
is always to "leeward" for the emergence of the
balloon.

Such is — or rather such was — ^the aeronautical leviathan.
The Grerman military authorities, as a condition of its
definite acceptance, demanded the accomplishment of a
raid of twenty-four hours " without descent or revictual-
ling." It was during the summer of 1908 that this
balloon, the fourth built by its learned author, attempted
this official trip. After several short flights, carrying
successively the King of Wurtemburg, the Queen, and
some royal princes, the Zeppelin set out on August 4,
1908, from its hangar at Friederichshafen. There were
twelve passengers on board. At 6.45 in the morning it
rose above the lake and set a course to the East ; it
passed over Basle, where it veered round to the north ; over
Mulhouse and Strasburg, where the clanging of church
bells and the salvoes of artillery heralded its passage;
at 2.45 P.M. it was over Mannheim, when, before reach-
ing Mayence, there was a slight "mishap." The fault
repaired, the balloon resumed its journey, passing over
Mayence during the night, and the return journey was
commenced ; at 6.30 a.m. it was south of Stuttgart
Some miles south of this town another accident neces-
sitated descent. A squall struck the balloon, and from
a cause still but little explained the immense airship was
completely destroyed by fire in a few moments ! This
was a national loss for Germany, and in a magnificent

HISTORY AND DESCRIPTION 107

reak of patriotism a public subBcription raised in a
days the millions of marks necessary to replace the

Turned aboub

Sfpasbonrg

6f r

OEchterdSzKqm ^^Sfuffe|apd

V destro/edlAaiS ^ ^^
A I 2. pjn

WURTEMBERO

<
tdbanse

Riedriabxhafkn

SVSriX2LBR.l^>N.N D

to. 88. Voyage of the Zeppelin^ August 4 and 5, 1908 (606 kilometres,
endiug in the destruction of the airship)

il vessel. Such is a beautiful example to be followed.
ing the erection of the new airship Count Zeppelin
^mmissioned Zeppelin No. III.
at Zeppelin No. IV. accomplished a magnificent per-
lance: its voyage of August 4 and 5, 1908, covered

108 THE CONQUEST OF THE AIR

as a matter of fiekct 606 kilometresp with two descents,
and an actually travelling stay in the air of twenty hours
forty-five minutes. With the new Zqppelin the record
for duration and distance was excelled on May 31, 1909—
1 1 00 kilometres in thirty-eight hours ! Unfortunately the
difficulty of handling such a mass as this again proved
disastrous, for the airship came to grief against a tree.
Despite its injury it was able to return to its hangar
after completing this magnificent journey.

Two other balloons, less bulky but more manageaUe,
have been built by two German officers : MM. von Gtobb
and von ParsevaL These airships are non-rigidL The
first made a beautiful flight vnthout descent — ^thirteen
hours. Afler having for a long time persisted in the
adoption of airships of sausage form — i.e., cylindrical
with hemispherical ends — the German aeronauts have
decided to revert to the tapering ends indicated by
Renard. The Gross has even adopted the stabilisators
ot' the Lt'bauJi/ and the Patrie.

In England military aerostation was represented by
the construction of a vessel, the Xulli SecundtLS^ trials
with which, at first satisfactory, had an xmfortunate
termination. The career of this dirigible was short ; but
no doubt we are only staying further progress to produce
at one stroke somethiuij strikioiX.

In Itiily Captiiiu Ricaldoni has constructed a remark-
able dirigible alter the principles of Renard, which
is one of the most pertect that has been realised up
to the present- A Belgian sportsman, M. Goldschmidt,
has built an airship beivring the name Belgique ; it has
two separate motors of oO horse-power each, two screws,
and capacity of '-700 meti-es : its length is 54-80 metres,

HISTORY AND DESCRIPTION 109

naster-diameter 9' 75 metres ; it can lift four per-
remain ten hours in the air, and travel at 40 kilo-

Fio. 80. Toyage of Zeppelin IIL in a olofod circle (April 1909)

iS per hour. Its radius of action is therefore 200
etres. Stability is assured by a cruciform stabili-

Stem ballonet

Envelope

nard ballontt
empt/)

Steering rocUen

Connecting
air pipe.

Car

JL£c

FiCk 40. The Qerman dirigible Parstval

This airship was constructed at the ateliers of
dard.

reover, an aeronautical construction society has been
ished in Belgium. Strongly supported, it has

110 THE CONQUEST OF THE AHl

mider way a pcTPatlal aiiihi|i» Xa .Rbniirv, of 6^

COM PABISON OF DIFFEBENT TTFBS OP DIRIGIBLBS :
THB ^CO-EFFICIEin*''

We see many typw cxf dirigible belloonaj widely dif-
ferent firom (me another. Each coti esp c Mi dB^ in short, to
a new idea ; eadi, (me may eay, indicatee a develepnient
But what ia the net reeolt? In aborts whidi is the
beet airship?

The problem is complex, more complaz even than in
the (sase (xf vessels where there is something to go upon.
I have accordingly attempted to resolve it, and I hope»
even if it b not complete, at least to have introduced a
new fiustor in aeronantics — the ** co-efficient of advcmtage''
of dirigible balloons.

To discover a mathematical formula combining speed
with the shape of the aerial vessel, mcytive power, and
dimenaionB of the propeller, is still somewhat impossible^
there being many factors to take into consideration to
formulate such a calculation. But, inspired with the
example of Dupuy de Ldme in connection with steam-
ships, I have sought to find an ''empirical'' fonnula.
On the basis of results of experiments spread over a
period of fifty years, the clever engineer evolved a
formula called the '' French marine formula," which has
the advantage of simplicity.

By a slight modification I have applied it to aerial
navigation. This is how : the power of the machine,
expressed in horse-power, is taken, and divided by the
number of square metres contained in the maximum sec-
tion of the envelope. This gives a quotient, of which the

HISTORY AND DESCRIPTION

11« THE CONQUEST OF THE AEEL

cobe root La then extracted. The independent speeii i-i
the airship, ezpreaaed in mTriametres per hour, is no^
divided by the above cube root : the result is a numc«.
eshcays hettceen 3 cmd 5, which qualiiies the airship — diii
is i&t coefficient of advofn^age. The value of this nnznb^
takes into conaideration all charactenBtiGs which theorr
IB fttill powerless to calculate correctly — shape of lon^I-
tndinal section, resistance to air, dBiciency of motor; as
well as pitch, slip, and efficiency of propeQ^r, &c.

Tn working with a number of dizigLbles of wUch I
have been able to obtain d^nite data, I
case been able to deduct an individual
is ^ven in the following Table.

Therefore, by means of such a method of " rlmiHii n
tion/' ''rating" the balloons in their order of merit
absolutely the same as if by trial, it is possible by means
of the indication of form attached to each unit to com-
pare one type with another. The more the co-efficient
\p, in tho neighbourhood of 5 the more advant^igeous ]s
tbo airship, whereas its efficiency is inferior if the
r/r^^fficient drops below 4.

Tfiin simple method shows the superiority of Colonel
fV^nard s ideas. The form of all dirigibles which does
not f/Jlow that of the fish, which he maintained to be
in^IiMfif'JiMablo, have an inferior co-efficient- The Zep-
jtrlin, notwithstanding its huge elongation, reaps but
c^liaht fi/lvant'ige from its motor. On the other hand,
Aa France, built twenty-five years ago, has an excellent
r.ff ^!nir.i*!nt. The best are the Patrie, the lUpublique,
urifl JJio Italian dirigible. Furthermore, the co-efficient
i and G of our military balloons of the Repvhlique type
m f&/]rlitionally remarkable, inasmuch as these balloons

/■*>•f'^ Gffiiwintfi

HISTORY AND DESCRIPTION 118

^e 60 horse-power motors, and always carry a
Lount of disposable ballast — from 700 to 800

mea

pointed out that the co-efficients inferior to 4
fusiform or cylindrical balloons, one may go

DIRIGIBLE BALLOONS.

of Dirigibles.1

Section.

Propor-
tion of
length to

Horse-
power.

Speed.

Value of

coefficient

diameter.

?.) .

113

3-66

0-90

3-20

i-L6nu (F.)

173

2-45

0-80

3-08

r (P.) '. .

300

1-5

1-08

880

10$ (Renard et

(P.) . . .

55-4

600

2-33

4-24

wumt (F.) .

27-9

5-50

2-70

3-26

[P.) . . .

5-60

8-25

4-20

.) . . .

5-50

4-00

460

bayard (P.)

500

100

4-50

4-31

« (P.) . .

5-50

400

4-60

[Oyl.) . .

106

1100

170

400

3-47

//. (P.) .

500

100

4-20

4-04

lUdien (P.)

500

4-50

4-90

nd say that in all pisciform balloons having the
iiameter at the prow, the co-efficient of advan-
always he between 4 and 5.

ElE THE IMPROVEMENTS TO BE EFFECTED
UPS?

lependent speed of 45 kilometres per hour may

be considered fulfilled by airships commercially

)&dL to-day. This speed enables them to set out

F.): fusiform; (P.): pisciform; (Oyl.): cylindrical.

114 THE CONQUEST OF THE AIR

in the vicinity of Paris with the certainty of being aUe
to cope with the wind, and to steer in all directions for,
on an average, about 300 days during the year. Sudi ib
a remarkable achievement without a doubt, but it is not
sufficient.

A speed of 70 kilometres per hour, that is 20 metres
per second, must be attained to enable them to go out
on the average 350 days during the year ; the impossible
days would thus only number fifteen per annum, and
these would be wildly tempestuous daya Will it be
possible to attain these speeds, and to increase Uie
velocity from 13 or 14 to 20 metres per second? Such
will probably be reached, but it will be difficult, since it
will be necessary to employ more powerful moton.
Calculations show that if 13 metres per second are
obtained upon a certain airship with 100 horse-power,
it will be necessary to use about 450 horse-power to give
the same vessel a velocity of 20 metres per second;
undoubtedly the motive power must be divided be-
tween two engines and two propellers. Thus a much
more powerful motor, that is to say heavier, would have
to be used, consuming four times as much fuel, and the
aerial vessel's radius of action would be decreased. The
balloon itself would have to be provided with a stronger
and heavier envelope, to be able better to resist the greater
thrusts that the increased speed would bring to bear
upon its surface. Perhaps it would even be necessary
to resort to compartments, which would increase the
weight still more.

The solution of high speed demands consequently that
airships shall be far larger and carry far more powerful
engines. But then another point arises, that of the

HISTORY AND DESCRIPTION 115

resistance of the air, which is proportional to the square
of the speed. Again, the balloon will assume an inclina-
tion, and will lift its nose slightly, the action of the air
will tend to lifl the envelope as it lifts a kite, and one
consequently reflects whether, in the case of an airship of
large dimensions, the naturally rising balloon, travel-
ling at a certain speed, would not be able to sustain
itself in the atmosphere without aerostatic interven-
tion by the Archimedean thrust, solely by the effect of
the velocity of the air upon its suitably inclined surface ;
in other words, whether it would not be advantageous
under these conditions to dispense with the " aerial
float."

Colonel Benard calculated that, with an airship of the
dimensions of La France, this result would ensue when
the speed attained 72 kilometres per hour. In that case
there would be no more need for the encumbering, expen-
sive, and dangerous hydrogen, and we would rise into
the air under a purely mechanical effort by an apparatus
heavier than the air.

This brings us to the study of this second form of
aerial navigation which has so brilliantly commenced in
the form of the aeroplane.

PART n

AVIATION APPARATUS

CHAPTER I

THE PRINCIPLES OF AVIATION

The *'hbatibr than air" problem: Birds and kites: The

PRdiU.EM or BQUIUBRIUM : How IT CAN BE OBTAINED : DIFFERENT

PORMs or AVIATION : The aeroplane
WHAT IS AVIATION?

Aviation is the art of lifting and propelling through the
atmosphere a hody " heavier than the air," by utilising
the resistance offered by the gaseous element to the move-
ment of the bodies which are plunged therein.

If the first successes of mankind in aerial navigation
were due to the invention and use of aerostats, un-
doubtedly his first ambition was to emulate the birds,
which themselves are '^ heavier than the air." As a
result it required centuries of intellectual struggle to
conceive the physical principles upon which are based the
action of the aerostat, whilst Nature placed under our
eyes the birds, those marvellous travellers of the air.
Consequently it may be affirmed that it was aviation
which from the first haunted the minds of those ambitious
to travel through the atmosphere.

To-day the solution has been found, and although bear-
ing in mind that mankind has not yet realised in a satis-
&ctory manner the solution presented by the birds, yet
the problem has been resolved by three quite distinct
types of flying apparatus. These

119

lit THE casf^cEsrr of the aik

edled ortiiaplAraB), a^ft-
_ _ to imitate the biids' method
of I'l'^'^" **^ -"Ttrrtititrn :

fMuatim vhidi doqityineB the metion«f
mnchfeiHMtainingeefe moving aiMJetBeriiig
in the air; aod finally,

Aervplama^ ntiliBng hj hige dbliqne sarfiuxs the
waiafauft <rf the air fiir their saatentatiaD nnder a hori-
nontal qieed imparted hj a aereir-pnpeDer.

Qmithoptirea hare onfy been raidy tried. Hdioopttraik
Tecy faariniting at firat^ are now relegated to a aeooad
pontaon. Only aeraplanea, the atnd^ of which haa ool^
been potaned really rationally during the paat two yeai%
haTO dewekfped with aocfa rapidity, and^fbmiahed BOoh
contrindng proob of th^ practioal Yaloe during the part
twenty-fimr montha, aa to csnafale it to be affinned that
they have at last aolved the problem of aviation. On-
aequently we shall devote the following pages almost
exclusively to their study.

HOW BIRDS FLY

Before commencing to discuss aviation, such as it has
been to-day fulfilled by man, it is indispensable to examine
somewhat, aviation as practised by birds, those inimitable
natural aviators, the Latin name of which {avis, bird) has
moreover provided the appellation of the new trans-
atmospherical locomotion.

Being heavier than air, birds sustain themselves therein
by utilising the resistance of this element to their move-
ment, which resistance, as we have seen in speaking
al)0ut '' dirigibles," is proportionate to the moving surface,
and increases as the square of its speed. Birds oppose

THE PRINCIPLES OF AVIATION 121

to the air verj large " sustainiDg " sur&ces, called wings ;
they have an organ, the tail, for balancing and guiding,
and the complex movements of their wings which, striking
the air, secure therein a fulcrum which enables them to
propel themselves forward.

The flight of birds, which for a long time appeared
mysterious, but as Marey's works completely elucidated,
18 effected in three distinct forms.

There is, first of all, the oary flight, wherein the birds
flap their wings both to keep themselves up and to move
about as desired.

Then, there is the soaring flight, which the bird
practises when, hurled on at a great speed, it ceases
flapping its wings, only spreading them out, and, by virtue
of their lai^ surface, gliding on the resisting molecides
of the air, having only to steer while moving forward ; it is
this phase of the bird's flight which the aeroplane imitates.

Lastly, certain large birds, such as the albatross
and the frigate-bird, practise the sail flight, in which,
without muscular eflbrt, they depend upon the varying
wind velocities, the " squalls " which occur in the atmo-
sphere. When the bird feels the speed of the wind
increasing, it faces the latter, and with winga outspread
allows the wind to bear it along, both in ascension and
progression. When it feels that the squall has reached
its maximum speed, and is about to decrease, it turns
ronnd and glides, owing to the velocity and altitude it
has acquired with the wind behind ; during this gliding
it can attain and maintain high velocities, therein bringing
into practice the soaring plane ; when it feels a new squall
coming, it turns round again, head to the wind, and the
same cycle of operations is repeated. In this manner it

lax itmie: (LummnEssr ow hme Jksm

tiliiliaeft tliBrwihiii^QiQBLy WAciBticniftwilduiuLanY muHindar
ddbrtsftotdiar tiimL tiiaaHiiBiBflHU!y Qsc mvesmigr fimiL bios

^mftdn^ by tbsr tfiustuadiig: inacgiafitiaEfF of tba^ intouwtj
of Afafr susseflB?^ar aqimlla^.'willeETOn. niBiiBgiS'lXi ^gyuLnpoK
tther wimiL"

mv&ce of die- ^nunf]^. iib mmp h» ac&niibtaefi \Sast t&qr
(Mnginate: frmni tdift ^wying: cfftfiHrtatiiiff of t&fr huriaootel
winii bjr tih& projisituiiiff pixiiiiiffiminiBfjr aeaistaacmi sfaost
(gmatiinifang tiiifr tscceatciaL fHu?(iiigtt- ; buii it bos afteB. been
pRfved t&jBUH mmk: aqnolb ^sk aii gp&uti aiamaBp&erir aid-
taR&&. Wlkoitt,. t&ffiOi. is tditt (suiHfr^' WiooM tibffjr be dae

iiifp aft to' w^isthiHr in0E& dir lisaiF dj^wpiB- dDoradi iciteiiapi
t&e pimnagfr of' tsike- ami s iskjos^. ami t&ns ipwlace vneqail
beflftnair ai t&e- atanoanftsciBal maaaes ?

ITatuI <*air^iil Q&fi«rvuii!ibns^ aire moiiev b^* aaroatatic
mesuia, conctanfiing nhm phtmomena, ^rdiSftl to aerial naTiga-
tion^ one <!armot ban be satniedtid with, the fine conception
6^ the (ij>Tia>mTi?aJ :§t&te ot* tihe ti^tmosphere^ set &xih faj t
dever French engini*«Kr^ )L R*. Sor^an^ an old pupil of
fthe Eo^le Potytecfi n Ti]^Tie-^ PwatienLt of the Frendi Aoial
5fa^ijb^aion SiMTiety^ ihp.d a msui wiiose excdlent theo-
retic^U itndies ha^re perhapi^ most coatriboted to the
•'* anra-velling ^ o€ so complex, a qniesfeioii as- aTiation.

M. Soreaa compajras zh/i centre oi tbe atmoephere
with that of the firee smrtaice of the ocean, always
tra^vwaed by ^* wave "^ systems obeying rhythmical well-
4^tennined laws, and rhe "^ swell ^ of whidi is tiie most
(ir>mtnonpIaee and simplest manlfestatioo. According to
tim dever engineer, the atmosphere would he the seat

THE PRINCIPLES OF AVIATION 128

of analogous aerial waves, communicatiDg to the gaseous
masses, isochronous vibratory movements, the progress
of which would be so much the more regular because
they would be, at such an altitude, too distant from the
ground and its projections for their regular propagation
to be susceptible to confusion. It is from these
''atmospherical waves" that the bird would profit in
most cases of sailing flight.

Will this sailing flight ever be accessible to man ?
Taking into consideration the more and more powerful,
and at the same time lighter and lighter, motors, which
he constructs, will man ever be in a position to obtain
its realisation ? For my part, I do not think so. But
it is interesting to bear in mind this variety of flight,
which we see practised by birds having a large spread,
the '' great sailers " as they are called, which cut the air
above the ocean, the fury of which is let loose by the
tempest. Even then, they will utilise those '^ ascending
currents of air, " caused by the reflection of the prevalent
wind upon the oblique slopes of the immense waves of
the Atlantic and of the Southern seas, where the height
of these liquid hills reaches 16 to 18 metres : this would
explain why, by resorting to this sailing flight, these
** birds of the tempest " always keep quite close to the
disturbed surface of the ocean.

As to the " circular " flight practised by birds of prey,
this is a soaring flight ; and sometimes when these birds
are seen rising, gaining height whilst describing their
majestic rings — as does, for instance, the buzzard — it is
because in so doing they utilise an ascending current of
air, which is often produced in summer above ground
particularly heated.

124 THE CONQUEST OP THE AIR

Thus, when soaring, the bird moves without effort
But a deep study of its movements shows that its wingB
fulfil two distinct functions : propelling and sustaining
surfaces respectively ; and it is especially the extremities
of the wings which propel the animal, the middle part
serving principally for sustentation.

Why has man not sought for the solution of the
problem of aviation merely by the imitation of the flight
of birds ? It is because human thought has conceived,
has realised, a more general and more efficacious me-
chanical movement than those which exist in Nature;
this is rotary motion^ of which Natui-e does not offer
us any example, except in regard to celestial bodies.
But there is a reason for this ; it is because all living
beings being liable to growth as time progresses, their
propelling organs must lengthen freely, in proportion to
this growth ; this would not always be possible in com-
bination with rotary organs.

Man has therefore sought — and success has shown
that he did so with reason — to accomplish high travelling
speeds on land and sea by means of revolving apparatus :
wheels, screws, turbines, &c. ; he has thus been able to
attain and to exceed the speed of the fleetest of animals.
Now, why should not what is good on land and sea also
suflSce for the air ? We do not construct motor-cars with
jointed feet nor transatlantic boats with fish fins. We can
therefore seek for propulsion in the atmosphere otherwise
than by flapping of wings, and if we use these tuings
for sustentation we must at least direct ourselves to
machines and revolving propellers to move in the Aerial
Ocean.

THE PRINCIPLES OF AVIATION 12i5

Pressure oflheair

Direction
of Ac wind

Weight.

THE ANCESTOR OF THE AEROPLANE : THE " KITE "

The excessive weight of the " human motor," a weight
which approximates as we have seen (page 8) ahout
1000 kilogrammes per horse-power, appears to forbid
man the realisation
of flight, by the use of
his muscular power;
the failure of all those
who have tried to
solve the problem of
aviation in this man-
ner may therefore be
easily explained. ^®- *2- BquiUbrium of the kite

But from time immemorial man haa found a means of
raising in. the air bodies ''heavier than air/' and the
" kite," this toy which in the course of a few years has
become one of the most valuable instruments of scientific
investigation, has been known in China and Japan from
the most remote times.

It is scarcely necessary to define the kite, which we
have all handled, more or less; it is a rigid frame of
wood and strings, on which is stretched a surface of
cloth or paper; a string holds the apparatus to the
ground, and when the wind reaches a sufficient speed,
the contrivance lifls itself into the air ; if the surface of*
the kite is large enough, it may even lift objects —
meteorological instruments or photographic apparatus.

The equilibrium of the kite is easily explained by the
combination of the forces which bear upon it (Fig. 42).
The surface exposed to the wind is, in fact, kept
"oblique" in relation to the direction of the latter.

: I ^*«_«>i:*.iti <^ ai. jmti\.

Tig^ ^infi lMiijW if

thetfarart

tlieaetaimor

€if ffe kiteft difidoB

dketllj tiha tfciwit of the
€E dbeciner ■uppoBod to tintof
anmjs oBrtrayod. l^ the
taJBM to he wlBrirMllj wmmtnA^ ani
Dot to biedc andcr Ifce dEiit to windh it i» Bulj o c fa^

Under tbew eondhiaoB^ the eonfarrranoe ii in eqm-
UbrinnL Let one of the abore fixeeB be TBried, and
c^aOibriiim wOl be disturbed immediatelj. If it is the
wind that increaaeB, its iM ea sme beoomea atronger, the
vertical force increases, and the kite riaea. !£, on the
contrary, the wind did not change, and the weight of
' the apparatus shoold unexpectedly be augmented as, for
infftance, if it should rain, the kite fiill& Lastly, if the
third force is annulled, that is, if the cord breaks, the
kite is borne away by '' the wind."

Buch is a veiy simple case of an apparatus, which lifts
itneU by utilising two forces : (l) the resistance of the
air ; (2) the tension of a cord, which may maintain the
surface exposed to the wind. There must, of course, be
a wind to lift the contrivance. Now there are some

THE PRINCIPLES OF AVIATION 127

days when there is no wind. What is to be done then ?
Children, the traditional operators of the kite, do not
allow such a small trifle to stand in their way. There
is no wind ? Well, ** they make some," by running as
quickly as their legs will carry them, for it must not be
foi^otten that wind is not an absolute thing ! It is the
relative movement of the air in comparison with a body,
and this movement may take place, either if the air
is in motion and the body motionless, or if the air is
still and the body moves rapidly in it. It is for this
reason that in a motor car one has a sensation of '* wind"
even when there is none. And children, by following
these instinctive actions, in one stroke invented and
realised the aeroplane.

DEFINITION AND ELEMENTARY EQUILIBRIUM
OF THE AEROPLANE

An aeroplane, in fact, is nothing but a kite which

'' creates its own wind," to accomplish which, the string

is replaced by a motor, and a screw which gives it

a speed equal to what the wind would have to be to

support it like a kite, were it retained by a cord.

The tension of the cord is replaced by the power of

propulsion (Fig. 43), and the conditions of equilibrium

are, at least fundamentally, quite as simple as those of

the kite. An aeroplane will therefore be composed of a

supporting surface divided into one or two parts, which

are often called the wings^ cutting the air in an oblique

manner by means of a propeller and motor ; it will be

connected to a shff or car^ in which ynil be the aviator,

the motor, and the mechanism for steering, comprising

at least two '* rudders " ; one a '' steering rudder," to go

us TBE COflTQCEST OF THK AIR

ti^xt (St [fftf; auui tsfie
iMniifTiigqr

,-fcc

Fk. til Eiivlihriiim. of siia

it, the
e&et of wiiidi kaper-
penifiRnlar/>reKfFg upon
thexDormfaleplmiieL Thk
preBBore mj be lepboed
by two other IbcoeB ; ooe
Tcrticftl^ wfaiidi t^ids to
lifk the eontiivmiioe, bj
annollmg the efBsct of its
iTfi^A/, which would XeoA to mmke it fidl ; the other,
horizontal, directed towards the stem, and tAnditig to
retard the speed of the i^jparatua Therefore equili-
brium is realised when the speed due to the motive
power is sufficient for the thrust to be able to lift the
weight of the apparatus. This speed is thus called the
'' critical speed/' and the aerial vehicle will continue its
travel in a straight line so long as the forces which act
upon it retain their relative values.

But if any one of the considered forces should change,
the equilibrium will be immediately destroyed. For
instance, if the speed of propulsion increases, the pressure
also increases, and therefore also the resultant vertical
lifting component. The weight not changing the equi-
librium is destroyed and the apparatus will rise; it will,
on the contrary, descend if the speed of propulsion
decreases ; it will also descend should the ^' supporting

THE PRINCIPLES OF AVIATION 1S9

sui&oe" for some reasoD or other be dixnimshed, in the
same manner as it will rise, if the weight of the apparatus
becomes less, which oocotb during a jonmey, on aocx>mit
of the oonsomption of the fael feeding the motor.

The very simple conditions of eqnilibrimn which we
have examined are, therefore, precarious, and the problem
must be investigated a little more dosdy to seek the con-
answering the requirements of cnirent practice.

BESISTANCE OF THE AIR : ANGLE OF ATTACK :
CENTRE OF THRUST

To learn exactly what will happen when the regu-
lating speed becomes varied, we must hearken back for
a moment to the laws of the resistance of the air, which
are fondamental in the matter of aviation.

Let us consider (Fig. 44) a movable sorfstce, inclined
in the direction of its advancing movement. The re-
sistance of the air increases proportionately to the
spread of this surface, in proportion with the square of
the speed at which it is driven, and increases at the
same time as the angle at which it is inclined to its
trajectory, and which is called the angle of attack.
Consequently, if this angle is very small, the resistance
will be very slight ; but on the other hand, the lifting
effort will be a more considerable proportion of the
thrust (Pig. 45, No. 1), whereas the resistance to advance
will be a fraction less. If the angle of attack increcises
(Fig. 45, No. 2), immediately the thrust becomes stronger,
but the proportion of this thrust, which constitutes the
lifting power, decreases if more inclined on the vertical,
whilst increasing that opposed to advance.

It will, therefore, be * necessary to seek the optima

Ifovmd surface.

W*^

rflacK

180 THE CONQUEST OF THE Am

value of the angle of attack. Calculation and experi-
ence agree that It must always be very smalL

But a more unin-
terrupted study of
the resistance of the
air upon a surfiu»
inclined in motion,
shows us something

Fio. 44. BeeiBtanoe of the air upon a sUnting OVen more important

•'^'^^■^ We have supposed,

in the elementary explanation which we have given d
the conditions of equilibrium of an aeroplane, that this
was absolutely symmetrical, and that all the forces whidi

Direction
cf wind.

Lifting power.

i^^

^^^^"''"

Lifting

-M— -.

Dix^ction of inavement.

Fio. 45. Influence of the angle of attack

act upon it were applied to a common point G, wbidi
would be its centre of gravity. In practice, things do
not happen so simply.

In reality the point of the moving surface where the
pressure is applied, a point which is called the " centre
of thrust," does not coincide with the centre of gravity ;
it is the nearer to the front edge of the moving surface,
as the angle of attack is weaker. This is what experi-
ment demonstrates : if one moves forward perpendicularly
through the air a flat surface, which squarely cuts the

THE PRINCIPLES OF AVIATION 1«1

moleculee (fig. 46), the phenomena are Bjmmetrical, uul

tiie thrust will be exercised at the centre of gravity itself;

bat if the moving

plane is inclined

(Fig. 47), the gaseous

molecules hare much

more difficulty to

xise up under the

entting edge than to

go downwards to gain

the other side. The

thrust will therefore

be greater on the

front extremity up

which they are forced to travel, and the centre of thrust

will he nearer the front edge.

This position away from the centre of thrust alters 'r

Fio. 46. Tkt Burfaca kdTuiaiDg nonuallj throoch
tbe sir. The air ihoImdIm gliding ijinnietri-
Mllf around tha enda

FlO. iT. The Burtaoa adruidDg obliquely ttirongh the air. The gaseoua
nwleculei gliding past in a diwjniinetrical maDaer

the conditions of equilibrium of the aeroplane, and
affi>rds us some data concerning construction.

Let us consider an aeroplane (Fig. 48) progressing
with a very small angle of attack. The centre of thrust

LiFtrinJ force

Direction
of movement

Weight.

182 THE CONQUEST OF THE AIR

will, as we have just seen, be brought forward to a point
near the firont edge. The lifting effort applied to this
centre will therefore no longer be directly oiq>osed to
the weight, the latter b^g always applied to the
centre of gravity. The disposition of the two forces will
therefore tend to cause the sm&ce Qf the aeroplane to

turn in the direction
indicated by the
curved arrows shown
in the figure.

Moreover it is
necessary to observe
that the position of
the centre of thrust
is not fixed, it varioi
for each value of the
inclination of the aeroplane, and advances more
towards the firont as the angle of attack is made
sharper. This is not all ; let us suppose that, through
an accident or even an incident on the way, the moving
surface should incline towards the bottom ; the air
would then strike from above, and this would mean
a certain rapid and fatal fall. A means must therefore
be found for readjusting the aeroplane when it inclines m
the direction of its length ; this means is the '' feather-
ing " or empennage.

The empennage will comprise a surface placed well to
the rear of the sustaining surface (Fig. 49) to which it
will be joined by a "connection" which, being light,
rigid and latticed, offers only a minimum of resistance
to the air. Under these conditions, under the influence
of the thrust applied forward of the centre of gravity,

Fzo.i8. JSqnUibrinm of the Mtiial MropUune

THE PRINCIPLES OF AVIATION 188

where the weight acts, the aeroplane would tend to turn
as shown in Fig. 48, in such a manner that it would have
its stem lowered towards the ground ; but the thrust
which is exercised upon the empennage, a thrust acting
with the aid of the long

effort*

Movement for
righting

c^f^

Centre
of gravity

Centre of

thrust

Ftf&iherinb

Weight

" lever arm " repre-
sented by the rigid
connection, lifts and
brings the apparatus
back to its lawful in-
cline, in accordance
with the calculation
concerning its dimen-
sions and motive power.

In the same manner a "fringe" (Fig. 50) not very
high projecting towards the stem of the sustaining
surface would become " effaced " behind the front during
the journey with a normal incline ; but if the apparatus
were to become inclined towards the bow, the air strik-
ing this fringe which

Fio. 49< Aotion of the empennage

Straightening

Directipn of iTLOvcmcnl

Fio. 60. Aotion of a Yertical "fringe" at the stern

would find itself un-
masked by the acci-
dental lowering of
the bow, would act
upon it, and this
action, bearing on
the stem, would lower it, and would restore the aeroplane
to its normal incline. It may therefore be seen from
these two examples that it is possible to give an aviation
apparatus an automatic longitudinal stability.

Let us remark that kites for a long time past have
been fitted with this very simple means of longitudiual

184 THE CONQUEST OF THE AIR

stabilisation ; they are, in &ct, provided with a tail.
This does not only serve as a counterweight to the
stem ; a piece of lead at the bottom of the framework
would answer this purpose without ensuring stability.
The tail acts as a true stabilisator, and kites mtist be
provided with it ; we shall, however, return to this
subject in the course of the next chapter. There is one
other question, also vital for balancing the aeroplane;
it is transversal stability. But in this question, the
shape of the wings, dimensions, even the construction of
the apparatus, are inferred as being known. Therefore
we will here conclude this explanation of the general
principles, to see, now, how they are applied to the
conception of a projected flying machine.

CHAPTER II

APPLICATION OF THE GENERAL

PRINCIPLES

From theory to practice: The wings: Monoplane or bi-
PLANE : Stability, and the means for realising it

SHAPE AND DISPOSITION OF THE WINGS

Wb have seen, by what effects of the resistance of the air,
a flykig machine may be sustained in the atmosphere.
We must now see in what manner we can most advan-
tageously utilise these effects.

First of all, must flat or concave wings be used ? This
is the first question one asks. If we take as example the
wings of birds, which are their sustaining surfaces for
soaring, we notice that they are always concave under-
neath. Since the first attempts at aviation, constructors,
therefore, have always sought to build wings distinctly
concave, the concavity being turned towards the earth.
Experience has shown, moreover, that a slightly concave
snr&ce towards the bottom gives to the aeroplane, for the
same speed, a lifting power much superior to that obtain-
able where the flat surface was carried right to the ex-
tremities. Further, M. R. Soreau, in a very fine calcu-
lation, has shown that for any concave wing a flat surface
may also be determined, which would act as if it were
connected with the concave surface in a rigid manner,

135

186 THE CONQUEST OF THE AIR

and the bearing power c£ which would be the same as
that of the concave surface, but that, at the same
time, the concavity

Air currm

DsrecHonoMrKyve ment

FXO. 61. A kMig And narrow mafmoB

a "counter-resistance''
to advance, in other
words, a force of re-
action which sligbtlj
increases the propelling
force by acting in the
same way.

Calculation and ex-

perience being, therefore, in agreement in the recom-
mendation of concave surfaces, these are what we shall
employ in the construction of aeroplanes.

Moreover, the wings will be elongated and disposed
at right angles to the length of the flying body.

For this purpose imagine a wing, a rectangular shape^
measuring 2 metres by 4 metres, viz.,
8 square metres (Fig. 51). If we
cause this surface to move in the
direction of its length, the currents of
confined air struck by its firont edge,
after having barely crept beneath the
wing, will escape lunder the edges
to which they are in close proximity,
and will no longer contribute to sus-
tentation. If, on the contrary, this
same wing be moved on its broader
edge (Fig. 52) the currents of air cannot escape side-
ways, because they are pressed back by their neigh-
bours, with the exception of those which are at the
extreme edges. In this second arrangement, all the
currents thus contribute to sustentation. Our wings,

Air currents

[ II 1 III

1'""

nil

^ ^^

Direction cf travel.

Fio. 52. A short and wide
surface

THE GENERAL PRINCIPLES 187

which we have aheady been induced to make slightly
concave, will therefore be disposed transversely.

This transversal arrangement of the supporting surfaces,
moreover, is what we find with all the birds and flying
insects; in birds par-

Fia. 53. Bpreod of ft bird'i wing

ticularly the

of the wings is always

considerable. (Fig. 53.)

Besides, no matter
what may be the extent
of this spread, the sup-
porting surfaces can be disposed in a horizontal manner,
or form between them an angle more or less open, in the
form of a very obtuse upright or overturned V ; this
disposition of the wings in a V has been adopted notably
by Captain Ferber for his aeroplane, whereas the wings
of the Wright aeroplane are straight.

"SUSTAINING CAPACITY "

Now arises a very important point, which Colonel
Renard introduced into the study of aviation, viz., the
principle of "sustaining capacity."

Let us remark, first of all, that in any attempt at avi-
ation there are two very distinct things. There is, first
of all, the " Bustentation " of the apparatus in the air,
and then propid^on in a given direction. Now propul-
sion only requires very slight motive power, on account
of the feeble density of the resisting centre ; the prin-
cipal effort to be made is that which must be expended
for sustaining the apparatus in the air, or, in other
words, to realise a power of lilting equal or superior to

188 THE CONQUEST OF THE AIR

Let us imagine an orthogonal aviator system, that is
to say, one in which the lifting effort is achieved by
surfitces vertically striking the air from top to bottom
(like pistons in vertical cylinders, for instance) ; let us
suppose that this contrivance weighs 100 kilogrammes,
and has a total sustaining surface of 50 square metres;
its load per square metre will be 2 kilogrammes. The
work of sustentation^ under these conditions, would be
equal to what would be necessary to lift the apparatus
with a speed, according to experiment of 4*90 metres
per second.

Let us now suppose another aviation apparatus, con-
ceived upon different ideas, and not belonging to the
** orthogonal system," about which we have just spoken,
but which, like it, had a total weight of 100 kilogrammes.
The orthogonal apparatus, with its 50 square metres of
surface, to sustain itself requires a work equal to that
which would have to be expended for liftJng its weight
of 50 kilogrammes at a speed of 4*90 metres per second
If the new system, to sustain itself, requires a surface
greater than that of the first — for instance, 75 square
metres instead of 50 — we say that its sustaining capa-
city is 0*66 ; it is therefore weaker. If, on the contrary,
40 square metres are sufficient, always under the same
weight and work, to realise its sustentation, we shall
hold its principle of construction as superior, and say
that its sustaining capacity is 1*25.

The aeroplane, attacking the air slantingly, is a
manner as simple as it is elegant for improving the
capacity for keeping up ; in the same manner, the lateral
disposition of the supporting surfaces, their concave form
towards the bottom, particularly improve this capacity.

THE GENERAL PRINCIPLES 189

MONOPLANES AND BIPLANES

We are led, by virtue of what has been said, to take
light sustaining surfaces of a great superficies if we wish
to raise a perceptible weight, as, for instance, a motor,
propeller and aviator. Let us suppose that the calcula-
tion based upon the data of experiments shows us the
necessity of a bearing surface of 50 square metres. Will
this surface have to be employed in the form of a single
transversal wing, or of two wings, or even three super-
imposed? Under these conditions the transversal
''spread" is decreased, which, as regards the encim)-
brance of the apparatus and its working efficiency, may
constitute an advantage ; in other words, will the aero-
plane be a '' monoplane " or '' multiplane " ?

Birds are obviously monoplane, and they are, more-
over, excellent monoplanes. Everything would therefore
tend to design our aeroplanes as monoplanes were there
not kites to recommend multiplanes, or at least biplanes ;
and the indications of this popular toy must not be
neglected, for, as Captain Ferber has so truly said, " the
kite IB an anchored aeroplane." In fact, if the old kite
is a monoplane, the '^ tail " constituting the stabilisating
empennage, the modem kite is always at least a biplane,
and the following will show by what series of trials one
has been led to adopt this disposition, which experience
has shown to be very advantageous.

Let us consider a kite (Fig. 54 A) which we are flying
in a very steady wind. So long as we do not seek too
great a height, the apparatus will behave beautifully.
But if we wish it to go higher and higher it must not
be forgotten that as we imroll the cord it has to bear a

IM TH£ CONQUEST OF THE AIR

praportiaD of the ahrays increamng weight. There will,
dioHfare, be a height limit mbore vhich the weight of
tlie onroQed eoid will exceed the carryiDg sur&ce, re-
SDhmg from the Uirnst of the aii upon the cloth of the
kite, and the latter would &1L An arrangement, as

ne. 5A. Brolntioa ot tlt« oaUolar, from the InIlItiple^ kite

simple as it is old, can then be employed, confiisting of
an auxiliary kite attached at an intermediate point of
the main kite cord, which will thus support a proportictn
of the cord's weight. Such a contrivance will be able
to rise to a much greater height thau a single kite. Tbe
two kites may be placed a short distance apart, or be
brought very close to, and parallel with, one another
(Fig. 54 B), or they may be so made up as to form
prisms covered with* cloth ; it is upon these lines, indi-
cated by the Australian Hargreaves, that the modern
kites of children (Fig. 54 C) are built, and those, larger
and better constructed, which are used by meteorolo-
gista for carrying registering instruments into the upper
atmosphere .

The " cellular " kite of Fig. 54 C is nothing else but a

THE GENERAL PRINCIPLES 141

biplane aeroplane, provided with a *' feathering tail/'
which secures its stability.

We can therefore distribute our supporting sur-
face upon two superimposed parallel planes; such is
the design of the Farman, Delagrange and Wright
aeroplanes, whereas those of Bl^riot, Esnault-Pelterie,
Grastambide, Santos-Dumont, and the ''Antoinette " are
monoplanes.

Naturally we can make triplanes or quadriplanes, but
one must not proceed too &r in this direction, as there
would result a " pile of planes," the stability of which
would be precarious. Here, as in all things, the happy
medium must be found. An inherent objection to mul-
tiplane construction must, however, be pointed out;
the rigid supports which connect the planes together
present a large surface of resistance to the air, and for
this reason monoplanes are much their superior.

LATERAL STABILITY: TURNING

We have obtained the longitudinal stability of the
aeroplane by the use of the ^^ feathering tail." But
lateral stability must also be secured ; in other words,
the wings of the apparatus must not incline from right
to left, or vice versdy during travel ; at any rate, if such
an incline were perchance to occur, the apparatus must
be constructed in such a way that it rights itself by its
own effort.

Now an aeroplane must be considered in two phases
of movement ; that in a straight line and that in a
curved line, otherwise called " turning."

In the case of the straight line movement, the lateral
stability is, if not ensured, at least very adequately

142 THE CONQUEST OF THE AIR

fulfilled by the spread of the supportmg sor&ceB,
the stretch of which counteracts sudden indinatioD.
Moreover, the centre of gravity of the oontrivaiioe is
always below the supporting planes (or the smftoe
which would be equivalent to them) on acooont of the
weight of the motor and passenger, a weight which
would tend to right the apparatus if it were to incline
unexpectedly.

But this is no longer the case when, describing a
curved line, the aeroplane is turning. Then there inter-
venes a complex phenomenon which causes it to indme
'* within " the turn, that is to say towards the centre of
the circle which the machine describes. This phencnneium
is the unequal resistance of the air upon the two ex-
tremities of the supporting wings.

Let us consider an aeroplane (Fig. 55) turning about
a centre, and let us suppose, to obtain a proper idea
thereof, that the spread of this aeroplane is 10 metres;
the circle which the centre of the machine itself describes
will have, consequently, a radius of 15 metres. It is
seen that, under these conditions, the extremity A of
the wing turned towards the centre will describe durmg
a certain time the arc of the circle AA', in passing from
position (1) to position (2), whilst the outer extremity B
of the same wing will describe, during the same timey the
jirc of the circle BB', double the length of AA'. The
exterior extremity B must, therefore, travel twice as fiif
during the turn as the interior extremity, that is to say,
in one word, go at twice the speed of that of the inner
edge, A ; and as the resistance of the air is proportionate
to the square of the speed, the result is that the interior
extremity A, moving less quickly, will be subjected to a

I'LATK XVIII

^^#

T'»

••'I

THE GENERAL PRINCIPLES 148

lesser resistance from the air, and therefore will be less
" sustained " by the air than extremity B. Therefore,
during the turUy the aeroplane m/ust incline itself more
and more towards the centre of the circle which it
describes^ as the radius of the turn is decreased.

We can confirm this by figures, and in a very simple
manner. If the speed

of the outer wing is
20 metres per second,
that of the inner
wing, in the example
we have selected, will
be only 10 metres.
The lifting efforts will
therefore be no longer
equal, but will be
between them in the
proportion of the
square of 20 with the
square of 10, that is
in a proportion of

Bl .*.-—*..

••..^i^Axis on which
/;i\x it tOrns

/ 2!\ V

••*.

Fia. 65. An aeroplane turning

400 to 100. It is, therefore, seen to what degree the
equilibrium will be destroyed. It is true that an aero-
plane will never have to make so '* short " a turn, and
we have purposely selected an extreme example; but
such always exists, and lateral incline must absolutely be
guarded against while turning.

This natural incline, however, has its advantage; it
appreciably counterbalances centrifugal force^ which is
unavoidable in any curvilinear movement, and is the
more important in the aeroplane inasmuch as the surface
of lateral resistance of the latter is weaker. Major P.

144 THE CONQUEST. OF THE AIR

Renard even proved that inclination of the aeroplane
was essential to combat the centrifugal effect. This
inclination lowers the trajectory. Therefore, aviators
must rise a little before making a ** turn/' if after doing
so they desire to retain their previous altitude.

PRACTICAL MEANS OF PREVENTING LATERAL
INCLINE: "AILERONS," PARTITIONS, WARPING

At all events, it is indispensable to keep up the hori-
zontal supporting surface as much as possible through-
out the trajectory, whether it be rectilinear or curvilinear.
Several means may be utilised for this purpose.

First of all there is a very simple one, which I am
surprised at not having seen experimentally used, or at
least tried, as it seems very rational to me. Since the
** lateral inclination " is a result of the unequal resistance
on the two extremities, let us equalise these resistanceB;
we cannot prevent speeds from being unequal during
turning, but we can cause the supporting surfaces to
vary in the opposite direction ; we can increase the
surface at the "inner point" A (Fig. 55) and decrease
it at the outer point B. For this purpose it would
suffice to carry at the extremity of the wings, varying
surfaces, either arranged in the form of a fan and able to
fold up in the same manner as birds' feathers, or of
sliding ribs, one drawing back under the sails and the
other extending by as much again. The surface of the
inner wing which dips would thus be increased, while
simultaneously that of the outer wing which rises would
be decreased, and it would reduce the difference of the
thrusts, that is to say, the cause of the inclination.
These two movements could be produced automati-

THE GENERAL PRINCIPLES 145

sally by a simiiltaiieoiis movement of the steering
rudder.

The celebrated Ammcan aviators, Wilbur and Orville
Wright, have adopted anoth^* arrangement, "" warping
Df the wings." The following shows in a few words how
this is done.

The extreme angles of their aeroplane can be moved

Actkm of ihe Air
tendinO lb depress
tke left comer
wkick ttumih^

Actum. oF air

tending to J "^^ I ^^^^ Without \

liiFfc vdhuh S ^^r I "^^^^T^^d ^^ \

burning I y^ ▼ I aeroplane I

lowers. ^ ^ I ^ttia J

decline . ^

Fio. 66. Principle of warping the planes (Wilbor and Orrille Wright)

ap or down (Fig. 56) absolutely like the " comer " of a
visiting card. As the Wright aeroplane is a '^ biplane/'
wooden battens lift up the corners disposed one above
the other at the same time, so that when a comer
of the upper wing is lowered the comer of the lower
wing placed below the first is also depressed. The
whole is governed by a manoeuvring lever pushed or
pulled by the aviator, and when the corners on the left
are forced down those on the right ascend, and vice versa.
Under these conditions, it is easy to see how this
arrangement permits of lateral inclination being dispensed
with. A turn is taken, and the aeroplane has a tendency

146 THE CONQUEST OF THE AIR

to incline inwards ; but the aviator immediately manosuT-
ring his lever, lowers the comers on the inside of tiie
turn and elevates those on the outer edge. And then,
as is shown in the diagram, the effect of the air on the
corners thus offered to its action rights the apparatus.

M. L. Bl^riot, the French aviator, evolved and
adopted on his aeroplanes some time ago, long before
the arrangements of the Wright Brothers had become
known, a very reliable system, quite as ingenioua,
which does not require the wings to be deformed by
warping : there is at each extremity of the fixed wings
of his aeroplane, small subsidiary moving wings (Ailerons)
(Fig. 57) capable of being inclined in relation to the
sur&ce by turning about a horizontal axis. When
turning the small wing on the inside is lowered in the
interior and that on the outer wing is raised ; the eSed
is the same as by warping the wings, but this arrange-
ment has the advantage of not bringing about any elastic
deformation of the frame ; this deformation, unavoidable
in warping, must inevitably end in endangering the indis-
pensable solidity.

These various arrangements for righting are governed
by the aviator ; it is therefore necessary for him to secure
the readjustment of the apparatus himself to perform a
special movement, completing that which he makes in
steering to right or left when manoeuvring the flier
by the rudder. But an automatic stabilisation indepen-
dent of the will of the conductor, and fulfilled by the
construction of the aeroplane itself has been sought for ;
it is this solution which has been simply obtained by the
Voisin Brothers, the French constructors who built the
aeroplanes celebrated by the exploits of the aviators

THE GENERAL PRINCIPLES 147

Farman and Delegrange. The arrangement employed
hy them is ** partitioning " (Fig. 58) and applies to
multiplane aeroplanes. It comprises the introduction
of ri^d vertical partitions between the two parallel
bearing surfaces. These partitions, owing to the resist-
ance they offer to the air, oppose any deviation due to
ce'liitrifugal force,
and the surfaces
combining with the
sapporting wings,
add resisting effort
tocombat the lateral
molination which
thereby becomes
pfactically elimin-
ated. The aviator, owing to this principle of construc-
tion has no longer to trouble about his equilibrium, he has

only to think of steer-

Fio. 67. The correctiDg aileronii (B16riot)

ing. Let us remark,
casually, that although
it is true that the
auxiliary surfaces of
the partitions add a
little weight to the
apparatus, they do not
increase, at least to
any significant degree,
its resistance to ad-
vance as they cut the air with their edges and are set in
the direction of travel.

Lastly, there is the "artificial" stabilisation obtained
fay the stabilisating organs bringing^ forces other than

CelU.

Fte. 58. Partitioning (MM. Voisin)

THE COmOSOMST €St IBM AMm

•f l3kB air iito acas^ TMm ^fft of

wHii • hesfj eiicuBifeM ce^ hsie tiiB nvtj inpartaBt
MadiMikaJ qoaKfrf of only bainif fiiwrf to dsviita fion
ilit noffml, the plane in whSA ratetion in dfartedJ^ty
grant diffienlty and nfc tim ptiee ot n tqij grant «ftri
The estent of tfaektter to facing abovt tins doviitioB
h met mtM ffrantv an tlio tii r i rff i'g nnwa ia inBraaaod. tad
ita qieed aogmpnted. li, thenfiMmp n gymafsagi^ is
m oan t ad on an aerofdane and ita rapid rataiy moFoaeBt
maintained by the motor, an eflbct is nucimnaiy to dayige
tbe rotating phne eonaoiidated with tbe fiame of tbe
amal Tehkle, and one may thna hopo^ in an nntomatic
manner, to obtain lateral stability. Theoretically thk
idea is excellent. In practice it is another thing.

Firat of ally a gyroscope when constructed on a large
scale is a very dangerous apparatus ; let it escape firom
one of the sockets between which the extremities of its
axis revolves and it then becomes a destructive projectile
both of men and everything else ; serious accidents have
already happened from this cause. In the second place,
for it to be efficient, it must be fairly weighty, and
in the matter of aviation, any extra weight is a very
vital condition.

Then — and here is the greatest theoretical objection
which may be urged against it — it might, if it worked
efficiently, compromise the solidity of the light frame-
work constituting tbe aeroplana In fact, what causes

THE GENERAL PRINCIPLES 149

the aeroplane to become inclined, is the effort resulting
from the action of air resistance bearing upon all parts
of its long sor&ce, whereas the gyroscope only acts at
one single pcnnt of its firamework. It is, therefore, in
supposing this means of stabilisation to be efficient, as if
the aeroplane were pinched in a vice at one of its points
and an inclining effort exercised upon the rest of its
mechanism ; what would happen then ? Twisting would
occur which might jeopardise the solidity of construc-
tion. For this reason, it seems to me that the gyroscope
would be dangerous if it really acted ; and if it does not
act, it is a dead weight which it is useless to lug about
in the air. Moreover, all this is only theory ; experi-
ments alone, many times repeated, will be able to supply
us with really reliable data.

Let us add, that in order to increase the stabilisation
the use of a double rudder at the bow and stern, moving
in opposite directions at the two extremities of the aero-
plane, has been suggested. Experiments have not as
yet been sufficient to decide as to the practical value of
this arrangement. Another means of automatic stabili-
sation is that which was evolved and tried a short while
ago, comprising the automatic variation of the '* angle of
attack" by articulating the whole of the supporting
wing around a horizontal axis. This wing is held in its
normal position by a powerful spiral spring which resists
the pressure of the air when the aeroplane is travelling
at the required speed, but which gives way to this
thrust, if the speed happens to increase suddenly, by
diminishing the angle of attack. Experience will shov^
what this ingenious conception is worth. In any case,
the ^'natural" means of stabilisation are the most

150 THE CONQUEST OF THE AIR

rational, because they act with effiaoto analogous to those
of the pertorbing fbroee of equilibrium.

STEERING: THE BUDDEBS

As we ha^e spoken of turning, the means by which
it is brought about must be indicated. This is the
** steering rudder."

The steering rudder is similar to that used on boats
and dirigible balloons ; it is a light and leeiflting thin
panel, turning about a vertical axis, operated bjr a
*' wheel '' or motor levers, at the will of the aviator, who
can turn it either to the right or left. The rudder is
placed as &r as possible to the stem of the aeroplaoe,
and as &r as possible away firom the supporting surfroes
(Fig. 59). When it is turned to the right or to the left,
the moleculn of air, striking its surface in an bUiqiie
manner, exercise a thrust which is all the mam efficient
in causing the body of the aeroplane to swerve, since it
is placed at the end of a long lever. For this reason, it
is most frequently placed at the rear end of the empen-
nage tail. When it is desired to travel in a straight
line, the steering rudder is brought back to the central
position, that is to say in the longitudinal plane of
the apparatus, and the air no longer acting upon its
surface, no deviating action as regards direction
resulta

Let us remark that the steering rudder could only be
efficient if the aeroplane present a '* lateral resistance to
drift" An aeroplane which had no opposing surface to
a lateral movement, would not comply with the move-
ment of the steering rudder. There must therefore be
a lateral surface, if only effected by the '* hull " of the

l^'l fHB^^H

* 7 / N

/ /

\ \« iP^^Bl

^\/ '

^W 1 ^^^^1

^ r

— ^y E ^^^^1

^1 «i

TF/.V-^

^fi^^^^r^it *^^^l

IHGii^l

^■

•fflT

"Ia bI^H

' l^..

jpwn^H

]|l

i-^

ri^

! -.'1 n

* •

Action of tKe air
upon tKe inclined

rudder..

'Rudde

DirccHon . of TgQvement

THE GENERAL PRINCIPLES 161

From this point of view, therefore, partitioned
planes are really superior.

be "elevating rudder" is a similar device, but
ing about an horizontal axis, and causes the aero-
e to deviate, not to the left or right, but upwards
downwards in its
3ctory, in a word,
;h causes it to as-
l or descend. Its
ation is explained
le same manner as
of the steering
ler. This invention
been attributed to
Wright Brothers, I

I believe errone- ^^' ^^' ^^® steering rudder

Yy as Colonel Renard applied it to his airship La
nee in 1885, as is testified by the official docu-
Ls published at that time, which contain the full
ription of the arrangement and also the explanation
3 working.

le steering rudder can be placed either at the bow
;em of the aeroplane ; each disposition has its advo-
3 and opponents. The Wright Brothers have placed

the bow, and as people " went a trifle mad " on all
bore their names, it was concluded to be " necessary "
it the elevating rudder at the bow, just because

placed it there. But Messrs. Esnault-Pelterie land
lot, the constructors of the Antoinette aeroplane, to
only these gentlemen, instal it at the stem, and it

moreover, L. Bi^riot who made the first round
J journey ; it is his name that subscribes to the

158 THE CONQUEST OF THE AIR

historical page of the first practical application of the
aeroplane.

LAUNCHING THE AEROPLANE

Every one knows that principle of reasoning, exten-
sively used in geometry, which commences, when a
problem has to be solved, by the use of those honoured
words, ** Let us suppose the problem as sdved.**

Present industry offers us a number of varioos
machines which, if I dare so to express myself, ''can
only go if they are already going ; '' for instance, the
explosion motor, which must be ''launched'' witii all
one's might to start and to enable it to assume its
normal speed.

The aeroplane is a new example of this method of
procedure : the conditions of its equilibrium suppose its
being already started : at rest, it remains on the ground.
Therefore it must receive an initial impulse, which
''launches" it into the atmosphere, and gives it that
speed which, owing to the molecules of air gliding
under its oblique wings, first lift and then sustain it
There are two ways of conceiving the launch ; they may
seek to endow the aeroplane with means enabling it to
launch itself, in which case it would reaUy be self-
starting. On the contrary, it may be launched arti-
ficially with the help of a contrivance remaining at its
point of departure ; then the launching is easy, bat the
apparatus if it lands cannot start again, it must first
return to its starting-point, under penalty of being
condemned to rise no more into the air.

French constructors and aviators have courageously
accepted the hard conditions which an aeroplane must

THE GENERAL PRINCIPLES 158

^Ifil to be ''self-starting/' and all our aviation apparatuses
leave the ground by their own means. For this they are
mounted on a frame- work with bicycle wheels, a carriage
^which must be as light and at the same time as
strong as possible, since at the moment of landing, the
shock of the apparatus coming against the earth, howso-
ever much it may be lessened through the skill of the
aviator, falls entirely upon that framework. It is an
additional load, which may vary from 50 to 80 kilo-
grammes, which any aviation apparatus desirous of
launching itself without outside help, must carry with it.
But there is another extra weight imposed under this
condition ; it is the increctse of motor power necessary
for launching, which commences . with a run along the
ground, under the impulse of the propeller screw
attacking the molecules of the air. The inertia of the
motionless apparatus must first be overcome, and for
this the motor must give a pull "at the collar"
sufficiently strong to develop an excess of power on the
part of the motor. This '^ collar pull '' causes the aero-
plane to roll along the ground, with increasing speed,
until the latter is sufficient to bring about the lifting of
the apparatus by the action of the air striking on the
under part of the wings. Once the apparatus is in
the air, but little effi>rt is needed to sustain and
propel it. However, it entails the transport of a
motor, heavier than was really necessary, but the extra
energy of which was indispensable for launching. This
additional weight, in conjunction with that of the frame-
work^ requires the . " self-starting '' aviation apparatus
to carry an excess of weight which may vary from 100
to 150 kilogrammea

154 THE CONQUEST OF THE AIR

Qaite different are the oonditions of the aeroplaDes
iviiich are launched in an '' artificial *^ manner, such
as thoee of the Wright BrothenL Freed from these
severe conditions, the American aviators have required
the &11 of a weight for the necessary lannchiog
effort for their apparatus, and to avoid any exta
weight, even that represented by the weight of the
supporting truck, they glide their aeroplane, in order
to start, along a "rail," attended with very little
friction.

The idea of the launching weight is ingenious and
effective, as it must impart to the aeroplane an increae-
ing speed ; now, the falling speed of a weight incresaaB
exactly in proportion with time ; this is the first kw
concerning the fall of bodies. This weight, in its fidL
in drawing the aeroplane along by a rope and return
pulley system, will therefore impart to it a speed which
will steadily increase. Relieved of the extra weight of
100 kilogrammes at least required for "self-starting,"
the aeroplane thus launched can use an ordinary
automobile motor, a little heavier than the special
type, but working more regularly, instead of the extra
light motors used in French aeroplanes, in which, every-
thing being sacrificed to lightness, there may sometimes
be defects, especially in regard to endurance. The
American aviators are therefore placed in better con-
ditions, and have been able to accomplish feats which
possibly they might not otherwise have achieved, with
the same facility, feats limited, moreover, since they
must land near their launching apparatus for fear of
being rendered powerless and prevented from starting
again.

THE GENERAL PRINCIPLES 155

THE DESCENT

When the aeroplane is in steady motion in the air,
when it is soaring at its '^ regulating speed/' everything
is working normally, sustentation, advance, steering,
in the manner we have explained. But the motor may
happen to stop, either by the will of the aviator, or
accidentally. Let us now examine what will occur in
80ch an event.

By virtue of its acquired speed, the aeroplane con-
tinues to advance; but, propulsion failing it, the
retarding resistance of the air will be felt more and
more, and its speed will be rendered useless. It must
therefore, keep it up, and, no longer having a motor, it
can only do so by descending in an oblique manner
towards the earth ; then its weight will serve as the
motor ; in this manner it will reach the soil as gently
ae the aviator desires. In the descent, moreover, the
steering-rudder will permit the landing-point to be
duMBcn, and the apparatus will come down quietly to the
ground. Thus, theoretically, at least, an aeroplane effects
a "descent," but never a "fall." This descending opera-
tion is effected in a ready manner by French aviators,
who have become clever experts. It is needless to
lay that the greatest presence of mind is necessary
to conduct an aviation apparatus; distraction may
prove fatal. With this presence of mind and skill in
manoBuvring, " motor failure " is no longer dangerous
to the aviator ; it only interrupts his journey.

Many persons ask aviators why their " heavier-
than-air" apparatus is not provided with parachutes.
This frequent question is answered fvllj by what

THE CONQUEST OF THE AIR

'6 have just said. It is useless to fit a parachute
an pparatuB which is in itself the most perfect
irachute.

"^ ) V ill now study the practical arrangements of an
plane destined to fulfil everyday service and to
possess lualities of safety, solidity, and speed.

CHAPTER III

AEROPLANE CONSTRUCTION

^ 1^ CRV18 : Motors and propellers : Safety : Wind
N S Btd the aviator : Must we fly high ?

J eURFACES : THE « POWER OF PENE-

^3 aeroplane to be provided with a motor

irr as perfect as possible (we shall go further

>^on of these two elements) its essential

^sustaining or supporting surface. This

*imes called the ''set of sails/' and the

^r£Bicee are also known as "wings." We

*& there is an advantage in making them

era on the under side. Moreover, they must

^tsverse to the line of travel, whether in a

^)r a very much opened V. The supporting

^med of cloth stretched upon a light and

ra frame-work. The same india-rubber
serves for the construction of dirigible
jl^fben used,
me-work is formed of members which have
this offers to the wind a resisting surface ;
latter must therefore be reduced to the
, in other words, the " power of penetra-
apparatus must be the maximum. It is
,ve a heavy piece, entailing a gresst^r loa^

157

158 THE CONQUEST OF THE AIR

to be lifted and sustained in the air, if well thought out
in regard to its shape relative to the resistance the air
will bring to bear upon it.

It will therefore be advantageous to give the sections
of the parts cutting the molecules of air fish-shaped
profiles, with the larger end foremost (Fig. 60)l' ITMse
lines are followed particularly in sections of tiie wings
of several existing aviation apparatuses ; the wing firtme-
work is pisciform in section, and the panels of oloth are
stretched on both sides of this skeleton.

For this reason it will be necessary to avoid too many
stretched wires, ropes, manceuvring cords extending to
the exterior, and cross-pieces ; and if it is remembered
that biplanes cannot do without the latter, which are
indispensable for joining the supporting surfaces together,
it will be understood how inunense is the superiority of
the monoplanes over the biplanes, at least from the
nir-roflistance point of view. The latter in their various
forms, in ])articular those of Voisin and Wright, offer to
ihd air very needless resistance to advance, as only the
Hupporting surfaces are efficient. For high speeds,
which are the aim of aviation, I would therefore be
tempted to believe in a much more brilliant future for
monoplanes ; those of Esnault-Pelterie and Bl^riot, and
tht^ Antoitn'ttc aeroplane already represent more than
promises ; their first exploits permit one to hope for
resnlts still more brilliant later on.

A part from the transveree sections, there is the nature
and character of the sustaining surfaces to be considered.
The fabric of which the set of sails is made must be
stretched upon the frame-work of the wings with the
greatest care ; the seams, knots, heads of nails must in

PLATE XX

<••''

• « a- * « -^ •■

Direction of mot ion.

Fig. 60. Fisciform seotion of
the wings

AEROPLANE CONSTRUCTION 159

DO way project; the surfaces must realise, as far as
possible, their geometrical definition, and be of an abso-
lute continuity and regularity, and the fabric, stretched
to the maximum, must also be varnished in an extremely
careful manner. It is these conditions, difficult to fulfil,
which render the con-
struction more or less
valuable, according to
how it is turned out
with more or less " finish."
It is this perfection of
workmanship which is
responsible for the relatively high price of the present
aeroplane ; it is how the French constructors, who have
carried it to the utmost limit, have acquired a reputation
which ensures them a superiority which is equivalent to
a real monopoly.

MOTORS EMPLOYED IN AVIATION

Aeroplane motors must be light, and only the explo-
sion motor, working with the combustion of a mixture
of air and petrol gas, fulfils the indispensable reduction
in weight. As early as 1884 Colonel Renard showed
that if the weight of the motor, everything included,
was reduced to 5 kilogrammes per horse-power, one could
realise dynamical sustentation and efiect ordinary avia-
tion. The colonel's prophecies have been amply attained,
and even surpassed to-day, because the motor with a
weight of 2 kilogrammes per horse-power is realised.
In regard to mechanical apparatus, we are therefore
equipped for the conquest of the air.

Nevertheless, too much must not be sacrificed to

• :r

titn ^r^^sL fe Tuilihinna^ "Anat jKt dinr ^""^^ It b

Ji H^s'jui rumsaiB of onMbimiig: wfo^OrvtdmaiaKk m to
ciitiv^9iiH^ i^'rLL tL vmam ntsftibaoBm ; fivm this point of
vji^v *mU^ '' nTJfa.iuaL mp&ois ^ -of vbt AwJmMkgUe make,
Vu'.iM yf JL Zfiuii.iih-'PtLiieraei. IL Beomiilt« mud even
'A:ji^nt: u-*: ^'j^Si-yr^Lj reoGaricfrble. In pmrticiilar, the
nt^i'^u of tiie Eezduoh-Pc^usie motor, having several
*:t^%*\Lk vir^jrk'iTj.^ ^yjL, the same shaft, and actuated by the
\n^m f^Aa tLirikfigfA in a xadial manner, has ensured a
fum^fl^rrnlAH rli^crease in weight. One single cam ensures
iUi: workiuff of the valves.

ir li^litniTHH is the paramount condition which the
motor rniiKt fulfil, it is yet inseparable from strength and
I'ti^iiliit'ity in working. With the beneficial realisation

AEROPLANE CONSTRUCTION 161

of this last condition, it will be possible — it will even be ad-
visable—to reduce the weight of the motor more and more,
as absolute safety will only be acquired when it is pos-
sible, on a given aeroplane, to instal two motors, each being
of a power alone sufficient to sustain and to propel the ap-
paratus. Then the '' break-down," the terrible break-down
which inevitably brings about the descent^ if not the fall,
of the aviator, will no longer need to be feared ; for if one of
the motors should fail, the other, already running, may
be speeded up ; and as each one is, according to calcula-
tion, adequate to ensure sustentation, a fall will no longer
be feared. The great development that has been realised
for some time past in motors permits us to believe that
this hope will soon become a reality.

There is another point to which constructors and
inventors will have to devote attention : this is the
perfection of the rotary motor. Shocks and unavoidable
vibrations, due to the to-and-fro movement of the pistons
in the motors such as are now used on aeroplanes and
dirigibles, cause the framework to warp and forcibly
tell upon the joints and bracings. These vibrations are,
moreover, ^transmitted to the suspension and stretched
steel wires, reducing the strength of the latter ; in the
event of a combined efPect these vibrations might even
bring about a rupture, by a phenomenon similar to that
which has brought about so many accidents to suspension
bridges.

The rotary motor, of which the " turbine " is a t3rpe,
has the advantage of suppressing shocks. Will it be
possible to accomplish with the explosion of gaseous
mixtures, what has been done by steam in turbines?
It is still impossible to say. But, in any case, the

162 THE CONQUEST OF THE AIR

eflEbrtB of oonstraoton mmrfe now be tamed to thk
question.

THE PROPBLLBR: SCREWS

The only propeller used in aviatiim (exeept intfae tridi
with omithopt^re apparatus) is the aorew. We hava
explained its general properties in spealdqg of diiipbb
balloons ; we have defined its '' j^toh,** «8' weU as Ae
" slip/' resulting from its workmg in the air.

But we must return to it a little in (peaking of its
application to aviation apparatuses.

We are not at present very well supplied with really
reliable " data " concerning aerial serews ; the eaLcellent
works of Colonel Benard lutve cleared the qoestion with-
out solving many individual points. Experiment akm
is able to furnish data as to the practical value of a aonw,
and then it works " at a fixed point/' &at is to say,
moves upon an immovable dynamometw, which gaugeB
its mechanical effort.

This data is not absolutely sufficient, as in aerial work
a screw does not furnish the same useful eflEeot as when
working in a fixed point ; in any caM» thia data is
necessary, and therefore above all tractive expenmants b?
mean, of. d^naMometer for <»ch <»»w mo^ll^^

Once this result has been obtained, a serious ijpjioBtiim
of vital importance arises, since, according as to Ikiar it
is settled in one direction or the other, there wiU ranlt
an aviation apparatus presenting an appearance and
qualities very different. This question is: Must the
screw be of a very small diameter, and revolve at high
speed, or must it, on the contrary, be very large, and
turn " slowly " ?

I'LATK \MI

rr^^ I

1 ''^^

M^^^Kt^lb. ilk .

/f~

¥■

n i^r'

AEROPLANE CONSTRUCTION 168

These two ways of planning the propeller have given
birth to ** two screw-propeller schools." Both solutions
have been experimentecL Large screws were the first to
be used, especially on dirigibles, and in particular on
those of Griffiuxl, Dupuy de Lome, and Benard. This
condition, moreover, was compulsory at the onset, owing
to the slow revolutions of the motors employed.

But when the explosion motor, with its very high speeds
of revolution^ entered aeronautical practice, preferences
changed, and there was a rush on small screws turning
very rapidly ; there was a fear that the actual rotating
speed of the motor would be " reduced," and it was desired
to govern the screw directly by the engine by mounting
it direct upon the shaft of the latter. Thus we see the
Lebaudy dirigibles, the Voisin aviators, the immense
airship of Count Zeppelin, fitted with small screws run-
ning at a speed ranging from 1000 to 1500 revolutions
per minute.

The appearance of the Ville de Pa/ris and Bayard^
Cl&memJb airships, fitted with large screws running at
from 300 to 400 revolutions only, and especially the re-
markable performances of the Wright aeroplane, the two
screws of which rotated at a fairly low speed, has served
to support those who very justly maintain that the
employment of screws of a large diameter is more advan-
tageous. To-day there seems a more general tendency
in the direction of screws of a greater diameter and
revolving less rapidly.

Another question, quite as important, is to whether
(me or two screws should be used ?

In principle, two screws, one forming a screw on the
right, and the other a screw on the left, and revolving

164 THE CONQUEST OF THE AIR

in opposite directions, are in every way prrferabla In
fact, with one screw only, the aeroplane tends to indine
in the direction of its rotation, and its great sur&oe alone
prevents this inclination firom becoming serioua

With screws of opposite pitch and direction, these tio
effects become neutralised, the one tending to incline the
aeroplane to the right, and the other to the left The
motive effort is then quite symmetricaL

But the use of two screws may in certain cases present

a great danger, and for the following reason : Let m

suppose an aeroplane provided with two screws (fig. 6U)

driven by identical motors, or by equal transmission of

the energy from a single motor ; each has a turning effioek

following its axis, and as they are placed symmetrically

with regard to the centre of the supporting surfiau^e, the

resulting propelling effort is steadily applied at one pomt

of the symmetrical plane of the whole contrivance. But

if one of the two screws — the right, for instance— for

some reason should cease to act (Fig. 61b), either through

a fracture or failure of the motor-power which drives it,

the aeroplane is instantly subjected to the action of one

propeller alone — the left one ; this movement is eccentric.

The apparatus will, therefore, be subjected to a propelling

effort which will itself be eccentric, and will tend to

assume an oblique direction ; it will take it too rapidly

for the aviator to have time to correct it by means of

the rudders, and a fall may be the result. This is,

unfortunately, what happened with one of the Wright

aeroplanes. Orville Wright, having on board an oflScer

of the American Army, Lieutenant Selfridge, was a victim

of this contingency. The aeroplane fell, the oflBcer was

killed, Orville Wright had an arm broken, and had to rest

AEROPLANE CONSTRUCTION

105

Ox- two long months. The French aeroplanes, perfectly
*»«)ught out, have never experienced such mishaps.

!7roin the point of view of safety, the use of one screw
fclcmo is, therefore, very preferable. If it is absolutely
. to use two, it is essential that the disconnection

with two propelliira ;

tr stoppage of one should stop the other, and with the
ud of an atUoTnatic arrangement, for instance, the trans-
mission of the power by a single chain. Under these
oircumstances, in the event of propulsion failure the
aeroplane would be in the position of an ordinary " break-
down/' and must descend by "gliding" upon the air,
&At is to say, by making an experiment in soaring
flight.

Ijastly, one more doubt may arise in the mind of the
ematnictor ; must its screw or screws be placed at the
bow or stern ? Must one, in other words, have screws
which "draw" or screws which "drive"? Opinions

iW THE CONQUEST OF THE AH.

' ^

anr arrttiijtrenient-f- art aiviaeo xi zn*r apDararjse? r.-^

cit ::jih* o^. Bifrioi. Emmuii -Peiteni . tn- smc^ screv s&t
Hit D'jv ii tii^r Farmaii aeropiart. i: is- a: zut sien^
tii»r fc?upporiiij£r BUiiaces thif- L^ alsi tiit- arrriijjr^rc:
wiuc-i Hit Wrich* brothcTf- iiavt- adoptee: ia: zii^vrf
b'j!>-\vt wijic'i. art ■■ urivmrr Bcrewfc.' Al uies*- aer'-iiiijiss
iiavt bijjvi difiert?u*i quaiiiiefc. buT buci. ai^ ait- iii:*ji:=?.*
aoj*r I: lb liiereiort impoBsibie tc declare o£-iiLi: b
lfc\'ju? vi oLit o! tbt- otiie:. and tbt- posixioL of zittssref
wiL Uf ]>fiiC upoL tilt spread, tbe emj>eiiiia£'t:. mj- iii:^
o! i»rbfc ibt ioui; itfvtfiifcert- o: iht^ iatte:

IHh, -bODV OI THE AEROPLAKT

'Jhert ifc. aibo. one pan of tbt aviaxioii apparuTas^A
>M: iiavt jje^rlecved up zo no v. bui irhicL if ne^srtiftifi»
JlJUl^^{Jellbable : it ih tbe '* bcidy '" vbicb piays Lbt jiaricJ
i)j«; ♦;ai of" ibe diriirlble. iba; it xo sbt tbe sDact aesdri'id
r'j ';;a'tv :.}]*: iiv.iio: . ibe T»roi»eIje: . and The 2iT-i&.T:»r, :Le

■

j/..fi i*J" ili«: aer'^piane. since i; c^niaiiis ibe ir&ve-irr ; it
fj-o-r ),'am:\<.-i. dinjensions, and bowever ^ir^ali ii iiiavbe
'!i-^:;'/ii-'l.. x\itih*: cannot b-- aToidtf-i : i: ttIII therefore
j.M ^'.l jji. lo tij'i air a resisting surfaoe. "wbicb must 1*
I ;.*!'' fj jfilii a':c"UJit.

In iIji' \\'ri;/lit JtJi-'.ibers' aeroplanes tbere is no "btHly:
ii i.'^ H'liir«;(l lo lliut 'jf tbe aviator, sitting over eiiipiv
hj/jui- ojj ;i l;itticu<l seat, with the feet simply restii:^:
iip'iij ;i if ohs bar. This is a possible arranijement wiUj
opiiaidih ah <:l<rver, as '* artistic," as master of their nerves
ah VVilbiij and Orville Wright, but in my opinion it is

AEROPLANE CONSTRUCTION 167

an arrangement to be condemned absolutely ; aviation is
already a sufficiently daring form of aericJ travel without
increasing the risk, by decreasing the conditions of safety.
!nie Wright aeroplanes moreover have not yet made
any * 'journey " properly speaking, either in Auvours or
in Paris ; they always limit themselves to performing
eivolutionSy sometimes for a long time, above a test field.
Bat practical aeroplanes able to extend real services,
saoh as those of Bl^riot, Esnault*Pelterie, Voisin, &c. . . .
all have a " body " serving as accommodation for the
ayiator and the machinery.

This body, thus being compulsory, it is necessary to
utilise it to the best advantage for the balance of the
machine. First of all, we must give it, undoubtedly, the
- ahape of the body of a bird or fish, the large end to the
jfiront; under these conditions, and if the firamework is
oarefully covered with fabric tightly stretched and very
nlooth, its resistance to advance will be reduced to the
Twiniinnm, This body will, moreover, serve a useful
purpose; it will increase the resistance on the sides,
that is to say, oppose *' drifting" and the action of
centrifugal force when turning.

Thus planned, the shape of an aeroplane becomes
eloeely allied to that of a soaring bird. The action of
the air upon the various parts of this '' body " inust,
however, be carefully studied as regards stability in the
direction of travel, and here it is that Colonel Kenard's
works must be borne in mind. More than ever (as we
have already said) the empennage is here indispensable
for securing the safety of the apparatus.

168 THE CONQUEST OF THE AIR

ABBOPLANBS AND SPEED: AEBOPLANSS
OF THE FUTUBE

The real groat advantage of aerqplaiieB in their appfi-
cation to aerial timTel ia tpeed.

In all trials wherein somewhat prolonged flights haifB
been aooomidished, it has heen seen that the present flpeed
of aviation apparatnses is at least 60 to 70 kilometres per
hour, and in Fannan's now historical jonrney fixxm Bhdsitt
to Ch&lons, not only did the daring aviator adiieve
on his French Voisin-biult aeroplane the first " aeriil
jonmey '' worthy of the name, leaving a field of experi-
ments and passing over villages and forests, bat he eves
made it at a speed of 78 kilometres per hour. No
dirigible, at least at present, can attain audi a qmd,
and the speed record in the matter of aerial navigation
therefore belongs to the aeroplane.

Can this speed be increased ?

Not only can it be increased, but it must be increased,
if it is intended to make really practical use of aviation.
At an imposing conference held at the French Society
of Aerial Navigation in December 1908, the engineer,
M. Soreau, a former pupil of the Ecole Polytechniqae,
dealt with this question in his highly competent manner;
he selected as a type a '* family " of aeroplanes of the kind
constructed by the Yoisin Brothers, and supposing them
to be all provided with motors giving the same weight
per horse-power, propellers having the same output, saik
having the same co-efficient of efficiency he showed that
the useful maximum weight would be obtained with an
aeroplane having dimensions only 10 per cent, heavier
than the original aeroplane ; but its speed must be treble.

AEROPLANE CONSTRUCTION ie9

that is to say must reach the figure of 180 to 200 kilo-
metres per hour. Now the '* useful '' weight would reach
one ton« M. Soreau has arrived at analogous results by
studying a ** group** of aeroplanes of the monoplane type
constructed by Esnanlt-Pelteria

But, when our ''artificial birds'* will have realised
such speeds, when ihey will have to carry such weights,
it will no longer be possible to be contented with this
construction of slender firame-work, a marvel of lightness,
certainly, but not sufficiently solid ; it will be neceasary
to make all its component parts very strong, and to
enable them to resist even the greatest strains to which
they may be submitted. Let us cite here M. Soreau's
important conclusions; ''aeroplanes of large carrying
capacity will have to be very stoutly built, not much
larger than the pres^it, at least for the next few years to
come, but their speed will have to be double or treble that
in vogue to-day. Now, for these new machines we shall
be forced to employ other materials ; it will be necessary
in particular to attend to the reduction of their resist-
ance to advance ; in short, it will not be sufficient to be
content with constructing aeroplanes based strictly upon
the present apparatus. These new apparatuses, so soon
acf they are perfected and have received the sovereign
sanction of experience, will thus become the first aero-
planes of a new fiEunily, and so on."

Aviation apparatus will therefore be perfected by
evdiution, which is the case in nearly all the great
developments realised in physical science or applied
mechanics.

What must be remembered in these conclusions of one
of the cleverest aeromechanics of to-day is that before

170 THE COVQDEST OF 1HK AMM.

loog« eweu rerj dxtlfy, we AaSSi mit umfu^ obot mamd
200 kilometres per boor. Thm k ^woll te* tDriikr
to my that "^ dittJUjce do hmget

WIND AND AEROPLAXE5

Wtiat we have said regai&i^ ttiie* acsaift af ik
wind upoD dirigiUea appfiea f|«ill1hr w«ill i&» arisai
apfmmttia; ''Wind doea not cxitft iar tiie mto^^
which niovea in tlie KUwkompktre; it ia as if tfcs
fiptiere were immovable ; the wind oaij taoM
of the aviator changing poaition m rela&M ndk tic
yroufid beneathJ'

We ahall conaeqoently have to rwiilfi the
valuea in aviation aa in aeronaaticiL If the
M{>eed of the aeroplane ia leaa than that of the wind, it
will only be able to approach the points of the spat
contained in the interior of a certain " afyroachaHc
un^li5 ; '' if itH independent speed equals that of the wind
it will l>e uble to approach any point to leeward of the
lino pcrponclicular to the direction of the wind at its
|H>hiliori of departure ; lastly, if its independent speed is
gt'Daior than that of the wind, it will be able to go any-
whnrn. In all cases, its speed is governed by that of
Miti winil to give its resulting movement. In an extreme
r.ann whoM it navigates exactly with '' wind behind,'' its
h|MM«l (if travelling, with regard to a fixed guiding-mark
(.iilinn on land, will be equal to the sum of the speeds of
tho wind and of the aeroplane. It will equal their
diirnrnnco if the aviator navigates against a '' head wind.'
Att to-day the speed of 78 kilometres per hour is reached,
it in NiHin that, at present^ an aeroplane may travel, in
iWiii, on an average 352 days out of 365 ; when a speed

AEROPLANE CONSTRUCTION ITl

of 150 per hour is reached, it will be possible *' to go out
every day."

I ina^t meet particularly upon this notion, as it is
often distorted or acquired in an incorrect manner.
Thus, if an aeroplane is going in an easterly direction

FlO. 62. Combiaed actJOD of wind uid propuUion gprada

in a south wind of 20 kilometres per hour at a speed of
60 kilometres per hour (Fig. 62) it will effectively navi-
gate with a speed of 60 kilometres per hour ; but the
" section of atmosphere " in which it will have effected
these 60 kilometres will be displaced towards the north,
by the effect of the southerly wind, by 20 kilometres ;
the aeroplane will then have followed an oblique trajec-
tory, represented by the diagonal of the parallelogram
constructed with the help of two speeds, its own inde-
pendent speed and that of the wind.

This conception may even be *' materialieed," so to
speak, in the following manner. Let us imagine an
enormous aerostat, formed of a perfectly impermeable
envelope, aud maintaining its equilibrium high in the
air (Fig. 63). We will suppose that this balloon has
dimensions sufiSciently large for an aeroplane to be able
to describe evolutions in its interior atmosphere. This

17a THE CONQUEST OK THE AIR

atmosphere will be forcibly sheltered from the actioo of Uie
outer wind, since it is enclosed in an air-proof env^<^ ;
the aeroplane will therefore mancenvre in still air, and wiD
go from A to B, but during the time it takes to aocotn-
pliah this journey, the whole balloon has been trsns-

Fio, e3. Wind aod tb* aeroplaae : kctu&l uid ceUUve routea rMpecttnlj'

ported by the exterior wind from (l) to (2); tba
aeroplane has therefore duly arrived at point B, hot
this point B has been transported without the aviator
being aware of the fact to B' ; so that he will bava
no longer below him the part of the terreBtiial sur&ce
which was below point B, but really that which ms
below point B'. Let us now remove in thought the
envelope which isolated the interior atmosphere of the
aerostat ; nothing is changed in the general conditiona,
but we can thus understand tiie true road of the
aeroplane, AB'.

AEROPLANE CONSTRUCTION 178

HEIGHT AT WHICH IT IS ADVISABLE TO
FLY : SAFETY

The height to which it is advisable to rise to practise
aviation is intimately connected with the conditions of
safety l«d down by the aviator.

At first sight it may be imagined that it is essential
to decrease the risks of accident by navigating very
closely to the ground, to sweep close to the earth like
swallows because, it is thought that " if one fall, one
will fall from a lesser height."

This reasoning is admissible for risks entirely " experi-
mental," when one is not quite sure of the stability of
the apparatus in which one is to ascend. But once this
apparatus has been tested, and once the efficiency of its
equilibrium has been ascertained, it is necessary then to
avoid too close a proximity to tbe ground, and to navi-
gate at a certain height, say, at about 1 00 metres.

As a matter of fact, let us consider what takes place
in tbe immediate neighbourhood of the ground (Fig. 64) ;
the moving molecules of the air, the horizontal dis-
placement of which constitute the wind, are forced,
when brought into immediate contact with tbe terrestrial
surface, to follow all its superficial variations and to be-
come deflected by its projections. The gaseous molecules,
approximate to tbe luidulations of the ground, will thus
follow at one time an ascending, and at another a descend-
ing path, and if their speed is of little consequence, that
is to say, if tbe prevailing wind is not very intense,
these inflections of the currents of air cause " ascending
winds" and "descending winds," as is illustrated in
Fig. 64.

ii:::

J&QK

IHITWIB

It* lir uia nittn lianriaamailjr \t^- itsh ^mi^p^.

uu«/\|>iAitft iTuinit;. uut; .« giiwih^; in time in. Lm^ diilihc ^

•mtifffaiiifflO iif i&t-aiir

nagmt

w^^.^ .*j:t ^•. ';■<: . *:.!* "w-oiijii zriirsLZ. It ripoi fill i.-^.. .rertAin

t.,//;. ;a^ or.<: m^ iT. tLe &^, a::<i a: a certain height, as is
:y>trf» .f. '/-if ftlct^ch, ihe siThtJdk Krf iiT become steady and
ft',yr t!. ?k \tnn7/juX;iA iriar^ner, beoig solely quickened by
»,J,//c;rfT ''ufi/iul;»Viry rrjovemei^ts ' so ingemously described
Sfy M. H^nf:i±n. C'>n?>equently it will only be at these
ol».ii'j'J«5ft that the aviator will be sure to find the normal
Kiors; of th'j atmosphere ; it will be at these heights that
\t^. will have to fly if he \*Tshes his aeroplane always to be
** III Um: happy medium " for which its various elements
wtrr^ tmlrAilathd : lastly, it is where, in the event of

AEROPLANE CONSTRUCTION 175

a breakdown to his motFor, he will be able to commence
the "gliding" upon the air, which, with a Bearing
flight, will carry htm harmlessly to the ground, whereas
he could not effect such if he were struck by a current
of ascending air which would capsize his aeroplane and
infallibly precipitate a faU. This descending glide will
be effected with the greater safety inasmuch as it
will commence higher above the ground, and also
because the aviator will be better able to select bis
landing-point.

Nevertheless, I believe that very great heights are
impossible to aviation : the too rarefied oxygen would
be insufficient for the combustion of the gaseous mix-
ture, the explosion of which constitutes the motive
power, and the supporting surface, as a result of resist-
ance to a thinner aii', would no longer be adequate
to ensure sustentation of the aeroplane, which would
become unstable. These objections do not exist with
average heights (from 100 to 300 metres) which are
easily accessible to an aert)plane ; at 100 metres altitude
the supporting power of the sails of an aeroplane is only
reduced, on account of the decreased density of the air,
by l>80th of its value at ground level.

This question of safety is closely connected with that
of landing, and the latter is, as may be easily understood,
of the greatest importance to the aviator undertaking
an aerial Journey. " It is not all skittles, I must get
out of this," said La Fontaine's fox ; it is not only
flying, one must regain the ground, and return to it
without breaking one's bones.

Now» calculation, and calculation based upon experi-
moital data, shows that for a given aeroplane, there is

m THE CONQUEST OF THE AIK

nodw pow neeenuy to obtain the
So ooQB ao a notifo powor oacooed*

ing tho mnunum is braopifc mfco Iwyy two ittulti
aiid, eonnqiMailf , two ^peadi ore poanhfe. Thoa^ifve
hftTO a motor the powar of whidi ar ge a e c la the minimiim
apead bj 4 par eent, the two apa a da wiB, one of theai,
be 16-lOOdia in exeiOB^ and the odiar 17-100th8 laaa thu
the goraming apead, a c c ot din g to the ineKnaticm of the
aaSk If the motiTe powar a »e e adi the mjnimnm pomr
hj 15 per cank^ the two poaaiHe apaada aie^ the one a
third in ezoaaa of the Beeeaaaiy qpeed, the other ooo-
qoartv ]aaa» according to whether the aaila are indined
mora or laaa bj the aetion of the elarating rodder.

Since it ia thoa poatibie^ bj maana o£ a aligfat exoM
of power, to have two yeda at diqioaal, it will be
poasiUe, aa the oiginear M. Soreaa remarked, to nae tbe
greater for the ''travelling apead" <^the awoplane, and the
lesser one for landing, which will thns be effected without
danger, for when the apparatus has approached close to
the ground, the fall caused • by the excessive inclination
of the sail will be appreciably deadened by the '' mattress
of air " interposed between the ground and the support-
ing surfaces. It is then, in coming into contact with
the ground, that the mechanical absorbers, on which the
wheels of the launching rolling-chassis are mounted,
become indispensable. The landing of heavy aeroplanes
undoubtedly will require elaborate precautions, and will
demand on the part of the aerial pilot extreme cleverness
and presence of mind.

How may accidents arise ? From two different causes
— the sudden stoppage of the motor, or the breakage of
one of the essential elements of the aeroplane. This last

AEROPLANE CONSTRUCTION 177

poBsibility can ecarcely be admitted, since, if the aero-
plane is well planned, carefully constructed with first-
class materials whose strength has been thoroughly deter-
mined by experiment, if, moreover, before each ascent
all parts of the apparatus are carefuUy examined, and
the mounting, connection, and assemblage have been
inspected in detail, when built, the unexpected
breakage of any essential part should riot develop. But,
you will say, there are the road accidents 1 No, not in
aviation; for on the "highway of the air" there are
neither shocks, bumpings, nor collisions to be feared, at
least not at present ; this road is wider than those which
traverse the earth in all directions, and there is not only
more room to pass others on one side, but it is also
possible to keep clear of them " above or below." More-
over, at pi-esent our aerial roads are not overcrowded.
Again, the governing speeds not varying very much, the
movements of the various controlling mechanisms will
not be subjected to much variation.

There remains failure of the motor ; but we have
pointed out, in speaking of explosion engines used in
aviation, that their continuous development will bring
about the desired reduction in weight. We shall,
therefore, very soon have motors at our disposal, the
weight of which will be sufficiently reduced for it to be
possible to place two weighing no more than, and each
of the power of, the single present machine ; that is to
say, each sufficient to sustain and to propel the aero-
plane. Under these conditions, together with a device
automatically setting the second motor in motion in the
event of sudden stoppage of the first, engine fiulure is
no longer to be feared.

17t TBOE OOSQjCJBST OP TUB JJK

dufjoram iypv IwhiMi ^wbon isub obbobb^ 'wdd bi
iMJBiraonSy if nrt ii'MipHi unb dngflc, «8r mbotwwoi^
owijDigto liie tnei^'ivladi wiiuM fnvefe njpijteik
fMHimgvw aad pfove dEoMHoMi te Ae

globe ** wliidi cfiba dMiger: w Hj e a Aie
onmitor The kig e gui& ce rflfap w Mg
prerant Che appantas wmmmBatdf Anderingp hft
the aTiiAor, pimied uder Ae plnHS aad *' flmgh d''
in Che eaib, imj eolf be dUe te free \ammiM tnm ib
ropae with difficaHy. ft wS Uiuwiau be «dl to
proWde eerapleiiee inteBded fiv bng jomneye urttk
q[i6Ctil flubly OMiltivmeBi^ n inew ef deeooot ipii
wftter.

^ Aioeideiito" imdoiibliedlj ^vOl faeppen. odoobtoiflr
there will be deriog pioiiean of die air who mantHmm
will pay with their lives their dashe to eoQie another
victory over the Uxces oi Natnre ; but have not all die
conquests of human genioB — navigation, raOways, the
motor-car, even cnrrent industry — beai made at the
cost of heavy sacrifices 1 And are not the *' acddeDts"
of daily life as fi>rmidable as those to be feared in the
new method of loccmiotion, which will^ however, be
attended with less mishap, because, having the repotar
tion of being more dangerous, it will be practised with
greater care ?

OTHER FORMS OF AVIATION : HELiCOFTERBS AND
ORNITHOPTERES

At the commencement of this study, we said there
vere three classes of apparatus '' heavier than air." We

AEROPLANE CONSTRUCTION 179

have inveatigated in detail those which so far have
given the most practical results — aeroplanes. It now
remains for ua to speak about the other two.

The first is k^icopth'es, that is to say, apparatuses
which sustain themselves in the air, not through the
vertical component of lur thrust upon a moving surface,
like kites, but by the direct sustentation ^ort of a
motor-driven screw, with horizontal blades revolving
about a vertical axi&

It was the h^licopt&re which first haunted the imagi-
nation of aviators. As &r back as 1852 Ponton d'Am^-
court and de la LandeUe, infused with the enthusiasm
of Nadar, the celebrated photographer, maintained by
Press campaigns, conferences, and publications, that the
future of the " heavier than air " machine would be by
meana of the screw — the " sacred screw," as it was called
by Ponton d'Am^court. Their scientific support was
Babinet, a membw of the Academy of Sciences, and
he it was who found the name of "h^icopt^re" for
baptizing the apparatus which he thought would realise
the definite conquest of the air.

What gave weight to the assertions of these tireless
apostles was the popular success of fiyiog toys, real
miniature h^licopt^es, which went up in the air with
the greatest ease, either through the effort of twisted
india-rubber, or when launched by uncoiling, a string,
and seemed to defy gravity and to open to all the
" highway of the air."

Intellects were fired ; controversies furious ; a study
was made of the manner in which the screws must he
arranged. To avoid the rotary movement . which one
single sorew imparted to the body of the apparatus.

leMW

fixned of • aDMll tttmm

9U9WM nww^nBg ID DfpiMlB oneboBB abptit tll6 I

borixontal UEUL ABdwhAeapCteoBnafind orplaimBd

hitherto oomprue the me of an ecat nnmber of Miein

of coDtrary pitch, reivolTiiig in c^posite direetians to one

Miother.

Experiments were made with h^lici^itbreB, and with
little miccefls; why is known to-day; the inot<Hs used
were too heavy, and the intimate diacnanon at the
problem, made scientifically hy mathematicians, dis-
onraged investigators from embarking cm these lines for
a long time, until Colonel Benard tackled the qneetaon,
wliinh, as usual, be enlightened in a new manner hj
publishing bis works on suttcUmng tcrewM.

Cr^lonel Renard, in a communication which he made
Ut the Academy of Sciences at the end of the year 1903,
f{iive the results of his long researches, carried out at
Ohalais-Meudon, on screws employed for lifting a certain

PLATE XXIII

-. r

AEROPLANE CONSTRUCTION 181

weight directly firom the ground — ^that is to say, with
'' sastaining lEtorews." Abeady he had previously de-
monstrated that aerial navigation by aeroplanes would
be possible the day when the weight of the motor
went down to 5 kilos per horse-power. Directly attack-
ing the case of the h^licopt^re, the learned colonel
showed that the maximnni weight which the screws of
this apparatus were able to lift increases inversely to
the sixth power of the weight per horse-power of the
motor employed. This result strongly encouraged h^li-
copt^re inventors, but we must reckon not with theoretical
^* limit " loads, which it would be impossible to exceed,
but with the real loads compatible with the resistance
itself of the screws. Under these conditions a really
transportable load limit is quickly obtained, and these
loads are lighter for the h^licopt^re than the aeroplane ;
hence the very legitimate enthusiasm which has been
manifested in this apparatus.

Colonel Renard, however, did not leave the question
of screws, and even indicated in 1904 sustaining screws
of 2*50 metres diameter, of perfect resistance, not liable
to distortion under the effect of thrust, although their
total weight was very small ; he obtained this result by
introducing a universal joint which permitted the screw-
shaft to assume the resultant direction of the various
efforts operating simultaneously upon it.

Amongst the various dispositions proposed for heU-
eoptkreSy there is one which has been realised under the
auspices of H.S.H. Prince Albert of Monaco, which was
conceived and constructed by Engineer L^ger, and
whereof Fig. 26 shows the principle. The two screws
of opposite pitch, turning in opposite directions, are

Fio. 65. Principle of the L%er
h^oopt^

THE CONQUEST OF THE AHl

mounted upon two concentric axes; this axis being
vertical, lifts the car itself; but, if the axis is inclined,
as shown in the figure, an oblique movement through
the atmosphere must be obtained.

A composite solution was jnoposed, one of which

Colonel Benard himselt
had thought ; it is an
apparatus which would
be hSliocaptire for lift-
ing itself off the ground,
and would become an
aeroplane once in the air.
Such a solution, if it were
ever realised, would be
that much sought for,
as the great disadvantage of aeroplanes is the'neoee-
sary space for ''launching/' So long as one remains
on level ground, or even so long as there are broad
roads, this is still feasible; but in wooded or moun-
tainous country a landed aeroplane will no longer be
able to re-start, whereas with screwj and vertical axis,
which would lift it " straight up," departure would be
easy, and once lifted up in the air, the apparatus would
have the advantages of an aeroplane. It is to be hoped
that serious investigations will be made in this direction;
they will constitute a great development and perhaps
even the future of aviation. The "gyroplane," of which
we speak later on, is the first step in this direction.

Omitfioptires, those apparatus vnth flapping wings,
seeking to imitate exactly the process of lifting and bus-
tentation which characterises the flight of birds, have
been less tested than helicopteres. The difl&culties found

AEROPLANE CONSTRUCTION 188

in their construction are so much greater, and the vibra-
tions and shocks to which their framework would be
subjected would not fail to tell on the joints. Despite
these difficulties, a Belgian aviating engineer, M.
Adh^mar de la Hault, has sought to realise an omithop-
tire, of which we give a few photographs ; the apparatus
was able, in the latest experiments, to rise slightly and
to leave the ground for a moment, but an accident to
one of its parts interrupted the trials, which will be
resumed later.

COMPOSITE SOLUTION : SOARING BALLOONS :
CAPAZZAS LENTICULAR

There remains another composite solution for us to
Bpeak about, consisting not in the combination of two
systems of aviation, but a balloon and a soaring arrange-
ment, a solution which recalls that of sailing-vessels
known as « auxiliary " engine vessels, often used in trade
Euid pleasure navigation.

Its inventor, M. Capazza, one of the French aeronauts
who has had the finest '' aerial " career (he was, in fact,
the first aeronaut to cross the Mediterranean in a balloon
Grom Marseilles to Corsica, which has not yet been re-
peated), conceived an immense aeroplane, but with its
sustaining plane lighter than air. For this purpose, M.
Capazza took a balloon, not of the ordinary spherical
or pisciform form, but having the flat shape of a pendu-
lum-bob. This is not symmetrical, however, as regards
its centre ; it is not a '' surface of revolution," its greater
thickness is brought to the bow, so that, cut in the
direction of its axis, its section is that of a fish (Fig. 68).
A longitudinal empennage forms, above and imder this

184 THE CONQUEST OF THE AIR

envelope, a kind of amall wing, a " keel " which oootri-
butas to stability, which will be still more increased hy

Stern, motcr

Fia. tIL Bids etavktion of the Capana tantlonlar bkllooa

an horizontal empennage at the stern. Besides, the whole
of the stem part of this pendulum-bob, thinned to its
back edge, constitutes a marvellous natural empennage.
The total capacity
of this bob is to be
15,000 cubic metres,
and will be rein-
forced internally by
metallic circles ; it
will carry a car in
which will work three
motors of 120 horse-power each, driving three screw-
propellers ; the weight of the car is carried below the
greater thickness of the balloon, i.e., well forward of the
centre of the hob, as is shown in the diagram. The in-
terior metallic circles distribute the load upon the whole
surface of the envelope.

Fio. ET. FroDt view of tbe lenticular balloou

AEROPLANE CONSTRUCTION 185

The apparatus, at first si^t, most therefiure work like a
dirigible; Imt, on acxxMmt <^ the flat and non-symmetrieal
shape of the mvelope, it will possess special fNroperties.
Let 08 imagine a movement of ascent or descent being
imparted to it ; the apparatos will immediately become

Circular metal stays

''central
shaH

Rudder

Elevating
rudder.

Fio. 6S. Plan of Captiia's lenticalAr balloon

lined, as the two areas, that of the bow and that of
the stem, will be unequally pressed by the air ; the back
area offers a greater resistance to ascent or descent than
the front If, for instance, the movement is an ascending
one, the back part will be depressed, the bow will rise
up, and the movement of vertical ascension will find
itself transformed into an oblique displacing movement
towards the bow. The screws add their propelling action
to what is thus obtained, and contribute, according to
the classic expression of artillerymen, to ^'extend the
tn^ectory." The direction of the balloon becomes the
more horizonal as its independent speed increases.

186 TEDB COMQUBST OF THE AIR

Let vm now wi|ip oBB that ai a grvan momflnt the total
w^;fat of the mfpeiataa^ envekq^ car, moton, pasBen-
gera, and eaigo^ finr aooM reaaon or another, escoeeda the
weight of air diaplaoeiij either heeaoae the lenticukr
baDocm in riaing haa gone heffond ita acuie of eqnilifannm
on aooonnt of ita aoqnired qieed, or beoanae phyaicalty
the inner gaa haa oontraeted, whidi the ballonnet wOl
have replaced with air : the balloon will immediatdj
tend to deagendy bat an inyene phenomenon will oocor.
The greater aoiftoe of the atem part wiU lift it, and the
balloon will become inclined; it will go down, bat
in gliding in an obliqne manner npon the moleculeB of
air in the manner of an aeroplane, will utiKae this da*
acending movement to progreaa horiaontally. Thia eftet
will be added to the apeed imparted by the acrewsi the
propelling force of which will thna be increaaed by auo-
cesaive aacenta and deacenta.

Such is this ingenioos apparatus, which ia so ori^al
in its conception» and which it would have been impos-
sible to let pass without saying a few words about it
It would be very interesting to see it realised, for,
independently of the services which it would render as
an airship, it might become a veritable experimental
laboratory for eveiything concerning aviation.

CHAPTER IV

DESCRIPTION OF SOME AEROPLANES

I. BIPLANES

French and American dcuon: The Voisin and Wright
aeroplanes: Comparison or their EFFiciENaEs and dis-
advantages

THE VOISIN AEROPLANES (FLOWN BY MESSRS.
FARMAN AND DELAGRANGE)

Ws will now describe^ somewhat more in detail, the various
types of aeroplanes, at all events, those which have accom-
plished brilliant performances, and consequently have
thereby demonstrated theactual existence of their efficiency.
And it is necessary, in all &imess, to begin with the admir-
able aeroplanes, swift and sure, built by the Voisin Brothers,
the eminent French constructors. Their name, as a matter
of fact, is inseparable from those of the audacious sports-
men who, in France and consequently in Europe, definitely
opened the highway through the air by their magnificent
achievements : I mean Messrs. Henri Farman and Leon
Delagrange. The details given in the preceding chapters
will enable the reader to appreciate and compare better
the different machines which we will now successively
describe.

The Voisin aeroplanes are of the "cellular" biplane
type, that is to say, between the two parallel supporting
surfaces which constitute the sails or planes properly so

187

18S THE CONCIUIST OF TBM AIR

ealled, ara Tertaoal wiQii foroMd of fiibm i^^
the croea iii«mbeni» daugmd to oppooo latenl domticD
and to maiiititiii aotonu^Mlly the oqmHbriiim ci tiia
aorcqplaiie in torning, Tho genmal amiigQiiient of thk
gyatem is shown in Fig. 80.

The design oomlnnes stre&g& and lig^toess. Uio
wings axe c^ india*rabber dieathiis^ stretdied xjcpoa i
diagonally-braced ashwood frame. The i^pread of ^
wings is 10*20 metres ; their d^th 2 metres ; and of tbi
" stays'* whioh yertically maintun the distance betwesl
the two supporting snrfiioeSi 1*50 m^tees. These sorfiMM
are slightly curved, the ccMieaTe &oe bdng presented
towards the earth. When the i{^paratus is in fli^t^ tiit
*' diord" of the arc formed by ^ profile of the wingi
makes an angle varying from 6 to 8 degrees with the
horison. Hie sur&ce of this flai&e ii about 40 squiis
metres.

The whole of the supporting surfaces, called the
" central cell," has a stabilisating apparatus or " empen-
nage," comprising a *^ rear box " following also the form
of a biplane, of less spread than the central cell ; 3 metree
only by the same depth of 2 metres, spaced 1 *50 metres
apart, and curved like those of the principal planes. This
rear cell is placed 4 metres behind the central cell : and
between its t^o surfaces is placed a plane moving about
a vertical axis which constitutes the steering rudder. The
superficies of this rear cell is thus 12 square metres,
which brings the total area of the planes to 52 square
metres. The "body" of the aeroplane is a wooden
framework with cut-water or wedge-shaped ends covered
with carefully stretched canvas. Its greatest width is
75 centimetres, length 4 metres. The seat of the aviator

•!]

BIPLANES

189

aced that the centre of gimTitj whiea he is seated
point which extends Tcrticallj 25 centimetres from
nt edge <^ the mtpportiDfr sar&oe ; in front of the

KMdacr

T.il

plan<es.

Fio. 69. The Voiflin aeroplane (H. Farman's type)

'e placed the wheel and the pedals controlling the
s.

body supports the elevating rudder composed of
irfaces projecting on either side of the prow and
^ upon a common horizontal axb. Their shape b

(

190 THE CONQUEST OF THE AIR

plane-conyex, the plane being always turned towards the
earth, the convex aide to the sky.

The engine is an eight-cylinder ** Antoinette " motor
developing 40-50 horse-power ; it weighs 80 kilogrammea
It is mounted upon the frameworiL in such a way that its
centre of gravity is a trifle forward of the rear edge d
the supporting surfaces.

The screw-propeller is double-bladed ; it is placed
astern of the central cell. It is built up of tubes of steel
covered with sheet aluminium. Its diameter is 2 metres ;
it is coupled direct, without any reducing gear, upon the
motor shaft, and runs at a speed of 1050 revolutions per
minute.

The whole is carried upon a rolling-chassis built of
tubular steel having four pneumatic-tyred bicycle wheels ;
those in fix)nt which directly support the central cell and
motor are of 50 centimetres diameter ; the rear only of 30
centimetres diameter. The total weight of the apparatus
together with the aviator is 530 kilogrammes.

Such is the simple and solid aeroplane with which
Henri Farraan has demonstrated the prowess of which
we spoke in relating the history of aviation. This aero-
plane has undergone some modifications; its pilot has
fitted a third surface above the first two, thus converting
it into a '* triplane " ; but the enthusiastic aviator seems
to have renounced this adjunct, and to have reverted
apparently to his original biplane. This machine attained
a speed of 70 kilometres per hour in the journey from
Ch&loDS to Rheims, covered at an average height of 40
metres (27^ kilometres in 20 minutes).

The Delagrange aeroplane (Fig. 70) vividly recalls the
Farman aeroplane in its broad lines, which is not surpri-

PLATK \MllA

*. »

BIPLANES 191

teeing that it came from the workshops of the ssme
QctoTB, save that thore are only 3 metres between
ntral cell and the rear stabtlisating oelL

Winjs

Kndder

"^Motor.

%,Z.

Fio. 70. The Voitlo Mroplane (Delagmige type)

nng given the details of the Farman aeroplane,
iagram sofficiently explains itself, but for which
or details of the Delagrange aeroplane may have
lecessary. Its total sarfiu» is 60 square metres,
t has attained with a SO-horse-power Ant<nnette

THE COXQl-EST OF THE AIH

wmd m. acx«w of S'lO BMHtrcs tisanaeier, & epefd i^
I per boar. Its totel we^i k 4^0 kikr
It was Jikeww 'opsi u aempliBk bitih by
T«iM aad drireo bj & 50-botae-pow c r A ntnipeit e outK
liMtlI.&pfel. one of tiie joqpgCBt F r mel i aTwb)n,vKiI
toBflrib tn l&OB, and carried ottt some vcayoselal i^
Ihb ax|MniDeota ; Uie higb rtaDdazd of tbft cngiiie u^
Ab wmfeteocy of Uie aviator were lugfaly ■{^vecuted
hf dw Berlin pablic, who fiv the fini tiiao witnesMi
tntim wilfli a heavier than aii ^jparatu.

THE WUGHT BBOTHEBS' aPLANB

We Wre Been a remarfa ble biplane aerofdue of
n«Mh flftnstrucdoD which f Els automatic stability, be
it loDg^dinal or lateral. 1 t os now give, with some
Artaflff. a deacrtptioQ of t famoas aeroplane irlucli
ereatod irideepread eDthiudasm daring the sonuiiar of
1908, and the prowess with which (we are apt to forget,
petiiapa a little too quickly, this attribute of the Freocb
aTiaton) would seem to open decidedly the "path
through the air." We will compare the Amencan
aeroplane with those which we have already described.

The aeroplane of the brothers Wilbur and Orville
Wright is, like the Yoisin aeroplanes, a biplane, with ao
elevating rudder in &ont and a steering rudder at tbe
stem. Its main feature is the absence of a fixed stabili-
sator. Tbe " foundation," that is to say the total length
of tbe syBtem longitudinally, is 9 metres. The two
surfaces of the biplane have a spread of 12'50 metres
each, by 2 metres breadth. The fabric of which they J
are made is stretched to the maximum upon tvo wooden
frames formed of two longitudinal members strength-

P««ll«...' ElevaiiniS plane

S&t.
(R-ont elevaiion.)

3 =i'"»'>»8

'^ -udder.

Jf.2««»<Mnfa»

IM THE CONQUEST OF THE AIR

ened by a serieB of transvene pieoe& Each of the latter
is doubloi and formed of two incurved laths, which are
kept taut by wedges at the stenL This hi^tter, vetj
fine, very thin, extends to the rear part of the wingB
a certain elasticityi a sufficient suppleness, to fiudlitate
the " warping/' by which means the celebrated Ameiicaii
aviator secures the lateral stttbility of his aerial vehida
Steel wire stretched diagonally ensures the indefonn-
ability of the wings. The &bric is riveted to the fitmt
edge of the plane members ; at the back, to secure ths
finest possible finish, they are sewn together. The two
planes are 1*80 metres (6 feet) apart, and this spaeiii^
is secured by vertical bracings, some of which are rigid
and others articulated. Those of the centre, by meani
of diagonal supports, constitute indeformable paraUelo-
piped^, in such a way that those of the extremitieB,
fixed to the wings by screw rings, are able through the
articulation to submit to warping which will deform the
extremity slightly.

The planes rest upon two skids which form a kind of
sleigh, because — ^it may be necessary to point out at
once — the apparatus of the brothers Wright is not sd/-
starting: there is no rolling-chassis to give it the
impetus to rise.

This latter is artificial, and requires an extraneous
force. These skates act as the part of the apparatus
which is brought into contact with the earth in landing ;
furthermore, they are curved, like those of sleighs which
travel upon the ice.

The skids form also the ''foundation" of the aero-
plane ; at the front they carry the elevating rudder, and
at the stern the steering rudder. The Brothers Wright

BIPLANES 195

have adopted an elevating rudder very similar to that
laid out by Colonel Renard, which he used for the first
time on La France in 1885. They have set it in such a
manner that its concavity may be varied as desired by
the pilot in synchrony with the movements which he
may have to give to the aeroplane. The inclination of
this rudder is controlled by a lever which the pilot holds
in his left hand.

The steering rudder, comprising two vertical planes,
is fitted at the stem. As the principal biplane is not
divided into compartments, and there is no cellular
stabilisator, the action of the rudder would be futile,
and turning impossible, if the inventors had not dis-
posed, between the two surfaces of the elevating rudder,
two small vertical planes which help to support the
whole system when turning, and to enable the rudder to
move efficiently to turn the aeroplana The two planes
of which the rudder is composed are 1*80 metres high,
60 centimetres in breadth, and are spaced 50 centimetres
apart. The rudder is operated by a second lever, having
double articulation in this case, held in the right hand
of the aviator.

Thus, the pilot seated on the edge of the under fi:ame
(the Wright aeroplane has no ^' body "), his feet upon an
open foot-rest, as is plainly shown in the photograph
(Plate XXIY.), holds a lever in each hand ; with the left
hand he inclines as desired the elevating rudder to cause
hb apparatus to ascend or to descend : with the right hand
according to whether he pushes the lever backwards
or forwards he can make his machine turn to the
right or left. But, in addition, he can give this,
lever an independent sideways movementi whereby

19« THE CONQUEST OF THE AIR

he warpB the wings at will. We will see by what

means.

Fig. 72 shows in detail the whole mechanism for
warping the wings, when be moves the lever L' on the
left-hand side of bis seat A. In the case of the diagram
we suppose that the lever L was pushed towards the
left a& shown by the curved arrow. Instantly the
square bent-end m, which answers this movement, is
turned also to the left and pulls in the direction of the
arrows the controlling wii'es which are on its right : it
thus depresses the right-hand rear comer of the upper
supporting surface. This pomer in depressing also
pushes downwards the rear right-hand corner of the
lower plane by means of a rigid and articulated member,
which maintains the distance between the two planes.
This right-hand rear comer in depression pulls the
cord, which is on its left, in the direction indicated by
the arrows, and through intermediate pulleys raises the
rear left-hand corner of the lower supporting surface;
the latter in this operation raises by means of the
spacing member between the planes the left-hand corner
of the upper plane, and so is obtained the warping
which will cause the aeroplane to turn to the left. In
pushing the lever L' towards the right, the warping
action is reversed and tends to incline the aeroplane
towards the right. The same lever L' controlling aJao
the steering rudder by its movement to and fro, com-
pensates through the play of the latter the irregular
rotations which might produce warping. The total de-
pression of the extremities of the wings by the warpiug
action Is about 1 foot (30 centimetres).

A cursory glance at these two levers the aviator holfis

BIPLANES 197

« what prodigious sangjinoid^ what
9 must have: a fiJse movement, a
ion in this aeroplane, having no

Angle lever
J^ connecHon

Comer
lo¥fered

^ Comer elevsJed.

mrticiilation

Steering
rudder.

'Rudder
\ Gonnecttt^ rod.

v«^lM

Stewn6 rudder
^v / coftrol.

JLU

Fio. 72. Details of the wing warping action in the Wright aerojilane

body/' no forward cells or empennage, would bring
K>at most terrible accidents. We had a striking
[ample of this on May 6, 1909, in the alarming mishap
hich just failed to cut short the life of the Italian
ieutenant Caldera, one of Wilbur Wright's pupils, who
as thrown to the ground by his unmanageable appa-

IM THE CONQUEST OF THE AIIL

ratos capsiring. Also one can inoontrovertibly stata
that undoubtedly it is ¥^bur Wright himself who ocm-
■titutes by his presence at the helm the greatest part of
the yalue of his aeroplane.

Let us turn to the mechanical installation. Tbt
engine is a 4-cylinder petrol motor developing 25 hone-
power. It runs at a speed of 1400 revolutions per
minute and its weight is from 95 to 100 kilogrammia
Set a Uttle to tiie right of the Aviator its weight
balances the former irfien in his seat, which is on tbe
left.

Propulsion is obtained by means of two screws of the
same pitch and of the same diameter ; they are wooden
and their diameter is 2*60 metres. Owing to a oos-
venient reducing gear they run in oppodte diredaoDi;
making 400 revolutions per minute; chains transmit
the power from the motor to the propeller shafta We
have pointed out the danger of such an arrangement afi
thiA) which in the case of one of the screws breaking,
leaves the other revolving, and submits the aeroplane
to an eccentric movement causing it to capsize. Wilbur
Wright, since the accident which befell his brother
and in which the American Lieutenant SeLfiridge was
killed, has, it appears, happily modified this dangerous
s\^tem«

In order to start the Wright aeroplane a rail and
pjfion are necessary. The rail upon which runs a ^olle^
carriage supporting the aeroplane is 70 feet (21 metres)
long ; it is laid on the ground and fiices the wind The
rail b connected with the ** pylon,'' a kind of pyramid
framework, to the top of which is hoisted a weight of
800 kikgrammee held in position by a trigger. In

BIPLANES 199

{ailing this weight releases a cord, which through an
arrangement of pulleys hauls the aeroplane along the
rail with increasing speed, since the velocity of a falling
body is proportionate to the extent of its drop, which
explains the uniformly accelerated movement.

This means of launching is ingenious, but it deprives
the American system of much of its practical value,
relegating it chiefly to the category of appliances for
research and experiments. It is an ingenious, an excel-
lent, demonstration apparatus for mechanical investiga-
tion, but so long as the Brothers Wright refuse to make
avail of this launching " rail," so long as they do not
openly accept the conditions that prevail among all
French aeroplanes, that is to say, start unaided and by
their own means, they will hold an inferior position, and
their machines will lack the features of ** practical "
utility. It is said that why they do not do so is
because they do not wish it; such is to be regretted.
It is true that twice they set out without the aid of
the £sJling weights, but they were " sped " along their
rail by men who could push the aeroplane rapidly. And
then, it is not so much the weight, it is the rail, because
it decreases to an enormous extent the friction at the
start We see this every day in the goods stations;
along rails a horse draws a heavily laden waggon,
whereas upon the road the same animal could not even
pidl the waggon empty.

The Wright apparatus moreover is rather dangerous
because stabilisation, as much when travelling directly
ahead as when turning, must always be secured by the
aid of the aviator, whereas in aeroplanes of French
construction, especially in the excellent monoplanes, it

aiM> TMBL COWSaSlES^ QV TTEEK AUK

ia only UUkSTfii ^aibiiit;]^ witii which the a^iflCar '»
(semeii) longitudmal ^aifailiiz^ being eamncsfiL by moHB rf
the - emparmnKa • ^1« (»a ana axpiaia tia cfii^
Chat die ijnericui a^vdatac hw axpffiisiaBd bt izimif
hie papila ? Hi* haft tawj^ nrnft hnw tn mampnktt kii
''^ hird " It ie true ;; but this- uuteoixtiim warn cnimiiHnMwi
a4> nhe AarM^oura camp ducmg the mmitn of AngaBC 19M,
tasf^ (Hjer seven manthA, and. it wna nan ontil l£»eh 18,
Iid01>r d^£^ tihe 4E^nr»wnmui a^ittibir £br the Ixcst tmtt (kni
to perniit hie pupile tie maoagsar their appacalms thea*
sei^ea ;. ftod e^nsa the mfflatamoy wiidi which: cfe b a*
aoonesfi that the po^pile hrnrn^ aik hu^ fficpwiL '^akae'
Acyoid aiadBee ta Aow the ^ffiienilgr of the tariL Oaths
eMrtnoj the Fffaocbi aaiap&iaaa ace- aa^ sbahlie^ tiiat taut-
qnentlj four oc fiiRir [ijimiiihh wiffimfr to randor aa aiiittf
Qa|>at>le of opera(aa^ tlboa with aai&tjr ffiarikBiwa withtia
Antcin^te aeroplaibe ftr iaotHaea).

Ne^erthefeaa the Brothers Wr^ht are enfeitled to
'y^^r^^ii/^lftrarxe praise- They have perfi^cted oce important
fpffiht in avuit'ori, that of Iat«ai equEibrixim by the
if#ir^;r.io'iA ?tr'>^'iti':L. of the warping of the wings, and they
h;kv^« ;{iverj a striking example of perseTerance, for they
htjiit ^;very pcirt themselves, including their motor.
Moreover, by their enthnsiasm they have shown the
true fj^th which must be followed by aspiring aviators;
f,}ifiy HfiT^e^l their " flying apprenticeship ' in practising,
fil f}tHt, fttraight flight, by numerous " glides " carried
ofit with aeroplanes without a motor. Thanks to these
i(hflnH they were able to discover, one by one, the neces-
Hfiry firrangements to obtain the best sustentation, the
minimum resistance.

Hut, after all, in this they were preceded in America

BIPLANES 201

by Chanute, io Germany by Otto Lilienthal. In France
Louis Bl^riot found a brilliant solution which gives the
lateral equilibrium as surely as warping of the wings —
the use of '* ailerons " or ** winglets."

To sum up, the Wright aeroplane, owing to its
simplification of the arrangements, has been able to
accompUsh some magnificent '' records " in height and
speed. Through not having to carry with him some 60
or 80 kilogrammes more weight, represented by the run-
ning-chassis of the French aeroplanes, freed from the great
effort necessary to start, and consequently the increased
weight of the motor, he has been able to use an ordinary
automobile engine, possessing greater reliability, and as
a result better able to secure the records for altitude
and duration. But he has not yet carried out a single
real ** voyage " because handicapped by the necessity of
his launching rail he is compelled to return to his pylon to
re-start ; if he comes to earth en route he cannot rise again.

This is where Bl^riot triumphs, for on October 31,
1908, he accomplished the first aerial voyage in what
may be described as a closed circle from Toury to
Artenay and back, descending twice during the journey
and re-starting under his ovm power ^ passing over roads,
villages, and wooda Such is an ''aerial tour" in the
fullest sense of the word, and that date, October 31,
1908, constitutes in our opinion the historical date in
iwicUion.

MAURICE FARMAN'S AEROPLANE: THE BREGUET
BIPLANE

M. Maurice Farman, the brother of the celebrated
^'ehampion of the air," had an aeroplane built at the

90S THE CONQUEST OF THE AIR

llallet workshoiNi which was ezhibitod at the Aero-
naatioal Salon in Deoember 1908.

This apparatus^ yery well oonoeivad, is a ** hiphoa"
Like the Wright appaiatna^ it admits of waiping oftiie
wings ; bat meanwhile by means of a sfaliilMlin||i tul,
it possesses the automatic longitiidiiial stabOhj qf tis
French apparatus (Fig. 78).

The two similar, and superimposed sumw r tiu g phooi
spaced Tertusally 1*50 mefcies ^fmr^ aie redk/Stj
strengthened by 8 pairs of ashwood ttpaJjghls L Those
supporting planes haye a qsreadof lOmsAna by S
breadth. Their individual supecficieB
20 square metres, and the aggregate
40 square metres.

These planes are buih up of ]i|^ and ngti. stajs
upon^whicfa is stretched, on both sides^ a vamisbed
cotton fiibric weighing only 85 grammes per square
metre.

The '' wings '^ are mounted upon a spindle-shaped
" body " of rectangular section, in which are placed
respectively the pilot's seat, the motor, and the man-
ieuvring and steering controls. The motor and screw
are placed behind the aviator; the wheel controUiiig
the elevating and steering rudders as well as the lever
jl>r uxifrpirig the ¥ring8 are set in firont of him.

The '' stabilisatiQg tail " is a '* rear cell " connected to
the planes forming the '* front cell'' by four long meoh
bers cross-braced and stiffened by tightly stretdied sted
wire. The rear cell has a spread of 3 metres, by 2 metres
breadth, which in view of the foct that it is composed of
two planes spaced 1 *50 metres apart, gives a total sur-
of 12 square metres. The curvature of these two

PLATE XXV

BIPLANES

208

£levatin| planes.

/'Skeering wheel.
Aviators seat.

Upper
plane

Ruddcf-l^"

Upper
plane

'Rear
cellular box

surfaces is calculated in such a way that they are slightly
** supporters " as well as being stabilisators.

The elevating rudder is at the front. It is a unique
type, comprising a plane of 4*90 metres spread, by 90
centimetres wide. It
is divided into two
panels, on either side,
at the extremity of
the body of the
machine. With re-
gard to the steering
rudder this is formed
of a vertical plane,
moving between the
two horizontal sur-
faces of the rear cell.

The engine has
been specially de-
signed for aeronau-
tical purposes by
Renault Brothers,
the well-known
motor-car manu&c-

turers. This motor Fio. 73. Maurice Farman'8 aeroplane

comprises 8 cylinders in two series of four, working upon
a common shaft : the cylinders, in pairs, are arranged
in the form of a V, the shaft being at the apex of the
angle. The cylinders are air-cooled. All complete, the
motor weighs 178 kilogrammes, and has developed, under
dynamometer tests, 58 horse-power, which gives a weight
of 3 * 1 00 kilogrammes per horse-po w^r. A special reducing
gear driven from the motor shaft reduces the engine

£levatizi^
/ plane*

fl04 THE CONQUEST OF THE AIR

speed from 1600 reyolutiioDS to 800 revolutions per
minute at the serew prc^Mller.

The screw is of wood* It was built by IL GhauvikOi
who designed the remarkable propeller of the jBayartt-
CUment. It is of the type whioh its diatingniBhad
designer calls ** integral screw,'' measures 2*50 metm
in diameter, with a pitch of 2*50 metres. It is placed
immediately astern of the two carrying surfiioes, the
exterior edge of which is slightly indented to aflford firae
passage for the revolution of the two blades.

The whole apparatus is carried upon a runninff-dkoim
which serves for launching and landing. It is foiu>-
wheeled, the two under the front cell being of 70 centi-
metres diameter each, and the two under the rear osDi
little smaller. As the figure shows, the articulated fixb
upon which these wheels are mounted are fitted inth
absorption springs to allow descent without injury to
the aeroplane.

Fitted with the Renault motor and carrying the
aviator weighing 80 kilogrammes, the apparatus has a
total weight of 528 kilogrammes. At Buc it made
some very successful attempts at flight which served to
demonstrate the actual possibilities of the machina

It will be remarked that the cells are not divided
into compartments. The body of the aeroplane is the
only surface opposed to lateral drift and giving a fulcrum
for turning. M. Maurice Farman, however, will box his
front cell should practice demonstrate the advisability of
such an arrangement.

In closing this description of biplane aeroplanes we
will mention the apparatus which M« Louis Breguet,
the eminent mechanician and one of the inventors of

BIPLANES 205

the Breguet-Richet " gyroplane," of which we will speak
later, built and exhibited at the Olympia Show in
London.

Breaking away from the general lines followed by the
Parisian designers, M. Breguet built his machine entirely
of thin tubular steel of large diameter. The supporting
wings have 12 metres spread, and are furnished with a
special differential warping evolved by the inventor.
This warping assists the wmgs in turning, and can also
aerve for lateral balancing as well as acting as an ele-
vating rudder.

The motor built by the automobile house of Gobron-
Brilli^ is of 60 horse-power. It drives a two-bladed
screw 2*50 metres in diameter, the total weight of which
is only 6 kilogrammes, and which in starting gives a
propulsive effort of 250 kilogrammes. It will be able
to attain a speed of 90 kilometres per hour.

An outstanding feature of this apparatus is the possi-
bility oi folding the wings by the most simple mechanism.
In this manner the bulk of the aeroplane, when it is not
in aerial service, is no more than that of a vehicle having
the same wheel-base as the supporting wheels of the
aeroplane. The whole is carried upon a three-wheeled
running chassis fitted with springs.

This notable aeroplane is calculated to lift two pas-
sengers and a ^'useful weight" in the form of fuel and
oil to the extent of 80 kilogrammes. It is therefore an
apparatus possessing real features of practical utility.

mscsiPiHni €» Bomm AntoriMANSs

hmsa a ^riudi ttil

Iwd it oaitiitedl 1^ €i^
iodattd fif tipo^ M ii
The MffinJinr €f
fiuDOUs; ifc k an hiihiriMl ■iwipliiiOji aaoa even At

Vjn gllA natioii denrad that it should be proeot ved at tbe

South KeDsingtoQ Museam. In fiu^ it has enaUed tiie
iUnstrioas aviator to aooomplish Uiat doaUe feat (the
glory of which no one can even attempt to rob him) ; in
the first place he completed the first *' aerial journey " in a
closed circle with intermediate descents^and subsequent^,
on July 25, 1909, he accomplished that performance which
created admiration throughout the whole world ; achieT-
ing in a single flight the passage of the Channel between
Calais and Dover. Moreover, Louis Bl^riot is entitled to
a dual distinction ; not only did he evolve his aeroplane,
but he constructed and experimented with it himself;
all the arrangements are his ovm work, and we wiU show
how ingenious, simple, and effective they are.

206

MONOPLANES 207

The Bl^riot aeroplane in its general lines recalls a huge
bird (Fig. 74). The supporting surface, set out in a single
plane, is divided into two wings, one on either side, and it
is between these that the aviator takes his seat. The
wings have at their tips small movable " ailerons," iving-
letSy which serve to right the machine when it dips. The
spread, body and small wings included, is only 9 metres,
and the supporting sur&ce has a total superficies of 26
square metres, the rear comers of the wings being
slightly rounded.

The wings are made of stiff parchment, and they are
mounted upon a framework built of mahogany and
poplar. The shape of the wings varies as they extend
firom the body, but they always present a concave surface
turned towards the earth. The planes cut the air at an
angle of 8 degrees. At their outer extremities are the
Btabilisating " ailerons " turning upon an horizontal axis,
and their movement is controlled by the aviator by
means of a device which we will describe presently.

The wing frames are connected to the aeroplane '' body."
The latter comprises a long spindle forming a *' strength-
ened beam" with the front section rectangular, and
triangular at the stem. The longitudinal members are
cross-braced by ashwood struts, the whole being further
strengthened by tightly stretched steel wire. The lattice
structure thus obtained is of extraordinary lightness and
solidity.

At the stem of this slender body is placed the
stabilisating ^^ empennage." This is rigid, and the
length of the leverage at the end of which it works is a
guarantee of its efficiency. The elevating governor is
similarly carried at the rear extremity of the body. It

SOS THE CONQUEST OF THE AIR

may be pointed cmt tliat^ in additioii to ikoB pcineipl
elevating rudder, the ayiator ean use mlso the tvo
''aiJerona" attached to the ertremitieB of the twowiiigii
turned one upwards Uie other downwards, they reBtol
the apparatus in case of lateral inclination ; moved boA
in the same directicm they give ascent or descent aal
act in the same manner as the elevating roddet
Accordingly one in ascending or descending in a stnig^
line can operate these two mechanisms in such a manner
that their actions are combined.

Lastly at the extreme rear end of die body is tin
steering rudder^ a rigid plane turning aboot a vartieil
axis. The pilot takes his seat in a space provided a ;
the body between the two wings, having in front of his
the novel lever by means of which the whole of tb
various movements of control are actuated.

This unique manoBuvring device of the Bl^ot sao-
plane is one of rare ingenuity and simplicity. It is a
lever and drum which we will now describe in detail

No one will deny the importance of maintaining surely
and easily the direction of an aviating apparatus. The
exti-eme mobility of the aeroplane in the atmosphere
demands that the apparatus should absolutely answer
to its controlling mechanism, because therein depends
not only the regulai*ity of the aerial route followed, but
also the security, even the life, of the aviator.

We have seen, d propos of the Wright aeroplane, the
inconvenience of a multiple lever system, which is so
complicated and the management of which requires such
prolonged practice, for each lever movement performs a
definite operation.

M. Bl^riot thought that directly the aeroplane beocxnes

MONOPLANES 209

a moving plane in space the moet simple device for main-
taining a direct line would be one where a centrally
placed connecting-rod, answering a decided action by
the aeronaut would be that in which the actuation
of one plane was communicated to the other, so

Fio. 71. L. BIMot's monoplane

that they moved together. This is the only example
yet perfected for controlling the one moving plane by
another.

The principle of this system is shown in Fig. 74.
dose examination will sufSce to show that the aero-
plane corrects by itself any deviation from stability,
while travelling in a straight line, whatever inclination
the apparatus may assutne, irrespective of the number
and position of the rudders, provided that the latter be
correctly connected to the controlling plane. Thus is
effected in one action, and to any desired extent, the

210 THE CONQUEST OF THE AIR

stability of the aerial yaaMl, and all without dqiri^
the aviator of the oontrol of his appaxatns or compeDiDg
him to maintain that much-desired automatic stabOify
ipidiich, despite some attendant advantages^ is not free
from many dangers.

With the lever and drum command^ thb base of this
barrel acting as the indicator, and taming in any deaiied
direction, control is absolutely ''instinctive,'' and the
aviator cannot possibly make a mistake. Moreover, in
combining this control with a level such as one uses in
photography, the pilot can discern immediate^ wbidi
way he must move his lever to correct the aeroplane and
thus preserve absolutely perfect stability while travelling.

Control is eflfeoted by means of a drum connected with
a control lever with ball-and-socket couplings and ocm-
sequently able to move in all directions. The dram
and lever are thus connected together. At the base of
the drum are attached all the flexible steel wires which
actiiate the different mechanisms for *' governing" the
direction of the aeroplane. There are connected to the
manoeuvring arm two levers for the simultaneous con-
trol of the motor, which must, indeed, work in concert
with the movements of the elevating rudder for fear of
terrible accidents, such as loss of speed in ascending, or
excessive speed in the descent

The motor is of 50 horse-power, of the Antoinette, 16-
cylinder type, with forced petrol feed. The radiator is
carried in the tapered body of the vessel. The motor
drives a four-bladed metal screw mounted on a lay
shaft, has a diameter of 2'10 metres, and 1'40 metres
'* pitch." This screw is mounted at the front of the
body ; therefore it " draws " the aeroplane.

MONOPLANES 211

The whole apparatus rests upon a running chassis for
unching, and to ensure descent without shock. This
is has two bicycle wheels placed under the front of
e tapered body. A third auxiliary wheel near the
^^^m secures balance of the apparatus when it rests

Tdiperini body

Fio. 75. The rolling chMsiB of the BU*iiot aeroplane

vpon the ground. The chassis is built up of a rigid

^ro88-braced framework of wood and tubes of steel.

This frame carries the body of the aeroplane (Fig. 75),

^which reposes in quite a springy manner upon a pair of

coupled parallel wheels turning about vertical axes.

The connection between the chassis proper and each of

the two wheels is by means of a collapsible triangle,

the apex of which is at the centre of the wheel, a

trifle below the principal leg, and in which the third

slides in a vertical tube, and bearing in its movement

against the head of a spring fixed to the chassis. By

this arrangement the whole, although not weighing

more than 35 kilogrammes, can absorb at landing a

blow of several hundred kilogrammes. Fig. 75 shows

the side elevation of the tapered carriage with the

wheeled frame under the front, and also the rear wheel

VSt S CONQUEST OK THE AM

tibmiHrgiTvn the ucotuW outiizus g£ rK^ iTi»fti% 1
I wm\\itn u kaamKtM£lenotIJ[., let nsiw coddiif 1
aaiNBg. thabtha totuL lunj^ iron end ze od • Q
mln^- Tfcaw pi w te spread lb 9 matecs;

wvppin* >'^ I'tittL UfO kilo^unmea : and its initial speei

)L Umu& ISfimt hMfrboilt i^l slightly dijferent aero-
[titutttv 'itt)^ '^.. ift vifaiok tfa* annJl wings ((M2ennu)
i>t' th» HttppurtiiifC sMfAfieBr aKftaiHoidbiiad. in fitvonr (^
sim^*- Nwxpuuj;, 'th» aikroofr acet rsfcumd aft felie tm

ini( mddtt-. TEw Jaxaaeeigmm: of t&ift^HvaiBiiph^an
inufh IcBB ctuui its ^nBBMMBm^. un|f : IhHrfl^ 6

reduued to 11 s^iiMn ib^i»; an||^ af «i«tia|( dip,

PttltMrie ^E.£LP.>. CToiiiHrtibaHiBudikinBftke support-
. M dbrt of 27 kilo-

PLATE XXVlA

Mw^ate

MONOPLANES SIS

grammes per Bquare metre, but such is the perfection of
construction that this end is successfully achieved,
the speed of the apparatus attaining 80 kilometres per
hour.

It was by slightly modifying this aeroplane that
Monsieur L. BIAriot
built the admirable
apparatus which en-
abled him to cross
the Channel in
twenty - seven mi-
nutes on July 25,
1909. The following
is the detailed de-
scription of this
historical monoplane
(Fig. 75b).

The ailerons are
suppressed in the
carrying planes, and
are replaced by a
slight warping of
the wings. These
ailerons are con-
fined to the rear on

OF dov£:r

Sangatte Baiti^i^

FiO. 7So. Map of B1Mot'i:ChuiDe1 flight

each side of the horizontal empennage ; they thus
constitute an elevating rudder.

The wings have a spread of 8 metres ; their
length in the direction of travel is 1'80 metres
(exactly 6 feet); total length is 7-20 metres (24
feet). The superficies of the supporting surface is
14 square metres. The inclination of the cutting

»M

tl4 THB OOlKQgaXgr OP

adge (aog^ of sttMky im 7 Aigitiai TW wenm m tk
mio prow*

The molor, haStk hj €hm
Me; ttdevokpiSO

Under thceo ffotj di t M i ie tibd MmMttiiiiri
a wdght of 27 kflognrnmes pw aq[iiam

THB BSNAULT*FBLTBBIB AIBOPLAIIB

We have ^already pointed oiifc tiie tendenef anoBg
aviAtors to redaoe the fmpet&ckl aiea of the s Mppo t ia g
•ar&ees, to avdd inoreaeing' their ranrtaaee, wUA
niiiet balanee the mora and greater aLrwwje THkm
tendenoy we eee manifteted a eeoond time in net
of the moat remarkable aeropianea among ihw
whioh have yet berai bnilt, that of IL Bobert EaDub*
Pelteriei whioh ita inventor^ bo iro w U ig the tiuei
initials of hia name, deaoribea nnder the abfarenatin
" RE.P."

Among the already important group of French aviators
M. Esnault-Pelterie occupies quite a distinct positian.
Though very young, he set out on the " path through
the air ''as far back as 1903, when the rumour of the
exploits, mysteriously held in secret, of the Brothers
Wright roused ambitions in him which led to success-
became resolved into persevering, continued, and rational
experiments. The young aviator (who at the time of his
appearance felt himself to be, nevertheless, one of the
oldest) sought nothing from anybody. He himself, bj
his own means, conceived, constructed, and tested his
aeroplane, which he knew to be a marvel of construction
at the time from the point of view of appearance and
solidity. And, moreover, being a practical mechaniciaD,

MONOPLANES 215

he created and made every part of a new type of explo-
sion motor, absolutely novel because of its compactness,
exceptional lightness, and at. the same time reliability of
action. So in the aviating apparatus that he fashioned
and brought to success everjrthing bears the imprint of
his personality — the general lines, construction, motor,
and even the arrangement of the running launching
chassis.

The Esnault-Pelterie aeroplane is a monoplane, dis-
tinguished by its flexible warping wings, and stem
supporting surface fulfilling the function of the ele-
vating rudder. It is fitted with a stabilisating em-
pennage, and its rolling chassis is mounted upon two
wheels "in tandem,'' which support its weight, the
tips of each wing carrying a wheel for contact with
the ground.

The shape of the body of the aeroplane is fusiform. It
is built up of steel tubes (bicycle tubes), autogenously
welded together ; moreover, they form a triangular net-
work similar to strengthened trelliework, which assures
complete indeformability of the system, as well as rigidity
and strength.

The wings have a total spread of 9*60 metres, and
their design is in accordance with the results of lengthy
experiments carried out by the inventor. Their surface
is 15 '7 5 square metres ; as they support the whole weight
of the apparatus, which aggregateis 420 kilogrammes, this
represents a proportion of 26*600 kilogrammes per square
metre, the same, be it noted, as in the new aeroplane,
Bleriot XL The wings are of wood, flexible, strong, and
light. They are made in slips, strengthened lengthwise
by steel and aluminium. Over these wings is stretched

816 THE CONQUEST OF THE AIR

the &faric, wliioh is the sni&oe o ffi ged to the renstant
aetionoftheair. Each of theee iringi is stratdied onder-
neath by two aeta of rapes coiiTargiiig to a point beoeath
tiie ohaana, and fay whieh the waxpin^ ia aoocmiplishei
Eachof theaeaetaof rapea aap p o gi a a.fiwirthaf thewei^t
of tiie apparatus. They ai9 plainly ahown in the photo-
graph, Plate XXYIL

Viewed from abovOi the Eanaolt-Pelterie aeroplane
strikingly resembles a Inid, with itsfim-dbaped tail formed
by the spreading of its feathers. The snrfiuse thus shown
(Hg. 76) has a variable indinatkm at its raar end, thereby
forming the elevating rudder, under which is placed the
welt-balanced steering rudder, turning about its vertical
axis ; it is what is: called in marine praotioe a " compen-
sated ** nidder, because the axis of rotation paaaes throng
its centre instead of at one or other of its aides. Under
the body is a veritable " keel," which aeeuras longitadinal
stability. The pilot has his seat towards the front of the
body of the aeroplane, and the screw is at the extreme
prow; therefore it *' draws'' the machine through
the air. The pilot, owing to the tapering of the
prow, has a clear view of the ground in front of him
when the aeroplane is running along preparatory to
launching.

The steering and manoeuvring control are by means of
levers and pedals. The manipulation of an aeroplane
comprises two essentially different operations, corre-
sponding to two widely divergent requirements. There
is first assurance of stability at starting, and aflerwards
the maintenance of forward direction. For each of the
two manoeuvring operations M. Esnault-Pelterie has pro-
vided a vertical lever. Stability itself also comprises

MONOPLANES

217

3 variants; longitudinal and lateral stability respec-
ely. The lever which controls stability has two
vements, one to and fro, the other from left to right.

Screw

"flevatin^
rudder.

Screw.

Motor Verticals plane.

Wing

£levating
RudLder.

Steering
rud£r.

Fio. 76. Esnault-Pelterie's monoplane

r this purpose it is fitted with a universal joint, and is
, to the left of the aviator. When he moves it from
b to right, or inversely, it warps the wings through the
ir sets of under-stretched ropes ; when he moves it from
nt to back, or vice versa, it actuates the elevating
Ider, and as a result enables the aviator to recover his

y -^ * „ ■ ; ' '^"'**'*.S5^ '^'^r'^i^Z'^^. F ^"^^^.s^.^^r^jM.^rrsm- ^ ^

« ^ '■'■*« i •* " - "■•< * . ' * . • •

n% THE COKQDBST OF THE AIR

loDgitodiiial bakiiae» w, if lie m dmktm, to aaoeod or
dasoend.

13ie Mocmd lever k plaeed in front d the plofe; ooe-
trolling lateral diree&m, it m moved tnnevetaelj, and
eommandg the steering rudder* One een aee wbtt
ingemiity axul rational nmfdmty faaTe acoompmiiri
the design of these steerio^ deviees ; the aviator mmk
push the levers in the direetion in wfaidb he vnshes \m
aeroplane to go ; the movements wfaiob he has^ tiieie-
fore, to carry oat himself for this purpose are, ao to qpdk^.
refleziye, and error is impossible. Finally, two peddi,
allow the aviator to control his motqr, one actof
npon the gas inlet, the otiiw open tibe propeBflr
connection. I

So fiur as the motor is ccmcemed, we have alreaity hsl'
occaaon to describe it. The Esnralt-Pelterie (B.£P.)
engine is one of the most ori^poial and one of the best-
conceived that there is in aviation circles. When this
excellent engine was completed La Soci^t^ des Ing^nieurs
Civils awarded their prize to the inventor. It is of 30-35
horse-power, and its cylinders, numbering five, seven, or
ten, according to the power, are disposed in two "semi-
stars," but in such a manner as to be all above the hori-
zontal diameter of the figure. In this manner lubrication is
perfect. The valves are of the sliding type, and, according
to their position, permit admission and exhaust ; there
is one to each cylinder, and they are operated by a single
cam. There is no water-circulation, the cylinders being
fitted with fins, and at a speed of 45 kilometres per hour
cooling is very perfect. The motor, of 30-35 horse-pow^,
weighs 68 kilogrammes complete. An oil reservoir
of 6 litres and a fuel tank of 40 litres suffice for two

MONOPLANES 219

hours' continuous flight under the propulsion of a four-
bladed screw 2 metres in diameter, mounted direct on
the motor shaft.

In completing our description of this remarkable aero-
plane, it is only necessary to say a word about the rolling
chassis used for launching and landing. The body of the
apparatus is carried upon a pair of wheels arranged in
" tandem " ; under these circumstances it falls to the left
or right ; but the tip of each wing being fitted with a
special wheel, permits the apparatus to run along the
ground without bringing the wings into contact with the
latter. Immediately the apparatus is launched, the
aviator, by the aid of the warping lever, lifts the wing
which is trailing, and the equilibrium of the machine is
established. The j&ont carrpng- wheel is mounted upon
an ''oil-pneumatic brake," assisted by a spiral spring.
Under ordinary circumstances the weight of the apparatus
is flexibly supported upon this spring. Vibrations caused
by the unevenness of the ground are absorbed by an air
cylinder, in which moves an air-compression piston.
Finally, the shock in landing is taken up by an oil brake,
in which this liquid, compressed by the blow, is forced
through a very small orifice : this brake, which weighs
only 6 kilogrammes, can absorb 350 kilogrammes. One
can see, therefore, that it is very efficient for the landing
of the aeroplane.

THE "ANTOINETTE" AEROPLANE

Among aeroplanes of the monoplane type, the An-
toinette deserves particular mention. Every one knows
that the motors of this make have already furnished
aviation with an engine powerful combined with light-

n$ THE C03IQ(JEST OF THE AIB
■■* cftnried to mdb a degne tfcsfc a lOO-faonB-pover
■vtor en be tfiiiMirtHi by «■ ■11114)1 h«& TW.
boiUm nf Itirar nynw W^ahp ■■ifcilalim thseoB-
■IraetUD of aeroplBDe*. and in tbea- ckiee fixed opCD

Tbcrjr aUrted boOdtiig the acvoiilNM Gawttmiimit-
Hengin, which aenred thcB as a BHana of
and reaearch, and, bj improri
tbey at last prodaoed a Btnking ^^le, wluefa ia known m

Tbfiae constmctorB, like bo many other aviators <^
to-day, preferred the moaopUine because of its extreme
Mimplicity, facility of constructioD, and greater efficiency,
recjiiiriDg leaa power for progrearaon through the air onder
the same conditions of weight and epeed.

One of the most remarkable features of the Antoin^te
■eroplaneH is the design and build of their supporting
mirTarj-H. Tln_^se, divided into two elements consti-
tuting wings in every sense of the word, have the
form of trapeziums, %he larger base being contiguous
to the body of the machine. When seen &om the
front the apparatus has the appeamnce of a very
open V.

The section of these wings is of such form as to secure
the maximum of " power of penetration." Their surfaces
are covered on both sides, and the fabric is mounted upon
u framework which is certainly a marvellous piece of
work from the triple standpoint of rigidity, solidity, and
lightness. This framework is composed of an assemblage
of longitudinal and transversal ribs, intersecting one
another so as to form a series of triangles, the whole
being consolidated in a rigid manner by riveted aluminium

MONOPLANES 221

" gussets." The wing surface is 25 square metres, and
yet their weight 'ib scarcely 30 kilogranunes. One can
thus see that the total supporting surface is 50 square
inches. The extreme spread is 12*80 metres. It is
very interesting to note that the builders have designed
their framing upon the lines and methods of the con-
structors of metallic bridges and the Eiffel Tower,
which consists of subjecting every part to tension and
compression.

The body is triangular in section ; it is a long girder,
ending at the front in a pyramid, prismatic at the wings,
and then tapering towards the tail of the apparatus. It
is likewise built upon the principle of metal bridges ; at
the same time it is light and rigid. Body and wings
are covered with fabric, carefully stretched and given
several coats of vamiBh : this imparts to the surfaces
moving through the air a remarkable smoothness, re-
ducing to the minimum the friction of the molecules of
air coming into contact with the force which displaces
them.

The constructors of the Antoinette aeroplane have
abandoned warping the wings for the following reason.
With Louis Bl^riot, though in a slightly different form,
they have adopted the ailerons fitted to the tips of the
carrying surfaces. These ailerons, which one may see
very distinctly in the photograph of this aeroplane, are
connected to the back edge of the wings, and when at rest
form a prolongation thereof. - They are connected with
the latter by an articulated system which lowers one
while it raises the other. This produces the same effect
as warping, but with greater power and without the in-
xx>nvenient danger of fatiguing the wing framework by

Coatrol is dBectod bf
three wheels. One may
not re&un from think-
ing that snch is too
much for an aviabv
wbohasonly (lOD haods.

rit.n. The-AntoinetW-mooophoe j^^ ^^ ^j,^,^ Control-

ling Kteering and the ailerons respectively, are close to-
gether, it is true, so that the hand can pass easily from one
to the other. For my part, I think that it would be po-haps
wiser to have recourse to a control arrangement of the
ilMriot aeroplane type. That is the only criticism which
I can offer of this apparatus, the conception and the con-
Htruction of which from all points are remarkable. In
(iddition, two bandies control the ignition and the inlet

■ ■LATE .\SVtlA

MONOPLANES 228

throttle of the motor, and there is a foot-brake to stop
the engine.

The whole apparatus is carried upon a supporting
chassis composed of a '' roller skate " placed under the
firont of the body, two '' shores/' one at the right and the
other at the left centre of each wing, and a " butt-end "
under the tail The ** shores " and '* butt-end " are set in
the direction of travel. The " roller-skate," comprising
a bicycle wheel at the back and a roller at the fix)nt,
owing to an ingenious and solid suspension spiral spring,
admits of absorbing to the maximum the severe shocks
which are produced at the moment of landing. The skate-
wheel, almost under the centre of gravity of the appa-
ratus, is so placed that the strain upon the tail is reduced
to the minimum. With regard to the " shores," not only
do they preserve the wings from all rough contact with
the ground, but they serve as an anchoring point for
the upper consolidating ropework. Moreover, a vertical
piece serves as a straining support for the cords stretched
over the upper face of the supporting surface.

When one wishes to launch the apparatus, one starts
the motor and connects the propeller : the aeroplane is
supported on the ground by its skate, shore, and stern
butt-end. As the speed increases it is the butt-end which
first leaves the ground ; after some lateral oscillation the
shores in their turn rise. Released, the apparatus gradu-
ally balances itself while poised upon its roller-skate,
until at last it definitely rises.

The motor is, naturally, an "Antoinette." It has eight
cylinders disposed in a V, and develops 55 horse-power.
It is placed towards the front, and drives a two-bladed
prow propeller of 2*20 metres diameter. This screw is

224 THE CONQUEST OF THE AHl

of metal ; its shaft is a steel tube with blades of aluminiom
riveted to the boss, which is flattened out into the shape of
a fan. Its pitch is 1 '30 metres, and it runs at 1 100 revola-
tions per minute. One can change the set of the two Uadeni
and consequently modify the pitch. By means of ex-
periment one can thus ascertain the most advantageous
pitch for the best regulation of the track of the aeroplane.

With regard to the pilot's seat, exceptional precantioos
have been observed to secure ample accommodation for
the aviator : the position is well sprung, so as to pre-
serve him as &r as possible firom all shocks, and at the
same time allow him the greatest freedom in movement

Such is the superb monoplane, the construction of whidi
from all points of view is striking. Perfected by M. Wei-
feringer, it was taken to the camp as at Ch&lons, and
there placed in the hands of M. Demanest, who served
his apprenticeship as pilot.

After Jive lessons only, the young aviator was able not
only to ** fly," but to win, on April 8, 1909, the latest
prize of the Aero Club of France for 250 metres. M.
Henri Farman, passing through the camp at Ch41ons,
oflBcially timed the trip, and warmly congratulated the
new aerial navigator.

And on June 5, 1909, the Antoinette aeroplane accom-
plished another performance : M. Latham, scarcely
familiar with the management of this remarkable aero-
plane, flew for one hour seven minutes^ darkness only
stopping him then. The following day, not content with
having beaten the world s record in a monoplane, he set
out with a passenger. The day after he performed an
unprecedented achievement in aerial flight, for, besides
himself, he cairied two passengei*s, MM. Fournier and

MONOPLANES 225

Santos-Dumont, and demonBtrated once and for all by
[lis marvellous skiU, the safety and facility of manipula-
bion, and consequently the absolute superiority, of the
French aero-monoplanes.

Finally it was with this aeroplane that Hubert
Latham was able to cross the Channel, after M. Bl^riot,
uid to reach within less than a mile of the English
soast.

This feat, so rapid, this safety, so promptly acquired,
demonstrates better than words how great is the security
of the French aeroplanes, and how much easier they are
to control than the apparatus which, like those of the
Brothers Wright, demand everything from the aviator.
And this rapid initiation is not the only one ; upon the
BlSriot^ EsnatUt'Pdterie^ Voisin, and Antoinette aero-
planes flying can be learned in a few lessons. This
exemption from a long, laborious, and perilous ap-
prenticeship is therefore quite a triumph for French
aTiation.

If. TATINS AEROPLANE, THE "BAYARD-CLfiMENT":
THE VENDOME AEROPLANE: SANTOS-DUMONTS
>" DEMOISELLE "

Among the apostles of aviation is a man who, one can
safely say, has devoted his life to the advance of ^^ the good
fight " in favour of transport by machines heavier than
the air ; not only has he contributed some remarkable
works upon this subject, but he built an aeroplane model,
which was tested at the Chalais-Meudon riding-school
in 1879 before a number of officers ; this model was
{nropelled by a screw driven by a compressed-air motor.
Ab a result of his efibrts, Tatin deserves to be placed

226 THE CONQUEST OP THE AIR

beside Penaud, Langley, Bichet, Marey, and the oth^
notables of the *' Pleiade " of initiators.

Some time ago, Victor Tatin conceived a type of
monoplane in which he sought to emulate the bird hj a
'' soaring plane." M. Clement, the automobile eogine^,
of whom we have already spoken in connection with our
description of the magnificent dirigible in the first part
of this book, enabled the inventor to carry out his idea,
and the TcUin aeroplane which, like the dirigiUet ^ ^
known as the Bayard-CUment^ is now building at the
workshops of M. Ghauvi&re, the aocompliahed and skiDed
designer of aerial screws. It is impossible to pas in
silence this aeroplane, of which much has been said prior
to its appearance, and on the subject of which ]£ Tatin
has written a very excellent book entitled MemefUs
d^Aviation.

Seeking to imitate the soaring bird, the Tatin wsro-
plane is perforcedly a monoplane. The inventor has
pointed out that in the soaring plane the tips of the
bird's wings are bent slightly upwards. He has conse-
quently imparted this form to the transverse profile of
his wings, which, instead of being separated from one
unother, constitute by their combination, a continuous
surface which projects horizontally, forming an elongated
ellipse. The surface of the rear empennage takes this
form also ; the spread is 12*50 metres.

The general appearance of the Tatin aeroplane is
totally different from any we have yet seen. It is dis-
till j^uisheil hy the elimination of all parts capable of
oflering resistance to movement and not acting as sus-
taining surfiices, recalling on the whole the general
outline of the bird known as the martin. The wings are

PLATE .WVIII

MONOPLANES 227

curved, their convexity being turned towards the
ground ; the supporting surface has a span of 25 square
metres. The stabilisating tail is 4*40 metres from the
wings, has the same curved form as the latter, and its
surface is 7 square metres.

The body of the apparatus is rectangular in section,
the sides being 90 centimetres. It is 6*50 metres
long ; it is really a " strengthened gu-der " carrying the
motor, the aviator, and tanks for petrol and oil. As it
is imperative that these resistance surfaces should be
held taut by shrouds, there are two thin vertical members
and eight steel wire shrouds, so arranged that they meet
above the surface of the tail for this purpose.

The front of the aeroplane is connected to the stern
by two wooden members spaced a sufficient distance
apart to permit of the propeller revolving between
them. The latter is of wood ; placed at the stem
of the body it is of 2*40 metres diameter, and has a
pitch of 2*50 metres ; it revolves at 700 revolutions
through a reducing gear mounted on the motor shaft.
It is built up of thin superimposed sheets let* into the
framing and assembled in such a manner that the
true form of the structure is preserved. The whole
is covered with varnished Japanese silk.

The motor, specially constructed at M. Clement's ate-
liers, after the designs of M. Clerget, can develop 60 hoi*se-
power, which can at will be reduced to 30 horse-power. It
is placed behind the aviator, and has radiating cylinders.

The stabilisating tail serves at the same time as the
elevating rudder. For this purpose it can be slightly
inclined upwards or downwards. A vertical rudder fixed
to the tail secures lateral steering.

Front elevation-
Rudder Tail

228 THE CONQUEST OF THE AIR

When the apparatus is in full flight it does not require
more than 25 horse-power, and will fly under such effort
at 72 kilometres per hour. By using the whole of the
available motor power this speed will be possible (f
increase : the aggregate horse-power is a little more
than twice 25, which
will multiply the fore-
going speed by VZ
thus giving a speed I
of 90 kilometres per 1
hour. This aeroplane
will thus be one of
the fleetest. Well
thought out, as a
result of prolonged
study by its author,
marvellously cod-
structed by the en-
gineer, Chauvifere, it
is now completed,
and its tests are
keenly anticipated.
Another very io-

WlQ. 78. V. Ttttin'i DtonopUne •■
Baj/ard-aim*nt

opIuM^ the

teresting aeroplane is that which has been built and
successfully tested by M. yend6ine. Here we find
again that tendency, of which we have already spoken
in Bleriot XL and the Esnavlt-PeUerie aeroplanes,
which consists in reducing the spread by the decrease
of the superficies of the wiugs, and the augmentatjon
of speed. This tendency we shall find more accen-
tuated still in Santos Dumont's very ingenious little
flying apparatus-

MONOPLANES 229

The Venddme aeroplane is fitted with two separate
wings, symmetrically placed on either side of a fusiform
body, having a quadrangular section. The membrane of
these wings is of very light, tightly stretched, unvar-
nished fabric. The wings are disposed upon new and
quite qriginal lines. M. Venddme has sought to combine
the ^' ailerons " with the warping action, thereby making
use of both these systems. To this end each wing can
be pivoted upon itself, independently of the other ^ by one
of the control levers. This is equivalent to warping the
whole of the supporting surface and ensures the main-
tenance of transversal stability. In manoeuvring the
two levers simultaneously one can change the angle of
incidence of the wings and so ascend or descend. More-
over the two wings present, as in the Antoinette aero-
plane, the form of a very open V. A stern tail obtains
longitudinal stability of the apparatus and acts likewise
as the elevating rudder.

There is no steering rudder ; turning even in a very
short radius is obtained by means of the extreme ailerons
placed above each wing. When at rest the ** ailerons "
lie upon the supporting surface ; the pilot, by the aid of
pedals, raises them when he so desires, producing a
dissymmetrical resistance to the air, thereby securing his
horizontal line of travel. The motor is of 50 horse-power ;
it drives direct a hoUow screw of hickory wood veneer,
mounted on canvas, of 2 '43 metres diameter, and of
which the weight is only two kilogrammes. The whole
apparatus rests upon a three-wheeled running chassis
fitted with absorption springs.

The whole apparatus is 12 metres long, and has a
spread of 9 metres only. The supporting surface is 24

m» THE CDffqCKST OP THK AIK

iq^H* aataiV Md «fc» talil w^ll^ dns not oeaed 31V

iirii I ii I II iirtiii It I iT irrr'Ti i

llMlw It ^lll l. Illll n i'iiMi.mTI llllt ■ lllllliri I 1

139 liliiyiwMiM m total w^gK nib » tfaii toaik-
dbia lagJM. vU tAmA wA St. Cjt, cwdy m A^ tihe

TfcM ■ iJMtMliil mil Ae &et that one «a gy wittiort

tiMMBOfi)

iribeeB, of we^itjand c

mmdunet. Before imtg, UmdIes to tlw explodon notar,
the arti6esal liird of Uam weigfat and Tolmiie wiU be dik
to go an y wh er e. A little mora prograa and ervery flos

will fly.

THE TWO SCHOOLS OF AVIATION

We see from tlie forgoing tliat wb are oonfrooted fay
two schools of aviating apparatos : the American sdwol,
represented by the Brothers Wright, which demands
everything of the aviator, and the French acbod, Yoisin,
Bl^riot, Esnault-Pelterie, Antoinette, which requires, en
the other hand, the minimum from the pilot.

Which of the two is correct ?

The best way to reply to this qaeetien is to quote the
words of Paul Painlev^, Sorbonne Professor, and member
of the Acad^mie des Sciences. M. Painlev^ is not one
of those abstract mathematicians who confines himself to
differential symbols or the study of elliptic action. He
has probed into aviation practice, has flown in turn witii

MONOPLANES 281

Wright at AuvoarB, and with Farman at the Gh&lons
camp, and this is how, in a snhsequent article, he ex-
pressed himself upon the subject :

'* Aviation is the most burning mechanical problem
appealing to mankind to-day. Its soltUian is (ichieved.
To-morrow it will be commercial ; in a few years it will
commence to transform the world. This solution one can
now indicate upon broad lines.

** Two schools are represented : the French and the
American, or if one so prefers — ^for it is confined to the
two constructors who have effected the most impressive
results — the Yoisin and the Wright systems respectively.^

** In the first place an aeroplane to be able to support
itself in the air must travel quickly, and at such a speed
that the resistance of the air, increasing with the speed,
prevents it from falling, whence the necessity of a motor,
powerful, light, and regular in action at one and the same
time. The more swiftly an aeroplane travels the more
stable and capable will the apparatus be of combating
the caprices of the wind. The perfection of an ideal motor
is no more than a question of months.

*' Then it is imperative (and this is the gravest di£Eiculty)
that the apparatus neither dips forwards nor backwards,
neither to the right nor lefl ; it must not even deviate
from its direction of travel. In a word, the aeroplane
must not pitch or roll, or swing round suddenly, or else
the pilot must be able to restore such unbalancing move-
ments as soon as they develop.

^ At the time the eminent mathematician wrote theee words (2^
J/irttn, October 28, 1908) M. Bl^riot had not made his "historical
journey " in a doeed circle by monoplane, and Latham had not accom-
plished his well-known brilliant triumphs on his *' Antoinette "
monoplane.

SSS THE CONQUEST OF THS AIR

"Here are the meuuof obtainii^ tliia ■tahility, whiA

are different in the two aohooli.

" Wright haa aonght ahove all mwapGekly and li^liw.
bat the equil&frium of Aw appamtiu w emiirjg m Ae
hand$of the ptioL Three diatinot movanoBta tmM
the three poanble perturbatu»ia ; waxfiag of .A* wiiy
parUoularly oounCeraota ndling.

" In partitioning the two winga liks the ooBa of a kita
In the form of a cigar-box, Voiain, on the contrary, eecont
lateral stalnlity. In turning tfieir apparatut awww»
tUelf to the mott eonvenwnf ttneHjialion, Two opentiooi
instead of three an all that is necessary to control Un
machine : that of the ateering rudder, and that <^ th&
elevating rudder. Y^ tkia last corUrol is now verf
timpUJied 6y the addition of a long taSt wkidt eppom
pitdUng.

" Laatly, the utaliaation of the motiTe power throogh
the large alowly-tnming acrewa of the Wright, or IJm
shorter and higher speed of the Yoisin, appear com-
parable.

" The Voisin apparatus is decidedly heavier than the
Wright (650 kilogrammes instead of about 500), due in
the first instance to the tail, and secondly to the running
chassis (80 to 100 kilogrammes) necessary to enable the
apparatus to raise itself under its own effort.

" These differences, well specified here, are the result
obtained by the two apparatusee. Wright lu^da the
record for distance by himself and with a passenger. He
htu tiever yet raised himadf by his own effort. He will
be aUe to do so though when he so deeiree, but wOl it be
^pUhMU increasing weight ? "

The Voiun apparatus, piloted by Fannan, holds the

MONOPLANES 288

record for speed : 70 kilometres per hour at least ;
but it must be pointed out that it is always self-
lifting by means of its running chassis, weighing 80
kilogrammes.

Before my own eyes Farman flew in a violent wind
(October 28, 1908) above the camp at Chd^lons ; he made
the first long distance flight that had ever been attempted
in an aeroplane ; he flew not only in public, but before
some officers who attempted to overtake him at the gallop.
He repeatedly described his usual circuit at great alti-
tude, frequently exceeding 40 metres. Lastly, notwith-
standing the weight of his running chassis, it lifted it-
self and me by its own effort^ and traversed a distance
of 1600 metres, and the apparatus completed a turn
showing as perfect a stability as if the pilot were
unaccompanied.

" A magnificent day's work for French genius ! " wrote
a young officer who was overcome by enthusiasm at these
experiments.

It would be useless to add a line of comment to this
criticism by one of our most learned mathematicians, a
criticism formulated on October 28, 1908 ; and two days
later Farman and Bl^riot substantiated his statements
by completing, on the 30th and 31st of the same month,
the two "first aerial voyages" from town to town.
That is a distinction of which none can ever attempt
to deprive them; they were the two first "tourists of
the air.''

One can by means of so exact a comparison intimately
grasp the fundamental difference between these two
" schools " of aviation. We see that the American school
demands everything of the aviator, longitudinal^ as well

284 THE CONQUEST OF THE AIR

as lateral, stability, whilst the French school assures Ute
longitudinal stability by means of an empennage and a
long leverage arm, which is an important point The two
schools may best be likened to those two machines, the
monocyde and the bicycle respectively : neither has latenl
equilibrium, and the rider must secure it in the same
manner upon both, but upon the monocyde he must also
obtain longitudinal stability, whereas, on the other hand,
with the bicycle this is inherent, owing to the two sup-
porting points on the ground

Consequently while every one can control the bicycle,
only those expert in balancing will risk themselves upon
a monocyde.

Our French aeroplanes : BUriot^ Voisin, Antoinette^ aie
the bicydes of the air ; every one will be able to use them,
and the latest exploits of Latham at the ChMons camp
where, after only a few lessons, he was able to remain in
the air on his Antoinette aeroplane for sixty -seven
minutes y to lift two passengers, &c-, demonstrate the
facility and safety of their management. Lastly, it
was on a Bleriot monoplane and an Antoinette mono-
plane that the sea was crossed for the first time with
apparatuses heavier than air^ mounted by Bleriot and
Latham towards the end of July 1909. On the other
hand, one knows the long practice, the skill that is
requisite to use a Wright. Wilbur Wright possesses this
Hkill to an extreme degree, but it cannot be acquired by
every one, no more than any one can become a mono-
cyclist : the serious accidents that have been precipitated
by the American aeroplane demonstrate this fact in an
overwhelming degree.

MONOPLANES SS5

APPARATUS OF AVIATION : HAJOOPTl£R£S
OBNITHOPrfcEES: THS BIEGUBT GTBOPLANE

A word remains to be aaad about aTiatioo i^pantm
based upon prindples other than these of the aeroplane ;
there are, first of all, the hdioopfeftras^ or apparatus with
aostainiog screws. UntO now these aj^Huratas have not
given decisive resolts ; it is true one sacoeeded in lifting
fidrly heavy apparatus finom the ground on several occa-
sions, even with the aviator ; but what is difficult, and
what is so fiur only promise, is the constant direction of
the apparatus through the air. The efforts of investi-
gators have been confined almost exclusively until now
to sustentation by screws. We have mentioned the
works of Colonel Benard upon tins subject, and the
hopes inspired by rather hasty interpretations of the
formulas which summed up his calculations. To-day a
few trials of direct sustentation by helixes have been
realised, and the most important are those of Engineer
linger (Monaco), M. Paul Comu, and M. Louis Breguet.
We have already spoken (p. 181) of the firet of these
apparatuses. Let us now say a few words about the two
others, which have furnished interesting results.

We know what the ** slip " of a helix is ; similar to a
screw, the propeller turns in the air, but the mobility of
the molecules of the latter causes the apparatus only to
advance a fraction of its ** pitch." The difference defines
the slip.

Until now, in the sustaining screws tried with h^li-
copt^res, attempts were made to render the slip as small
as possible, and to do this by decreasing the pitch of the
screw. This slip, however, cannot be entirely overcome.

286 THE CONQUEST OF THE AIR

M« Comu therefore, not being able to avoid it, soaght
to use it for the horizontal propulsion of the aviatin
apparatus. This is the principle of his apparatus.

A frame carries a motor, which transmits its power
to two screws through endless belts, one to the right and

Sf^hf hand propellor. Left hand propeilor.

plane propellers. I I plane propellors.

Motor.

Fio. 79. Principle of the Ck>rna H61ioopt^re

the other to the left, and turning in opposite directions
to annul torsion efforts. These are the '* sustaining "
screws devised to lift the apparatus into the air. The
effect of their slip produces back- thrust of the air
towards the bottom, whereas their useftil effort secures
the sustentation of the apparatus. This driving back
of the air is used for horizontal propulsion by means of
inclined planes placed under the screws ; these inclined
planes receive the rush of air driven from the top down-
wards, and their oblique surfaces transform this vertical
effort into a horizontal component which may displace
the apparatus in a given direction. By differently in-
clining two series of these planes placed on both sides
of the axis, turning and inclination may be obtained.
Such is the principle of the Comu apparatus. Plate
XXIX. represents its real construction. The results seem
encouraging ; the apparatus rose once with its aviator

MONOPLANES 287

>n board ; a second tinie w::h two LLien, the total weight

^TUfted being 32 S kilo& This sustentation lasted one

minute. The propulsion, according to the horixontal

effort exercised upon the oblique planes, was weak :

only 12 kilcMnetres an hour. It may be seen from the

^^bregoing that this h^oopt^re is amongst the most

iterestiog, and such researches must be encouraged, as

3>fc 18 from this development that the perfect sustaining

^i«crew will doubtless be eyolyed, and which, perhaps,

Bome day it will be possiUe to associate with the

aeroplane.

It is necessary to mention specially a very interesting
aviation apparatus, the gyrcplane of Messrs. Breguet
and Richet, realising in a happy manner the combination
of the aeroplane and the hdlicoptdre. This apparatus
comprises an association of Jixed wings and of revolving
wings. The photograph enables their arrangement and
operation to be very clearly understood.

The total surface of the revolving wings is 1 1 square
metres each ; the surface of the fixed wings is 50 square
metres, which, in the event of a vertical descent, pro-
vides a total area which would form a parachute of
approximately 72 square metres. The oblique disposi-
tion of the screw shafts is seen ; the reaction of the air
upon the fixed surfiuses gives in this manner, as soon
as the propellers are in motion, a double effort : an
upholding vertical effort, and a horizontal effort serving
for forward propulsion.

With aviator and petrol for one hour, the apparatus
weighs 600 kilos ; the engine is an " Antoinette " motor
of 40 horse-power. A warpable equilibrator placed at
the bow, and lateral small wings, ensure stability, and

r
I
I

888 THE CONQUEST OF THE AIR

allow the aviator to regain each in the event of acfr
dental ioclination. A steering mdder is placed at the
stem of the apparatus bodj, and acts as the verticsl
WDpennage. The fixed and revolving surfaces are supple,
and constracted apon very ingenious principles; thtsj
are covered partly with very thin aluminiuin sheets, anc
partly with special waterproof and non-bygrometrial
paper.

The apparatos has been successfully tested at Doua^
on groond purposely selected as unsuitable for t^
launching of ordinary aeroplanes ; the area was beetiwl
fields. The apparatus rose, however, straight into tbf
air with the greatest facility. An accident internipteJ'
the experiments, but the results are most encouraging
and of a nature to induce the authors of the appanita|
to persevere in the path they have selected.

The ormthoptkre has been studied and constructett
upon rational lines by a Belgian aviator, Mr. Adh. de I'
Hault. Witboat seeking to " fly " right away, thin
distinguished oonstnictor first set to the study, working,
and efficiency of the " flapping " wings, and constructed
an ingenious apparatus, which, with organs of a ver^
elegant mechanical conception, realise the movement
in the form of the figure 8, according to the curve
which mathematicians call " lemniscate." Thanks to
this complex movement, the author hopes to realise the
double function of the bird's wings, both propelling and
AiiAtaining. The apparatus of Mr. de la Hault figured
in the 1908 Brussels Kzhihition, and the mechanical
part, quite remarkable, was much admired by engineera
The inventor is now pursuing his researches, and impor-
tant results will certainly be obtained.

MONOPLANES 289

There remains but to point out an American omithop-
tire with flapping wings, provided with Venetian blind
Uades, which close when descending, to rest upon the
air, and open in ascent. We have no data regarding
ihe practical results of this apparatus.

Finally, to conclude this history of the principal avia-
tion apparatus as constructed up to now, we may say
with confidence that the aeroplane has alone, so far,
furnished really practical results, and that in its various
forms it has shown an absolute superiority over the two
other aviation systems. This justifies the enthusiasm it
has provoked and which its continuous development is
maintaining. What it is necesssry to do is to ascertain
how either supporting screws or propelling surfaces
oould be added to it. One can therefore see, with the
aeroplane in its present form so ftill of promise, that
aviation, the '* heavier than air " science, is far from
having said its final word ; it has barely said its first.

CRAPRK VI

EARLY DATS OF AVIATION

THE FOtaaUJSKERz SIB GBOIGB GATLET

Lsr vm noir, knowing the eonditioiis that must be ful-
filled bj an aviatioii appumtaa, realimng tiie difficahiei
that one ODoouiten in neeting to evolvey raise and oon-
tral it^ gbneing faadL to see how the traveller has ani^
prafitahlj at the end of his journey and instmcted
in an that it m neammrj to do^ we ahall be better able
to af^ireciate the immeniie eflfort of those who w^re the
creators of " heavier than air '* aerial locomotion.

Let us at once reassure the reader we will not hark
back to Icarus or legendary history : we will take avia-
tion only from its modem ori^n; start from the time
when methodical ideas were sufficiently calculated so
that investigators were able to proceed on serious and
rational lines, instead of aimlessly groping about in the
dark.

The first serious investigations relative to aviation
date only from the commencement of the nineteenth
century, and it was the aeroplane which then occupied
attention. By a curious coincidence, even as the first
projected airship, that of General Meusnier, was '* com-
plete," and in a single stroke anticipated all the necessary

S40

EARLY DAYS OF AVIATION 241

equipment, so was the first aeroplane conceived *' com-
plete " and everything indicated by its author.

This inventor, this incontestable forerunner of aviation
was an Englishman, Sir George Cayley^ and it was in
1809 that he described his project in detail in iVu^^^on'^

Ito. 80. Victor Tatin'B aeroplane model driyen by compressed air, which

flew at Meadon in 1879

Jcfwrrud. In the course of an excellent paper presented
to the Soci^t^ des Ing^nieurs Civils, M. Soreau recalled
this date, when he remarked how sad it was to think
that such a valuable invention as this had not been
possible of application immediately upon its conception.
In fiBM5t "everything" was there in Sir George Cayley's idea
— the wings forming an oblique sail, the empennage, the
spindle forms to diminish resistance, the screw-propeller,
the ^* explosion '' motor, the calculation of the centre of
thrust, and demonstration of the &ct that displacement
takes place towards the fix)nt. The author even
described a means of securing automatic stability I Is

■■■ * -^ ■ ■ '■:• >■/-'■-". '- J, *ra

til THE CONQUEST OF THE AIR

iiokall tiiat iiiftrv6lloii% aiidiBifc not m nniiinViitai meS*

ThM it ii MOB— iiy to hmakm the ijmus of Shr Qeoy
CSaylejr, in ktten of gold* at the biginning of fti
hietoiyofthetaraplaM. Baridflf» the kerned B^jlP^
men did not oonfine hiniBetf i»^^ dnrnkkg-ptspm* : k
hnilt the fint eppentne withiNtt e motor whidi gete Im
feeolta fbU of promiee ; then he built a eoeand mefllaii^
this time with a metc»r/hot«mifix)bmalely during ^
trials it wee emeehed to pieoea m 1842 enotfMr
BngKiihmeni Heneon, atteoqptod to build a modd mtth
plane npon this prindj^ hot without eooeeee^ end om
mnet paw on to the year 1^56 to eee tibto first eiperi*
menta with appafatnaee that ^ lifted^** that k to eay wift
a paaoenger on board ; it waa onl^ a matter of anetaitih
tiim from a huge kite» hankd lij ^ vehiok^ but it waa a
Freneh naTigator» Le Bri$^ who denied out thk imtal
tentative effort The first attempt to glide aoriaUy by
a '' soaring plane " was made with what was really a
triplane by Wenham in 1866, which constituted, in
short, the apparatus which was used thirty years later
in the experiments of Chanute, Wright and ArchdeacoD.
Nor must it be forgotten that it was towards 1860 that
Nadar, Ponton d'Am^urt and de la Handelle carried
out their '* heavier than air '' campaign, and that it was
in 1862 that the first steam h^licopt^re was built by
Ponton d'Am^court, a model, it is true, but a working
model, which is preserved in the archives of the French
Aerial Navigation Society. Another steam h^licopt^
a small model, due to JSrmco, driven by a email steam
engine, weighing all told 3 kilogrammes, lifted itself
from the ground and remained in perfect equilibrium

EARLY DAYS OF AVIATION 248

without any material contact with the earth in
1878.

The three first aeroplanes or models of a^eroplanes
which truly " soared " were the small apparatuses of
A. Penavd which followed the lines of a monoplane with
empennage tail (Fig. 43) ; and the aeroplane of Victor
Tatin constructed and tested in 1879 at Chalais-Meudon.
The latter was driven by compressed air and its trials
were absolutely convincing : held by a cord at the centre
of a small circular track, it ran round the latter stretch-
ing the cord, and lifting its weight. Subsequently in
1906 the celebrated American physicist, Professor
Langley, contrived an aeroplane weighing 1 3 kilogranunes,
carrying a small steam engine, and formed of two pairs
of wings placed, not one above the other, but one in
front of the other, in " tandem " (Fig. 45). This aero-
plane although it did not lift itself, accomplished the
first aerial journey ; it covered 1^ kilometres through
the air. A second aeroplane was built some time after
(in 1903), it rose this time, but undoubtedly owing to
the inexperience of the aviator, it fell into the Potomac.
Yet the investigators were continually working, and
two names are inscribed in the golden book of aviation,
both well known in industry. One is that of Sir Hiram
Maxim, the famous inventor of quick-firing guns, who
expended over £40,000 in the cqnstructien of a very
large steam-driven aeroplana This apparatus, notwith-
standing the great achievement of its inventor in regard
CO the lightness of the steam engine (15 kilogrammes
per horse-power) only displayed a "tendency to lift
itself," but it never actually rose.

The other industrial magnate was M. Clement Ader,

S44 THE CONQUEST OF THE Am

well known hy his great de^rdqpiieote in the ooDsfaoctioB
of telephcmic i^ipaimtoa. In 1890 and 1896 he built
two aeroplanes wfaidi he christened JLviotL, On both
occasions the appaimtoses Ufted 'tkmmmkfm Jrom the
ground^ and at Satory in 1896, befixe o ffipsi a delegated
by the Minister of War, the ai^aratns ^fietad a figki
ofZQQmetTtB after leaving the gmmd onder fta own eflK^
If, therefore, the honour of having emeeeMd the first
aeroplane renuuns with an Eng^Bshman, the merit of
having oonttrwAed the first apparatns that efiectivdy
flew, rests with a Frenchman: sndi is a glorioos
example of the entente cordidU BmodakBi with the
history of human progress.

THE ''HUMAN BIBDS": ULIENTHAL, GHANUTE,
CAPTAIN FERBER, THE BROTHBBS WRIGHT

Whilst some engineers were seeking " to hnsk in"

machines for sustaining in the air, other investigators
were compelled to seize the mechanism of the *' soaring
plane/' and upon these motorless gliders utilising oiily
their weight and the resistance of the air, served their
*' bird-apprenticeship/' Foremost among these perse-
vering and audacious men, must be placed the rightly
renowned name of the German, Otto LiUerUhal^ who
long before the Brothers Wright (who no more than
followed in his footsteps in their preliminary attempts),
accomplished some remarkable experiments in this
direction, in the course of which he lost his life in his
devotion to aviation science.

Lilienthal, a Berlin engineer, built some veritable
birds'-wings, fixed to his body, with which he sought
to achieve the ''soaring flight" of birds of which

^^^"

■«#r"^

, - ."^m ■■'■ *-

EARLY DAYS OF AVIATION 245

we spoke in the first chapter. These wings, of which
the photograph (Plate XYII.)! gives a very good idea,
were formed of an osier framework, covered with light,
stretched fabric. Two horizontal rudders, forming a
bifurcated bird's tail were at the rear, surmounted by a
large steering rudder of rounded form. Lilienthal, well
poised in the centre of this framework, jumped from the
top of a low tower, against the wind. The inclination
of his body and legs enabled him to shift the centre of
gravity of the whole systeuL In this manner he carried
out some remarkable flights, some of which attained 300
metres in a horizontal direction. After he had made
about a thousand such Lilienthal changed the form of
his "flier." Abandoning the monoplane he built a
biplane and in a fatal fall &om a height of 80 metres
broke his neck in 1896.

The experiments of the unfortunate Grerman engineer
were of incontestable value in demonstrating the
efficiency of supporting surfaces and the possibility of
realising under the best conditions equilibrium during
flight. The Americans followed in his footsteps and
among the first of those who, in the United States,
sought for the solution of the problem by the study of
the soaring plane must be mentioned a Frenchman, long
resident in New York, M. Octave Chanute, born in
Paris in 1831 of French parents. Chanute, although
well advanced in age continued the experiments of
Lilienthal. He emphasised the biplane and happily
conceived the first disposition of the stabilisators.

In 1899 Ferber^ captain of artillery, commenced in
France a series of very beautiftil experimental researches
in glides at first, afterwards in the conditions of equili-

IE CONQUEST OF THE AIR

jrtUu.. e even tried an aeroplane £tted with a
' manceuvring " motor, that is to say describing a circular
>vement about a fixed point to which be was mechani-
Jly connected. His work, his writings, place him
ominently among those to whom we owe so much, and
is inspiring to see a French officer occupy a difltin-
tished position in the glorious rants of these "fore- ,
inners," who planned out the path so well. ]

So, when, in 1900 the brothers Orville and Wilbur

ight, bicycle makers yton, set out to tackle '

le problem they found 3 ground well prepared, i
mthal had opened the ', Chanute had indicated ■
l6 arrangements, the Brothi i Wright perfected them, i
nd they "strove for the t" with great judgment, |
I, and, above all, an e; i irdinary determination to |
come " human birds." 1 sy commenced by carrying *
mt numerous aerial glides th their biplane 8o as to i
secure aerial equilibriurn. These glides suggested to
them many happy modifications, and encouiaged by the
doyen of aviators, Octave Chanute, they built, in 1903,
their first motor-driven aeroplane with which they fa-
formed several flights in a straight line. It was not
until 1904 that they efiected their first turn, &om which
point they readily made long flights of many kilometres
at an average speed of from 60 to 65 kilometres per
hour. Their experiments were surrounded by sud
mystery that many would not believe them. In France,
Captain Ferbar, M. Bodolphe Soreau, M. Henri Letellier
were among the few persons who loally credited the
performances of these two transatlantic aviators ; IL
Letellier, in view of its military possibilities, even sent
one of his collaborators M. Fordyce to Americf^ to nego-

EARLY DAYS OF AVIATION 247

tiate with the two inventors for the cession of their
apparatus to the French Government. These negotia-
tions were not successful and it was not until the
summer of 1908 that Wilbur Wright came to France at
the request of a group of financiers with whom he had
been in treaty. He carried out his first trials at Mans, at
the camp of Auvours, upon the Hippodrome des Hunan-
di^res, where he executed numerous flights all under
''experimental'' conditions: but never once setting out
under his own effort, and without accomplishing actual
trips. Nevertheless it must be remembered that thanks
to his aviating skill Wilbur Wright completed some
flights of very long duration, and among them he suc-
ceeded in repeating the exploit of the Frenchman,
Delagrange, by carrying a passenger with him, notably
M. Paul Painlev^, of the Acad^mie des Sciences, with
whom he remained in the air for over an hour.

Overwhelmed by great publicity^ these experiments
created an immense sensation, and one began to forget
somewhat the French aviators when two of them
established a record, unique to-day, and had too the
glory of completing an " achievement " the merit of which
they cannot possibly be deprived of, because this '' raid ''
recorded two historical journeys in aviation by the com-
pletion of the two first aerial, voyages " in an apparatus
'' heavier than the air" on October 30 and 31, 1908.

•

EXPLOITS OF THE FRENCH AVIATORS : SANTOS-
DUMONT, VOISIN, DELAGRANGE, &c. THE MiECENE :
HENRY DEUTSCH, K ARCHDEACON, ARMENGAUD

The flights of the Brothers Wright were very beautiful
demonstration experiments, but none the less the aero-

t48 THB CONQUEST OF THE AIR

pLuie of the Amerioans is not perfiMst. Its sfcafaili^
demands a constant eflEbrt on tlie part of the aviste,
because of the suppression of tiie empennage tail, and
the apparatus for this reason is dangerous. In Ameritt
it caused a serious accident to Orville Wright, snd
brought about the death of one of its paasengeri, the
American Lieutenant Selfridge in the aatunm of 1908.
In the spring of 1909 the Italian Lieutenant Oslden
was thrown to the ground through a capmae due to
the inherent instability of his aeroplane) moreover, as
we have said, and as we repeat, the apparatus is not np
to the present self-starting.

French aviators, however, were quietly working towaidB
the solution of the problem, and to its complete solution,
that is to say, to the perfection of a edf-starting saro-
plane, able to rise from the ground under its own effiHt,
and to set out agun after having landed, without eithar
rail or pylon.

At the end of 1903, the ardours of our audacious
aeronauts were revived. Colonel Benard pointed out
that year, that, if the weight of the motor fell below
5 kilogrammes per horse-power, realisation of flight by
means of '' heavier than air " machines would be pos-
sible. The great authority, the sureness of the views
of the illustrious and learned officer were more than a
hope ; they were a guarantee for the pioneers of the air
who set out towards the conquest of the atmosphere.

Distinguished among the most prominent of ardent
sportsmen Was Ernest Archdeacon, who, as far back as
1904, made some experimental glides with an aeroplane
among the dunes at Berck-sur-Mer. What perseverance
was necessary at that time to pursue, without faltering,

EARLY DAYS OF AVIATION 249

this struggle with the uncontrollable element ! What
faith in the future, not to allow one's self to be turned away
by the criticisms and the more or less witty satires of
the detractors always more numerous than the ** actors ! "
But the latter were enthusiasts ; nothing would stop
them. Voisin built and tested with Archdeacon, Ferber
and Santos-Dumont ; the latter sought to forge the
^* connecting link " between the aeroplane and the kite.
He constructed a biplane which could float upon the
water, and had it towed along the Seine by the Rapikre^
one of the fastest motor boats. The apparatus rose,
carrying the aviator, thus excelUng courageous efforts
of many persevering workers. Hereafter the possibility
of aviation was established. Also the experiments in
aviation multiplied.

It is necessary — it is essential — to point out that
nothing had transpured concerning the experiments of
the Brothers Wright, whose existence was scarcely
known ; a stronger reason for not knowing any details
of theb mysterious machines was that their authors
jealously preserved them from prying eyes. Also does
not the merit of the French aviators stand alone ? Not
only have they done as well but they have done better.
What more can one ask ?

The first to succeed was M. Santos-Dumont. The
intrepid Brazilian aeronaut was the first to carry off the
prize which the generous Msecene of aviation established
in 1906 ? With what is this date to be compared ! In
1906 not a motor-driven or self-starting aeroplane had
left the ground. One can appreciate that hje who could
accomplish a flight of 100 metres would achieve an
admirable exploit, and ''the prize for 100 metres'*

Noraiiiber 12, 1906; bj a lii|^ of SaO flMtm Drift-
ipmgs and L. UMot now Iom aftarim liie pria far
SOOmefarM.

Tbaii appeand on tiie aene twa ge nUoBiMi who ty
Itfaair briUiaat geoflranlgr h^m gwitlj cottfanfantad
towttds the dewelapnattk ot aerial q^ort— MIL Hiaiijr
Daotaeh and Emeafc AnbdaaocMu The ffiriita so far
aooomidiflhad were ia a afera%lti Itoe ; liie aviatoia liea*

diffieoltieBy as we have already pouiled onl^ MM.
Deutadi and Arehdeaoon cffeted a ^nm of JI2000 ta %
first aviator who aeeompliaiied a icifremlm r IdloasakMs
the prise was won fay Henri Farman, at the ]sfly4ei»
Moolineaiix manoBavring gtwmid^ on January 1^ 190&
Theraafter tiie triniiqihs of the pe t aeverin g aviator
ocmtibned without intem^tion, and on July 6, 1908^ hf
remaining in the air for twenty*one minutes, he won the
prize so spiritedly offered by the engineer, M. Armen-
gaud, to the aviator who could remain aloft for a quarter
of an hour.

THE TWO HISTORICAL AVIATION VOYAGES BY
FARMAN (OCTOBER 80) AND BLfiRIOT (OCTOBER 31, 1908)
ACCOMPLISHING THE TWO FIRST «< AERIAL JOURNEYS'*
FROM TOWN TO TOWN : BL£RI0T REALISES THE FIRST
SEA PASSAGE BY CROSSING THE CHANNEL ON
JULY 25 1909

All the preceding records were doomed, however, to
be well broken by the %wo exploits of EL Farman and
L. Bl^riot.

Up to this time aeroplanes had simply described
. evolutions above race-courses or manoeuvring spaces,

EABLT DAYS OF AVIATIOK 251

wrlfeea:^, the grcfond pnrpaBdy levelkd, oflEered the best
EMslitifiB for the lanodiflB and dfiBoentB of the Prancfa
aeroplanflB; iheae adrsntagBGOB ocnditiimB were not
sxM&casnt &r the Ameruxn AeraphcoflB, beoanae it wm
neoeBsary for them to hsve also a jfyhja and kminhing
raiL The aeroplane had tfaoB to dflmanstnite ite poaai-
bilitieB of enduranoe, to thaw tfaact it posBBaaed really
practical utility, and liiot it did not require qieeial
£icilitie6 at haltrng-plafleB in itB aenal paaaage.

It wBB MIL fi. latman and L. Si^riot who had the
unquestioned and mdnpntahie datinctiaBQ of fblfillinf^

this demonstratiaii, antic^aEiiBd by the wiiole world.
They proposed to embark upcm an actual journey from
town to town and they smneeded. On October 30, 190R,
Henri Farman left the precmctB of bis hangar at Bony,
near the Chfilonfi Oaiiq>, at 3.50, and set ont for TtKftiitMa
The wind was S.BJE1. The aviator immediatehr gained
a h^ght of about 50 metrea, whidi waa neoeaaary, owing
to the stretcheB of tall poplars baning bia patb. Tbus
he passed over rrrexs, viSages, woods, Arc, and, after
being twenty minutes on the journey, reached Rbdms,
wliere he landed with the most perfect ease in a park
between the cavalry barradcs and Pommery House. During
this twenty minutes he covered 27 kilometres, which
gave a " start to stop " q>eed of 79 kilometres per hour.

And on the following day, October 81, 1908, Louis
Bl^riot completed a still more sensational and mora
perfect "journey.'' Leaving Toury (Eure-et-Noir) at
2.50, he steered towards Artenay (Loiret), a point
situated some 14 kilcHnetrea from the starting-point
There he had caused to be installed some captive bal-
loons, to indicate the point where he was to turn.

252 THE CONQUEST OF THE AIR

Flying a dozen metreB above the groand, the aen>-
plane pasBod over Ch&tean-Gaillaid and Damhroo, and
the aatomobileB which were following him were speecUly
'' scattered " along the roada. Eleven minutee after the
atart a fault in hia ignition caused him to alight; he
landed withont difficulty, rqHured his fnagneto^ and sti
out again under his own effort^ after a descent lasting an
hour and a half, to continue lus journey ; and now,
holding more to the west, passed Pourpry, and made a
second descent of some minutes at Villiers Farm, near
Santilly. He re-started a second time, passed Pointville
at five o'clock, and returned in quite a matter-of-fiict
manner to his starting-point, having accomplished the
first '' cross-coimtry '' voyage with descents. During
this flight his aeroplane acted marvellously well, attaining
a velocity of 55 kilometres per hour (Fig. 81).

Louis Bl^riot thus demonstrated that the French
aeroplanes mounted on wheels are complete apparatuses,
truly self-startiug, practical, and capable of resuming
their flight when it is interrupted ; he showed the ser-
vices that aero-locomotion could render us, illustrated
that aviation from that time henceforth could enter into
everyday practice.

Certes, one had been so persuaded, but a good prac-
tical demonstration is worth more than exhaustive
arguments : contra factum non valet argumentum. Con-
sequently Farman and Bl^riot were absolute demonstra-
tors, and definitely opened for us **the Highway of the
Air " ; and it was a fair act of the Acad^mie des Sciences
to divide the Osiris prize between Bl^riot and Voisin, the
creators of these marvellous aviation apparatuses.

But these exploits came to be surpassed ! By a

EARLY DAYS OF AVIATION 268

remarkable flight Bl^riot crossed the English Channel
on July 25, 1909, in 27 minutes 27 seconds.

pQUrpry

I'fStop
& Turn

Fia. 81. The flnt " Mrlal *(i;ft([e " eSeoted Id % cloaed circle betweeo Tour;
Mid Art«DB7 with dflMwU, bj Loaii BUriot (October 81, 1908).

StartiDgfromBaraque8,on the French coast, at 4.35 a.il,
his objective was Shakespeare's Cliff, but the fog com-
pelled him to seek a landing-pmnt on the Margate side.

tM THB CONQUEST CMP THS Am

Tlds adnoTonioiit lianlfitod tiis definite eooflMrt of
^bm air hj men in tlie worid'e hkfcofy. Rngfaund and fliB
e^f of London gn^e IBMnot a leeeption sodi ts is
eartonded to a ▼iotonoos genofalt end this honour
e eoo rf ed hf tlie English pabIio» wbb appreciated b^
tta IVenoh people. When !l^riot retnmed to Pam
llie Franoli oiq^ital weloomed lum aa erne of its most
l^oiiooi aona, and leoeiTod him with an mithnaaoB
whioh win never be forgotten.

And two days after BMriot^ on Jvlj 27^ Hnbert
Ijttham^ on his AntainMte moncq^ane^ erMaed the Stait
from the Fnmxk mde, bat nn&rtnnately feSl into the
aaa when onty a mile froitt the Rigliah ooastb

TeB» trofy I Man has now definitdy eonqoered tiie
atmosphere!

THB BNTHUSIASnC PUBUC MOVBIIENT IN FAVODE
OF AERIAL NAVIGATION

Prom the day when Farman won the Deutsch-Arch-
deacon prize aviation created an indescribable enthusiasm
among all classes of society. For a year the shops and
vendors of post-cards sold nothing but photographs
of aeroplanes, portraits of aviators, and illustratioDS of
motors; the widespread publicity with which the managers
of the Brothers Wright surroimded the experiments of
the American aviators, helped to maintain this movement,
and the numerous excursions of the Bayard- Clement
airship, which on more than forty occasions went and de-
scribed evolutions over Paris, prolonged the absorbing
interest of the people, provoked by the success of aviation.

At Auvours enormous crowds flocked from all parts to
assist the Wrights' flights ; at Issy les Moulineaux the

EAJELLT DAYS OF AVIATIOX «5

use of a manoBUvnng gronnd liad been veary ni^arcUy
spared to the FiBnidi airifttoEB; another wus liberally
placed at the difipoBitian of Idie foreign aviators ; not-
withstanding the eaify hoar (firom 5 to 7 A-Il) that
was imposed npaa oar investagstcra, Ijionsands of the
corioos were always l^iere to aasiBt a £i^xt or a descent.
Cinematographs have leprodnoed and popnlarised the
most soocessfbl ffights ; iiie aomial revje w s have exten-
sively introdnoed llie aeropIaDe into '&ear jnctoi^es.

Bat it was in the imaginatiaD of Hie yo^mg Iblks that
aeronaotical schemes were eonoeoved; tiiey dreamed of
nothing bat aviation; at ooUege they made paper
aeroplanes ander 12^ cover of their desks, to goaid them
against detection faj their totor; whilst the latter,
stadying f<nr his science degree, was occopied on his part
in calcalating the elements ct some flying-machine that
would revolationise the field of aerial travel !

Aeronaatical ccmstroction iahops sprang ap on every
side, and aeroplane coostroctors have already issaed
catalogues of aviaticm apparatos, '' pajraUe after trial by
the customer,'' whilst — rign of the times — agencies have
been established to £M»litate such transactiona

This mov^nent was interpreted, some years ago in
France at any rate, by the foundation of an aerial
League^ which had the happy inspiration to have
resort to the knowledge of Professor Paul Painlev^.
But it has shown itself especially by redoubled efforts
among the Societies which are so actively concerned in
aeronautics : the Socik^ franfoise de navigatian aSrtenne^
presided over by M. Soreau» generally recognised as the
oldest, since it was founded in 1872 ; PAiro dub de
France, equally publicly appreciated, presided over by

SM THE I^ONQUBST OF THE AIR

IL GaiUetet, of the AcacMmie des Scagnees, tite Am]
of wliidi have been 00 fioitfvl m tlie difbnon
developnient of aeroiiautioe m ell itrnhnnichmi^fAi^}
nauUque CM>, fAcadkme Ah im ^v^tique dm
^Aviation CZtifr, and oilier eodetJee have
inereeaed the nmnbw of their membeni, At
fAhv ChA de Bdgique^ 9ijfy fnti^^
a learned doaUe of MtteenOy has followed tbe
of ita French brothera, and ia pfo gr eaai ng in a
ahlemaiUMr. T f^ Qf^^^^YiTinfflandi ^ff^ T^ylr ^Ih ^'
activity la manifeated. And m tnnit qieeial
and joomala have been created; let naneeal^ fint, tleshl
original oigana of aerial locoiaotioBy PASnnamt^,
in 1866, and tAirapkUe^ that reaaadkaUe paper
by ao great an anthttity aa IL QeoigeaBeaaa^oai*

oonatitute the archivea of aerial nav^atko^ and^iv^haii

largely drawn upon their files, with the requiaite permis-
sion, in writing this book; to their editors we extend
our thanks. Around them have been bom — VAiro^ la
Revue aerienne^ la Revue de rAvtatian^ P Avion, VAmaiion
iUustree, &c. In Belgium two excellent reviews, Za
ConquSte de VAir and VAiromicaniqtie, have a wide cir-
culation ; it is the same in London, Berlin, and Italy.

And all this is the result of the triumphs achieved
during the past few years. What is the outlook for
to-morrow? and how striking is the consciousness of
mankind of the value of the great inventions which are
perfected to modify in a far-reaching manner the con-
ditions of existence and of social life !

What is the future of aerial navigation! * That
remains to be investigated in the following diapter.

CHAPTER VII

THE FUTURE OF AERIAL NAVIGATION

AbRONAUTICS and aviation : ApPUCATION to war, civil LIPB,
AND scientific INVESTIGATIONS : ECONOMIC IMPORTANCE OP AERO-
LOCOMOTION

DIRIGIBLES OR AEROPLANES ?

It now only remains for us to ascertain what is the
ftiture of this aerial locomotion, which at present is
80 full of promise and has developed with a rapidity
never before witnessed in the evolution of any other
invention ?

And, above all, it is necessary to examine individually
the possible applications of the two forms of aerial loco-
motion, and the two types of atmospheric vehicles —
dirigible balloons and aeroplanes. To which shall we
^ve the preference, and what is the future of each ?

If one were only to be guided by public enthusiasm, a
trifle '^ packed,'' so strenuous in exaggerating the merits
of an invention when it '^ succeeds," as it is often slow to
recognise it in its infancy, then aeroplanes, the last to come
into popular favour, would be the only machine capable
of widespread application ; the scientific writers of the
Press have already put them to all kinds of work, and
they hasten to anticipate all the services which they
must fulfil in the very near future, whilst they cannot
defend themselves against a shade of disdain for the large

«57 R

'HE CONQUEST OF THE AIR

urehipe vhich we saw perfected "yesterday" in tbe

ageruess for that of " to-day."

It is oecesaary to allay a trifle this prematore entiiD-
aiastn, which is prone to be overdone. It is necessary to

void again, in the desire to advance too quickly, those
(falling experiences that occurred with motor-boats when

le ianatics hailed them as the torpedo-boats of tlie
iuture: the ridiculous venture upon the transmediter-
"anean race, which a Httle consideration would have

voided, and in the course 'hich all the boats partid-

iting, ezoept one, were lost, must serve as a lesson

nd give food for thouj /i those organisers of too
i^romature, sensational

Let us say at once that he future is immense, so

amense that it ig t to set it out in detvl

it it will be by e* :, and all that one can actually

Jo is to sketch out iti oad lines.

In the first place, there must be no exclusion of either
of the two systems, balloons or aeroplanes : botJi have
their raison d'Stre because they correspond to dlffermt
requirements.

When it is necessary to travel very rapidly, when,
above all, progressive development has assured the per-
fect security of aviation apparatus, one will have recourse
to the aeroplane, and without doubt we shall see " aero-
plane liners" of huge dimensions, carrying nuroeroos
passengers, securing sustentation with nothing but their
enormous speeds. But these velocities would he truly
attended with dangers in case of landing, or, above all, a
" mishap to the machine," becatise, if the apparatus sus-
tains itself by great speed, it would not have sufficient
supporting surface to keep soaring without the motor.

FUTURE OF AERIAL NAVIGATION 259

Perhaps for this reason aeroplane liners will be reserved
even for transatlantic passages, as the ^' hull " with
which they must necessarily be equipped will render
landing less dangerous upon the water. Transatlantic
journeys would then be made at speeds exceeding 200
kilometres per hour ; that is to say, one would travel from
Europe to the United States in a single day !

But when this speed is unnecessary, it appears scarcely
possible to disclaim the envelope charged With light gas,
this ^^ bladder," as it is disdainfully called by some
aviators, because, if it ti*avels at less speed, it has
nevertheless the advantage of sustaining the aerial
navigator in the atmospher! without the li of meoha-
nical energy. Consequently here is safety, and should
the motor of an airship break down one is always master,
or able to continue the journey " before the wind," if the
latter is in the right direction, or to land, which with a
good aeronaut wiU always be possible without very great
risk. Moreover, an airship can carry many more pas-
sengers ; it can convey them in greater comfort ; when
it will have attained its independent speed of 60 or 70
kilometres per hour, instead of 40 or 45, it will be able
to set out practically at any time. Lastly, it can " stop "
at any determined point in the aerial ocean, which the
aeroplane, tributary to an indispensable sustaining speed,
cannot do. Also, I do not deceive myself in stating
that its career is far from ended. It has no more than
begun, and it will develop side by side with the aeroplane.
Let us now examine some of its applications to aerial
navigation, and we will then see which is the type of
locomotion best adapted to each case.

• HE COVQCEST OF THE AIS

ccunr AmjcATioKfi

1 rr gin r] pi*! i »1 tcndcmcr 'wlutdi
ftothnnieD todeKtrcrcBic

tsKiB bas roBoHed, first aad

r MriaJ narigatduu to warfiirfi.

I ijl know haw ocm |JtaJj

wria^ over all ot^er ocnudxiM bf As

■17 ArigiUe, Xa/)ViMM. M leSfs wfaeoBM BD Otis

m bad «■» «t its ei 1 ; and dHng tbav In*

r j««a tbe ■ooosMnv ancMof the LAit^g.la

4ne. rHk de Pari*, i « JZ^«Wfwr (I onit aQ

it tike faoA) tisv« sbown irope tint Ft«Dee bas an

Aerial zary " in being, an 3^ far tlie defenee of ber '

Mfea.

What foHD of aerial Temsl will hat serve tiie Deede

rwaHare? Airafaipaoracro laneaf As "eombatantB^
or " aoouU " i

I fear, after what I have heard fimn <Aoei8 who are
more competent on this sulject tiiao I, that as a com-
batant it will not often be used. Aerial battles do
not appear imminent becaoae tiie inatallataon of aoy
artilleiy whatever on board dirigible balloons woold be
extremely incoDvenient; with regard to aeroplanes, their
requisite high q>eed, and the impoesibility of " pulling
up," practically prevent the use of caoDon except of
small calibre.

There is one good use for the airship in war : that is
dropping melinite shells (or some other still more devu-
tating explosive that may be invented) from a height
within a fortified area or a beseiged fort. Here we are
in the realm of the possible, and this utilisation of the

FUTURE OF AERIAL NAVIGATION 261

airship is not chimerical ; it is only requisite to consider
if the " result " would be very advantageous.

Let us point out that the range for the projectiles
would not be very correctly known because the balloon
would be forced to hold itself at great altitudes so as to
be able to escape the fire of the enemy. Moreover these
projectiles, to produce a sufficiently destructive efiect,
would have to be of considerable weight — 50 to 100
kilogrammes at least. Now a balloon suddenly lightened
by 50 or 100 kilogrammes would take much too rapid an
ascensional a movement, and the operation would not be
without danger to the aeronauts. So far as concerns
aeroplanes, the impossibility of " pulling up " practically
precludes them from this form of action without speaking
of the certain peril which would result from the fatal
upset of their equilibrium caused by the sudden
unballasting.

Moreover, let us point out at the same time that aerial
vessels, on the other hand, have little cause to fear hostile
projectiles, because of the altitude at which they are able
to float, and the aeroplanes because of their speed.
During the siege of Paris in 1871, only one balloon
was captured by the German troops, and then the
pilot who controlled it was but little experienced in
aerostation.

Pausing to consider the possibility of an '' aerial
combat " between isolated units, it is certain that if two
hostile aerial vessels met in the air they would seek to
destroy one another ; but if they were two aeroplanes,
and unless the gun-fire of a mitrailleuse of one put the
motor of the other out of action, or rendered the aviators
hors de combat, they would be unable to withstand the

MS THS COVQUIST OF VHB AIX

foilMirm ; ^bmt tibwe wwdd W no mmpmm, no
tiiara woold to cttty tw» ttmdtsBMos «t^^

Would dirifOilfliy ahmys amwivo and ulnti^wiy ibw,
arodli dwad tho pwawnng q pao dy aagopiMW? Idamfc

ipoeify Mridl (ddfl^ the Mraiiai^ would avdfl hiawdf tf a
iwiottiMtliedBEttieiiey^of triw&it^^ rwebjfliBav-
ing out ballart ; lie would tlifla fly «p m a Tortieal bia,
tibat is to aay^ Twy fi^idly , irfiikit the STiaton coidd od|jr
liw oUiqoefy^ aad then ta a alii^alope, thexofajaaEaeut*
iag JBgaage, m a woid, "irwticelly tacdmy^; anonovar,
the motor of an aaropkiie will nrn dower and dAimt in
aoeoidaiios with the prog r ess of ite aoosati own^ to ilie
drareaaed mupptj of tiie oKjgsn aeoesssty Sx tii* o»h
bastion of the gaseoiui miztaie which drr^
Lastly, whilst making ite vertieal imk to eome vp witik
the aiiship, the lattor, more staUe and aUe to eaxiy, if
not guns, at least a quick-firing weapon, or in any case
grenades, would have ample time to riddle it and much
more easily than it could fire upwards, the more so,
because the artificial bird would offer to the fire of the
airships the large target of its supporting winga

For these reasons I fear, therefore, that aerial vessek
will be poor combatants. On the other hand, they will
be useful scouts, and there will lie, in all truth, their
principal rdle in the time of war. The dirigibles, able to
carry instruments of precision, capable of stopping to take
a photograph or make telemetric measur^nents, will be
extremely valuable to the chief of an army who has them
at his command. The aeroplanes, owing to their great
speed, will be the instruments par excellence for rapid
reconaissances, for " raids " carried out over great dis-

FUTURE OF AERIAL NAVIGATION 268

tances ; moreover, their capability of returning very
speedily to recount what they have seen will thus render
them more indispensable than their larger brethren to the
general of the Aiture war. For communication with
besieged positions the aerial vessels will be without rival,
and it will no longer be possible to completely isolate a
fortress, what with wireless telegraphy and a fleet of air-
ships, or a flotilla of aeroplanes.

With regard to uses in naval warfare, these will be
numerous, without a doubt. A cruiser can always have
on board one or several aeroplanes; it has even the
mechanical energy necessary to launch them. It can
consequently send one into the air to sweep the horizon,
and a hostile fleet could not easily conceal itself Un-
doubtedly submarines will not be increased in number,
for the aeroplanes peering vertically into the waters of
the ocean will perceive the torpedoes and submarines at
a very great depth, whereas from the surface of the sea
they could not be seen at all, owing to the obliquity of
the visual rays coming from less distant points.

Will battles then be solely decided under the waters ?
Mystery and horror ! Let us hope that these events will
never come to pass.

APPLICATIONS TO CIVIL LIFE

What will be the " civil " applications of locomotion in
the air ? Evidently they will be numerous and varied,
and it will be possible to travel either by " public service "
or private vehicles.

Undoubtedly the latter will first come into vogue ;
private airships and aeroplanes will for a long time yet
be the vehicles de luxe, I may even say of great luxury,

SM THE CONQUEST OF THE AIR <

«Dd only those prinfeged hy Fortune, or those who wA
to *ppMr eo, will be Mb to make atbU of thor iia& Bat
^ we not eee the Hune derelojunent in the cue of the
mtomobilel and will not the desire to ^pear, like "our
fiiends," in • dizzy aeroplane, tam aooiety npnde down?
without epeaking of the attraetiona of the "^teool
oostome " which the enterprise of our great dteamaken
will not &il to bring out at the h^^^ nKMiient» and to
charge accordingly 1 It oannot be denied that speed
has an irrebiatiUe fiuoination ; it produoea peculiar sen-
sations, a veritable intoxioatirai, and to taato these senaa-
tiona oomluned with a deoreaae in the time occupied ona
voyage will be one of t^ next fbtms of refined luxury.
Besides, doea not the reduottra in the length of a jouniey
increase the avulable time £» other things, and therefoie
does it not, in an tndireot manner, lengthen the span of
life!

Among these vehicles de luxe tiie aeroplaoea will be
the " racers " : they will go rapidly ; will be able to
carry two, three, or more persons. They will replace the
extra-rapid automobile with which fanatics hurtle along
at some 80 kilometres per hour; only in the air it
will be " some 200." So &r as concerns those who are
desirous of travelling quietly and in conqpany, and
possessed of " the means," they will use the dirigpiUes
which before long will proceed at 60 or 70 kilometres per
hour. Certainly it is highly enjo3rable to have an eztenmve
uninterrupted view. Let us point out, moreover, that if
by a head wind the speed of the wind curtails that of
the balloon, on the other hand, when the wind is follow*
ing, the two speeds will have to be added ; and in choosing
his wind — that is to say, the day for his trip, which is

PLATE XXXI

ft -.,

FUTURE OF AERIAL NAVIGATION 265

possible to those of independent means — one will make
'* some 1 00 per hour " in an airship, with the addi-
tional advantage of comfort that will obtain with this
^* travelling coach" of the air. Then, without doubt,
numerous hangars — " hostelries for balloons " — will be
staked out along the great highways, and one will be
eible to stop en route as one actually does in motor-
trips.

Let us remark though, without delay, that for some
time yet the greater bulk of the population will
have to go on foot, by motor, boat, or railway, and the
great aerial speeds will be a luxury or sport. The con-
veyance of merchandise will always be by land or water ;
these will be accelerated, but I do not think for many,
many years one will consider despatching goods by the
aerial highway.

But one minute : there is one phase of transport — the
"post" — which will use the highway of the air, and
perhaps more so than we anticipate. I believe that
before long " mail " will be sent aerially, and for this
aeroplanes will be vastly superior to balloons. Being
able to set out at any time, travelling at enormous speeds,
they will carry letters and valuables ; it will be easy to
despatch them at any time, one after the other, in all
directions; and thus we shall have "hat- bands" for
*' aeroplane messengers," who will go straight from city
to city every hour, or even more often. The only inter-
ruptions to such will be those days of heavy storms.
Then it will be necessary to trust the messenger to
express trains, which will travel at far greater speeds
than now, and yet distant points will complain bitterly
of an unacceptable delay.

SM THE CONQUXST OF THK AIR

Undoabtedly dw appauanoe t^on the aeana of ami
▼ehiclaB will profiMUidly modify the coDditions of oar
existenoe, bat it ia not neowsary to count upon this
change oooiiiig too qniekly. It will be some timebefcre
m see " aero-taziB,*' and the transit in towna will be
maintuned fin* many yean yet by terrestrial vdiietifc
But it is oertain that bchuc d^y houBe-designer» will fed
the neoeanty of catering fat the aerial vehicle by elevMd
mooring^tationB. B00& will disappear in favour of flat
terrace* auited to launching and lauding stages. Probablj,
however, departure will not entail nuwa tlian a ibort
start. They will be made m aUu, ^'"■^"it the flying
apparatus will be, without • donbt, eomlMnalaoiw oCthe
h^copt&TB and the aooplane, an. association whidi
aasures security in the deaoanta oi the aerial vehicles is
confined areas and at a very great a^eed ; and perhaps
upon these flat roo& a£ iaigp hoteb -vre may eveo see
garages for airships I What is certain is that the " future
city " will not have quite the same appeaianoe that
it has to-day, and wealthy residents will alwaya ton
their ambition towards the clearer, healthier, and less

SCIENTIFIC APPLICATIONS: EXPLOEtATION OF
UNKNOWN COUNTRIES

One of the first applications of the new locomotion will
be scientific, and more especially geographical. The
facility of moving above all the obstacles with which the
sui-face of the earth bristles renders it eminently suited to
the exploration of unknown continents, to traverse which
no means of communication exist.

One knows how difficult and dangerous is the explom-

h.—l-Ui.-*..*

FUTURE OF AERIAL NAVIGATION 267

tion of these mysterious countries, such as those of
Africa, the centre of Asia, Central South America, whilst
the torrid climate, the dense vegetation forming impene-
trable obstacles, dangerous animals, the hostile natives,
seem to league against the explorer bold enough to
penetrate for the first time those territories where the
foot of a European has never trodden.

Also, what blanks still exist upon the maps of Africa,
Asia, Australia, South America, and the Polar regions,
Arctic and Antarctic, and how slowly, in fact, are geo-
graphical discoveries efiected when it is necessary to
explore the details of our planet by "crawling," so
to speak, over its surface. When the explorer advances
through the torrid equatorial regions, when he must
toil through the bush, it is as much as he can cover 15
to 20 kilometres per day ; this is the average progress
of an exploring expedition ; if a passage must be cut
through the dense primeval forest by hatchet and axe, to
clear the way, to cross very closely tangled stretches of
tropical vegetation the advance is slower still. When
one explores the glacial lands of the Poles, the '' ice-
fields" of Greenland, Spitzbergen, or of the Antarctic,
it is not always in kilometres that the distance
between the daily halting-points is figured, and
in the meantime the privations and the dangers are
as a result proportional to the road travelled over
each day.

What are the data which the geographical traveller
secures at the cost of such innumerable perils ? Does he
bring back the complete map of the country he has
traversed at the risk of his life ? No, unfortunately,
because in order to prepare a complete survey of a

268 THE CONQUEST OF THE AIR

region it is necessary to stay there a long time, and to
travel in all directions ; more often than not the ex-
plorer only shows merely his itinerary, that is to say,
only a " fringe " of the country along the path which he
followed. Certainly he will record what he sees to the
right or left of this route, will indicate the hills and
mountains which he has perceived on one side or the
other, with their distances and heights, estimated
according to " bearings," But they will only slightly
widen his " fringe " without giving a general map ;
moreover, the regions described in this manner ivill be
rather more indicated than charted with the necessary
geographical precision.

In reflecting upon these difficulties one can under-
stand the existence of these "white spaces" in our
atlas ; what is marvellous is that man has been able to
gain such actual knowledge of the Earth, in face of this
lassive hostility of the unknown country.

All this time, however, although we have been
powerless to learn the details of the surface of our
planet, astronomers hare succeeded in gathering all the
details of the surface of the sky, to enumerate up to a
very extended limit the brilliant stars which are sprinkled
above us ; in a word, they have made a map of the
heavens.

They have prepared it, moreover, through a unani-
mous understanding among the civilised nations ; they
have prepared it by a surveying method which furnishes
indisputable testimony : photography. The photo-
graphic plate, as was happily said by Janssen, is the
" retina of the savant," but a retina which retains the
impressions it receives.

FUTURE OF AERIAL NAVIGATION 269

Up to now, certainly, it has been impossible or, at the
very least, difficult to apply photographic processes
to. the representation of terrestrial surfaces in the same
manner as it was in the preparation of the map of
the heavens ; one had, in short, no means of '' seeing
the earth from above." The balloon, and captive at that,
was the sole means available, and it was scarcely able to
provide more than "local" views of the country beneath.
Moreover, to obtain sufficiently numerous photographs
it would be necessary to tow a captive balloon across the
continent to be explored, and consequently to transport
it, and his accessories, by means of a caravan ; up to
DOW this difficulty has never been overcome.

To-day, on the other hand, the dirigible balloon
furnishes us with the solution so much sought after, and
I believe that it will fulfil it in a complete manner, thanks
to the addition of topographical photography in the
form so excellent and so precise devised by Colonel
Lauss^dat about 1852.

Let it be pointed out at once that taking only the
road traversed, and even if it were kept within certain
limits, the dirigible aeronaut-explorer, by vertically
photographing the earth above which he manoeuvred,
would be able to obtain a route survey of a superior cha-
racter to that which explorers travelling over the surface
of the ground would be able to procure. Indeed if, for
example, he stood at a height of 1000 metres while
photographing the earth underneath with an apparatus
of which the wide-angled lens had a "field" of 90
degrees of angle, and a focal length of 20 centimetres, he
would thus have a photograph which would be a topo-
graphical map on the scale of xj^; but this map

270 THE CONQUEST OF THE ATH

would be both exact and complete. Numerous photo- I
graphs would be able to be obtained, and by placing
them side by side one would thus have the detailed and
correct topogi'aphy of the route followed by the airship;
as, moreover, the latter travelled at 58 kilometres per
hour, the explorer would take in one hour more maps
than the ordinary explorer would make in three days,
and it would be done without danger, without fatigue,
safe from the attacks of natives, and protected above all
&om the onslaughts of poisonous insects, from marshy
miaemffl, which are the greatest enemies against which
explorers have to contend. To-day a balloon (as the
Zeppelin has demonstrated) can travel for 38 hours
without descent ; therefore it would be able to make an
outward journey for 19 hours, with 19 hours for the
return journey, stop for the night, and in this manner
explore the country within a radius of a circle of
1000 kilometres, which would take a traveller from 40
to 50 days to pass over.

But by this simple means, notwithstanding the
already very marked superiority of an aerial voyage
from the point of security, speed, and the data obtained,
one might wonder whether the results would justify the
despatch of a dirigible to an accessible point of the
continent which it is desired to study. But then one
can and must rely more and rather upon the collabora-
tion of the dirigible and the camera.

Let us state at once that the dirigible will be greatly
improved within a very short time ; its present speed
of 50 kilometres per hour will be easily increased to 60 ;
its volume will be augmented, and in place of 3000 to
3500 cubic metres it will be given 5000 to 6000 cubic

FUTURE OF AERIAL NAVIGATION 271

metres while still preserving its '' elastic '* construction
and not falling into the drawbacks of the rigid baUoon ;
already an airship of this volume is under construction
in Paris. If, under these conditions, one is content with
a speed of 50 kilometres per hour, which is magnificent,
one will be able to carry sufficient fuel for a continuous
Toyage of 50 or 60 hours, which means 25 to 30 hours
for the outward and the same for the return journey.

But in 25 hours a balloon travelling at 50 kilometres
per hour would cover 1250 kilometres. It can descend
during the night when photography is impossible, set-
ting out again the next day and even stopping en
route if necessary. The perfection of the special
balloon " fabrics," the judicious use of the air-ballonnet,
enables the balloon to remain in the air without any loss
of gas, and the airship Patrie which was perceived
floating in the North Sea ten days after the storm tore
it firom its bonds, shows the strength of the modern
airship. We anre able to say that there is in course of
realisation^ in the field of aeronautical construction^ air-
ships of from 5000 to 6000 cw6ic metres volume, and
having from 1000 to 1200 kilometres '^radius of
action.'^

Consequently, in choosing convenient " centres " for
establishing aeronautical stations, centres which will
coincide with inhabited and accessible points to which
one can easily convey the material axid personnel, one will
be able to cover a continent with a network of circles of
fix)m 1000 to 1200 kilometres radius, each of which can
be traversed in 20 or 25 hours, by an airship carrying
the explorers and their instruments. Fig. 82 shows how
one can apply this system of exploration, which is so

)F AERIAL NAVIGATION 278

s base, have their optical axes turned

point, one has a triangle, the two photo-

lultaneously from which enable one to

1 structure. It is in fact " plane table" f

keying, with this difference, that instead

the graphic work upon the spot, one

nd with him " and completes the work i.

nethod is even capable of simplification.
3 at the two extremities of a " base,"
ich is absolutely known, two cameras,
vhich have their axes absolutely parallel,
3ir shutters at the same moment, which
latter with a battery and two electro-
these two photographs one could com-
e country up to the limits of the visible
I of Dr. Pulfrich's remarkable instru-
rnpa/rateur^ buUt by Zeiss, the eminent
►f which is retained in the museum of
5les Arts et Metiers. A most renowned
i. Professor, 0. Hecker, of the Potsdam
"te, has shown how one can make the

sneous use of the parallel two cameras
-ae of known length is essentially pes-
rigible of the Bayard -Clement type, for
f cS and indeformable car, of which the
» will be the base, the two cameras will
^3d at the two extremities, and their
one and the same time definitely
Qe. The photographic data necessary
f the map by the aid of the stereo^

t ,

1 1

i':

■y

•ii

■ r:

f ■!.

• Ii

s > ■■

A-

! HE CONQUEST OF THE AIR

simple, so rapid, and so safe, to a prescribed re^oa; to
the African continent, for example.

The centres indicated are accessible ; two are in Frencli,
two in English, and one in Belgian territory. They are
Timbuctoo, the shores of Lake Tchad ; Leopoldsville, for
the Belgian Congo ; Dongola and Lake Albert for the
glish stations. In tracing round the centre of these
circles of .1100 kilometres radius it is seen that the whole
af Central Africa can be covered thereby, and the circles
Day even " overlap." The exploring traveller in hia
lirigihle, therefore, can actually touch every part of the
inknowD country. The provision and the maintenance
f the aeronautical stations can even be dispensed with
r the immediate return journey, as it can halt at a
different centre to that from which it set out, which
might be of great value in case of an unexpected storoi.
In this instance I have confined myself to Central Africa;
hy adding a si.xith centre at Dakar the whole Mauretania
would become " explorable."

Would the airships which accomplished these expedi-
tions be limited to securing " route photographs " ? No,
they would do much better, thanks to Colonel Lauss^t's
process, the principle of which I will explain in a few
words.

In 1852, Colonel (then Captain of En^neerB) Lauss^at,
impressed by the adrantages that photography would
afford in the compilation of maps, evolved a means of
preparing topographical surveys by means of Baguerre'a
invention ; for this purpose he employed not one photo-
graph, but two, taken from the extremities of a long-
known so-called base. If one knows the angle of the
lines of vision of the two apparatuses which, from the two

FUTURE OF AERIAL NAVIGATION 278

extremities of this base, have their optical axes turned
towards the same point, one has a triangle, the two photo-
graphs taken simultaneously from which enable one to
build up the actual structure. It is in fact '' plane table"
topographical surveying, with this difference, that instead
of carrying out the graphic work upon the spot, one
" carries the ground with him " and completes the work
at his desk.

This excellent method is even capable of simplification.
It suffices to place at the two extremities of a '^ base/'
the length of which is absolutely known, two cameras,
the objectives of which have their axes absolutely parallel,
and to actuate their shutters at the same moment, which
is a very sunple matter with a battery and two electro-
magnets. From these two photographs one could com-
pile the map of the country up to the limits of the visible
horizon by means of Dr. Pulfrich'8 remarkable instru-
ment, the stereocom/poArateur^ built by Zeiss, the eminent
optician, and one of which is retained in the museum of
the Conservatoire des Arts et Metiers. A most renowned
Grerman Geodesian Professor, 0. Hecker, of the Potsdam
G^odesical Institute, has shown how one can make the
most of this process.

And this simultaneous use of the parallel two cameras
at the ends of a base of known length is essentially pos-
sible on board a dirigible of the Baya/rd-Clernent type, for
example. The rigid and indeformable car, of which the
length is 28 metres, will be the base, the two cameras will
be permanently fitted at the two extremities, and their
distance apart is at one and the same time definitely
known and invariable. The photographic data necessary
for the compilation of the map by the aid of the stereo-^

itttd Ui tluf> nmmi i^r tt *nll bo JoiiKsr lie merely jibflbK
pntpiib of iiw sul^aaaiii pvnud iHms. &t manmaait idl
isiuf^lAck witli tlMtm: tkew- mrt tht aan^iaatf fMtofir ;|
ft *' j^tft^n^ibiai! map " ■§ &t as tbe litnit ^ iflH «ilHl |

iBCtiy " fixed " 'ood
vercicbUv BJid iii £t
tauce far plsjiitnetiT
TboB a few anal
expadioooB made a ]
tike ioierior of cne rf I
tbe ofdee of wiud {
WQ have qxifcgn ii3
iDore tliui Boffioe H
iuiBishthemapoftbB !
entire coontiy a- !
duded therein.

But in order to
render this endeavour ,
practicable, the aaa>-
tance of several j
natiotm iH necessary : the map (Fig. 82) shows that ftv
Central Africa that of France, England, and Belgium
would suffice. The cost of an expedition of this nature
will t>o infinitely less than that attending ordinary
exptMjitiotui acliieviog the same results ; the time
will be perhaps one hundred times leas, the predsira
will be superior, and the dangers very appreciably
diminished. •

So far as concernB the country adjoining the fVench
North African posBessiooa, no places would be misaad

Zr^^i^ ' ASIA

,/-^

rS^ ^

(v^

^^^

\ "-^

£Su*Ttf

^^-"^T^

->.

\Jfc' V-J* f V

S^^^wv' ?*

•^^
•^

\ /^

•^^

_i,^aAFRlCA

rw, tZ. TV «i|<lvntMW vt Cednl
AIrk* bj dirigible

FUTURE OF AERIAL NAVIGATION 275

where one would be able to establish dirigible
depdts.

This system of working is not only applicable to Africa :
"tike whole of the " Matto " of South America, the interior
of Australia, as well as of Asia, would be able to be
explored in this manner with material results through the
co-operation of the interested Governments, and it will
thus be possible to complete the ^* map of the earth,"
which, indeed, is the least that might be done, inasmuch
as the photographic map of the heavens has been carefully
oompieted.

With regard to the North and South Polar Regions,
undoubtedly it will be in this manner, and in this manner
only, that we shall be able to learn their geography
completely and rapidly. We know how slowly explora-
tions are able to proceed after the vessel is left — that is
to say, in the same manner as one explores a new country.
It is only by heroic eflfort that polar explorers have made
their perilous discoveries. Consequently it will be by
dirigible that it will be possible to study the glacial
regions, not only in the vain curiosity " to reach the
pole," but to learn scientifically the geography of the
axial caps of our terrestrial globe. To have dreamed of
this five years ago would have been madness, but in view
of the achievements of the airships Patrie^ Bayard-
Clement, and Zeppelin, it is a feasible achievement. The
distance from Spitzbergen, where one would be able to
have a station, to the North Pole, is only 1300 kilo-
metres (720 knots). It is thus within the limits of
possibility of actual dirigibles, when they have been
perfected. Likewise, to solve the problem of the complete
exploration of Greenland, a station at Uperniwick would

Cnnitfiii ftr aahtf tm A« ■ bjj i ^u
Umb i1<— !■ of in^ dHthiMcer •■
utHy dfntnd Ifae sae ef mmrt^
•oatber at aome dirtaaee^ sad cfhie at ertaodiHg:
muiaal — itttnfe is eaae of neeesity. So &r as t^
Antarctic ii ooncerned, its exploratioa wtjold be
difficult, otriog to tbe extent of ita nr&oe^ and, wJtmt
all, the remoteoeH of its shoreB from riTiTiaiifinii
would be neoe— aiy to establish qiedal statkna, and Ai
" raids " that would have to be carried out by the m-
■hips would exceed 20O0 or 2500 kilometres outward, as
well aa return. Undoubtedly, nherefore, this will be
the last part of the terrestrial globe that will be made
known.

Be that as it may, the 'aerial exploration of unknown
onntinenta is quite possible l^ means of dirigibles. I do
not think that aeroplanes will take part therein so long as
tlipy are not provided with sustaining screws to permit
thorn to remain in the air, and in their present form their
iint"^i'*'^>'''^y °^ "stopping" prevents recourse to photo-
(iijtntfi-aphy by them. But they will be valuable auziliuies
it) the iense that by rapid reconaissances made at
hitlli Npeeds, they will be able to indicate the most
iB^raibing points of which it will be useful to have a

FUTURE OF AERIAL NAVIGATION 277

detailed map, and upon which the dirigibles, after their
indication, can be engaged.

One other application of dirigibles and aeroplanes, a
sphere in which their use will be extended, is the necessity
to learn, by careful study, the laws of atmospheric
orculation in the highest and middle altitudes. As a
matter of fact we scarcely know the laws of this move-
ment in the inunediate neighbourhood of the earth, and
but for the work of the Prince of Monaco upon the ocean,
and those of M. Teisserenc de Bort by means of kites,
France would be very much behind other nationa

If it is desired that aerial navigation should develop as
it ought, it is therefore urgent to pursue the exploration
of the higher atmosphere, and the further knowledge that
we shall acquire in this way will be completed, if not ex-
clusively furnished, by savants travelling in dirigibles
and aeroplanes.

THE INDUSTRIAL MOVEMENT CREATED BY AERIAL
NAVIGATION

Not one of the least benefits to locomotion through
the air is the creation in a few months, as if by the wave
of a magic wand, of a new industry, and the development
of a considerable commercial movement the significance
of which it is impossible to indicate.

In the first place the generous initiative of M. Henry
Deutsch speedily found many imitators : there are actually
over £64,000 offered to aviation in France alone. More-
over, the Osiris legacy endowed aeronautics by £4000,
which the Academic des Sciences divided between the
constructors, Bl^riot andVoisin, and, through the generous
and active initiative of M. Barthou, Minister of Public

X80M ilmdy «M, Mi gbift

uaCUbiwf JKmotA Imad£ticMtat
JgfOwl-CTfcmiif, JMjpi'fB, aadAuM (bdim]
ynMkOfB). That totak in kD te* i
boOt in i>ur yo^n. Wb«o one r
OD tba menge £12.000, that makoB XU(M>00 ;
BOntiMaX120,000 if ooetakeBintoaoooiuit tiiepon^ei
Mid tbe moDej expended tipon experiments. I do not
take into ooiuideration the numeroos efibrts <^ HH.
Santoe-Uumont and Comte de la Yanlx ; of the attempts
of MU Mal^tt Mar9a7, and others; by adding all
together one obtains for tiiis period of in&ncy and
ex|>erimentB something like £400,000- This is an economic
aapeot of the question that one must not overlook, espe-
oially if one reflects that we are yet only in the early
stages.

And aeroplanes I It is by tb6 hundred that one nov
oountu their ooostniction ; the money circulated for an
aviation apparatus is less than for an airship, that is
pertain, but it la precisely for this reason that a veiy la^
number of persons are participating therein, and it is hj
hundreds that it is necessary to enumerate them at tliis
moment. If one admits t^t each, including the tmk.

FUTURE OF AERIAL NAVIGATION 279

represents an outlay of £800 (and we under-rate the
truth), we thus arrive, under this head, at many thousands.
And here it has heen more rapid since the true experi-
ments in aviation do not date back more than eighteen
months. If one keeps account, moreover, of the money
expended in fruitless experiments, in repairs, in expenses
of all kinds, the balance-sheet of aerial navigation, both
dirigibles and aeroplanes, shows a money movement
daring the past five years of more than £800,000 ! That
18 excellent for a start.

And this is only in France ; the whole world knows
that Grermany has expended enormous sums upon its
military dirigibles : it exceeds 12,000,000 marks already.
In England, the United States and Italy the movement
18 equally important. Aerial locomotion has therefore
given birth to an industry which appears likely to
undergo a tremendous expansion. This industry creates
a financial reflex because in France alone ten limited
companies have been actually established, representing
a total capital of over £200fi00. There are many others,
also very important, abroad, and the Bourse is entangled
because, rightly or wrongly, speculations have already
taken place in these new stocks.

WHAT REMAINS TO BE DONE ?

Now what progress remains to be accomplished in
order that aerial locomotion may maintain its excellent
prospects for the future, in order that new conquests may
justify the enthusiasm provoked by its glorious d&mt ?

In connection with dirigibles the first condition will
be to obtain at once the speed of 60 kilometres per hour
at least, so as to reduce to twelve or fifteen days per

S80 THE CONQUEST OF THE AIR
year the period of compulaory idleness- It will then be
Decessaiy to increase their volume so as to altov
the increase of fiiel-carrying facilities for participa-
tion in lengthy voyages ; in a word their mding of
■ action must be extended to 1000 or 1200 kilometres;
I consider this indispensable. Then it will be available
for armies and exploring expeditions, of which services
we have already spoken.

But as the possibility of any accident to the motor
must be prevented, it will be necessary to provide them
with two independent engines and two propellers ; in
this manner the failure of one engine would not bring
about disablement, or compel landing at some place
where an accident might result. The balloon fabrics
will be still more perfected, and will assure to an airship
the possibility of remaining inflated in the air for fifteen,
twenty, or thirty days without taking another charge of
gas. Their construction will certainly be improved, and
one will learn the best means to avoid the cause of that
" fermentation " of the rubber which is incorporated
therein, and which may render the dirigible's envelope

But one thing which will be indispensable, in fact
necessary, will be the construction of garages, landing
stations and shelters ; by this means, and by this means,
only, will the airship render great service, not only in
France but in the colonies.

With regard to aviation apparatus much remains to
be accomplished. At first it will be necessary to in-
crease to a great extent their security, and to assiire
their lateral and automatic equilibrium. We haw
seen that it is compulsory to increase their speed up to

FUTURE OF AERIAL NAVIGATION 281

150 or 200 kilometres per hour, velocities which we shall
witness soon without a doubt. And at the same time
it will be necessary to reduce the dangers of shocks
at landing, dangers which will increase in proportion as
the supporting surface will be diminished, because of
the progressive increase of the speed of the aerial
vehicle. It will be essential, more so than in balloons,
to equip aeroplanes with two independent motors, each
of which cdone will suffice to assure sustentation and
propulsion. In this manner only will it be possible
to reduce to the minimum the risks of an aerial
journey. The number of the devices for steering and
control of the motor must be restrained to the minimum,
80 that the pilot has less to do ; the facilities for accom-
modating passengers must be improved; it will be
necessary to increase the radius of action which scarcely
equals two or three hours' actual travelling at 80 kilo-
metres per hour ; special safety arrangements for cases
where the aeroplane would have to descend upon a lake,
a river, or the sea must be provided.

And above and before all, the necessity of launching
from level ground must be suppressed, as such may be
unavailable, as, for instance, in a mountainous or forest
country; if this obligation be persisted in, it will be
a serious obstacle against the general application of
aviation.

This is the goal to which the efforts of the investi-
gators must now be directed. Flying machines must be
able to " rise from the spot " ; then they will have an
immense future, and maybe we shall see aeroplane-lingers
ploughing the air with numerous passengers, whereas as
yet we have only aeroplane birds. Possibly this deve-

nil ilM|,Trii Ifi iMjwIffi

tUtogtfh

! to HMj tf ffe Sv^qpeaa^lM
I Ma, ^Mfa to the iinl • n, dtrnt of Urn haa,
taac tke liiwiali, to iii^iiiw tli^ and to
r! Tkmt dmnain oT the air, wiiA
I pnUilad to Unfile fcaa peoetimted, aooo iri&
gwcra rt ■• he boUl sv^npoa tlie earth, as be p«-
vaiW ttpoo sad nnda the watczs ! Certainlj the histoiy
of all bis ODoqnests b magnificeDt, bat I think tbst
nodoabtodljr the niost fascinatiDg is that which we hare
described ; it is that by which man has at last freed
himself froizi serritiide upon terrestrial soil ; he has
brokea the fetters that the laws of balanced weight
imposed npon him by the speed of his machines, and
now, henceforward &ee of all shackles, be will be aUe
to dash without hindrance along the " Highway of the
Air."

APPENDIX

SM AFPENDIX

Tli« tihnut P moving »gpinA tiw obiiqae aorface ia <L4ii e —!J

(2) p = ^sy«/(i)

/(i) hmg an aistum of the angla i. ISiiH action ib ample nul
mttit be of tke fbrm

/ (*) = X am i.

Wilb regasrd to the ^ne of X, it ia given by Sormnla which £fo
• gco f dia y to the mtmmUM who hsfe emtnciated them. Hsce an
the three which aie the most used :

^^ ^ "^ H^Liii (Colonel Dnchemin)

(4) X » a - (a - 1> m* i (Colonel Benini)

in which a is » number between 1 and 2 aztd more in the oeigb-
boarhood of 2 ;
and hctly,

formnla in which m is the ratio, , " , if one calls 2/ th€ spread of

1 + A ^

th« Bnrface and 2A ita dimension in the direction of travel; m
c^inHef|nently depends apon the elongation of the surface as well
as X.

At all fjvftnts X varies with the angle i. Let us call Xo its Tn^aa
value and let ns admit :

K = Xo

w(^ have tlien for expression of the normal thrust bearing npon a
flat Hail, in the case of an angle of attack small enongh to draw it
without confounding the arc with its sine :

(6) P = KSV«i

ihn angle i was expressed in the function of the radius.

N.n. — Many authors often confound K and ; it is important
to avoid this confusion.

APPENDIX 287

{C) Position of the Centre of Pressure (or centre of thrust). —
In reverting to Fig. 48 which graphically expresses as the result
of experiment that the centre of thrust is drawn more to the front
edge of the moving surface, one has to calculate the distance d
between this centre and the centre of the diagram of the moving
rectangle, the formula conceived by the engineer M. Soreau.

^^^ ^ = 2(l + 2tgi)

2h being the dimension of the rectangle in the direction of travel.
Avanzini's formula, a little simpler, is the following :

(8) d = 0-6 A (1 - sin t)

(D) M. Berget's Speed Formula for* Dirigible Balloons. —
This formula is

(9)

in which V is the speed in myriametres per Jumr, F the engine
effort in horse-poweTy S the surface of the maximum transversal
section in square metres, and G the coefficieiU of advantage of the
airship (see Table on page 118).

{E) Measuring the Speed of Aerial Vehicles. — ^This operas
tion, indispensable to aeronauts, and which will be to aviators also
as soon as they can undertake voyages of some duration, is simply
effected by means of the apparatus of the engineer Joanneton of
which front and back views are shown in Plate XXI.

The apparatus is a copper quadrant of which one face carries
an engraved *' table " over which moves a rule. This rule indicates
by the aid of ^-ratio gearing, the part of the angle at which turns
a mirror with which it is solid and which projects from the back
face. The aeronaut by the aid of a small telescope sees in
this mirror the image of some arbitrarily chosen point upon the
ground (a tree, steeple, building or what not) and follows this
object for one minute while turning the mirror in such a manner

28S APPENDIX

Uistthe image always rests ia the field of the teleaoope. There U
nothing more to do than look upon the " table," to see the inter-
sectioa of the role with the line of altitude ehown by the barometer;
the abscifisa of the correBpoadiog point indicated upon the hori-
zontal edge of the quadrant gives the epeed in kilometres per
hoar.

The apporatna weighing about one kilogramme Baspenda itself
by its weight in the desired position : it is snScient to hang it np
by a cord and a ring to the soapensioa ring of the car.

INDEX

AOAD&KIB a^rooantique da ftanoe, 25<{

Ader. 248, 244

Aerial League, 256

•• Aerial yachts," 77-79

A^ro, 1% 256

olnb de Belgiqne, 256

club de Franoe, 256

-M^haniqne, \\ 256
A6ronante, V, 256
A^roDaxitiqne-clnby 256
A6rophile, 1', 256
Aeroplane*, 164, 268-66, 276, 277. 278

accidents in, 176,178,197

AntoineUe, 219-25, 284, 280

biplanes, 189-41, 187-205

B16riot, 141, 201, 206-14,250, 251, 252,
258, 254

body of, 166-67, 207, 220-27

chassis, 211, 219, 228

CUmerU'Bayard, 225-28

oonstmction, 157-86

oonstmction of wings, 185-87

descent of, 155-56, 194, 228,224

elevating rudder, 151, 189, 195^ 203,
205. 212, 216, 217, 218, 22% 227,
229

faU of, 155

Farman. Henri, 141, 166, 168. 187-91,
283, 250, 251, 252, 254
Maurice, 201-204

Gaitambide-mengin, 141, 220

landing shores, 194, 222, 223

launching, 152-54, 198, 201. 219, 228,
288

launching-xaU (Wright), 154, 198, 201

Maxim, 248

monoplanes, 189-41, 206-289

partitioning of, 146, 147

Aeroplanes — conHnued
propellers, 168-66, 190, 198, 204, 208»

210. 228, 227, 229. 285, 287, 288
regulating speed, 126, 178-78
SafUnt-Dumant, 141. 280, 249, 250
security. 178-78
self-starting, 152-^. 201
Skates, 194, 228, 224
spread, 186, 187, 188, 192, 202, 207, S0»

215, 221, 227, 229, 237
stabilisation, 188-34
stabilisation empennage, 182, 188, 188,

202, 207, 218, 222, 238
steering-rudder, 150, 151, 188, 195-98,

202, 205, 208, 216, 222, 227. 229
Tatin, 100, 225-28
turning of, 141-44, 286
VerMme, 225, 228-280
warping wings of. 145. 194, 195, 196

202, 216. 229
Wenham, 242
wings, 185-41
Wright Brothers. 187. 141. 146. 146,

151. 158, 164, 166. 167, 192-2^01, 202,

214, 225, 280-81, 242, 244, 245, 246,

247, 248, 249, 254
Ailerons, 144
Antoinette, 221, 222
Bl^ot. 146, 207
Air, atmospheric density of, 4
ballonnet, 26, 27, 28, 36, 37, 42, 83, 84

88,96
co-efficient formula of resistance, 15,

285
Oonqudte de 1*. 266
resistanoe of. 14, 126, 129
transport, 257, 258,259, 263, 264,265, 866
▼agaries of, 122, 178, 174, 175

889

I3n>£X

tfiMM^ftV*^ M. «>. M. K. •«, «B.

Tt-n. a. U*. Ml HL «■. SU.

Omm« «• te T^b, «, Hb i^ Ml,

Mkr.M«-»f

AvMt, b, to, tS-M. H. lis, UI. 1»,
VM

Omw«l MauBUr'a, R-M
Oarauo. W. 21. 71. IIM-IOS. 370, z:«
GI9ud'a.«, IT, It, E«-U, lU

InjiroramaBU M b« affaeted in, IIS-

IIS. 2T(I-M
iixlepMutMit apMd, 4S-SI, M. BT, V3.

MS-IU
lo4u.trr, 2T7-27B
iMiiilliiK of, 72, 7»-TC
lAlmuty, to, He^», S78

InDKitiiillnkl ■tablllt}'. S3-37
rutin«>UTrIn|[ nf, 06, 70-75. 79-81
mlllur)' ait'llcallon*, 280-281, 279
"niunrinft" ftrruigemeut for, 7J'7S
Rli'ton, K, Aa-86, 89, 92, S4, 95
JV«Hi *cun.iu», ILS
f'lruvnl, 108

/>alri<, la, 40, 44, 73. 99, SSO, 271
{iruiwllDn. 09-48, 09, 84, 8S, ISS

t«.M.a.31.M»H.»

fpHMAai^ n, SI, IKBI

.m.ua.ui
■otw^ IM. iM. in. SI as-a

A^ pdBt 0*. 41-4*, 81, M
ARfadMCOB. 2U, SW. 3S1

of. j,m

eC€n,4-*
Anatioo. 119
clafai, 2S5. SH
OeoUch prii«, 2S0

motora, 203, 204. ZIS
A*ioil,!41

r (jounui). 2ea

Babiskt, 179
Ballftft, 5, 202
BAlloiuiet, Bir, 26, 27, !

S4. 88, 96
Balloon,

tulvantage of lai^e voIoom of, IS,

diiiineas in, 80, 81

hugarB, 70, 71. 106, 2S5. 286, SSD

leulicular, 183-1S9

I, 36, 37. 41

INDEX

291

JBrnXkoon—eorUintud
lifting ropes. 61, 62
Montgolfier, 18, 82
mogpeoBioik parallel, deformable, 62

triangnlar, indefoimable, 62
weighing, 71

»o, Leon, 278
LoniB, 277
f, 108
[et. A., formula of, 110-113, 287
Aeronautical exploration project, 266
ly Georges, 256
.JBicjole, comparison of French aeroplanes

with, 283
Airds,119

flight, 119-124
wings, 121
316riot, L., 141, 146, 168, 167, 201, 212.
218, 250
Channel flight, 218, 225, 252-54
monoplane, 146, 207-214, 234. 251-54
^ladskj, de, 80, 96
JBiegaet, Louis, 204, 235, 237

Caillstst, 256, 285
Caldera, 197, 248
^Capacity sastaining, 137, 188
Otpazsa, 75, 80, 183-186
Oar, construction of, 64
Oaylej, Sir George, 240, 241, 242
Cell, rear, 188, 191, 202

central, 188. 191
Cellular type, 187-192
Centre of gravity, 23, 24, 180

of thrust, 23, 24, 130, 131, 132
Chalais-MendoD, 55, 93, 94, 180, 225, 243
Channel, flight oyer —

Bl^ot, 225, 252, 253, 254

Latham, 225, 254
Channte, 201, 242, 245, 246
Chanvi^e, 68, 204, 226, 228
Civil life, applications to, 263-266
Clement, M., 41, 102, 225

'Bayard aeroplane, 226, 227, 228

-Bayard dirigible — mu Airships
Clerget, 79, 227

Co-eificient formula of air resistance, 14,
15,285

of advantage, 110, 111, 112, 118, 287

Colardeao, 285

Colonel Renard, 7, 9, 11, 17, 37, 38, d9»
44, 48, 49, 60, 67, 90-94, 115, 137,
163, 167
airship, 102, 278

Comparison of aerial with marine naviga-
tion, 12-16

Conditions of eqnilibrinm, 23

Conqoete de I'air, 256

Construction of airship, 59-81
of aeroplaw», 157-186

Comu, 235, 236. 237

Critical speed, 38, 89

Cylindrical shapes, 17, 18

DxFOBMATiON of envelope, 34, 35»

36
Delagrange, 141, 190, 191, 192, 247
Demanest, 224

DemoisdU, Santos Dumont*8, 280
Descent, airship, 72, 73, 74, 75

aeroplane, 155-156
Deutsch de la Menrthe, Henry, 94, 100
102, 250, 282

aeronantical prise, 95, 96

aviation prize, 220
Deviation, 41
Dizziness in airship, 80, 81

dirigibles — tee Airships
Dnpny de Ldme, 17, 44, 88, 163

BiFFBL, 285
Empennage, 39, 40

craciform, 41, 99

pneumatic, 42, 1 00

sUbllisator, aeroplane, 132, 139
Bnrieo, 242
Envelope, profile of, 59-61

deformation of, 34, 35, 36
Equilibrium, dynamic, 37

of dirigibles, 23, 25, 26
Esnault-Pelterie, 141, 151, 158, 160, 166
167, 169, 212, 230

aeroplane, 218-219, 225, 228

motor, 214, 218
Explorations, aeronautical, 266

elevating rudder — $ee Airships and
Aeroplanes

INDEX

FAniAF, Haoil HI, IM. ICa, IflT'ttI,
m. 350, *». US, SSI

•««|lu^9a3,Mli.m
Taibtr.ChpiBlB. !»;, Mi, US

aireitar,ISS
flmiDB. IM. 131
•^^ ISI-I22

FttmaU, B«|M'a dirfglbl*, I1(»-IIS.

MT
rormiil*, RMeoMtlMd, SSB, 9H, 3S7
Fonndai, ZI4

J>n->n, U, *Q. M-ML M. US. 151, IM
- FriBKe " ootnctias. 1», IM

GAaTAMBIDK. Itl

-MeogiD aerofJuie, 230
Gtognphi. Bpiplic&tion W, MS
OiAkrd. Henrj, 9, 17. 41. BS-SS. ISS
Oinh tatpetuaoa, S2, U
OtUiiig. 173, I8«. 121. SU. 2i5. 248
Uodud, lOB
Gndtj, oeolre ol, 130
Giou. Ton, 108

mllit&rr kinhip, lOS
GyropUiie. Bregaet, 201, 205. 23S. 237,

238
OTToicope, SB. lis, 119

efTecti. 69, 118. UB

HA!cgA£8, ballooD, 70, 77, 106, 365, 266,

280
HArgrakveg, 140
H&dU. I>,ie3, ^38
Hilicopl^rei, 120, 178,212, 213

antomolor, ISO

Btegaet. 235. 237, 238

Cornu, 23C. 236

de U Laodelle, 178, 213

Liger, 181.235

PoDtOQ d'Ameconrt, 179, 213

Renard'a cotDposite, 180, 183, 335

Ibne-powei^ 10. 11. IB, IS

-bom-. II

bonr. w ei g ht per. 11

voifhtper. 10. M
HonM de VillcBra**. IW
Brdnga^l. 5

i,2j7,rB.ir»

iMtnmttio, dijlgtbla g^dbf> 'M^

KjprfcKKS. 75. W

KltM, 1S6-199

oallolu'. HO, 111

eqnUibriBtn, 1 25. 123

Haifitarss, 140

■UBlUple. ISB
Krebs, 90-91

LA HAUI.T, 18S-288
UndeUe, de U, 179, 24S
LADglej, 213
Latham. 200, 224, 225. 231,131

Chaonel Sight, 22S, 2£4
XADDchiDg an •CToplano, 1S3-1M, IH> |

219, 223, 230
Leagoe. aerial. 2fi6
Lebaad}', 96. 97, 99

airehlp.40. 14,97, 98, 113
Lfl Bria. 212
L^er, 181. 235

Lentlcalu balloon, 1 S3, 181, ISS, IN
Letellier, Henri, 216
U'/erU, 100
LiEting ropes, 61, 62
Lilientbal, Oito, 201. 214, 345

Malecot. 27B *J

pallet, 202

MancEQVring a diriglblo. 65, 70-7E, 7W

Mai^y, de, 278

~ dm. Sir Uinm, 213 ■

INDEX

39S

ainliip, 82. SS. S4, SSC M
Hllitaiy apptknini, l«aL 9B»-»I.S9
Monaco, PrioMcC 10t» 151, SSL S7
Monocjcle; w|ilw aC Wi%ht

Fiftfw. 1^ «i»M,n ML an
SIS

IffonopSuie, 139

aUenms, 144. 14C 307. 20. 2S

Antoinette. Hi. n»-SS

Blefiot. 141. 906-211. 23S. SO, SI,

252. 253. 2M
chunt, 211. 219. 223
control. 206,212
Bnaalt-Feltcrie. 141. 213-219
Gastamfaido, 141, 220
8aatos-D«moBl» 14U 230
Tatin, 225-228

of
41-44

17.199

praptDkif teetw

d'AnJcoait, 119. 212

of peae uaU oa. 157-159. 220
to U cffoctad. 113-115, 279
FropeOcEi. 09-«^ iM, S4. 8S. 193-119*-
168. 190t 19S, Sfl^. 293, 210.2i3» St^^-

wing.warpiag. 145^ 194, 19ft. 196, 202.
216,229
MontgoUler, 13, 82
^Mooring" aRaogemnt for dfriglblea»

74.75
Hoton, 159-162. 198

Antoinette, 160, 190, 210, 223, 224

Ansanl,214

Clement, 228

Cl^eot-Bayard (Tatin). 227, 228

Electrical, 89, 92

Bsnaolt-Ptiterie, l«K 212. 214. 215,218.
219

explosion, 10, 94

hnman. 8, 84

Mercedes, 98

Renault, 160, 203

rotary, 161

steam, weight of, 8-9

Nadab. 242

OBinTHOPT^n. 120, 182, 238, 289

Adh. de la Hanlt, 182, 238

American. 239
Orthogonal system, 138
Osiris Prize, 252, 277

PAiNLXvi, 280, 281, 232, 233, 255
Parsend, von, 108
military airship, 108

P^jloii. laaacbiag (WifgM)* 1^ ^^ 201
QuAUTT. sastamtwg. 133, 137, 138

«* Radius of actMm,**
somplsnoB. 281

aiiBbips, 21-23, 270. 271. 275, 276, 290
fiaU. Wr^ht Uoncbing, 154, 196. 201
Renard. Colonel, 7, 9, 11, 17. 37, 38, 39»
44. 48, 49, 60, 67, 90-94, 115, 137,
163. 167, 180. 182. 195, 235, 248, 286
Commander Paol. 90. 143
Renaalt. 160-203
R^tMifme. la, 67, 99, 100, 112, 113,

278
Resistance of the air, 14. 126, 129
Reme, airienne, la, 256

de I'aviation, 256
Ricaldoni, Captain, 108
Richet,237

Rigid halloons, 28, 104-108
Radders,
etefating of aeroplanes, 151, 189, 195,
203, 205. 212, 217, 218. 222. 927.
229
of ainOiips, 29-31
steering of airships, 29-31, 64
of aeroplanes, 150. 151, 188, 195-198,
202, 205, 208, 217, 222, 237, 329

Savitt, airship, 61, 79-81

aeroplane. 173-178
SantOB-Dnmont, 20, 95-96, 113, 141»

280, 249, 250

S94 im

BoMW* (M Piop«Ucn).
MTOplane, 163-166. ISO. IBS, 208, 210.

•m, S2B, 236, 237, 238
dimeiuloiii. 67, 6S, S9. 92. 98. 103.

104
DDinbeiof. iea,lS4. ISG
pitob. 66, 67, 92, 192. 164
poailion of, 41-44. 68, H S8, 103,

17B
■Up.66,67. 69, 162
■peed. 67. 68, 611, 92. 102, 104, 113, 162,

US
■DBtalnlDg. IKO, 181, 23S-237
SmIIod, tnniveiBe ol wiDgi. Ii7, 1GS>

>Je1fridge, Ueutenant, 164, 198, 24S
BeTeto d'Albaqnerqae, 96
Shape, IcltuenQe of front, H-t6

Btem, 16
Sboroi. Utiding. 223. 221
fikaCes, laodiDg, 194
Sociute fcEUi^BiBe de navlgatkiii a£rieiia«,

122, 2S5
SOTUD, 122. ISG. 168, 174, 176, 246.!fiG,

286, 2S7
Speed, critical, 38-49

aeroplane, 1S9, 170. 171

indepeodent of airships, 49-G4, 69, 67'
93, 113, 114

regulating, of aeroplacies. 126, 17l~
179
Bpread— <(( Aeroplanes
StabllliatioD,

aeroplane automatic, 116. H7. 118,
149

artificial, 149
Stabilisator, 64, 65, 66
Stability,

direction, 33-7, U^IGO

height, se, 30

loDgitadinal, 33-S7, 111

transTerse, 141
Snrooof, 14, 71-76. 97, 100, 102
Sarfaces, aopportiog, 126, 127, 167

■lUtaJDiog, 124, 13T-I3S
BOBpenslans, parallel (delormable), 62

triangular (icdeformable}, G2
tjostectatioa, 124

capacitiei, 137-13S

Tabls of wind speeds micimd Pari*, SS
TatiD, 100,226.226

aeroplane, 225, 226, 227. 228
Thrail. centre of. 130
TUHodier, 17, J4, 89
Tibs sport, aerial, 257, 258. 3S9. 36S, 361,

265, 266

VAOA.BtEB of atmosphere, 122, ITS. 171,

176
Valve, 61

Bippjng, 61
Vauli, Cowit de la, 13, 7». 80. 103
Tendfime. aeroplane, 226. 228, 229. 230
ViUt-de-BoTiUatix. 102

■Parii, 10, 41, 67. 100-103, IBS, 260,
279
Voisin, 167, 168. 187-192. 226, 230, 231,

232, 249, 253
Voyages :

Bayard- Cltmml, 76,77, 2G4

BUrlot, 301. 212, 213, 260, 2G1. 2G2
263, 264

Fannaii, Henri, 190. 233, 260, 261
2G3

Franct, la, 93. 94

Latham, 224, 226. 2G1

Patrit.la. BS

JUpvUiifiit, 100

SarUoi-Dviaont, B6, 96, 230, 219, 250

y-iUc-de-Farti,\02

Wright Brothers, 247, 265

2tpfilin, 100, 107, 108

Weight lannchiDg, 151, 198. 201
Welfetinger, 221
Weabam. 212
Wind, 46

ascending, 173-78

dtscendiog, 173-78

direction, 46

preaaore, 15-47

relaUw, 47-52. 170-72

table of speeds, 66
velocity. 46-47, 56-58
Wings, birds. 121
constmctioD , I3S-37
ipread — «e Aeroplane

ot,H6.1». l0G.lSS.2O2.aifl.
229
Wright Brotben. 137, 141. 14S, 140| 161,
108, 164, ISa. 167, 102-201, 203. 219,
22G. 230-34, 342, 341, 245, 248. 247.
343,349,204

INDEX

TAOHTS,aaia), 77. 78. 79

Zahaboff. 282
Z«ppellii, Coont, lOS

Unblp*, 20, 2B, 78. 104-8, 370
ZIpM, 102
jbdiaaainhip, 77, 78, 79

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "The conquest of the air; aeronautics, aviation; history, theory, practice"

See other formats