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■ V 




The subject of " Aircraft in Warfare," with which 
Mr. Lanchester deals, is, and for some time will be, 
highly controversial. In each of its three aspects, the 
scientific, the military, and the material or manufacturing, 
it is still in the stage of experiment and speculation. 
The results obtained cannot always be made available 
for the information of the general public, and those 
which are available have usually been set forth in 
terms so technical, either in a scientific or a military 
sense, as to be somewhat difficult for the general reader 
to understand. Very little trustworthy information, there- 
fore, has been disseminated, and the uninstructed public, 
hungry for information on a novel and alluring subject, 
of which the national importance is evident, has fallen 
an easy prey to the imposter. Any plausible rogue, 
gifted with sufficient assurance, and aided by a ready pen 
or supple tongue, has been able to pose as an "aero- 
nautical expert," and to find some kind of following. 
To those who, as a matter of duty, or in search of 
information, have perused the aeronautical discussions 
carried on in the Press, or the reports of such dis- 
cussions elsewhere, the very word "expert" calls up a 
strange procession of inventors, politicians, motor - trade 
touts, journalists, trick -fliers, novelists and financial 
agents, most of them, axe in hand, on the way to the 

Mi RQft^ 1 

▼i. . PREFACE. 

national grindstone ; a few, innocent, following on the 
same track, on a vague quest for supernatural powers 
of flight. 

As a matter of fact, there are no experts in 
military aeronautics. There are experts in the 
various branches : in flying, in scientific research, 
in the design and construction of aeroplanes and 
engines, in military organisation and tactics. But, 
as yet, there is little opportunity for the expert in 
one branch to gain definite knowledge of the others, 
except by hard personal experience ; in every direction 
there is progress, in every section of work opinion 
is fluid, and the views of the workers are not yet 
sufficiently crystallised to permit of definite instruction 
to others. Yet there are some students who, by reason 
of their receptive minds, and their wide and varied 
experience, have mastered so many of the fundamental 
problems that they are well qualified to review the 
general position, and to put forward a reasoned state- 
ment of their views. And of those so qualified, none 
has a wider view than Mr. Lanchester. 

Of all the fields in which work for the advancement 
of military aeronautics has been undertaken, in this 
country, that of scientific research has, up to the present, 
produced the results that will probably be the most 
enduring. It is only by the solution of fundamental 
problems of science that improvement in the power of 
flight can be won. Solutions may be obtained, and some 
few have been, by chance, or by intuition ; but to gain 
the full value of the result, it is necessary that the 
scientific solution should also be found, as a basis for 
further deductions. In this work of stating and solving 
the problems of aeronautics, Mr. Lanchester was one of 


the pioneers ; he was bold enough to publish the result 
of his investigations at a time when flying had only just 
been proved possible ; and he has reason now to be well 
satisfied with the quality of his early work. In this new 
book he has discussed matters of wide interest and, at 
the present moment, of vital importance, and has con- 
sidered in many bearings the relations between aeronautic 
science and military art. In this effort many difficulties 
have had to be faced, not the least of which is the lack of 
definite knowledge of the methods which have been em- 
ployed and of the results which have been achieved by 
aircraft in the present war. And, further, there has been 
the necessity of exercising extreme discretion in the use 
of information which is within his knowledge. In the 
first respect I have some advantage over Mr. Lanchester; 
in the second he, in writing the book, and I in introduc- 
ing it, suffer under the same disability. 

During the past three years Mr. Lanchester and I 
have had several tussles in private on the questions 
debated in this book. Bach can put up a pretty good 
defence on his own ground. Mr. Lanchester is well 
protected by his profound knowledge of physical science 
and his practical acquaintance with several branches of 
engineering. I am strongly entrenched behind a barricade 
of military prejudice, with some dim recollections of 
early scientific training as reserves for counter-attack. In 
my incursions into Mr. Lanchester's territory, I have 
now and then received a buffet which has made me more 
wary. And occasionally, I think, Mr. Lanchester has found 
himself hung up in my wire entanglements. I should 
like nothing better than to fight out, in public and with 
due formality, these points — not a few — on which he and 
I disagree ; but at the present moment this is impossible, 

viii. PREFACE. 

nor is it advisable that I should do much towards indica- 
ting those on which we are in agreement. 

There are two theories, however, evolved by Mr. 
Lanchester to which I may safely draw attention. The 
first he has called the N-square law, and it is, to my 
mind, a most valuable contribution to the art of war. It 
is the scientific statement of a truth which, although but 
dimly perceived, has been skilfully used by many great 
captains, both Naval and Military, but it is now for the 
first time stated in figures and logically proved. We can 
never be governed by the rules of exact science ; there 
are too many conflicting factors, too many fortuitous 
circumstances ; but there are certain rules, whether based 
on experience or calculation, which no commander may 
lightly transgress. Concentration of force is one of these 
rules, and a statement of the inevitable disadvantages of 
dispersion is valuable. The examples chosen from sea 
and land warfare illustrate the working of the law with 
admirable precision. 

In the other case, Mr. Lanchester's calculations are 
less satisfactory. In considering the proportion of air- 
craft which is suitable for the requirements of an army in 
the field, the aircraft are compared with cavalry, and the 
aeroplane with a single trooper. This is no sound basis 
for calculation. To begin with, a single aeroplane absorbs, 
on the average, the services of some twelve officers and 
men, and its cost, which is not an immaterial factor, would 
provide more than a score of horses. But even the most 
accurate display of comparative figures will bring us no 
nearer to a correct result. The aeronautical arm is a 
new force in war, performing new functions, extending 
its activities every day and, at present, recognising but 
few limitations to its possible development. There is, as 


yet, no rule-of-thumb method of arriving at a definite 
and correct allotment of aircraft to an army of given 
strength. The only safe line on which to proceed is to 
consider, first, what are the services which the aircraft 
are to be required to perform ? Second, how much of 
our available resources are we justified in devoting to 
these services ? The answer to the first question shows 
a list which increases with each successive month of war. 
The mere propounding of the second will inevitably 
raise a controversy of which the only possible settlement 
will be a compromise. The final decision, however, ought 
to be based on relative value, not on relative numbers. 

On the merits of these and other questions raised by 
Mr. Lanchester, the reader must be the judge. I hope 
that there may be many readers, and that they will give 
consideration to their judgments, for, whether they agree 
or not with the author, they will find here much that is 
worthy of study and reflection. 

David Henderson. 


The Military and Naval importance of aeronautics, 
more especially of mechanical flight, has in the past been 
slow to receive adequate recognition. Even to-day, in 
spite of the awakening which has been brought about 
by the Great War, we are far from a full appreciation 
of the extent to which, as a nation, our destiny will be 
determined by aircraft and by military aeronautics. 

The early pioneers of mechanical flight were but 
little concerned with the prospective future of flying ; 
they were rightly occupied in overcoming the difl&culties 
standing in the way of achievement. That ultimately a 
field of utility would present itself was generally accepted 
as an article of faith. Many suggestions both as to com- 
mercial and military usage were put forward, more 
frequently than not in ignorance of the limitations by 
which flight as a mode of locomotion is circumscribed: 
often claims were made of an altogether extravagant 
character. If it be true that in some directions, from the 
point of view of those early engaged in aeronautical 
development, the outlook has proved a disappointment, 
it is no less certain that military aeronautics has not 
only fulfilled, but already transcended, the most sanguine 

Without going so far as to claim having predicted or 
foreseen in its entirety the many-sided utility of aircraft 


as it is to-day manifesting itself, tlie author can point to 
the fact that he has in the past taken every opportunity to 
insist on the importance of dynamic flight in its Military 
and Naval application. Thus, so long ago as 1897, in a 
patent specification* in which all the main features of 
the present day aeroplane were figured and discussed, 
the proposal is made for an air-borne torpedo, a device to 
which the first nine figures specifically relate. 

Writing in 1907, in the preface to the first volume of 
his " Aerial Flight," the author expressed his view in a 
passage as follows : — 

"The importance of this matter [provision for the 
scientific study of aerial flight] entitles it to rank almost as a 
National obligation ; for the country in which facilities are 
given for the proper theoretical and experimental study of 
flight will inevitably find itself in the best position to take 
the lead in its application and practical development. That 
this must be considered a vital question from a National 
point of view is beyond dispute ; under the conditions of the 
near future the command of the air must become at least as 
essential to the safety of the Empire as will be our continued 
supremacy on the high seas." 

And in 1909, the "Morning Post" (May 11th), re- 
porting the 3rd Cantor Lecture delivered before the Royal 
Society of Arts, quotes the author as follows : — 

" He considered that the immediate future of the flying 
machine was entirely confined to its military possibilities." 

Again in the spring of 1914 (a few months prior to 
the outbreak of war) the author wrote : — t 

" Without looking so far ahead as has been attempted 
in the preceding paragraph, t it cannot to-day be disputed 

• No. 3608 of 1897. 

t "James Forrest" I<ecture. Proc. Inst. C.B., cxcviii., p. 251. 

X The paragn'aph in question is that quoted incidentally on p. 158 of the 
present work. 


that the immediate future of the flying-machine is guaranteed 
by its employment by the Army and Navy. It is already 
admitted by military and naval authorities that for the 
purpose of reconnaissance an aeronautical machine of some 
kind is imperative, and its more active employment as a 
gun-carrying or bomb- (or torpedo-) bearing machine will 
without question follow : its utility in this direction has 
already been experimentally demonstrated. In the author's 
opinion, there is scarcely an operation of importance hitherto 
entrusted to cavalry that could not be executed as well or 
better by a squad or fleet of aeronautical machines.* If this 
should prove true, the number of flying-machines eventually 
to be utilized by any of the great military Powers will be 
counted not by hundreds but by thousands, and possibly by 
tens of thousands, and the issue of any great battle will be 
definitely determined by the efficiency of the Aeronautical 

In addition to the foregoing, the author gave 
especial prominence to military aeronautics, as present- 
ing the most promising field of development, in his 
Presidential address t to the Institution of Automobile 
Engineers, in October, 1910. 

The intention to write specifically on the subject 
of Aircraft in Warfare had been in the author's mind for 
some years, it was only after the outbreak of hostilities 
however that this intention came to be realised. The 
present work may be said to date from its contribution 
as a series of articles to " Engineering," covering a 
period from September to December, 1914. The text 
and order of the original articles have been preserved 
in the present volume, and thus the matter appears 
under the dates of its original publication. Revision 

• Perhaps an overstatemeot of the case. Compare § 18. 
t Proc. Inst. Automobile Engineers, Vol. V, p. 10. 



has, in the main, been confined to ordinary legitimate 
corrections, the articles having been regarded and treated 
to all intents and purposes as a first proof. The last 
two chapters, however, include new matter ; they are for 
this reason undated. 

That it is at least desirable to give the dates of first 
publication is determined by the fact that the ever ready 
plagiarist commonly has one's writing over his own name 
almost before the ink of the original has had time to dry.* 
Beyond this the author has no wish to present as a new 
edition, matter which is more justly entitled to rank as a 
reprint', he has the satisfaction of knowing that articles in 
a technical journal, whatever its standing may be, can never 
appeal to so wide a circle as publication in book form. 

* A coincidence such as the following scarcely requires comment. 

From a paper read by the author 
December 8th, 1908, before the Aero- 
nautical Society of Great Britain ; as re- 
ported in "The Engineer," December 
18th, 1908, and as subsequently publish- 
ed in the prceedings of the Society, 
January, 1909 :— 

"The gliding machine originated 
by I<ilienthal, was improved especially 
as to its structural features and its 
method of control, successively by 
Chanute and the Brothers Wright, until 
the latter, by the addition of a light- 
weight petrol motor, and screw pro- 
pellers, achieved, for the first time in 
history, free flight in a man-bearing 
machine propelled by its own motive 

Unfortunately, even though one may be morally certain as to the fact, it is not 
usually possible when broad opinions or the general results of an investigation are 
taken without acknowledgment, to " pillory " the offender ; it is only when concerned 
with a quite trivial matter of words, as in the foregoing, that an accusation can be 
brought home. If such cases were clearly deliberate they would morally constitute 
a theft, since Editors commonly pay according to the space filled, but it is fair to 
assume that plagiarism of this kind is quite unconscious, what is read or heard one 
day, masquerades in the writer's mind as inspiration the next. 

Occasionally one is fortunate, as the author when his theoretical method of 
treating the problem of the screw propeller was attributed to Drzewiecki in a report 
in which the author's specially invented terminology was used throughout. Those who 
misappropriate another man's gold should take the ordinary precaution of throwing 
away the purse. 

From an article contributed by a 
certain writer to the " Westminster 
Gazette," February 26th, 1909 :— 

"... that Ivilienthal invented a 
gliding apparatus, which was improved 
in its structural features and in its 
method of control successively by 
Chanute and the Wright brothers, until 
the latter, by installing a comparatively 
light-weight motor and screw propeller, 
achieved, for the first time in history, a 
man-carrying machine propelled by its 
own motive power." 


Looking back to the time at which the original 
articles were penned, it must be admitted that very great 
progress has been made, progress not only in the number 
and quality of the belligerent aeroplanes, but also more 
generally in the understanding of the potential capabili- 
ties of the Aeronautical Arm ; the author finds, however, 
that his own ideas also have developed and expanded; 
the experience gained has, in a sense, cleared our vision, 
and enabled us to look still further into the future. Thus, 
in spite of the great advance, the pressing needs of the 
future seem in no wise diminished. 

The author in conclusion desires to acknowledge his 
debt of gratitude to Maj.-Gen. Sir David Henderson, 
K.C.B., to whom the preface of the present volume is 
due. He counts himself singularly fortunate in having 
been accorded the support of so great an authority on 
Military Aeronautics, and feels confident that his grati- 
tude will be shared by those into whose hands this book 
may fall. 


November^ 1915. 



Aircraft as Constituting a New or Fourth ** Arm." 
Primary and Secondary Functions of the Aeronautical Arm. 


Aeroplane versus Airship or Dirigible — Speed Limitations. 
Aeroplane and Dirigible in Armed Conflict. 
Means of Attack and Defence. 


Strategic and Tactical Uses of the Aeronautical Arm. 
The Strategic Scout and its Duties. 
Directing Artillery Fire by Aircraft. 
Aircraft as Vulnerable to Gun-fire. 
Armour and Altitude as Means of Defence. 


Low Altitude Flying. 

The Aeroplane in a Combatant Capacity — Armour Plate. 

The Machine Gun in the Service of the Aeronautical Arm. 

The Fighting Type of Aeroplane and its Future. 

As Affecting the Cavalry Arm. 


The Principle of Concentration. 
The Value of Numerical Strength. 
The N-Square Law. 


The Principle of Concentration — Continued. 

The N -Square Law in its Application. 

Applications of the N -Square Law in Naval Warfare. 

British Naval Tactics in 1805. 

Nelson's Tactical Scheme — The N -Square Law at Trafalgar. 

CONTENTS. xvii. 


Attack by Aeroplane on Aeroplane. 

The Fighting Machine as a Separate Type. 

The Question of Armament — Treaty Restrictions. 

Importance of Rapid Fire — Machine Guns Multiply Mounted. 


Rapidity of Fire and its Measure. 
Armour in its Relation to Armament. 
Importance of Upper " Gage " — Attack from Above 
Armour and Shield Protection. 


Gun-fire Ballistics — The Energy Account. 
Expanding and Explosive Bullets. 
Theory of the Expanding Bullet. 
The Light-weight Shell. 


Miscellaneous Weapons and Means of Offence. 
The Bomb and the Hand Grenade. 
Bomb Dropping, Difficulties of Aiming. 
Rockets, Air-borne Torpedoes, etc. 
Supremacy of the Gun against Aircraft. 


Aircraft in the Service of the Navy — Naval Reconnaissance. 

Mother-ship or Floating Base. 

Armament of the Naval Aeroplane — the Employment of Bombs. 

Torpedo Attack by Air. 

Aeroplane and Submarine — Attack by Bomb. 


Aircraft in the Service of the Navy — Continued. 
The Naval Air-scout. 

The Flying-Boat Type — The Double Float Type. 
The Ocean-going Floating Base or Pontoon-ship. 


The Command of the Air. 

Air Power as Affecting Combined Tactics. 

Defeat in the Air an Irreparable Disaster. 

Employment of Aircraft in Large Bodies — Air Tactics. 

xriii. CONTENTS. 


An Independent Combatant Air Fleet and its Duties. 

Tactical Importance of Altitude. 

Formation Flying — Airmanship and Signalling. 

The " V " Formation and its Value. 

Aircraft Bases at High Altitude. 


The Command of the Air and its Limitations. 
Belligerent Aircraft and the Rights and Obligations of Neutrals. 
Other International Questions Relating to Aircraft. 
Aircraft in Neutral Territory. 


Present Day Position — The Fourth Arm in Peace Time. 

The Flight Ground Question — Depreciation and Obsolescence. 

British Ascendancy in the Air. 

Causes which have Contributed to British Ascendancy. 

The Advisory Committee for Aeronautics. 

The Royal Aircraft Factory. 


The Maintenance of British Supremacy. 
Government versus Private Manufacture. 
Continuity of Policy — A Scheme of Control. 
A Board of Aeronautics Advocated. 


Retrospect — The Scope and Limitations of the Work. 

Supplementary Notes on the N -Square Law. 

Air Raids and the Value of Numbers. 

A Further Note on Aircraft and Submarine. 

The Strategic Employment of Aircraft on a Large Scale. 


Air Raids — Some Questions of National Defence. 

Power of Aggression as Affected by Radius of Action. 

Air Raids as Affecting the Naval Outlook. 

Aeronautical and Naval Defence Indissolubly Associated. 

Future of Air Power: Essentially a National Question. 

Categorical Statement of Recommendations for Future Policy. 




I. R.A.F. Type B.E.2. As flown at the Inter- 

national Competition in August, 1912 - 4 

II. Field Tent for Aeroplane; Back View - 12 

III. R.A.F. Type B.E.2c. Fitted with R.A.F. 

(British Built) Engine - - - 20 

IV. Skeleton of Type B.E.2. Showing position of 

Tank, Seats, Engine, and Body structure 28 

V. Test of "Bullet-Proof" Steel Plate, 3 m.m. thick 36 

VI. R.A.F. Type F.E.2. Designed to carry gun 

weight 300 lbs. - - - - 68 

VII. R.A.F. Type R.E.5. An " R.E. Portable " Tent 

Pole used as Derrick for dismounting 
Engine - - - - - 76 

VIII. " Flying Boat " Type. Built by Messrs. White 

and Thompson - - - - 108 

IX. Hydro-Aeroplane H.R.E.3. R.A.F. Design for 

the "Naval Wing" in 1912 - - 108 

X. Floats 1912 Type, as fitted to H.R.E.3 - 116 

XI. R.A.F. Type R.E.I. (1912) Folded for Trans- 

port or Storage - - . . 124 

XII. An Example of Rough Usage. The Sopwith 

" Scout," a very fast single seater - 158 

XIII. R.A.F. Type S.E.4. Single Seat Recon- 

naissance Machine - - - - 160 

XIV. Early (Experimental) Model of B.E.2c. Calcu- 

lated and Demonstrated as inherently Stable 

by the late Mr. E. T. Busk - - 164 

P. 179, line 2 from top, for " our " read " an." 




{September 4th, 1914). 


§ 1 Introductory. All authorities may to-day be said 
to agree on the broad fact of the utility and importance 
of the flying-machine or aeroplane — or, more broadly, 
aircraft — in warfare ; but at present the air service as a 
fourth Arm of the military organisation, either of this 
country or of any of the other great military Powers, 
can only be regarded as of a tentative and experimental 

It is, unfortunately, not yet possible to draw con- 
clusions of a lasting nature from the actual usage of 
aircraft in the present war, mainly for two reasons. 
Firstly, the machines at present available (with possibly 
a few exceptions) are entirely without armour or defence 
of any kind, and, dirigibles apart, are, generally speaking, 
without guns or other offensive armament of an effective 
character. Secondly, the machines are numerically so 
weak that, as an Arm of the Service, the aeronautical 
forces are a negligible factor. The question of sufficiency 
in numbers is evidently dependent upon the point of view 

1 B 


taken. On the one hand, if we regard the flying corps 
as merely the successor to the pre-existing balloon corps, 
the numbers, as they at present stand, may be regarded 
as sufficient ; indeed, perhaps, even liberal. On the other 
hand, if we would recognise in the advent of the aero- 
plane the dawn of a fourth Arm (this being the point 
of view adopted by the author), the present strength, 
which in no case represents numerically one-twentieth 
part of 1 per cent, of the number of bayonets, is a truly 
negligible quantity. In order to get a fair perspective 
of the position, it is sufficient to institute a comparison 
with the cavalry, to which Arm, from its function, the 
aeronautical Arm is most closely akin ; here the accepted 
numerical proportion in a modern army is about 6 per 
cent. Now there are many otherwise competent authori- 
ties who would deny to the aeroplane (or to aircraft 
generally) the potential importance which the author 
hopes satisfactorily to demonstrate is its due ; let us put 
the matter to the test. We hear frequent reports of the 
work done by German aircraft, and particularly the 
effective tactical reconnaissance of the German aero- 
planes, which appear to be continuously employed during 
the course of every engagement for locating our gun 
positions, directing gun-fire, following up bodies of troops 
in retreat, etc. We also hear reports of their wider field 
of operations, presumably reconnoitring th^e__strategic 
distribution of the forces of the Allies at points remote 
from the enemy's lines. We may presume that the 
Belgian, French, and British aircraft are employed with 
equal success ; but here, in the nature of things, the in- 
formation which appears in our Press is meagre. As 
already pointed out, the total number of machines engaged 
is microscopic ; the Germans are reputed to have possessed 
at the outbreak of hostilities some 500 machines in all. 
If the German cavalry had been limited to 500 mounted 


men, would it have proved of any real utility ? Answer 
is unnecessary. It may be reasonably argued that the 
capital value of an aeroplane, with pilot and observer, 
being so much greater than that of a cavalryman, the 
above comparison is unfair ; granting this objection, the 
position is not seriously altered, the equivalent force would 
be quite unperceived and be of no tangible service to 
the German army of to-day. 

If, then, instead of the present moment being that 
of the introduction of the aeroplane (and dirigible), it 
had chanced to be the moment when mounted men were 
put on trial for the first time as a fighting force, and 
presuming the initial trial to have been made on a 
similarly modest scale, the mounted men would, relatively 
speaking, have proved a failure, and no one, not possess- 
ed of exceptional intuition or foresight, would have had 
the least conception of the possibilities of cavalry when 
I numerically sufficient, boldly handled in masses and with 
' appropriate supports. 

The foregoing does not constitute a demonstration 
that the air service is in the future destined to become as 
important an auxiliary to an army in the field as the 
;avalry of to-day, although this is in effect the belief of 
the present author. Clearly, if we may judge from the 
scale of preparation which obtains, it is far from being 
the accepted view, in this country at least. The difficulty 
in connection with the present subject is that in order to 
get the future into true perspective, it is necessary to be 
able to look forward along two parallel lines of develop- 
ment — i.e., to visualise the improvement of aircraft 
possible in the near future as a matter of engineering 
development, and simultaneously to form a live conception 
of what this improvement and evolution will open up in 
the potentialities of the machine as an instrument of war. 
The author does not wish it to be supposed that he is 



endeavouring to lay down complete axioms as to the 
military future of aircraft of a positive character, or that 
he pretends to be in a position to formulate a cut-and- 
dried constructive programme ; his intention is rather ta 
give something in the nature of a lead in the direction 
in which it appears development may be logically antici- 

§ 2. The Primary and Secondary Functions of the 
Aeronautical Arm. It is generally recognised that in its- 
employment in connection with military operations a 
most valuable property of the flying-machine or aeroplane 
is its mobility ; it is mobile to a degree which can 
scarcely have been dreamt of in the warfare of the past.. 
When, therefore, we look for uses in co-operation with 
an army in the field in which the aeroplane may show to 
advantage, we naturally turn to examine the duties at 
present fulfilled by the cavalry, hitherto the Arm to be 
employed wherever mobility is of importance. Thus it 
is well recognised that one of the main duties for which 
the cavalry have hitherto been responsible — namely,, 
reconnaissance — is a duty to which aircraft are pre- 
eminently suited. It is at the outset important to- 
realise that cavalry, in face of the improvements in 
small arms and artillery,* with the advent of the 
armoured motor-car, and with the greater mobility of 
the main bodies of troops in modern warfare, have been 
finding the difficulties of eff^ective reconnaissance con- 
tinually on the increase. It is stated by one of the 
greatest authorities on the subject that of the reports, 
sent in by cavalry patrols not more than 1 per cent, are 
of any use to the commanding officer, usuallj^ owing to 
events having anticipated the receipt of the information; 
in other words, the whole process of tactical recon- 

•Not to mention entanglements of barbed wire. 



naissance by cavalry has become far too slow to keep 
pace with the conditions of modern war. 

So far as the author is aware, there has, up to 
the present, been no serious attempt to work out in 
complete detail the duties which can be undertaken by 
aircraft, or to define in specification form by any process 
of logic the types of machine which will be necessary at 
the outset to deal with the various duties so postulated. 
It is necessary to say at the outset, in view of the fact 
that if to-day we had a perfect organisation based on 
existing conditions, the first great Power to be similarly 
equipped would require to be answered in the form of a 
further equipment especially directed to his destruction, 
and so (as in the evolution of the Navy) we may in 
due time have aerial destroyers and "super" destroyers, 
and again still faster and more heavily-armed machines 
for the destruction of these. 

The primary function of, and basic justification for, 
any Arm is the execution of its duties in relation to 
other than its own kind; thus, although it is admittedly 
one of the first and most important duties of cavalry 
to drive the enemy's cavalry out of the field, and estab- 
lish ascendency, this is actually the secondary function 
of the cavalry Arm ; its primary function is the observa- 
tion and harrying of the other Arms of the Service. 
Again, the primary function of a fleet is neither to 
hold nor defeat a hostile fleet, although this, its second- 
ary function, is universally admitted to be its first and 
most important objective. Ultimately, in every case, 
there must be some primary purpose which gives rise 
to the need for any kind of fighting machine, apart 
from its power of offence or defence against its own kind ; 
it is this primary purpose that imparts the initial impulse 
and direction to its development. 

It is proposed forthwith to define the primary 


function of the aeronautical Arm as comprised by its 
duties and actions relating to the three pre-existing 
Arms of the Service — viz., the infantry, cavalry, and 
artillery.* Its secondary function is defined as comprised 
by its duties in the attack on and defence from its like 
Arm — i.e., the destruction or countering of hostile aircraft. 

It is necessary to be perfectly clear as to the above 
definitions. In considering, in the first instance, the 
comparative merits of the aeronautical and the older 
Arms of the Service for any particular duty, as it is 
needful to do in order to justify, or otherwise, any 
particular type or usage, it is futile to import into 
the initial discussion the action or possible counter- 
manoeuvres of the enemy's aircraft; this latter may, or 
may not, eventually prove an important factor, but its 
influence, when taken into account, must be studied not 
only as touching the air service in contemplation, but 
also at the same time as afi"ecting the other Arms of 
the Service (more particularly the cavalry) in its corres- 
ponding usage. In brief, as a matter of logic, in 
discussing the functions and duties of the aeronautical 
Arm, and the type-specifications of machines by which 
its objects are to be secured, the primary function alone 
has to be considered. Subsequently, when a provisional 
scheme and specifications have been formulated, it is 
time to take count of the secondary function, and to 
endeavour by careful prevision to forestall the enemy. 

*Al60 the Navy and merchant marine where naval warfare is in questioa. 


(September 4th, 1914). 

§ 3. Aeroplane and Dirigible: Speed Limitations. 
Two questions are involved in the consideration of the 
relative merits of the aeroplane and dirigible. We are 
firstly concerned with their respective advantages and 
disadvantages in relation to their primary function — 
namely, as instruments of reconnaissance, attack, and 
defence ; secondly, we have to take into account their 
secondary function — j'.^., their relative power of mutual 
destruction ; the question whether, for example, either 
can drive the other from the field, or whether each 
may have its own role to play in securing and hold- 
ing the command of the air. 

Before going into either of these questions in 
detail it is convenient to review a few of the facts by 
which limitations are imposed on the ultimate perform- 
ance of either type of aircraft. We must avoid falling 
into error by judging each too closely by its performance 
of to-day. 

The all-important question of speed is a matter 
depending primarily on the lightness {i.e.^ horse-power 
per given weight) of the prime mover, and the law of 
resistance. The horse-power per unit weight of motor 
is roughly the same whichever type of aircraft is in 
question, and any future advance in the art of motor 
construction tending to diminish weight will, we may 
presume, be equally available for either type. The 
laws of resistance of the aeroplane and dirigible are 



well understood ; in the case of the former the resistance 
is approximated by a curve a a, Fig. 1, representing 
the sum of a resistance following the V -square law 
and a constant ; the latter (the dirigible) may be taken 
as following the V -square law implicitly, Fig. 1, & &. 

O Miles Pe^Houf 



Fig. 1. 

Fig. 1 represents approximately actual values of the 
resistance coefficients, in tractive effort per cent,, in 
machines of average size as they exist to day, for the 
speeds given in miles per hour.* 

One salient fact is at once evident ; the greater 
the horse-power available for a given engine weight 
the greater the advantage in the matter of speed in 
favour of the aeroplane ; the highest speed of flight 
of an aeroplane attained to-day (through, i.e., relatively 
to, the air) is already more than twice that of which 

• The maximum speed attained by an airship is approximate!}- 50 miles per hour ; 
the maximum in the case of an aeroplane is considerably over 100 miles per hour ; 
thus (Fig. 1) the tractive coeflScient in the case of the aeroplane is actually 
greater than in the case of the airship. The reason for this is that the dead-load in 
the airship — represented by the envelope and its appurtenances— is disproportionately 
great, and the proportion of the weight that can be devoted to the motive-power 
installation is relatively smaller than in the aeroplane. Were it not for this fact the 
airship would have held the advantage until speeds about 60 miles per hour had been 
reached and the aeroplane after. 



the fastest dirigible is capable. There is every prospect 
that its advantage in this respect will increase rather 
than diminish with the march of progress. 

Beyond the above, it is well understood that an 
increase in size is conducive to a reduction in the resist- 
ance coefficient; this applies to both aeroplane and 
dirigible. This fact has been one of the controlling 
considerations in dirigible design ; no dirigible, other 
than of comparatively large size, has been found to be 
of real service. It is, moreover, evident that, in the 
case of some of the large Zeppelins, it will not be found 
practicable to go very much further in the direction of 
increase. Here again the aeroplane is at an advantage ; 
we can in nowise regard the aeroplane of to-day as 
defining the limit. 

It is abundantly manifest therefore that the dirigible 
is at a permanent disadvantage of not less than two 
to one in the matter of speed. 

§ 4. Aeroplane and Dirigible: other points of 
comparison. The question of range and duration of 
flight is largely determined by petrol-carrying capacity. 
In the aeroplane both range and duration depend 
definitely upon the petrol supply holding out; in the 
case of the dirgible the same applies to a limited extent ; 
but here the duration and, to a less extent, the distance 
can be greatly prolonged by reducing the speed to the 
minimum possible without jeopardising the control. In 
the dirigible the gradual loss of buoyancy, due to the 
leakage and escape of hydrogen, is an independent 
determining factor., Taking everything into account 
there is not much to choose between the two types of 
aircraft in the matter of range or radius of action ; 
on the other hand, under favourable conditions, the 
dirigible has undoubtedly the advantage on the score of 
duration of flight. The maximum is about 24 hours in 


the case of the aeroplane, against 48 hours in the case of 
the dirigible. This may be taken as a fair indication 
of their relative capacity, though of no quantitative 
value as a guide to what is to be expected under service 
conditions. The possibilities of the future are here rather 
in favour of the airship ; there is an absolute limit both 
of range and duration where the aeroplane is concerned. 

On the question of storage or housing the advantage 
of the aeroplane is overwhelming ; the aeroplane, especi- 
ally if furnished with folding wings, can be stowed 
away in any ordinary shed or barn, or may be anchored 
in the open without serious risk, whereas the '* balloon 
hall " necessary for the safety of an airship is not only 
costly, but is an unmistakable landmark for hostile 
aircraft at 20 miles distance. Again, bad weather 
affects the storage of an aeroplane but little, whereas 
the housing or getting out of an airship in a strong^ 
wind is a difficult and risky business, even under the 
best of conditions. A large Zeppelin may sometimes- 
call for the services of 300 men. 

The foregoing by no means exhausts the grounds 
of comparison, but is sufficient for the present purpose. 
It is scarcely necessary to point out the very great 
disparity of weight, and, incidental thereto, carrying 
capacit}'', between the two classes of machine ; the large 
German Zeppelins have a gross weight, taken from 
their displacement, of 22 tons- (military) up to 35 tons 
(naval) ; of the aeroplanes in service, practically all the 
military machines are less than 1 ton " tare," and most 
types do not exceed 1 ton gross — i.e., with full com- 
plement, petrol, oil, etc. 

If we were concerned with the primary function of 
the aeronautical arm alone, there appears to be no 
reason to doubt that both kinds of aircraft would have 
their place ; the large air-ship has unquestionable 


advantages under suitable conditions: cruising at high 
altitudes over the battlefield, or over or in the rear of 
the enemy's lines, and reporting to headquarters by 
wireless every movement of strategic or tactical import- 
ance, it might render the most vital service. It is able to 
carry a complement of officers trained to observation, 
capable of giving an accurate interpretation of what they 
observe, and acting under most favourable conditions, 
such as are not possible in any existing aeroplane ; it can 
move at some fifty miles per hour, if required, or 
remain to all intents and purposes stationary; it can 
follow continuously the course of events from sunrise 
to sunset, and remain the whole time in touch with 
headquarters, either for sending or receiving. On the 
other hand, for bearing despatches, for flying at low 
altitude within range of shot and shell, as may be 
necessary for detail reconnaissance or in cloudy or 
misty weather, for bringing machine-gun fire to bear 
at some important point or at a critical moment, etc., 
all these are duties for which the aeroplane is pre- 
eminently suited, as also for rapidly locating and 
signalling gun positions, directing fire, and duties of 
such-like character. 

It is more than questionable whether actual fighting 
is any part of the primary function of a dirigible at all ; 
it is at least becoming apparent that bomb-dropping is 
an entire misuse of the large airship ; the results are 
incomparably small in view of the means employed, 
and can never afi'ect decisively the course of any battle 
or campaign. 

It is important to note that though it is possible 
effectively to armour an aeroplane, at least to be proof 
against small-arms fire, and that in any case the vulner- 
able target is small, the dirigible, presenting a mark 
larger than the proverbial haystack, cannot be effectively 



protected. In spite of the fact that injury to the 
envelope is not necessarily dangerous, it has been reported 
that such injury has already necessitated a hurried 
descent into a hostile country, with the effective loss of 
both vessel and crew. These are the considerations 
which place the dirigible at a formidable disadvantage 
when within reach of the enemy's guns. 

§ 5. Aeroplane and Dirigible, analogy between 
Air and Naval Forces not tenable. We may now pass 
to the discussion of the secondary function of the 
aeronautical Arm in its present relation — that is to say, 
we shall consider the question of aeroplane versus 
dirigible in armed conflict. 

At the outset it is desirable to dispose of the 
much-worried analogy that crops up again and again 
when the present subject is discussed. Some of the most 
strenuous supporters of the airship as an auxiliary to the 
aeronautical service are fond of drawing a parallel 
between the air service and the Navy, the airship being 
put forward as analogous or comparable to the battle- 
ship or battle-cruiser, and the aeroplane to the torpedo 
boat or destroyer. In the author's opinion any such 
analogy is totally fallacious. The effective area of the 
target presented by an aeroplane is but a few square 
feet. The effective target area of a torpedo boat or 
destroyer is more than one hundred times as great. 
The time during which an aeroplane is visible and 
under fire, owing to its small size and high speed, is 
short compared to that of torpedo craft at sea.* The 
armament which a Zeppelin can bring to bear on an 
attacking aeroplane is confined to that which she can 
carry on a platform arranged on top of the structure, 
since the hostile aeroplane making its attack from above 

* Added to this, in order to detect the approach of a hostile aeroplane, the sky has 
to be scanned in the three dimensions of space. 

























































can manoeuvre to remain in billiard phraseology, "snook- 
ered" so far as the gondolas and their armament are con- 
cerned. Beyond the above, the speed of the aeroplane 
is approximately double that of the airship, whereas 
the speed of a fast destroyer is not more than 25 or 30 
per cent, superior to that of a fast and heavily-armoured 
cruiser or battleship of modern type, and even this 
advantage is lost in heavy weather. 

It will be realised in considering the above facts 
that the whole analogy breaks down — the continued 
existence of the battleship or cruiser in the face of 
torpedo-craft does not in the least degree imply or 
involve the continuance of the airship as a logical 

September 11th, 1914. 

§ 6. Aeroplane and Dirigible in Armed Conflict. 
Having in the preceding sections devoted some attention 
to contrasting the respective merits and limitations of 
the aeroplane and airship or dirigible, and to disposing 
of the false analogy so frequentl}^ drawn between the 
air forces and the Fleet, we pass to the consideration in 
greater detail of their mutual relationship in matters of 
attack and defence. Firstly, it is evident that the attack 
will essentially be on the side of the aeroplane; the 
dirigible can do no more than act on the defensive. The 
great disparity of speed alone, whatever armament the 
airship may carry, settles this definitely; it is within the 
power of the aeroplane to choose precisely when, how, 
and where it will engage in conflict. The dirigible, like 
the submarine, is too slow to run the enemy to earth or 
to bring him to bay, and, to its disadvantage, cannot, 
like the submarine, make itself invisible and attack by 
stealth. Beyond this, its quarry' (the aeroplane) is of 
small size, often scarcely visible at a mile or two distance, 
and when not actually in the air can be either concealed 



or efficiently protected. Any attempt at aggressive 
action on the part of the dirigible is totally and com- 
pletely out of the question ; it is, in fact, beyond the 
conceivable range of possibility. 

On the other hand, if the airship is to continue as 
a factor in warfare at all, it must be abl^ to defend 
itself against hostile aircraft, and in particular be capable 
of repelling the attack of the enemy's aeroplanes. Now 
the only power of defence possessed by a dirigible 
when attacked by an aeroplane is counter-attack by 
gun-fire ; hence the extent, character, and distribution 
of its gun armament is one of the most important 
factors in its design. 

In the earlier days of the development of the aero- 
plane when its horse-power was but little in excess of the 
minimum required for the bare necessities of flight, its 
rate of ascent was so extremely slow (if it could be said to 
have any real rate of ascent at all) that it was commonly 
assumed that a dirigible, or airship, could seek safety in 
altitude. To-day, however, many aeroplanes will make 
altitude at a speed of 700 ft. or 800 ft. per minute, thus 
being more than able to hold their own with the lighter- 
than-air machine, and can ascend to over 10,000 ft. 
altitude (even twice this height has been reached) ; again 
having the dirigible at a disadvantage. 

§ 7. Aeroplane versus Dirigible , means of Attack 
and Defence. The method by which an aeroplane may 
most effectively attack a dirigible is a matter that 
remains for future experience to settle. If the aeroplane 
pilot is prepared to sacrifice himself, and has at his 
disposal a powerful machine of modern design, no 
dirigible can stand against him. Thus, if, as a matter of 
experience in actual service, men are found of sufficient 
grit and grim determination to adopt ramming tactics, 
and to hurl themselves and their craft bodily at the 



gas-bag of the dirigible, its destruction is immediate and 
complete. There is no defence possible against this 
mode of attack. The crew of the dirigible may not have 
even the most slender chance of stopping the aeroplane 
by machine-gun fire; 'the attack can be made from above 
by a steep vol plane or a vertical dive. In the case of a 
large airship of the Zeppelin type, even with machine 
guns mounted '* on the roof," the chances of defeating 
such an attack are remote ; the speed of a machine 
descending vertically, or steeply, is approximatel}'' that 
of its limiting velocity — commonly about 150 miles per 
hour — leaving a very brief period in which to score a hit. 
Beyond this, no ordinarily fatal hit is effective under 
the conditions in question ; no injury to the motive- 
power installation is of the least effect as a stopper, 
and the pilot is in almost perfect security in his position 
behind the engine. If by an exceptional chance he 
should be wounded, he is still able to effect his purpose, 
unless totally disabled. 

The steep or vertical descent is admittedly a 
dangerous feat of airmanship, but it is not intrinsically 
dangerous ; the risk involved is due to the structural 
stresses to which the machine is subjected when "flatten- 
ing out." These, it is well known, may become exces- 
sive ; any objection on the score of danger has obviously 
no weight whatever under the conditions contemplated. 

It is an open question whether airmen will be 
found ready to step forward at the critical moment to go 
to certain death, and so the general feasibility of ramming 
tactics must for the time being remain in doubt. How- 
ever, there are many other modes of attack open to the 
aeroplane pilot, all more or less untried at present ; un- 
questionably also there are still other methods that will 
in due course be devised. In the case of the non-rigid 
dirigible, as in the ordinary spherical balloon, it is almost 



certain that a hundred or so yards of barbed wire trailed, 
beneath an aeroplane would be a quite sufficient weapon ; 
equally effective would be an incendiary shell, or a rocket, 
presuming any part of the envelope to be hit. Ordinary 
small-arm or machine-gun fire is comparatively ineffective, 
since the bullet holes are, in any case, small, and in some, 
of the modern machines repairs can be effected without 
coming to earth. However, jeven rifle fire has proved 
sufficient to bring a balloon down. It is evident that the 
weak point of any dirigible or airship is its liability to 
attack from above ; in the non-rigid type, without going 
to the length of any elaborate apparatus, and without 
endangering the attacking aeroplane, almost any angular 
and weighty object dropped from a height cannot fail 
to be of conclusive effect if it fairly, hits the envelope,^ 
and likewise in the case of the rigid type — such as the 
Zeppelin — the structure would not stand up under a blow 
from, say, a steel bar of any ordinary stock section of 
70 lb. or 80 lb. weight dropped from a height of 200 ft. 
or 300 ft. Without saying that the above are suitable 
methods of attack, it may be claimed that they fairly 
indicate the inherent weakness of the dirigible in face of 
attack by an aeroplane of sufficient power to master it in 
the matter of altitude. There are methods not mentioned 
here which are actually in use or in contemplation, but 
which, for obvious reasons, require to be treated as con- 
fidential. It is, however, in the author's opinion, quite 
unnecessary to carry the matter further ; the weaknesses 
of the dirigible on the defensive are so great and of such 
a character as to render it quite unfit to remain an active 
participant in aerial warfare. It may escape for a time, 
and may render a certain amount of useful service, but 
only thanks to the circumstance the number of high- 
powered, fast-climbing aeroplanes is comparatively limited, 
and to the fact that scientific methods of attack have not 



yet been fully worked out or put into practice. However, 
even to-day, the finest of Germany's fleet of Zeppelins 
would be absolutely at the mercy of a modern aeroplane 
in the hands of a man prepared to make his one and last 
sacrifice. So fragile and combustible a contrivance as a 
dirigible, whether rigid, or non-rigid, can never, in the 
author's opinion, survive in the face of the rapid develop- 
ment of the aeroplane and the engines of offence with 
which before long it will be furnished. 

Before proceeding to the broader considerations, it 
has been thought desirable to dispose of the airship as a 
factor in the aeronautical service — its dismissal being an 
initial simplification. It is not altogether important 
whether or not this conclusion turns out to be literally 
true. It may be that, in spite of all that has been put 
forward, the large airship may retain some degree of 
utility ; even if this be so, the main conclusions will be 
unaffected. It is the aeroplane, and the aeroplane only, 
either as a reconnaissance or a fighting machine, acting 
independently or in flights or squadrons, which will in 
effect constitute the aeronautical Arm ; and whether the 
considerations we discuss are strategic or tactical, it is: 
the potential capabilities and limitations of the aeroplane 
that we require to keep constantly in mind. 



(September 17th, 1914). 


§ 8. Strategic and Tactical Uses of the Aeronautical 
Arm. In the present distribution of the cavalry Arm, the 
distinction between the strategic and tactical uses of 
cavalry is clearly recognised. For purely tactical purposes 
it is customary to attach one or more squadrons, usually 
a regiment of cavalry, to each infantry division. The 
main cavalry force on the other hand, — known as the inde- 
pendent cavalry, — constitutes a separate command, taking 
general instructions from the headquarters staff. The 
independent cavalry may be engaged in operations of stra- 
tegic import, as in the conduct of a reconnaissance in force, 
or in the execution of a wide turning or out-flanking 
movement, or in the countering of such a movement on the 
part of the enemy. Alternatively it may be employed in 
its tactical capacity, its full weight being thrown at some 
critical moment into the fighting line, it may be to attack 
and destroy the cavalry of the enemy, to raid and capture 
or put out of action his artillery, to harass him in retreat, 
or to convert a retreat into a rout. The divisional cavalry 
are, generally speaking, employed for the latter — tactical 
— duties only. 

In a similar manner aircraft are capable of employ- 
ment in duties of both strategic and tactical import, and 



accordingly will probably need to be divided into divisional 
and independent commands. Thus there is the machin- 
ery of strategic reconnaissance, whose function it is to 
inform the headquarters staff of the main disposition and 
movements of the enemy's forces, positions of his depots, 
magazines, etc., points of concentration and strength of 
his reserves, and last, but not least, his main and perhaps 
auxiliary lines of communication. On the tactical side 
there are similarly many duties to be carried out, 
analogous to those at present performed by cavalry; 
there are also duties which must be regarded as new, 
brought into being by the peculiar power and capacity 
of the aeronautical Arm; these are, in the main, such 
as would indicate control by the divisional command. 

§ 9. The Strategic Scout and its Duties. The 
strategic value of the aeroplane depends mainly upon 
its utility for the purpose of reconnaissance ; briefly it is 
its value as an informer, rather than as a fighter, that is 
of service to the headquarters staff. The duties of a 
machine thus acting are necessarily of an entirely different 
character from those of a machine employed in the minor 
operations of the field, whether for tactical scouting, 
direction of gun-fire, or otherwise. Firstly, the flight 
range or radius, as determined by petrol capacity, is a 
far more important factor in its design, since it will 
require to operate over a large area, and to cover long 
distances over the enemy's territory, where any renewal 
6{ fuel supply is impossible; secondly, its flight speed must 

/be such as to render it reasonably secure against pursuit. 

I Anything serious in the direction of armour or armament 
will be entirely out of place, since under no circum- 

1 stances will such a machine be required to act in a 

\ combative capacity ; its defence lies in its speed. It 
"appears from all reports that the duties in question are 
s^ch as to require an observer (probably a staff officer) 



of mature knowledge from a military standpoint, with 
considerable flying experience, possessing something of 
an intuition for reading the meaning of the incomplete 
and fragmentary indications which are obtainable from 
high altitude observation. It is evidently not impossible 
for a strategic scout (as we may term the machine under 
discussion) to descend to low altitude in pursuit of more 
accurate and precise information; but it is always to be 
remembered that any such manoeuvre is dangerous to an 
unarmoured machine ; it may be too easily shot down or 
destroyed by shrapnel. In this latter event it must be 
regarded as having failed in its purpose. The possession 
of a wireless installation may be assumed, but, in the 
event of the machine being lost, the fact that reports 
had already been transmitted to headquarters would in 
no way mean that the machine had completely fulfilled 
its mission. 

The work done by the strategic scout thus comprises 
the gleaning of information hitherto only to be obtained 
by espionage or by a reconnaissance in force — that is to 
say, by a large force of cavalry with supports of horse 
artillery and infantry, often involving considerable 
fighting and loss. It is quite improbable that aeroplane 
scouting will prove an entire substitute for such recon- 
naissance ; in may be said that cavalry can fetl and act 
where the air-scout can only see and report, but, as a 
prelude to cavalry reconnaissance, and as an auxiliary 
thereto, the services of the strategic scout should prove 
of the utmost utility. It will, at least, enable the cavalry 
force acting at a distance from its base, frequently in 
the rear of the enemy, to keep in constant touch with 
headquarters, and thus relieve the despatch rider of one 
of his most difficult and dangerous tasks. In service 
of this character it would seem probable that a flight or 
squadron of aeroplanes \V'ould be temporarily or per- 


< X 

^ Si 

ii -A, 


manently attached to the independent cavalry, as in the 
case of the supports representing the other two Arms 
of the Service. Under these circumstances the command 
of the combined force would remain, as at present, with 
the cavalry leader. 

(September 18th, 1914). 

§ 10. The Aeroplane as an Auxiliary to Tactical 
Operations. The aeroplane in its employment in connec- 
tion with tactical operations finds itself under conditions 
entirely different from those discussed in the preceding 
section ; its duties are of a more varied character, and 
involve flying at lower altitudes than are compatible with 
security. It is likely to be almost continuously under fire, 
and, according to some of the experiences of the present 
war, it has almost as much to fear in this respect from its 
friends as its foes. Whereas the strategic reconnaissance 
machine is able to perform all its most useful work at 
high altitude, and avoid as far as possible the atten- 
tion of, or actual contact with, the enemy, and evade 
pursuit by flight ; the tactical machine (acting under the 
divisional command), whether engaged in local recon- 
naissance or in locating or directing gun-fire, or in other 
duties, must be prepared at once to tackle the enemy, 
and, in brief, to interfere as much as possible with the 
hostile aeroplane service. Under certain circumstances 
the instructions will undoubtedly be to make the aircraft 
of the enemy the first objective. 

It is more than probable that it is in connection 
with the varied duties which in the future must fall to the 
Fourth Arm in its tactical usage, that differentiation of 
type and specialisation will eventually become the most 
marked. At present practically no attempt in the 
direction of specialisation has taken place. It is true the 
different machines in service vary considerably, and those 
responsible for the construction and specification of 



Service aeroplanes have already begun to talk of 
" reconnaissance machines " and " fighting machines ; " 
but the distinction is one that has scarcely yet pene- 
trated to the field of operations. When all has been said, 
differentiation of type must, from the Service standpoint, 
be looked upon as an evil, only to be justified when, and 
to the extent that, service conditions prove it to be 
necessary. So far even the broad distinction between 
machines for strategic reconnaissance and for tactical 
operations has scarcely been drawn or received recog- 
nition. The military aeroplane of to-day is something 
like the frontiersman's knife — made for nothing in 
particular, used for everything in general. 

For the purpose of directing artillery fire the 
experience of the present war has shown the aeroplane to 
be effective almost beyond the most sanguine expecta- 
tion. For this purpose it appears to have established 
its utility beyond question. Its duties in this respect 
may be regarded as a special branch of local recon- 
naissance, its function being to locate the objective and 
signal its whereabouts to the gun batteries to which it is 
attached; further to report and correct inaccuracies of fire. 
The exact mode or modes of signalling adopted do not 
so far appear to have been definitely disclosed. Some 
reports give the aeroplane as turning sharply when 
over the enemy's position ; according to other accounts 
a smoke bomb of some kind is let fall to indicate the 
position to be attacked ; other reports, again, mention 
lights as being used. It appears that lamps of sufficient 
power to be visible in daylight are actually being 
employed by the German aircraft. Possibly all these 
methods are in use experimentally, or different kinds of 
signals may be used for different purposes, to indicate 
initially the position, and subsequently to give corrections, 
cither as to direction or range. Whatever the methods 



employed may be (and the details do not much concern 
us at the moment), they seem to be quite effective, and, 
it may be presumed, very considerably increase the 
fighting value of the guns. More than this, the value 
of aeroplane work will be relatively greater the longer 
the range ; in fact, it may in future be found possible to 
employ heavy artillery of long range under conditions 
where, without the help of the aeroplane, it would be 
comparatively useless. As an illustration, there is 
nothing to-day to prevent a long-range battery, well 
served by its aeroplanes, from effectively shelling an 
enemy without knowing in the least the character of its 
objective — i.e., whether an infantry force or position, a 
body of cavalry, or the enemy's guns. In the present 
war the aeroplane appears to have been utilised by the 
German army, as a matter of regular routine, as an 
auxiliary to the artillery in the manner indicated. It has 
been reported again and again that the appearance of 
an aeroplane overhead has been the immediate prelude 
to the bursting of shrapnel, frequently the very first 
shell being so accurately placed as to indicate that the 
method of signalling, and, in fact, the whole perform- 
ance, must have been well thought out and equally well 

It is well understood that the determination of the 
distance of an aeroplane of known size with approximate 
accuracy is a matter of perfect simplicity. Thus, if the 
aeroplane be flying fairly overhead, or directly towards 
or away from the observer, and the span be a known 
dimension, then by measuring the optical angle pre- 
sented by the span, the distance or range is given by 
simple proportion. For example, holding a foot-rule 
square in front of one at arm's length — approximately 
20 in. from the eye — the span, known to be, say, 36 ft., 
subtends an angle represented by, say, \ in. on the scale ; 



20 X S6 
the distance is ^ n — = 1440 ft. Using such rough- 
and-ready "apparatus," the degree of accuracy to be 
expected is not great ; however, the author has found it 
quite sufficient to determine the altitude of a machine to 
within 5 or 6 per cent, of the truth. If for the observer's 
arm and foot-rule we substitute a low-powered telescope 
or binocular of, say, 2 or 3 diameters magnification, with 
micrometer cross-wires, with which to follow up the 
apparent reduction in span of a receding aeroplane, until 
some prearranged signal is given, the range could 
undoubtedly be determined easily within 2 or 3 per cent. 
At 1 mile distance this means a degree of accuracy 
represented by a maximum error of about 40 yards, or 
sufficient to enable shrapnel to be dropped right on the 
mark. Parenthetically, it may be pointed out that the 
same method will enable the range of a hostile aeroplane 
to be determined, provided the type be identified, and its 
leading dimensions are known ; it also suggests the 
importance of not flying exactly towards or away from, 
or exactly broadside to, any position of the enemy 
guarded by counter-aircraft artillery ; flying end on to the 
enemy is also to be deprecated on the ground of fixity of 

§11. Attack by Gun- Fire. An aeroplane operating 
in a hostile country is liable to attack by rifle and 
machine-gun fire, also by shell-fire from special anti- 
aeroplane artillery. It has comparatively little to fear 
from field artillery owing to the want of handiness of 
the ordinary field-gun. The " laying " of a field-piece is 
far too clumsy a business to permit of its effective use on 
so small and rapidly moving a target as presented by an 
aeroplane in flight, though it may be effective when used 
against a dirigible. With regard to rifle or machine-gun 
(small bore) fire, calculation shows that aircraft is abso- 



lutely safe at an altitude of somewhat over 7000 ft. ; it is 
in that region that the top of the trajectory lies for 
vertical shooting. 

The duties of a strategic scout on long-distance 
work would, without doubt, permit of flying at such a 
high altitude, and it may be added that, although 
absolute immunity is not reached at less than about 
7000 ft., a solitary aeroplane can only present a very 
unprofitable target at far lower altitudes. In fact, it may 
be taken that at, say, 5000 ft. or 6000 ft., the amount of 
small-arm ammunition required to bring down an aero- 
plane would be enormous. Not only has the velocity 
become so reduced as to render a " hit " capable of but 
little mischief, but the time of flight of the bullet, rising 
vertically to this altitude, would be about 8 or 9 seconds 
and the distance moved by the aeroplane 1000 ft., more 
or less. Therefore it would be necessary to fire into 
■quite a different part of the heavens from that in which 
the aeroplane is seen, something akin to sighting into 
the Great Bear to hit the Pole Star. Beyond this the 
gyroscopic drift of a bullet fired vertically is nil, against 
some 30 ft. or 40 ft. under normal conditions ;* also the 
error due to the earth's rotation is a matter of about 
30 ft. westward, and cannot be allowed for without taking 
reference to the compass bearing. Taking all these 
things into account, it is evident that for the infantryman 
or gunner not specially trained, the task of bringing 
down an aeroplane flying at high altitude is no light 
one, especially when we recall the fact that for every 
inclination and bearing of the line of sight, the conditions 
differ. In designing the mounting of aeroplane-stopping 
artillery or machine-guns, it would be possible to render 
the sighting corrections for such items as gyroscopic 

• The normal sighting of a match rifle is arranged partially to correct for the 
gyroscopic drift. 



drift and earth's rotation automatic ; this could be done 
without difficulty, and would mean the elimination of 
errors whose combined value may amount to something 
like 60 ft. at 6000 ft. altitude — i.e., an angular magni- 
tude represented roughly by the apparent diameter of 
the sun or moon. 

The height to which aircraft artillery will carry is by 
no means subject to the same limitation as that of the 
small-bore machine-gun or rifle, the resistance of the air 
being many times greater than that due to gravity. 
Thus the ordinary rifle bullet, at 2,000 foot-seconds 
muzzle velocity, would carry to a height of over 60,000 ft. 
in vacuo, instead of approximately 7,000 ft. actual. If 
we take the case of a 1 -pounder having the same velocity, 
its eff'ective vertical range is well over 12,000 ft., and 
from that calibre upwards the range will, in practice, 
be more a question of the shell being properly directed 
than whether it will attain the height. At the best, 
firing from the ground at an aeroplane at high altitude, 
will require skilful gunnery, and when near the limit of 
the trajectory nothing but sheer good luck will render a 
hit eff'ective. The angle of " lead " it is necessary to 
give to allow for the velocity of flight, as already stated, 
is one of the difficulties of high-altitude shooting. This 
angle is only constant so long as the velocity of the 
projectile is constant, assuming (as fairly represents the 
conditions) the flight speed not to vary; at extreme 
heights the velocity of the projectile has fallen so low 
that a very slight error in range-finding will be fatal to 
accuracy. The solution of this difficulty may be found 
in the employment of guns of about 3-in. bore — i.e., a 
12-pounder or 15-pounder, with the concurrent advantage 
of a full shrapnel charge, and, in shot-gun terminology, 
a larger killing circle. The obvious disadvantages, how- 
ever, of artillery, in place of a light automatic or 



machine gun, lie in its want of portability and its 
unhandiness, difficulties which may, in course of time, 
be overcome. 

All things considered, it would appear probable that 
attack on aeroplanes at high altitude from the ground 
will be found impracticable, or at least uncommercial. 
Not only have we to reckon with the various consider- 
ations above discussed, but also with the fact that, in our 
climate at least, not more than one day in four is 
sufficiently clear to render high-altitude shooting possible, 
and though it is true that an aeroplane, to make observa- 
tion, cannot remain above or in the clouds, it presents but 
a poor mark under bad weather conditions. 

An aeroplane operating at high altitude will prob- 
ably need to be hunted and driven off or destroyed by 
armed machines of its own kind. 

§ 12. Defence from Gun-Fire. It is manifestly not 
possible for an aeroplane to perform all the duties 
required of it, in connection with tactical operations at 
high altitude,* and whenever it descends below 5,000 ft., 
or thereabouts, it is liable to attack from beneath ; in fact, 
at such moderate altitudes it must be considered as being 
under fire — mainly from machine-gun and rifle — the 
whole time it is over or within range of the enemy's 
lines. Protection from the rifle bullet may be obtained 
in either of two ways ; the most vital portions of the 
machine, including the motor, the pilot, and gunner, can 
only be eff'ectively protected by armour-plate ; the 
remainder of the machine, including the wing members, 
the tail members, and portions of the fusilage not pro- 
tected by armour, also the controls, struts, and the 
propellor, can be so constructed as to be transparent to 
rifle fire — that is to say, all these parts should be so 

♦For military piirposes we may take the term "high altitude" as defined by 
effective vertical range of small-armi fire — in other words, as denoting an altitude 
of some 5000 ft. or 6000 ft. or more. 



designed that bullets will pass through without doing 
more than local injury and without serious effect on the 
strength or flying power of the machine as a whole ; in 
certain cases components will require to be duplicated in 
order to realise this intention. It is important to under- 
stand clearly that any intermediate course is fatal. 
Either the bullet must be definitely resisted and stopped, 
or it must be let through with the least possible resist- 
ance ; it is for the designer to decide in respect of each 
component which policy he will adopt. The thickness of 
the armour required will depend very much upon the 
minimum altitude at which, in the presence of the enemy, 
it is desired to fly ; also upon the particular type of rifle 
and ammunition brought to bear. There is a great deal 
of difference in penetrative power, for example, between 
the round-nosed and pointed bullets used in an otherwise 
identical cartridge. 

If it were not for the consideration of the weight of 
armour, there is no doubt that an altitude of about 
1000 ft. would be found very well suited to most of the 
ordinary tactical duties of the aeroplane. At such an 
altitude, however, the thickness of steel plate necessary 
becomes too serious an item for the present-day machine, 
even allowing for the very excellent and highly efiicient 
bullet-proof treated steel which is now available ; at the 
altitude in question the minimum thickness that will stop 
a 0.303 Mark VI. round-nose bullet is 3 mm. (i in.), but 
if attacked by the modern pointed-nose Mauser, nothing 
short of 5 mm. or 6 mm. is of avail. If we compromise 
somewhat in the matter of altitude and prescribe 2000 ft. 
as the minimum height for which protection is to be 
given, the figures become 2 mm. (about 14 S.W. gauge) 
for the 0.303 round-nosed bullet, and for the pointed 
Mauser 3 mm. or slightly over; at present it is not 
expected that it will pay to armour a machine for the 





1 1 SL^'v 



] 'HiiiK 



ial] -'/i 






i^^^^Hi \ ■ 



■ 1 l^M 



^^BjK' V/^W 


^^K^tfi^K § ''.•^■'^'T^L. 




W^ ^>^^l 





duties ill question more heavily ; thus we may take 
2000 ft. as representing the lower altitude limit of 
ordinary military flying. Anything less than this will 
be referred to in the present series of articles as low- 
altitude flying. On this question of armour it cannot 
be too strongly insisted that anything less than the 
thickness necessary definitely to stop the projectile is 
worse than useless ; a " mushroomed " bullet, possibly 
accompanied by a few detached fragments of steel, is 
infinitely more disagreeable and dangerous than a bullet 
which has not been upset. 

An aeroplane armoured in all its vitals with 3 mm. 
steel, and otherwise designed on the lines indicated, 
flying at not less than 2000 ft. altitude, will be extremely 
difficult to bring down ; so much so, that unless its 
exposed structural members be literally riddled and 
shattered by rifle and machine-gun, or unless a gun of 
larger calibre be brought to bear, it will be virtually 
impossible to effect its capture by gun-fire alone. 



{September 25th, 1914). 


§ 13. Low- Altitude Flying. Our interest in the 
subject of low-altitude flying from the military point 
of view is entirely prospective; there are certain advan- 
tages to be derived from low-altitude flying that are 
not at once apparent ; the disadvantages are too 
obvious to need mention. 

It has often been noticed by the writer, and it is 
probably a matter of common observation, that an aero- 
plane, however visible it may be with the sky as back- 
ground, is readily lost to sight and becomes exceedingly 
difficult to pick out when backed by a hill or a 
mountain-side. This is the case with a machine finished 
** bright;"* when machines are given protective colour- 
ing, as is now customary, the difficulty of detecting 
their presence when below the sky-line will be far 
greater. Thus, so long as an aeroplane approaches any 
position at medium or high altitude, it may be clearly 
seen at some few miles distance, and measures will be 
taken to give it an appropriate reception ; whereas a 
machine making its approach at low altitude would 
frequently be able to take the enemy quite by surprise. 
Beyond this it has been found that, except for recon- 
naissance, high altitude is not altogether advantageous. 

• A term used by boat-builders to denote a varnished boat — not painted. 



A certain amount of harm may be done by bomb- 
dropping, machine-gun fire, the raining of steel darts, 
etc. ; but an aeroplane at a height cannot take an 
intimate and decisive part in a fray, as, for an example, 
cavalry charging, or infantry with the bayonet. It might 
prove of enormous and overwhelming value if at any 
critical moment, or at any critical point, it were 
possible to let loose a few squadrons of aeroplanes each 
mounting one or more machine guns, to bring short- 
range concentrated fire to bear, or alternatively to 
make an attack by the aid of bombs or hand-grenades. 
The scene that would ensue, for example, on a con- 
gested line of retreat would be indescribable : horses 
thrown into hopeless confusion or stampeded, mechanical 
transport lorries holed in a dozen or more vital points, 
water-jackets or radiators damaged, cylinders pierced, 
etc., gun teams wiped out, infantry decimated ; in brief, 
chaos over endless miles of high road. 

§ 14. Armour for Low-Altitude and Point Blank 
Range. The question arises whether it is possible for 
the aeroplane to fly at a sufficiently low altitude to 
act effectively in the manner indicated without expos- 
ing itself to immediate destruction. The matter is 
entirely a question of armour ; the unarmoured portions 
of the machine, which derive their immunity from their 
transparency to rifle-fire, are no worse off at point-blank 
range than at 2000 ft. or 3000 ft. altitude. Taking the 
altitude as 500 ft. (a reasonable maximum for the 
effective execution of the duties contemplated), the thick- 
ness of armour necessary is approximately /^ in. (4 mm.) 
for the British service Mark VI. ammunition, or slightly 
over i in. in the case of the pointed Mauser bullet, the 
latter thickness representing a weight of 10 lb. per sq. ft. 
It is evident that the problem of giving complete pro- 
tection to the motor, pilot, and gunner will become a 



problem of some difficulty ; probably in the present state 
of the constructor's art the protection would need to be 
somewhat " scamped," and a certain amount of risk 
admitted. Whatever economies are effected in armour^ 
the main principle must not be lost sight of — i.e., the 
thickness must not be tampered with ; armour too thin 
for its duty is worse than canvas or brown paper. 

Once the altitude has been brought down to 500 ft. 
— that is to say, if and when it is recognised as advan- 
tageous and found possible to utilise such low altitudes 
in aeroplane tactics — it becomes a question whether it 
will not be found to pay to "go the whole hog " and fly 
at the very lowest altitude possible. It may be at once 
admitted that all the dangers of flying, qua flying, will be 
thereby increased, but danger of the degree in question 
is a matter of little or no consideration in actual warfare. 
Briefly, the immediate suggestion is that if low-altitude 
flying is systematically to be undertaken, it should be 
conducted quite low — dangerously low, according ta 
ordinary standards. At an altitude of 500 ft. an aero- 
plane still makes a very clear mark against the sky, 
visible from a considerable distance. By following the 
contour of the ground, never rising more than 100 ft. or 
200 ft., unless to clear an obstacle not otherwise to be 
avoided, an attack will be made with comparative sudden- 
ness, and the machine will be gone out of sight almost 
before there has been tim^ to bring a gun to bear. Even 
when under fire it will have a certain tactical advantage 
in the fact that it will be attacking a line* parallel to 
which it is flying — it need never miss its target — whereas 
it itself offers the worst kind of mark to the enemy, 
combining small size, high speed, disconcertingly short 

• In nearly all cases the objective of attack will be a line of some kind ; thus it 
may be a convoy or column in retreat ; alternatively, if the attack be on an 
entrenched position or on the attacking force, the line formation is again in 
evidence; the pilot's instructions in every case would be to fly directly over or 
parallel to the line to be attacked. 



range, in addition to which it is, in effect, a disappearing 
target. If one is tempted to be over-influenced by the 
obvious danger of such tactics, it is well to recall the 
exploits carried out as a matter of ordinary experience by 
cavalry under fire, without the advantage of armoured 
protection, while presenting a target (man and horse) 
something like 20 sq. ft. in area, and with a speed con- 
temptibly small in comparison with that of flight. It is 
only necessary clearly to admit that in this form of 
fighting we may have to reckon with serious losses of 
men and machines, not occasional losses, as at present, 
but rather such as can be expressed as a percentage of 
the force engaged. 

The further reduction of altitude now under dis- 
cussion means that rifle-fire must be faced literally at 
muzzle velocity, and corresponding provision made in the 
thickness of the armour. For the pointed Mauser bullet, 
representing the maximum requirement of to-day, the 
thickness of plate needed is scarcely less than | in., and 
the weight 13 lb. or 14 lb. per sq. ft. Evidently the 
question of weight of armour will become a difficulty of a 
most serious character, and no pretence can be made to 
give complete protection ; the area must be cut down to 
an absolute minimum. 

§ 15. The Machine-Gun in the Service of the 
Aeronautical Arm. Rapidity of fire to the aeronautical 
gunner is a matter of first importance ; the time during 
which he has the enemy under fire is necessarily brief, 
and in that time he must do the maximum injury 
possible ; consequently amongst present existing weapons 
we may regard the machine-gun as without rival. 

The degree of accuracy attainable in firing with a 
machine-gun from an aeroplane depends primarily upon 
the weapon and the man, as in every other kind of 
shooting, but in addition the steadiness of the aeroplane 

33 D 


is an important factor, this being mainly dependent upon 
the wind and weather. Under favourable conditions an 
expert shot using the Lewis gun has delivered the whole 
contents of a magazine (of 47 cartridges capacity) into an 
area 10 ft. by 60 ft. from an altitude of 600 ft. at a range 
of 1,000 yards. Making allowance for this expert hand- 
ling of the weapon, as being superior to the average 
ability available under service conditions, there can be no 
doubt as to the deadly efficiency of a gun of the Lewis 
type as an aeroplane armament. The author has himself 
witnessed a performance very little inferior to the above 
in weather that could by no means be considered ideal. 
Apart from many detail points of merit, the Lewis gun 
for aeroplane service, has many advantages ; firstly, on 
account of its self-contained magazine, which, by the 
abolition of the cartridge-belt, etc., permits of the gun 
being trained freely in any direction from vertically 
upwards to vertically downwards ; secondly, its light 
weight, which also allows of its use as a shoulder-arm ; 
and, thirdly, the adoption of direct air cooling in place 
of the usual water-jacket.* 

Assuming the proved accuracy of the Lewis gun 
as the criterion of machine-gun fire, it is evident that 
an estimate of the effectiveness of low-altitude aeroplane 
attack becomes little more than a matter of simple 
arithmetic. We may take, for example, the problem to 
be that of executing a counter-attack upon infantry, 
themselves attacking a position in open order, the 
counter-attack to be delivered against the foremost line, 
lying prone at two or three paces interval. We are 
justified in assuming that the magazines will be emptied 
over an area defined as a belt of 10 ft. or 12 ft. width, in 
which, therefore, there is one man to approximately 
100 sq. ft. of ground under fire. Now the area of target 

• Compare Appendix. 



offered by a man prone is approximately 5 sq. ft., 
so that, as an average, one bullet in twenty will find its 
mark. This represents a man knocked out for every 
10 oz. of lead expended, which must be regarded as 
extremely economical, in view of the fact, that it is 
usually supposed to take a hundredweight of lead to kill 
one man, say 30 lb. or 40 lb. for every man put out 
of action. 

§ 16. Points in Favour of Extreme Low- Altitude. 
In any such work as the foregoing, the question of 
lowness of altitude is of vital importance. Since no 
attempt to aim at an individual mark is contemplated, 
there is no disadvantage from the point of view of the 
gunner in flying quite low. His target may appear as 
blurred as the side of a railway cutting viewed from the 
window of an express train, but so long as he " delivers 
the goods " within the belt of ground intended, his 
average hits will not be detrimentally affected. If he is 
shot at by the infantry line he is attacking, or by a 
supporting line (usually 300 yards, more or less, in the 
rear), every man attacking him breaks his cover, and 
becomes a prominent mark for the defending infantry 
force. Beyond this, the aeroplane carries armour and 
presents a comparatively small vulnerable target. The 
advantage of extreme low-altitude flying in the present 
connection lies in the fact that it is, in effect, a perfect 
defence against attack by long-range fire. No matter 
what developments may be made in air-defence artillery 
— even if means should be found to render an 18-pounder 
as handy as a sportsman's shot-gun — if the attacking 
aeroplane fly low enough, the enemy cannot bring long- 
range fire to bear without bringing his own infantry 
lines under fire at the same time. 

§ 17. The Future of the Fighting Type of Aero- 
plane. A reservation has already been made to the 



effect that low-altitude flying — «".e„ under 2,000 ft. — as 
affecting the service use of the aeroplane, lies mainly 
with the future ; the design of the machine for this class 
of work will require the most careful study on the lines 
already indicated, the essential point being immunity 
to attack by small-arm fire. In obtaining such immunity 
sacrifice of some kind will have to be made. Whether it 
be in the armour-plating of vitals, or in the provision of 
redundant members or material, a great deal of otherwise 
unnecessary weight must needs be carried which ultimately 
reduces the carrying power in other directions. This 
means eventually either a reduction in the speed or a 
positive all-round increase in the size and weight of the 
machine. Granted that all initial difficulties be overcome, 
the advent of the armed and armoured low-altitude 
machine will initiate a new phase of aeroplane tactics, 
and one that cannot fail to have a far-reaching effect 
•n the other Arms of the Service. The difficulties of 
cavalry operations will be increased incalculably ; a body 
of cavalry, unless protected by a covering force of aero- 
planes, will find itself continually open to attack, both by 
short-range machine-gun fire and by bombs and hand- 
grenades : in addition to this the demoralising effect of 
numbers of high-powered aeroplanes flying overhead, per- 
haps within 200 ft. or so, will be by no means a negligible 
factor. Up to the present the cavalry have been the 
Arm of greatest mobility, and nearly all cavalry opera- 
tions on a large scale are fundamentally based upon, and 
rendered possible by, that fact. Once the aeroplane has 
taken its place in the actual fighting arena, this condition 
is definitely a thing of the past, and, so long as daylight 
lasts at least, any cavalr}'- force not itself accompanied, or 
supported, by its own aeroplane auxiliary will find its 
every movement dogged by the hostile aeroplane, and its 
every operation baulked by counter-attack from above. 


Ran^e 300 yards. vService Rifle- Mark VL Aiiuiiunilion. 


Caught in the open, its only defence will be in dispersion 
over the widest possible front or area, otherwise it must 
take to the woods or whatever other cover is available. 
Further, it will be impossible for it to undertake a 
dismounted action, for the led horses (the bugbear of 
dismounted cavalry) will be either stampeded or destroyed, 
and its existence as an effective unit will be at an end. 

§ 18. As Affecting the Cavalry Ann. It must 
not be supposed, however fully the present anticipations 
of the development of the aeroplane as a fighting 
machine may be realised, that the value of cavalry is at 
an end ; this is not the author's view. It is probable that 
in the early stages of a battle, or of a campaign, the 
cavalry Arm will cease to play the important role that at 
present is, and has hitherto been, assigned to it, and that 
the pushing out of advance posts and reconnaissance will 
devolve more and more on the armed and armoured 
motor-car and aeroplane. However this may be, there 
will still remain country in which cavalry can be advan- 
tageously employed, country in which cover (woods, 
forests, etc.) is plentiful, where mounted men are secure 
from aerial observation and attack, and where a mounted 
force is virtually the only means by aid of which the 
terrain can be effectively reconnoitred. 

Thus, also, in wooded country, in the reconnaissance 
that accompanies or precedes an army on the march, it 
would seem probable that the aeroplane and cavalry will 
be used in conjuction, the more distant work being 
accomplished by the aeroplane, whose presence would 
also ensure the protection of the cavalry from hostile 
aircraft. The detail work, including the holding of 
bridges and advance positions of importance, also the 
location of and dealing with any patrols or other bodies 
of the enemy that may be encountered, will be accom- 
plished by the cavalry. The obvious disadvantage of the 



use of the aeroplane for reconnoitring is that it informs 
the enemy of the advance or presence of a hostile force. 
Where this fact is of weight, the protecting flight or 
squadron of aeroplanes would be best handled as a 
supporting force, with perhaps one machine at high 
altitude to maintain contact, the duties of this latter 
machine being to keep in touch and transmit information 
to the divisional or army corps command, and to call for 
the supporting aeroplane force should occasion require. 
Kxactly how the combination of the two Arms (aircraft 
and cavalry) will be controlled and handled it is impos- 
sible, without actual experience, to lay down. The main 
point is that in the new Arm we have a force altogether 
transcending the cavalry in mobility and range of ob- 
servation, and which before long will become an actual 
fighting force of no mean importance, and these facts 
cannot fail to be revolutionary in their ultimate influence 
on the role and employment of the cavalry Arm. 



{October 2nd, 1914). 


§ 19. The Principle of Concentration. It is neces- 
sary at the present juncture to make a digression and to 
treat of certain fundamental considerations which underlie 
the whole science and practice of warfare in all its 
branches. One of the great questions at the root of all 
strategy is that of concentration ; the concentration of 
the whole resources of a belligerent on a single purpose 
or object, and concurrently the concentration of the main 
strength of his forces, whether naval or military, at one 
point in the field of operations. But the principle of 
concentration is not in itself a strategic principle ; it 
applies with equal effect to purely tactical operations ; it 
is on its material side based upon facts of a purely 
scientific character. The subject is somewhat befogged 
by many authors of repute, inasmuch as the two distinct 
sides — the moral concentration (the narrowing and fixity 
of purpose) and the material concentration — are both 
included under one general heading, and one is invited 
to believe that there is some peculiar virtue in the word 
concentration, like the "blessed word Mesopotamia," 
whereas the truth is that the word in its two applications 
refers to two entirely independent conceptions, whose 
underlying principles have nothing really in common. 

The importance of concentration in the material 
sense is based on certain elementary principles connected 



with the means of attack and defence, and if we are 
properly to appreciate the value and importance of con- 
centration in this sense, we must not fix our attention 
too closely upon the bare fact of concentration, but rather 
upon the underlying principles, and seek a more solid 
foundation in the study of the controlling factors. 

§ 20. The Conditions of Ancient and Modern 
Warfare Contrasted. There is an important difference 
between the methods of defence of primitive times and 
those of the present day which may be used to illustrate 
the point at issue. In olden times, when weapon directly 
answered weapon, the act of defence was positive and 
direct, the blow of sword or battleaxe was parried by 
sword and shield ; under modern conditions gun answers 
gun, the defence from rifle-fire is rifle-fire, and the 
defence from artillery, artillery. But the defence of 
modern arms is indirect : tersely, the enemy is prevented 
from killing you by your killing him first, and the fighting 
is essentially collective. As a consequence of this diff"er- 
ence, the importance of concentration in history has been 
by no means a constant quantity. Under the old con- 
ditions it was not possible by any strategic plan or 
tactical manoeuvre to bring other than approximately 
equal numbers of men into the actual fighting line ; one 
man would ordinarily find himself opposed to one man. 
Even were a General to concentrate twice the number of 
men on any given portion of the field to that of the 
enemy, the number of men actually wielding their 
weapons at any given instant (so long as the fighting line 
was unbroken), was, roughly speaking, the same on both 
sides. Under present-day conditions all this is changed. 
With modern long-range weapons — fire-arms, in brief — 
the concentration of superior numbers gives an immediate 
superiority in the active combatant ranks, and the 
numerically inferior force finds itself under a far heavier 




fire, man for man, than it is able to return. The import- 
ance of this difference is greater than might casually be 
supposed, and, since it contains the kernel of the whole 
question, it will be examined in detail. 

In thus contrasting the ancient conditions with the 
modern, it is not intended to suggest that the advantages 
of concentration did not, to some extent, exist under the 
old order of things. For example, when an army broke 
and fled, undoubtedly any numerical superiority of the 
victor could be used with telling effect, and, before this, 
pressure, as distinct from blows, would exercise great 
influence. Also the bow and arrow and the cross-bow 
were weapons that possessed in a lesser degree the 


— ^^J^^*** 

aae . 

" """ — -^ilJL 



»»o - 

'- ^ 







(a) Fig. 2. (b) 

properties of fire-arms, inasmuch as they enabled 
numbers (within limits) to concentrate their attack on 
the few. As here discussed, the conditions are contrasted 
in their most accentuated form as extremes for the 
purpose of illustration. 

Taking, first, the ancient conditions where man is 
opposed to man, then, assuming the combatants to be of 
equal fighting value, and other conditions equal, clearly, 
on an average, as many of the "duels" that go to make 
up the whole fight will go one way as the other, and 
there will be about equal numbers killed of the forces 
engaged; so that if 1,000 men meet 1,000 men, it is of 
little or no importance whether a "Blue" force of 1,000 



men meet a " Red " force of 1,000 men in a single pitched 
battle, or whether the whole " Blue " force concentrates 
on 500 of the " Red " force, and, having annihilated 
them, turns its attention to the other half; there will, 
presuming the " Reds " stand their ground to the last, be 
half the " Blue " force wiped out in the annihilation of 
the " Red " force* in the first battle, and the second 
battle will start on terms of equality — i.e.^ 500 " Blue " 
against 500 "Red." 

§ 21. Modern Conditions Investigated. Now let 
us take the modern conditions. If, again, we assume 
equal individual fighting value, and the combatants 
otherwise (as to " cover," etc.) on terms of equality, each 
man will in a given time score, on an average, a certain 
number of hits that are effective ; consequently, the 
number of men knocked out per unit time will be directly 
proportional to the numerical strength of the opposing 
force. Putting this in mathematical language, and 
employing symbol b to represent the numerical strength 
of the " Blue " force, and r for the " Red," we have :— 


-jt = -^>^<^ ■ ■ ■ ■ (0 

jt = -bxk . . . . (2) 

in which t is time and.c and k are constants {c = k if the 
fighting values of the individual units of the force are 

The reduction of strength of the two forces may be 
represented by two conjugate curves following the above 
equations. In Fig. 2 {a) graphs are given representing 
the case of the " Blue " force 1,000 strong encountering a 
section of the " Red " force 500 strong, and it will be 
seen that the " Red " force is wiped out of existence with 

• This is not strictly true, since towards the close of the fight the last few men 
will be attacked by more than their own number. The main principle is, 
however, untouched. 




a loss of only about 134 men of the " Blue " force, leaving 
866 to meet the remaining 500 of the **Red" force with an 
easy and decisive victory ; this is shown in Fig. 2 (6), the 
victorious " Blues " having annihilated the whole " Red " 
force of equal total strength with a loss of only 293 men. 




Fig. 3b. 

In Fig. 3^ a case is given in which the " Red " force 
is inferior to the " Blue " in the relation 1 : V2 say, a 
"Red" force 1,000 strong meeting a " Blue " force 1,400 
strong. Assuming they meet in a single pitched 
battle fought to a conclusion, the upper line will repre- 



sent the "Blue" force, and it is seen that the "Reds" 
will be annihilated, the " Blues " losing only 400 men. 
If, on the other hand, the " Reds " by superior strategy 
compel the " Blues " to give battle divided — say into two 
equal armies — then Fig. Sb, in the first battle the 700 
" Blues " will be annihilated with a loss of only 300 to the 
" Reds " and in the second battle the two armies will meet 
on an equal numerical footing, and so we may presume 
the final battle of the campaign as drawn. In this second 
case the result of the second battle is presumed from the 
initial equality of the forces ; the curves are not given. 

Fig 4. 

In the case of equal forces the two conjugate curves 
become coincident ; there is a single curve of logarithmic 
form, Fig. 4 ; the battle is prolonged indefinitely. Since 
the forces actually consist of a finite number of finite 
units (instead of an infinite number of infinitesimal units), 
the end of the curve must show discontinuity, and break 
off abruptly when the last man is reached ; the law based 
on averages evidently does not hold rigidly when the 
numbers become small. Beyond this, the condition of two 
equal curves is unstable, and any advantage secured by 
either side will tend to augment. 




§ 23. Graph representing Weakness of a Divided 
Force. In Fig. Sa, a pair of conjugate curves have been 
plotted backwards from the vertical datum representing 
the finish, and an upper graph has been added represent- 

Fig. 5a. 

Total "p^yf " I 

— ■ — -_^ 


|i "^"-^^ 

" Blut. " 

"^ """"--^ 

?■ . , 

■ ———._____ 

o, • 

' — --^ ^ 









■^ ^^v^ 

> "^-.^ 

■§ ""^\^ 

■^ "^-^ 




Fig. 5b. 

ing the total of the "Red" force, which is equal in 
strength to the " Blue " force for any ordinate, on the 
basis that the " Red " force is divided into two portions 
as given by the intersection of the lower graph. In 



Fig. 5 6, this diagram has been reduced to give the same 
information in terms per cent, for a " Blue " force of 
constant value. Thus in its application Fig. 5 h gives 
the correct percentage increase necessary in the fighting 
value of, for example, an army or fleet to give equality, 
on the assumption that political or strategic necessities 
impose the condition of dividing the said army or fleet 
into two in the proportions given by the lower graph, the 
enemy being able to attack either proportion with his 
full strength. Alternatively, if the constant (= 100) be 
taken to represent a numerical strength that would be 
deemed sufficient to ensure victory against the enemy, 
given that both fleets engage in their full strength, then 
the upper graph gives the numerical superiority needed 
to be equally sure of victory, in case, from political or 
other strategic necessity, the fleet has to be divided in 
the proportions given. In Fig. 5b abscissae have no 
quantitative meaning. 

§ 24. Validity of Mathematical Treatment. There 
are many who will be inclined to cavil at any mathema- 
tical or semi-mathematical treatment of the present 
subject, on the ground that with so many unknown 
factors, such as the morale or leadership of the men, the 
unaccounted merits or demerits of the weapons, and the 
still more unknown *' chances of war," it is ridiculous to 
pretend to calculate anything. The answer to this is 
simple : the direct numerical comparison of the forces 
engaging in conflict or available in the event of war is 
almost universal. It is a factor always carefully reckoned 
with by the various military authorities; it is discussed 
ad nauseam in the Press. Yet such direct counting of 
forces is in itself a tacit acceptance of the applicability of 
mathematical principles, but confined to a special case. 
To accept without reserve the mere " counting of the 
pieces " as of value, and to deny the more extended 



application of mathematical theory, is as illogical and 
unintelligent as to accept broadly and indiscriminately 
the balance and the weighing-machine as instruments of 
precision, but to decline to permit in the latter case any 
allowance for the known inequality of leverage. 

§ 25. Fighting Units not of Equal Strength. In 
the equations (1) and (2), two constants were given, c and 
k, which in the plotting of the figures 2 to 5b were taken 
as equal ; the meaning of this is that the fighting 
strength of the individual units has been assumed equal. 
This condition is not necessarily fulfilled if the combat- 
ants be unequally trained, or of different morale. 
Neither is it fulfilled if their weapons are of unequal 
efficiency. The first two of these, together with a host 
of other factors too numerous to mention, cannot be 
accounted for in an equation any more than can the 
quality of wine or steel be estimated from the weight. 
The question of weapons is, however, eminently suited to 
theoretical discussion. It is also a matter that (as will be 
subsequently shown) requires consideration in relation to 
the main subject of the present articles. 

§ 26. Influence of Efficiency of Weapons. Any 
difference in the efficiency of the weapons — for example, 
the accuracy or rapidity of rifle-fire — may be represented 
by a disparity in the constants c and k in equations (1) 
and (2), The case of the rifle or machine-gun is a simple 
example to take, inasmuch as comparative figures are 
easily obtained which may be said fairly to represent the 
fighting efficiency of the weapon. Now numerically 
vcqual forces will no longer be forces of equal strength ; 
they will only be of equal strength if, when in combat, 
their losses result in no change in their numerical pro- 
portion. Thus, if a " Blue " force initially 500 strong, 
using a magazine rifle, attack a "Red" force of 1,000, 
,armed with a single breech-loader, and after a certain 



time the "Blue" are found to have lost 100 against 200 
loss by the " Red," the proportions of the forces will have 
suffered no change, and they may be regarded (due to 
the superiority of the " Blue " arms) as being of equal 

If the condition of equality is given by writing M as 
representing the efficiency or value of an individual unit 
of the "Blue" force, and N the same for the "Red," 
we have : — 

Rate of reduction of "Blue" force: — 

— - = _ N r X constant . . (3) 





= - Uh 

X constant 

And for 



of equality, 
r dt 


- Nr _ 



b r 


N r2 = M 62 . . . (5) 

In other words, the fighting strengths of the two 
forces are equal when the square of the numerical 
strength multiplied by the fighting value of the individual 
units are equal. 

§ 27. The Outcome of the Investigation. The 
n-square Law. It is easy to show that this expression 
(5) may be interpreted more generally; the fighting 
strength of a force may be broadly defined as proportional 
to the square of its numerical strength multiplied by 
the fighting value of its individual units. 

Thus, referring to Fig. 56, the sum of the squares of 
the two portions of the " Red " force are for all values 
eqijal to the square of the " Blue " force (the latter 



plotted as constant) ; the curve might equally well have 
been plotted directly to this law as by the process given. 
A simple proof of the truth of the above law as arising 
from the differential equations (1) and (2), § 21, is as 
follows : — 

In Fig. 6, let the numerical values of the " blue " and 
" red " forces be represented by lines b and r as shown ; 
then in an infinitesimally small interval of time the change 
in b and r will be represented respectively by db and dr of 
such relative magnitude that db / dr = r / b or, 

b db = r dr (1) 

If (Fig. 6) we draw the squares on b and r and 
represent the increments db and dr as small finite incre- 

y////////////////////////////// \ 

Fig. 6. 

ments, we see at once that the citange of area of b^ is 
2b db and the change of area of r^ is 2r dr which accord- 
ing to the foregoing (1), are equal. Therefore the 
difference between the two squares is constant 
^2 — r^ = constant. 
If this constant be represented by a quantity q^ 
then 6" = r^ + q^ and q represents the numerical value 
of the remainder of the blue " force " after annihilation 



of the red. Alternatively q represents numerically a 
second " red " army of the strength necessary in a 
separate action to place the red forces on terms of 
equality, as in Fig. 5b. 

§ 28. A Numerical Example. As an example of 
the above, let us assume an army of 50,000 giving 
battle in turn to two armies of 40,000 and 30,000 
respectively, equally well armed ; then the strengths are 
equal, since (50,000)' = (40,000)' + (30,000)1 If, on 
the other hand, the two smaller armies are given time to 
effect a junction, then the army of 50,000 will be over- 
whelmed, for the fighting strength of the opposing force, 
70,000 is no longer equal, but is in fact nearly twice as 
great — namely, in the relation of 49 to 25. Superior 
morale or better tactics or a hundred and one other 
extraneous causes may intervene in practice to modify 
the issue, but this does not invalidate the mathematical 

§ 29. Example Involving Weapons of Different 
Effective Value. Let us now take an example in which 
a difference in the fighting value of the unit is a factor. 
We will assume that, as a matter of experiment, one man 
employing a machine-gun can punish a target to the 
same extent in a given time as sixteen riflemen. What 
is the number of men armed with the machine gun 
necessary to replace a battalion a thousand strong in the 
field ? Taking the fighting value of a rifleman as unity, 
let n = the number required. The fighting strength of 
the battalion is, (1,000)' or, 

^ _ /1 ,000,000 _ 1,000 _ o.^ 

or one quarter the number of the opposing force. 

This example is instructive ; it exhibits at once the 
utility and weakness of the method. The basic assump- 
tion is that the fire of each force is definitely concentrated 



on the opposing force. Thus the enemy will concentrate 
on the one machine-gun operator the fire that would 
otherwise be distributed over four riflemen, and so on an 
average he will only last for one quarter the time, and at 
sixteen times the efficiency during his short life he will 
only be able to do the work of four riflemen in lieu of 
sixteen, as one might easily have supposed. This is in 
agreement with the equation. The conditions may be 
regarded as corresponding to those prevalent in the Boer 
War, when individual-aimed firing or sniping was the 
order of the day. 

When, on the other hand, the circumstances are such 
as to preclude the possibility of such concentration, as 
when searching an area or ridge at long range, or volley 
firing at a position, or " into the brown," the basic con- 
ditions are violated, and the value of the individual 
machine-gun operator becomes more nearly that of the 
sixteen riflemen that the power of his weapon represents. 
The same applies when he is opposed by shrapnel fire or 
any other weapon which is directed at a position rather 
than the individual. It is well thus to call attention to 
the variations in the conditions and the nature of the 
resulting departure from the conclusions of theory ; such 
variations are far less common in naval than in military 
warfare ; the individual unit — the ship — is always the 
gunner's mark. When we come to deal with aircraft, we 
shall find the conditions in this respect more closely 
resemble those that obtain in the Navy than in the 
Army; the enemy's aircraft individually rather than 
collectively is the air-gunner's mark, and the law herein 
laid down will be applicable. 

§ 30. The Hypothesis Varied. Apart from its 
connection with the main subject, the present line of 
treatment has a certain fascination, and leads to results 
which, though probably correct, are in some degree 



unexpected. If we modify the initial hypothesis to 
harmonise with the conditions of long-range fire, and 
assume the fire concentrated on a certain area known to 
be held by the enemy, and take this area to be indepen- 
dent of the numerical value of the forces, then, with 
notation as before, we have — 


= 6 X N 1 
= r X M 6 j 
U db N dr 


X constant. 

dt dt 

or the rate of loss is independent of the numbers 
engaged, and is directly as the efficiency of the weapons. 
Under these conditions the fighting strength of the forces 
is directly proportional to their numerical strength ; there 
is no direct value in concentration, qua concentration, 
and the advantage of rapid fire is relatively great. Thus 
in effect the conditions approximate more closely to those 
of ancient warfare. 

§ 31. An Unexpected Deduction. Evidently it is 
the business of a numerically superior force to come to 
close quarters, or, at least, to get within decisive range as 
rapidly as possible, in order that the concentration may 
tell to advantage. As an extreme case, let us imagine a 
" Blue " force of 100 men armed with the machine gun 
opposed by a "Red" 1,200 men armed with the 
ordinary service rifle. Our first assumption will be 
that both forces are spread over a front of given 
length and at long range. Then the ** Red " force will 
lose 16 men to the "Blue" force loss of one, and, if the 
combat is continued under these conditions, the " Reds " 
must lose. If, however, the " Reds" advance, and get 
within short range, where each man and gunner is an 



individual mark, the tables are turned, the previous 
equation and conditions apply, and, even if " Reds " lose 
half their effective in gaining the new position, with 600 
men remaining they are masters of the situation ; their 
strength is 600' x 1 against the "Blue" 100' x, 16. It 
is certainly a not altogether expected result that, in the 
case of fire so deadly as the modern machine-gun, circum- 
stances may arise that render it imperative, and at all 
costs, to come to close range. 

§ 32. Examples from History. It is at least agreed 
by all authorities that on the field of battle concentration 
is a matter of the most vital importance ; in fact, it is 
admitted to be one of the controlling factors both in the 
strategy and tactics of modern warfare. It is aptly illus- 
trated by the important results that have been obtained 
in some of the great battles of history by the attacking of 
opposing forces before concentration has been effected. 
A classic example is that of the defeat by Napoleon, in 
his Italian campaign, of the Austrians near Verona, where 
he dealt with the two Austrian armies in detail before 
they had been able to effect a junction, or even to act in 
concert. Again, the same principle is exemplified in 
the oft-quoted case of the defeat of Jourdan and Moreau 
on the Danube by the Archduke Charles in 1796. It is 
evident that the conditions in the broad field of military 
operations correspond in kind, if not in degree, to the 
earlier hypothesis, and that the law deduced therefrom, 
that the fighting strength of a force can be represented 
by the square of its numerical strength, does, in its 
essence, represent an important truth. 



{October 9th, 1914) 


§ 33. The n-square Law in its Application to a 
Heterogeneous Force. In the preceding article it was 
demonstrated that under the conditions of modern warfare 
the fighting strength of a force, so far as it depends upon 
its numerical strength, is best represented or measured by 
the square of the number of units. In land operations 
these units may be the actual men engaged, or in an 
artillery duel the gun battery may be the unit ; in a naval 
battle the number of units will be the number of capital 
ships, or in an action between aeroplanes the number of 
machines. In all cases where the individual fighting 
strength of the component units may be different it has 
been shown that if a numerical fighting value can be 
assigned to these units, the fighting strength of the 
whole force is as the square of the number multiplied 
by their individual strength. Where the component 
units differ among themselves, as in the case of a fleet that 
is not homogeneous, the measure of the total of fighting 
strength of a force will be the square of the sum of the 
square roots of the strengths of its individual units. 

§ 34. Graphic Representation. Before attempting 
to apply the foregoing, either as touching the conduct of 
aerial warfare or the equipment of the fighting aeroplane, 
it is of interest to examine a few special cases and appli- 
cations in other directions and to discuss certain possible 
limitations. A convenient graphic form in which the 



operation of the n-square law can be presented is given in 
Fig. 7 ; here the strengths of a number of separate armies 
or forces successively mobilised and brought into action 
are represented numerically by the lines a, b, c, d, e, and 
the aggregate fighting strengths of these armies are 
given by the lengths of the lines A, B, C, D, E, each 
being the hypotenuse of a right-angle triangle, as indi- 
cated. Thus two forces or armies a and b, if acting 
separately (in point of time), have only the fighting 


strength of a single force or army represented numerically 
by the line B. Again, the three separate forces, a, b, 
and c, could be met on equal terms in three successive 
battles by a single army of the numerical strength C, 
and so on. 

§ 35. Special or Extreme Case. From the diagram 
given in Fig. 7 arises a special case that at first sight 
may look like a reductio ad absurdum, but which, 
correctly interpreted, is actually a confirmation of the 
n-square law. Referring to Fig. 7, let us take it that the 
initial force (army or fleet), is of some definite finite 
magnitude, but that the later arrivals 6, c, d, etc., be very 
small and numerous detachments — so small, in fact, as to 



be reasonably represented to the scale of the diagram as 
infinitesimal quantities. Then the lines 6, c, d^ «, /, etc., 
describe a polygonal figure approximating to a circle, 
which in the limit becomes a circle, whose radius is 
represented by the original force «, Fig. 8. Here we 
have graphically represented the result that the fighting 
value of the added forces, no matter what their numerical 
aggregate (represented in Fig. 8 by the circumferential 

Fig. 8. 

line), is zero. The correct interpretation of this is that 
in the open a small force attacking, or attacked by one of 
overwhelming magnitude is wiped out of existence with- 
out being able to exact a toll even comparable to its own 
numerical value ; it is necessary to say in the opetiy since, 
under other circumstances, the larger force is imable to 
bring its weapons to bear, and this is an essential portion 
of the basic hypothesis. In the limiting case when the 
disparity of force is extreme, the capacity of the lesser 
force to eflfect anything at all becomes negligible. There 
is nothing improbable in this conclusion, but it manifestly 
does not apply to the case of a small force concealed or 



" dug in," since the hypothesis ie infringed. Put bluntly, 
the condition represented in Fig. 8 illustrates the com- 
plete impotence of small forces in the presence of one of 
overwhelming power. Once more we are led to contrast 
the ancient conditions, under which the weapons of a 
large army could not be brought to bear, with modern 
conditions, where it is physically possible for the weapons 
of ten thousand to be concentrated on one. Macaulay's 

" In yon strait path a thousand 
May well be stopped by three," 

belong intrinsically to the methods and conditions of 
the past. 

§ 36. The N-square Law in Naval Warfare. We 
have already seen that the n-square law applies broadly, 
if imperfectly, to military operations ; on land however, 
there sometimes exist special conditions and a multi- 
tude of factors extraneous to the hypothesis whereby its 
operation may be suspended or masked. In the case of 
naval warfare, however, the conditions more strictly 
conform to our basic assumptions, and there are com- 
paratively few disturbing factors. Thus, when battle 
fleet meets battle fleet, there is no advantage to the 
defender analogous to that secured by the entrenchment 
of infantry. Again, from the time of opening fire, the 
individual ship is the mark of the gunner, and there is 
no phase of the battle or range at which areas are 
searched in a general way. In a naval battle every shot 
fired is aimed or directed at some definite one of the 
enemy's ships ; there is no firing on the mass or " into 
the brown." Under the old conditions of the sailing-ship 
and cannon of some 1,000 or 1,200 yards maximum 
effective range, advantage could be taken of concentration 
within limits ; and an examination of the latter 18th 
century tactics makes it apparent that with any ordinary 



disparity of numbers (probably in no case exceeding 2 to 
1) the effect of concentration must have been not far from 
that indicated by theory. But to whatever extent this- 
was the case, it is certain that with a battle-fleet action 
at the present day the conditions are still more favourable 
to the weight of numbers, since with the modern battle 
range — some 4 to 5 miles — there is virtually no limit to 
the degree of concentration of fire. Further than this, 
there is in modern naval warfare practically no chance of 
coming to close quarters in ship-to-ship combats, as in 
the old days. 

Thus the conditions are to-day almost ideal from the 
point of view of theoretical treatment. A numerical 
superiority of ships of individually equal strength will 
mean definitely that the inferior fleet at the outset has to 
face the full fire of the superior, and as the battle 
proceeds and the smaller fleet is knocked to pieces, the 
initial disparity will become worse and worse, and the fire 
to which it is subjected more and more concentrated. 
These are precisely the conditions taken as the basis of 
the investigation from which the n-square law has been 
derived. The same observations will probably be found 
to apply to aerial warfare when air fleets engage in 
conflict, more especially so in view of the fact that aero- 
plane can attack aeroplane in three dimensions of space 
instead of being limited to two, as is the case with the 
battleship. This will mean that even with weapons 
of moderate range the degree of fire concentration 
possible will be very great. By attacking from above 
and below, as well as from all points of the compass, 
there is, within reason, no limit to the number of 
machines which can be brought to bear on a given- 
small force of the enemy, and so a numerically superior 
fleet will be able to reap every ounce of advantage 
from its numbers. 



§ 37. Individual value of Ships or Units. The 
factor the most difficult to assess in the evaluation of a 
fleet as a fighting machine is (apart from the personnel) 
the individual value of its units, when these vary 
amongst themselves. There is no possibility of entirely 
obviating this difficulty, since the fighting value of any 
given ship depends not only upon its gun armament, but 
also upon its protective armour. One ship may be 
stronger than another at some one range, and weaker at 
some longer or shorter range, so that the question of 
fleet strength can never be reduced quite to a matter of 
simple arithmetic, nor the design of the battleship to an 
exact science. In practice the drawing up of a naval 
programme resolves itself, in great part at least, into the 
answering of the prospective enemy's programme type 
by type and ship by ship. It is, however, generally 
accepted that so long as we are confining our attention 
to the main battle fleets, and so are dealing with ships of 
closely comparable gun calibre and range, and armour of 
approximately equivalent w^eight, the fighting value of 
the individual ship may be gauged by the weight of its 
" broadside," or more accurately, taking into account the 
speed with which the diflferent guns can be served, by the 
weight of shot that can be thrown per minute. Another 
basis, and one that perhaps affords a fairer comparison, is to 
give the figure for the energy per minute for broadside fire, 
which represents, if we like so to express it, the horse- 
power of the ship as a fighting machine. Similar means 
of comparison will probably be found applicable to the 
fighting aeroplane, though it may be that the downward 
fire capacity will be regarded as of vital importance rather 
than the broadside fire as pertaining to the battleship, 

§ 38. Applications of the n-square Law. The 
n-square law tells us at once the price or penaltj'' that 
must be paid if elementary principles are outraged by the 



division of our battle fleet* into two or more isolated 
detachments. In this respect our present diposition — a 
single battle fleet or " Grand" fleet — is far more economi- 
cal and strategically preferable as a defensive power to 
the old-time distribution of the Channel Fleet, Mediter- 
ranean Fleet, etc. If it had been really necessary, for 
any political or geographical reason, to maintain two 
separate battle fleets at such distance asunder as to 
preclude their immediate concentration in case of attack, 
the cost to the country would have been enormously 

( U/ne^ alvey 'TtuTnerictU -vahte^ ) 

Fig. 9. 

increased. In the case, for example, of our total battle 
fleet being separated into two equal parts, forming 
separate fleets or squadrons, the increase would require 
to be fixed at approximately 40 per cent. — that is to say, 
in the relation of 1 to V2 ; more generally the solution is 
given by a right-angled triangle, as in Fig. 9. It must 
not be forgotten that, even with this enormous increase, 
the security will not be so great as appears on paper, for 
the enemy's fleet, having met and defeated one section of 
our fleet, may succeed in falling back on his base for 
repair and refit, and emerge later with the advan- 
tage of strength in his favour. Also one must not 

* Capital ships -.—Dreadnoughts and Super-Dreadnoughts. 


overlook the demoralizing effect on the personnel of the 
fleet first to go into action, of the knowledge that they 
are hopelessly outnumbered and already beaten on paper 
— that they are, in fact, regarded by their King and 
country as " cannon fodder." Further than this, pre- 
suming two successive fleet actions and the enemy finally 
beaten, the cost of victory in men and materiel will be 
greater in the case of the divided fleet than in the case of 
a single fleet of equal total fighting strength, in the 
proportion of the total numbers engaged — that is to say, 
in Fig. 9, in the proportion that the two sides of the 
right-angled triangle are greater than the hypotenuse. 

In brief, however potent political or geographical 
influences or reasons may be, it is questionable whether 
under any circumstances it can be considered sound 
strategy to divide the main battle fleet on which the 
defence of a country depends. This is to-day the 
accepted view of every naval strategist of repute, and is 
the basis of the present distribution of Great Britain's 
naval forces. 

§ 39. Fire Concentration the Basis of Naval 
Tactics. The question of fire concentration is again 
found to be paramount when we turn to the consideration 
and study of naval tactics. It is worthy of note that the 
recognition of the value of any definite tactical scheme 
does not seem to have been universal until quite the 
latter end of the 18th century. It is even said that the 
French Admiral Suffren, about the year 1780, went so far 
as to attribute the reverses suffered by the French at sea 
to " the introduction of tactics " which he stigmatised as 
" the veil of timidity ; "* the probability is that the then 
existing standard of seamanship in the French Navy was 
so low that anything beyond the simplest of manoeuvres 
led to confusion, not unattended by danger. The subject,. 

* Mahan, "Sea Power," page 425. 


however, was, about that date, receiving considerable 
attention. A writer, Clerk, about 1780, pointed out that 
in meeting the attack of the Bnglish the French had 
adopted a system of defence consisting of a kind of 
running fight, in which, initially taking the " lee gage," 
they would await the Bnglish attack in line ahead, and 
having delivered their broadsides on the leading Bnglish 
ships (advancing usually in line abreast), they would bear 
away to leeward and take up position, once more waiting 
for the renewal of the attack, when the same process was 
repeated.* By these tactics the French obtained a con- 
centration of fire on a small portion of the Bnglish fleet, 
and so were able to inflict severe punishment with little 
injury to themselves.! Here we see the beginnings of 
sound tactical method adapted to the needs of defence. 

Up to the date in question there appears to have 
been no studied attempt to found a scheme of attack on 
the basis of concentration ; the old order was to give 
battle in parallel columns or lines, ship to ship, the excess 
of ships, if either force were numerically superior, being 
doubled on the rear ships of the enemy. It was not till 
the "Battle of the Saints," in 1782, that a change took 
place ; Rodney (by accident or intention) broke away 
from tradition, and cutting through the lines of the 
enemy, was able to concentrate on his centre and rear, 
achieving thereby a decisive victory. 

§ 40. British Naval Tactics in 1805. The Nelson 
^^ Touchy The accident or experiment of 1782 had 
evidently become the established tactics of the British in 
the course of the twenty years which followed, for not only 
do we find the method in question carefully laid down in 
the plan of attack given in the Memorandum issued by 

* Compare Malian, "Sea Power," page 162. 

t Incidentally, also, the scheme in question had the advantage of subjecting 
the English to a raking* fire from the French broadsides before they were them- 
selves able to bring their own broadside fire to bear. 



Nelson just prior to the Battle of Trafalgar in 1805, but 
the French Admiral Villeneuve* confidently asserted in a 
note issued to his staff in anticipation of the battle that : — 
" The British Fleet will not be formed in a line-of-battle 
parallel to the combined fleet according to the usage of 
former days. Nelson, assuming him to be, as repre- 
sented, really in command, will seek to break our 
line, envelop our rear, and overpower with groups of 
his ships as many as he can isolate and cut off." Here 
we have a concise statement of a definite tactical scheme 
based on a clear understanding of the advantages of 
fire concentration. 

It will be understood by those acquainted with the 
sailing-ship of the period that the van could only turn to 
come to the assistance of those in the rear at the cost of a 
considerable interval of time, especially if the van should 
happen to be to leeward of the centre and rear. The 
time taken to " wear ship," or in light winds to " go 
about " (often only to be effected by manning the boats 
and rowing to assist the manoeuvre), was by no means an 
inconsiderable item. Thus it would not uncommonly be 
a matter of some hours before the leading ships could be 
brought within decisive range, and take an active part 
in the fray. 

§ 41. Nelson's Memorandum, and Tactical Scheme* 
In order further to embarass the enemy's van, and more 
effectively to prevent it from coming into action, it 
became part of the scheme of attack that a few ships, a 
comparatively insignificant force, should be told off to 
intercept and engage as many of the leading ships as 
possible ; in brief, to fight an independent action on a 
small scale ; we may say admittedly a losing action. In 
this connection Nelson's memorandum of October 9 is 
illuminating. Nelson assumed for the purpose of framing 

* "The Enemy at Trafalgar," Ed. Fraser ; Hodder and Stoughton, page 54. 




his plan of attack that his own force would consist of 
forty sail of the line, against forty-six of the combined 
(French and Spanish) fleet. These numbers are con- 
siderably greater, as things turned out, than those 
ultimately engaged ; but we are here dealing with the 
memorandum, and not with the actual battle. The 
British Fleet was to form in two main columns, com- 
prising sixteen sail of the line each, and a smaller column 

COMBINED ** ~ 40 

Fig. 10. 

of eight ships only. The plan of attack prescribed in the 
event of the enemy being found in line ahead was briefly 
as follows : — One of the main columns was to cut the 
enemy's line about the centre, the other to break through 
about twelve ships from the rear, the smaller column 
being ordered to engage the rear of the enemy's van 
three or four ships ahead of the centre, and to frustrate, 
as far as possible, every eff"ort the van might make to 
come to the succour of the threatened centre or rear. Its 
object, in short, was to prevent the van of the combined 
fleet from taking part in the main action. The plan is 
shown diagrammatically in Fig. 10. 



§ 42. Nelson's Tactical Scheme Analysed. An 
examination of the numerical values resulting from the 
foregoing disposition is instructive. The force with 
which Nelson planned to envelop the half^ — i.e., 23 ships 
— of the combined fleet amounted to 32 ships in all ; this 
according to the n^ law would give him a superiority of 
fighting strength of almost exactly two to one,* and 
would mean that if subsequently he had to meet the 
other half of the combined fleet, without allowing for any 
injury done by the special eight-ship column, he would 
have been able to do so on terms of equality. The fact 
that the van of the combined fleet would most certainly 
be in some degree crippled by its previous encounter is 
an indication and measure of the positive advantage of 
strength provided by the tactical scheme. Dealing with 
the position arithmetically, we have : — 

Strength of British (in arbitrary n^ units), 
32' 4 8' = 1088 

And combined fleet, 

23' -f 23^ = 1058 

British advantage .... 30 

Or, the numerical equivalent of the remains of the 
British Fleet (assuming the action fought to the last 
gasp), = V30 or 5 J ships. 

If for the purpose of comparison we suppose the 
total forces had engaged under the conditions described 
by Villeneuve as " the usage of former days," we have :— 
Strength of combined fleet, 46' .... = 2116 
British „ 40' .... = 1600 

Balance in favour of enemy .... 516 

Or, the equivalent numerical value of the remainder 
of the combined fleet, assuming complete annihilation of 
the British, = V516 = 23 ships approximately. 

•23 X Va == 32.5 

65 F 


Thus we are led to appreciate the commanding import- 
ance of a correct tactical scheme. If in the actual battle 
the old-time method of attack had been adopted, it is ex- 
tremely doubtful whether the superior seamanship and 
gunnery of the British could have averted defeat. The 
actual forces on the day were 27 British sail of the line 
against the combined fleet numbering 33, a rather less 
favourable ratio than assumed in the Memorandum. In 
the battle, as it took place, the British attacked in two 
columns instead of three, as laid down in the Memoran- 
dum ; but the scheme of concentration followed the 
original idea. The fact that the wind was of the lightest 
was alone sufficient to determine the exclusion of the 
enemy's van from the action. However, as a study the 
Memorandum is far more important than the actual event, 
and in the foregoing analysis it is truly remarkable to find, 
firstly, the definite statement of the cutting the enemy into 
two equal parts — according to the n-square law the exact 
proportion corresponding to the reduction of his total 
effective strength to a minimum ; and, secondly, the 
selection of a proportion, the nearest whole-number 
equivalent to the •n/2 ratio of theorj'', required to give a 
fighting strength equal to tackling the two halves of the 
enemy on level terms, and the detachment of the 
remainder, the column of eight sail, to weaken and 
impede the leading half of the enemy's fleet to guarantee 
the success of the main idea. If, as might fairly be 
assumed, the foregoing is more than a coincidence,* it 
suggests itself that Nelson, if not actually acquainted 
with the n-square law, must have had some equivalent 
basis on which to figure his tactical values. 

• Although we may take it to be a case in which the dictates of experience resulted 
in a disposition now confirmed by theory, the agreement is remarkable. 



(October 16th, 1974). 


§ 43. Attack by Aeroplane on Aeroplane. In the 
present war the services of the Flying Corps have, in the 
main, been confined to scouting and reconnaissance in its 
various forms, the amount of work which has been done 
in this direction being very great; according to present 
reports, a mileage equivalent to many circuits of the 
globe has already been covered. So far the casualties 
have been slight, and the actual risk and danger are con- 
sidered less than in the other combatant branches of the 
Service. The meaning of this evidently is that the 
methods of attack on aircraft have not kept pace with the 
development of the craft themselves. Considering the 
importance, from the enemy's point of view, of interfering 
with the operations of our aircraft (for from a modern 
standpoint to annihilate the aircraft of an enemy is 
virtually to deprive him of his power of vision), it is quite 
certain that the present conditions cannot last, and means 
will assuredly be found before the next great war, if not 
during the continance of the present war, by which the 
attack of aeroplane on aeroplane will be rendered far 
more deadly than at present, and the air forces of both 
combatants will be more highly organised to this end 
than is the case to-day. 

It has already been remarked that attack on so swift 
and, in effect, on so small a moving target as an aeroplane 



is by no means an easy problem. We have already dis- 
cussed the difficulties of attack from the ground, and it 
now remains to examine the problem of attack by air — 
i.e., attack by aeroplane on aeroplane. 

At one time the author was disposed to be somewhat 
sceptical as to the possibility, or rather the general 
feasibility, of such a mode of attack. It seemed as 
though aeronauts might spend hours manoeuvring and 
firing, and between them blow away hundreds of pounds 
weight of ammunition without any decisive result. On 
closer consideration, however, it would appear that, pro- 
vided one machine can, either by greater speed, or power 
of manoeuvre, force the other to close quarters, there are 
conditions (as when both machines are moving in the 
same direction), under which gun-fire (especially machine- 
gun fire) could be brought to bear with conclusive effect. 
We have already been regaled from time to time by the 
Press with florid descriptions of aeroplane fights in which 
pilots or observers were said to blaze away at each other 
with automatic pistols, and it has frequently been stated 
that the enemy has been brought down by this means. After 
careful inquiries in quarters believed to be well informed, 
the author is disposed to discredit these stories. Doubtless 
attempts have been made by one pilot, or aeronaut, on 
another by rifle and pistol fire, but there is not, so far as 
the author has been able to ascertain, any definite record 
of casualties resulting.* 

§ 44. The Fighting Machine as a Separate Type. 
It is at present uncertain whether the scouting or reconnais- 
sance machine will itself in the future be called upon to 
fight : the view has already been expressed in these articles 
that the long-distance machine or strategic scout should 
not in any sense be considered as a fighter, its speed and 

• Quite true at tlie date of the original article ; the Press accounts were in no 
sense reliable. Intelligtnt anticipation is the usual designation. 






1 1 

^^^^B/ ^^^B 

J3 -Z 


O « 



power of rapidly putting on altitude alone form its natural 
and most appropriate means of defence. The tactical 
scout is not in the same position ; its duties are of such a 
character that if it be driven by hostile aircraft away 
from its place of operation, it has for the time being 
ceased to fulfil its mission, and so either it must always 
operate with a protective force of fighting machines 
within call, or it must itself be armed, and be rendered 
capable of putting up a fight. In any case the tactical 
scout or machine for local reconnaissance will require to 
be furnished, to some extent at least, with both offensive 
and defensive armament. But it is by no means clear 
that it will require to be armed more heavily than may be 
sufficient to hold its own with the aircraft of the enemy 
engaged on similar duty, or than required to enable it 
to perform the minor acts of aggression against the 
enemy's land forces that fall to its lot. 

Evidently it can be only a matter of time before 
the specialised fighting-machine is called into being. 
We may admit that the first and more immediate step 
will be to render the tactical reconnaissance type capable 
of taking the offensive, so that it may establish its 
ascendency over the similar craft of the enemy. But 
the struggle for supremacy in the air which must 
then ensue will call imperatively for something more 
powerful and efficient, a specialised and heavily-armed 
fighting-machine in fact. It is this type, the fighting 
machine of the future, that the author proposes to 
make the subject of present study, discussing primarily 
the factors upon which its armament and its usage, 
or tactical employment, depend. It may be taken 
that for the period during which the tactical scout 
is playing the double role of reconnaissance-machine 
and fighting-machine the main general considerations 
will apply. 


§ 45. The Question of Armament ; Treaty Restric- 
tions. In the specification of a fighting type of aeroplane 
the first and foremost consideration is its means of attack. 
These fall into two broadly distinct categories : fire-arms^ 
chief amongst which for the purpose in question is the 
machine-gun or mitrailleuse ; and gravitational weapons, 
including bombs, hand-grenades, steel darts, etc. ; the 
latter being mainly useful when attacking a terrestrial 
objective. Bxcept when dealing with a dirigible or air- 
ship, gravitational weapons are but ill suited to the con- 
ditions of attack on aircraft. Light artillery may certainly 
be mounted on an aeroplane, but only the very smallest 
calibre — namely, the "1 -pounder" — can be considered 
suitable for machines such as are built at the present day; 
even the mounting of a gun of this size is a matter of 
great difficulty. The only advantage obtained by the 
employment of a weapon of this character is in the fact 
that it is permissible to throw shell, high-explosive or 
otherwise, the use of which for smaller sizes of projectiles 
is prohibited by treaty obligation. Any explosive pro- 
jectile of less than 1 lb. weight (more exactly 400 
grammes, or 14 oz., about) is banned by the Declaration 
of St. Petersburg,* of 1868; the paragraph with which we 
are concerned reads : — " The contracting parties engage 
mutually to renounce in case of war amongst themselves 
the employment by their military or naval troops, of any 
projectile of a weight below 400 grammes which is either 
explosive or charged with fulminating or inflammable 
substances." This is reaffirmed in the text of an abortive 
declaration of the Brussels Conference of 1874, Article 
13 (e) : " The use of arms, projectiles, or material which 
may cause unnecessary suffering, as well as the use of 

* The signatories to this Declaration include representatives of the following : — 
Great Britain, Austria and Hungarj', Belgium, Denmark, France, Greece, Italy, 
Netherlands, Persia, Portugal, Russia, Sweden and Norway, Switzerland, and 
Turkey. The German Confederation and semi-independent States were also 
signatories ; but in view of the doctrines of modern Germany as touching the 
value ef international treaties, her signature cannot be taken as meaning anything. 



the projectiles prohibited by the Declaration of St. Peters- 
burg in 1868." In the Hague Conference of 1899, 
Article 23 (e), it is prohibited "To employ arms, projec- 
tiles, or material of a nature to cause superfluous injury." 
Also Article 60, Declaration ii. : — " The contracting 
parties agree to abstain from the use of bullets that 
expand or flatten easily in the human body, such as 
bullets with a hard envelope which does not entirely 
cover the core, or is pierced with incisions." In view of 
the fact that the Brussels Conference of 1874 was sterile, 
and that the Hague Declaration ii.. Article 60, was not 
subscribed to by the British representative, the Declara- 
tion of St. Petersburg with its 14 oz. minimum for explo- 
sive projectiles is the only definite statement by which we 
are bound. However, the restriction as to the employ- 
ment of dum-dum or expanding bullets appears to have 
received our tacit acquiescence, at least in so far as 
concerns warfare with other civilised States. There is 
also the rather indefinite statement of the Hague Con- 
ference of 1899, to which we have subscribed, to the 
effect that we shall not employ arms, projectiles, or 
material of a nature to cause superfluous injury. The 
subject of these restrictions will be taken up again in a later 
chapter; it is here sufficient to point to their existence, 
and to the fact that they considerably hamper and restrict 
the development of aircraft and counter-aircraft arma- 
ment. There seems to be no proper reason why we 
should be compelled to use some hundreds of unsuitable 
projectiles, specially designed to afford the least possible 
injury to the struts, spars, etc., through which they pass, 
when a comparatively few expanding or explosive bullets 
would do vastly more injury, and result in a machine 
being incapacitated both in less time and at less expense. 
It cannot be supposed that if one of the nations at 
present at war were to inaugurate the practice of utilising, 



against aircraft, projectiles infringing the Declaration of 
St. Petersburg, there would be any great wave of indig- 
nation created in the world at large. If, for example, we 
were to find our aircraft being knocked about by such 
means, we need not imagine that we should receive much 
compensation in the way of international sympathy. The 
author is not for a moment suggesting that we should 
initiate any departure from the accepted usage of warfare 
in this respect ; he is rather questioning the ethics of a 
procedure by which a country, whose obligations and 
responsibilities are as wide and as heavy as those of Great 
Britain, and whose traditions and the force of public 
opinion make solemn contracts binding, should become a 
signatory to agreements which are always liable to be 
(and sometimes are) signed by the other party with his 
tongue in his cheek. At the best the signing of 
restrictive agreements relating to the conduct of war may 
at some time after turn out to be no more or less than 
the drawing of a cheque on another's banking account — 
a cheque that will be honoured in another man's blood. 

§ 46. The One-Pounder as an Aeroplane Gun. 
For the time being we will take the restrictions imposed by 
international agreement as though they were restrictions 
imposed by Nature, and accept the fact that for the 
throwing of explosive or inflammable projectiles the 
" one-pounder " is the smallest gun available. At present 
this offers considerable difficulty in the case of an aero- 
plane. In order to throw a 14 oz. projectile with a 
muzzle velocity of 1,700 ft. -sec, the weight of gun and 
its mountings, including suitable recoil mechanism, could 
not be much less than 1 cwt., and with 100 rounds of 
ammunition the total would be about 2^ cwt. Now this 
weight alone cannot be considered in any sense prohibi- 
tive ; in fact, it is no more than most of the existing 
machines in service would be able to carry. But the 



difficulties of design are not confined to the weight 
problem ; the gun would have a length from muzzle to 
breech of 4 ft. or 5 ft., in addition to about 1 ft. represen- 
ting its movement on recoil, as permitted by the buffer 
mechanism. To accommodate such a weapon, with reason- 
able freedom in elevation and traverse, would almost 
require that the gun be designed first, and that the 
aeroplane be designed round it. The difficulties can only 
be properly appreciated by taking a drawing-board and 
paper and endeavouring to find a practicable solution. 
Beyond the initial difficulties of the problem, it is very 
doubtful whether it will be found to pay to attack a 
hostile aeroplane with so large a shell as required by 
the 14 oz. limit. If a thoroughly sensitive fuse were 
available, so that the shell would explode on impact with 
canvas, matters would wear a different aspect, for the 
wing spread of an aeroplane presents a target of 
respectable size. However, as things stand, with a total 
of only about 100 rounds at command, and so small and 
elusive a target, it is doubtful whether, save under very 
exceptional circuimstances, it would pay to throw away 
ammunition in pursuit. If the problem be that of attack- 
ing a dirigible, it may be considered more hopeful ; there 
is actually more to hit, besides the fact that the aeroplane, 
in the matter of speed, has the balloon always at a 
disadvantage ; here again the importance of a sensitive 
impact fuse is paramount. 

The necessity for being sparing in the use of 
ammunition must not be taken to mean (as sometimes 
represented) that there is no advantage in rapidity of fire, 
but rather the contrary, and any aeroplane armament 
gun must be essentially a quick-firer, if not actually 
automatic or semi-automatic; it is of vital importance 
that when the opportunity does occur, the utmost use 
should be made of it. When an aeroplane is within 




decisive range of its prey, it must be presumed that it is- 
itself also under fire, and all the conditions discussed in 
the foregoing articles apply. If a machine, type A, has 
four times the rate of fire of another machine, type B, 
the machine A, so long as its ammunition holds out, is 
worth as much as two machines of the type B. In 
the case of the one-pounder now under discussion, this 
condition of the exhaustion of the ammunition is just the 
weak point which renders it doubtful whether under 
existing circumstances it is worth while seriously to 
consider the mounting of such a weapon. It is doubtful, 
also, whether a fully automatic gun of this calibre is 
admissible with aeroplanes of present-day dimensions, on 
account of the mean recoil reaction. This is approxi- 
mately 1 lb. per shot per minute, or at a rate of 100 per 
minute, 100 lb. ; a quantity that would still further 
hamper the designer in the arrangement of his gun 

§ 47. The Machine-Gun ; Importance of Rapid 
Fire. For the time being there is no doubt that the 
ordinary machine-gun is the most serviceable and 
effective weapon available. Taking, for example, the 
Lewis gun with its self-contained magazine, the weight 
of the weapon mounted in place is under 30 lb., and the 
service ammunition runs 17 to the pound. Assuming, as 
before, 2J cwt. as the available total, and taking 4 lb. as 
the weight of a magazine of 47 rounds, it will be possible 
to carry some sixty magazines representing nearly 3,000 
rounds. The usual manner of employing such a weapon 
on a moving target, as presented by an aeroplane in 
flight, is to fire by "bursts," each burst being sighted 
afresh and commonly consisting of some six or eight 
shots, so that the speed of fire never averages as high as 
that of which the gun is capable ; thus the supply of 
ammunition above given would be sufficient for a con- 



tinuous and hot engagement of about a quarter of an 
hour's duration. From the point of view of recoil the 
machine-gun is quite harmless ; the mean recoil of the 
Lewis gun firing Mark VII. ammunition amounts to 
slightly less than 2'5 lb. per shot per second, or at 600 per 
minute the recoil reaction is about 25 lb. 

§ 48. Rapid Fire, Machine-Guns Multiply Mounted. 
In view of the advantages of rapid fire, it would seem 
desirable to increase the speed of fire of the machine-gun 
to the maximum extent possible. When, on land, the 
obvious thing to do under similar circumstances would be 
to bring two guns into action, a similar course is not 
possible on a flying machine, owing to the weight of the 
additional gunner. An extra man must either mean the 
sacrifice of a couple of thousand rounds of ammunition or 
a couple of hours' petrol supply, neither of which alterna- 
tives can be entertained. The conditions indicate the 
mounting of machine-guns in pairs, or the design of 
double or triple-barrel guns, the breech actions of which 
would be independent, but so arranged that they could 
be fired one, two, or three at a time ; by this means a 
" burst " of twenty-five or thirty bullets could be got off 
in less than one second. It may be found that a gun 
designed to take the 0.45 service revolver or automatic- 
pistol ammunition will be better suited to the conditions 
than the present weapon, in which the service rifle (Mark 
VII.) ammunition is employed. Such a gun would be 
far more handy, owing to the shortness of the cartridge, 
and would be furnished with a comparatively short 
barrel ; also the magazine could be made of more compact 
form better to permit of the multiple-barrel design. 
Beyond the above, the shattering efi"ect of the round-nose 
pistol bullet is known to be far greater than that of the 
0.303 spitzer, so that greater injury will be inflicted on 
any spars or other structural members that may be hit^ 



Incidentally, also, the stopping effect on pilot or gunner 
will be greater in the event of a shot getting home. In 
addition to the advantages enumerated, the 0.450 pistol 
ammunition weighs 21 to the pound, against the service 
rifle 17, which gives an addition of 25 per cent, to the 
number of rounds. When drawing on a limited supply 
of ammunition it is clearly necessary to select whatever is 
best suited to the work in hand. 


Pf,ATE \'II. 

R.A.F. TYPR R.K.5. Au • R.K. Portable'' Tent Pole 
is shown used as Derrick for (lisniounting Kngine 


(October 23rd. 1914). 


§ 49. Rapidity of Fire and its Measure. The 
measure of the rapidity of gun-fire from an aeroplane or 
dirigible as an index of its fighting value depends upon 
the nature of the objective or target. It is evident that 
in some cases the mere number of projectiles per minute 
is the most important factor, as, for example, in attacking 
any object in which a hit is a hit whether the projectile 
be large or small. In other cases, where the mischief 
done is in any reasonable relation to the weight of the 
projectile, the total weight of projectiles discharged per 
second (or per minute) affords a better criterion. In view 
of the comparatively flimsy and fragile nature of aircraft, 
it is doubtful whether the energy equivalent of the 
discharge will ever be of the importance which it is in 
the case of the battleship, where the destruction of the 
enemy depends to a very large extent upon the number 
of foot-tons with which he is assailed. Thus it is doubt- 
ful whether a factor representing the horse-power of the 
offensive armament would, as applied to the fighting 
aeroplane, will have any useful significance. Now it is 
scarcely probable that in the immediate future the 
fighting-machine can be furnished with complete bullet- 
proof protection, at least such as can be considered 
effective at short range. Consequently we may take it 
that it is quite unimportant whether the bullets used in 
its destruction be of the u.sual British 215 grains or the 



162 grains of the Mannlicher, or the 530 grains of the 
old Bnfield. The advantage of size and weight only 
becomes important when a single hit is sufiB.cient to carry- 
away an important strut or structural member which 
would have been penetrated without great injury by a 
bullet of ordinary size. Thus, so long as we are dealing 
with ordinary rifle, pistol, or machine-gun fire, we are 
concerned merely with the number of bullets that can be 
discharged per unit time, and this number — i.e., number 
per minute or second — fairly and properly expresses the 
value of the armament. This, of course, does not mean 
that the weight and muzzle energy of the bullets are of 
no importance whatever; it is merely an expression of 
the fact that with such weapons as are commonly avail- 
able the differences, such as the}'' are, and important 
though they may be in other applications, are not 
appreciable in relation to attack by aircraft on aircraft. 

§ 50. Measure of Fire Value in the case of Explo- 
sive Projectiles. When we pass to the consideration of 
weapons capable of throwing explosive projectiles, it is 
impossible to maintain, or even suggest, any direct basis 
of comparison. The effectiveness of shell fire depends 
entirely upon the conditions being present necessary to 
the correct timing of the fuse — that is to say, either the 
range must be known with great accuracy and the time- 
fuse mechanism correspondingly perfect, or the nature of 
the target must be such as to permit of the effective 
employment of an impact fuse of some description. 
Granted that the necessary conditions exist, the destruc- 
tion wrought by any given type of explosive projectile 
may be taken as, in a measure, proportional to its weight. 
However, there are cases when a 3 lb. high explosive 
shell would be just as effective as one of 181b., as, for 
example, if it were to strike the motor or fuselage of an 
-aeroplane in ffight, and so, in assesssing the value of 



shell-fire by the aggregate weight of the projectiles 
thrown, it is evident that we should only be making an 
approximation to the truth. 

If we go further and endeavour to compare the rela- 
tive value of armament of diverse type for aeroplanes, as, 
for example, in computing the relative merits of machine- 
guns and small artillery in any given case, we are 
inevitably thrown back on examining the service for 
which the armament is required ; it is impossible to 
institute a direct quantitative comparison which would 
be generally applicable. If it be conceded that in any 
particular case a given weight in the form of shell is of 
greater effect than the same weight in the form of bullets, 
then we have a prima facie case for the use of artillery. 
If, on the other hand, it is conceded that the bullets 
would do the greater mischief, then a machine-gun 
armament is indicated. However, although the weight 
of ammunition is a matter of first importance, the weight 
saving and convenience of the machine-gun in itself are 
sufficient to give it a preference where the other advan- 
tages are not overwhelmingly against it. 

§51. Weight thrown per minute; Machine-Gun 
and One-Pounder Compared. It has in the preceding 
paragraph been rather assumed that the capacity of the 
armament, as represented by its weight-rapidity factor 
of fire, is a constant; this is a matter that depends, firstly, 
upon the mechanism of the gun. The Lewis gun, which 
has been taken throughout these articles as representative 
of the machine-gun in its aeroplane usage, will fire as 
an ordinary maximum 600 rounds, or 18J lb. of lead per 
minute. Unfortunately, there is no standard 1 pounder 
with which to institute a comparison. The 37-mm. gun 
is given by different makers as throwing in some cases a 
projectile 1 lb., and by others the same bore is given as 
throwing IJ lb. Also the question arises whether an 



automatic gun of this size is, on account of its heavy- 
mean recoil, an altogether workable proposition. The 
Vickers automatic 37-mm., for example, is made in two 
weights ; one of these throws a 1 lb. shell at 1 ,800 foot- 
seconds at 300 rounds per minute, at which speed of 
discharge the recoil reaction would be about 300 lb. The 
weight of this gun is given as 3| cwt. This gun is quite 
unsuited to aeroplane service, both from the point of view 
of recoil and weight ; there is, however, a lighter type 
by the same firm, of the same calibre, semi-automatic, 
throwing a l^lb. projectile with a velocity of 1,200 ft. per 
second, the weight of the gun being given as 1101b. 
Presumably the maximum rate of fire of this gun would 
be about thirty rounds per minute, or the weight of metal 
thrown per minute, 45 lb. This is about 2| times the 
weight per minute given above for the machine-gun. 

§ 52. Weight per mimite as limited by Recoil. Quite 
apart from mechanical details, however, a real limiting 
factor exists in the recoil reaction to the momentum per 
second permissible, and this limit may be taken as apply- 
ing whatever the type of gun may be ; consequently, since 
the muzzle velocity of one type and another is not widely- 
different, the weight discharged per second or per minute 
will have an approximate maximum for any particular 
aeroplane no matter what the type of gun may be. This 
is the reason why it is possible and, in the author's 
opinion, advantageous to employ duplication, or even fit 
three or four barrels in the case of the machine-gun ; 
whereas an automatic 1 -pounder under like conditions 
could not reasonably be allowed to fire at over 60 or 80 
rounds per minute. 

§ 53. Present Advantage of Machine Guns. Future 
Possibilities discussed. At present there are very few 
cases in which the automatic or semi-automatic 1 -pounder 
could compete with the machine-gun as an aeroplane arm. 



If a percussion or impact-fuse were available sufficiently 
sensitive to explode with certainty on encountering 
balloon-clotli, the 1 -pounder would be an excellent 
weapon for the destruction of the airship or dirigible. 
Every part of a shell exploding within the envelope is 
effective, and the fragments of a shell leave wounds in the 
envelope and give rise to loss of gas of a more serious 
character than that due to the rifle or machine-gun bullet. 
Beyond this the danger to the crew (and structure in the 
case of a Zeppelin) is considerably greater under these 
conditions than under equivalent machine-gun fire. It 
may be some time, however, before the impact-fuse 
reaches the required degree of perfection. 

In the author's opinion there is room for a well- 
designed light-weight automatic to fire 14-oz. shell at 
a moderate velocity, say 1,200 ft. per second, with a 
maximum rate of 100 rounds per minute, the weight of 
the gun to be kept, if possible, under 100 lb ; the length 
should be kept as short as the requirements of the 
internal ballistics permit. The value of such a weapon, 
however, would depend almost entirely upon the 
development of suitable ammunition, and in particular, 
as already pointed out, the perfection of the impact-fuse 
to a point not yet within sight. 

§ 54. Armour in its relation to Armament. We 
have already given considerable attention to the question 
of armour in connection with the primary function of the 
aeronautical Arm — the attack on and co-operation with 
the other Arms of the Service. It is now time to extend 
our study to the secondary function of the Arm, and 
discuss the question in relation to problems of aerial 
attack and defence. The first instalment of the conditions 
which need to be fulfilled by the aeroplane constructor 
arises directly from the consideration of the primary 
function ; thus, it is already given us that the armament 

81 o 


to be of maximum service must be capable of action to 
the full in a downward direction with the greatest angle 
of fire (both forward and aft, and laterally), that the 
limitations imposed by structural considerations permit. 
Similarly, we know that the initial need for armour is 
mainly to resist attack from below. These facts remain, 
and cannot be altered by the additional duties imposed 
when aeroplane attacks aeroplane. We may, and in fact 
shall, have to provide for a far wider range of fire ; we 
shall need to make provision for training our gun or guns 
upward as well as downward ; likewise we may find it 
expedient to provide protection against fire from above as 
well as beneath. But any extended scheme of armament 
or protection so developed takes essentially as its starting 
point the more elementary condition. 

§ 55. Importance of Upper *' Gage " or Berth. The 
first result of importance arising from the above facts 
is, in any aeronautical engagement, the importance of 
the upper berth. The machine which is able to attack 
from above is acting under the conditions for which its 
armour and armament were initially provided. Beyond 
this, the taking of the upper position at the start, or 
perhaps, we may say, before the start, gives the power 
to outmanoeuvre an enemy, in spite even of inferior 
speed capacity in the ordinary acceptation of the term. 
The initial difi"erence in altitude represents a store of 
potential energy which may be drawn upon when 
the opportunity occurs ; this is, in fact, the principle 
utilised by the hawk, the kite, and other birds of 
prey. The objective of securing the upper berth, or 
position, or " gage," if we adopt the old-time word 
used by naval writers, will probably prove to be, and 
will remain, the key or pivot on which every scheme of 
aeronautical tactics will, in some way or another, be 
found to hang. 



§ 56. On Protection against Attack from Above. 
The question of employing armour as a protection against 
attack from above, or against dropping fire, is one which 
requires consideration on an entirely different basis from 
that of attack from below. In the latter case, the employ- 
ment of protection in some degree ma}'- be looked upon as 
essential. The steel employed may be thin and only 
suflficient to be effective above some prearranged altitude, 
but, nevertheless, it will be essential. Protection from 
attack by other aeroplanes, or, more broadly, aircraft, is 
another question ; we may express the utility of armour 
under these conditions definitely in terms of gun-power. 

To make this clear let us consider two machines 
in combat — an aeroplane duel, in fact — and we will take 
it that at their average distance apart or range the mean 
number of shots fired by either to score a decisive hit is 
found to be 600. Now if either aeronaut by the employ- 
ment of armour or gun-shields, or equivalent device, can 
reduce the effective target offered by his machine to one- 
half that previously presented, it will on an average take 
1,200 shots to knock him out in lieu of 600 without 
protection. But in order to provide for the weight of 
his armour he must cut down his armament ; he must 
sacrifice either his gun weight, and with it his speed of 
fire, or he must carry a lesser total weight of ammunition, 
and risk finding himself without means of attack, this 
being virtually synonymous to being without means of 
defence. If the only alternative were the cutting down 
of the speed of fire — tersely, if he were to substitute, say, 
30 lb. of armour for 30 lb. of gun — and if this represent 
half his total gun capacity, and involve a reduction in his 
speed of fire by nearly one-half, then the change might 
be considered as nearly justified, since he would receive 
two shots for every one he could discharge, but would at 
the same time be proportionately less vulnerable. 



Obviously, rate of fire should be one of the last 
things to be sacrificed ; but the alternative — a reduction 
in the load of ammunition — involves a curtailment of the 
period of activity, and, as a corollary, an increase in the 
number of machines required for a given combatant duty. 
Once admit the necessity for such additional machines, 
and we must estimate the sacrifice, or price paid for 
the armour, in terms of the loss of fighting strength 
due to the absence of a section of the air-fleet occupied in 
replenishing. This is evidently a serious matter under 
the best conditions — i.e.^ when fighting in the immediate 
vicinity of the base; if, however, an air-fleet be engaged 
far afield it becomes still more serious, and the sacrifice 
of rapidity of fire, rather than reserve of ammunition, 
might well prove to be the lesser of evils. 

The foregoing illustration shows that, tangibly or 
intangibly, the matter is one of figures, or, at the worst, a 
balance of advantages not capable of ready numerical 
expression. It may thus not always be possible to lay it 
down definitely whether in theory given conditions mean 
the abandonment of armour or otherwise ; but neverthe- 
less the fact is determined by the sum of the conditions, 
and where theory is dumb the decision will require to be 
taken on actual experience, as in analogous problems in 
naval construction. 

§ 57. Protection by Armour and Shield Contrasted, 
It is, perhaps, opportune to draw attention here to the 
difl'erence between shield and armour as a means of 
protection. The shield is essentially mobile, it is moved 
round and about to give the best protection possible, 
according to the direction of attack. A shield commonly 
forms part of a gun-mounting, but this is by way of being 
an accidental circumstance ; the gun has to be trained on 
the enemy, and so the shield is made part and parcel of 
the gun, thus automatically taking the best position 



for the gunner's protection. In the aeroplane, however, 
the pilot is of almost more importance than the gunner ; 
hence this traditional method of handling the shield may 
not be the best possible arrangement ; perhaps it will be 
found advantageous to provide the pilot with a shield 
separately mounted or otherwise adjustable. There is 
rarely any intention in the case of a shield to give full 
and complete protection as is done with armour. It is an 
error to suppose that partial protection is of no value ; 
every square inch covered diminishes proportionally the 
chances of a fatal hit, and so increases the fighting value 
of the machine, just as would a commensurate increase 
in rapidity of gun-fire ; on the other hand, as already 
insisted, either armour or shield which is insufficient in 
thickness is worse than useless. 

It is probable that in cases in which it may not pay- 
to fit armour, it will still be found profitable, owing to 
the considerations already discussed, to provide shields 
to give partial protection both to gunner and pilot. 



(October 30th, 1914). 


§ 58. Gun-Fir e. The Energy Account. The kinetic 
energy of a projectile commonly represents from 10 to 30 
per cent, of the total energy of the explosive or powder 
charge by which it is projected ; the lower figure 
corresponds to the performance of a small-bore low- 
velocity rifle such as a rook rifle, the latter being that 
approached under the most favourable conditions by the 
military or big-game rifle. The British Service rifle 
with Mark VI. ammunition thus has an efficiency of 
approximately 28 per cent. ; in the ordinary sportsman's 
" 12-bore " the figure is about 11 per cent. 

The total energy released on combustion by black 
powder is the equivalent in round numbers of 500 foot- 
tons per pound. The corresponding figure in the case of 
cordite is half as much again, approximately 750 foot-tons 
per pound ; in general it may be taken that most of 
the explosives in common use have an energy content 
between 500 and 1 ,000 foot- tons per pound. In the case 
of the Service rifle with Mark VI. ammunition the 
weight of the powder (cordite) is 30 grains (0.0043 lb.), 
and the bullet 215 grains (0.0307 lb.), the velocity being 
2,050 ft. per second. Thus the total energy of the 
charge is 0.0043 x 750 = 3.2 foot-tons, and the muzzle 
(kinetic) energy is 2,000 foot-pounds = 0.895 foot-ton ; 
the efficiency, therefore, is 0.895/3.2 = 0.28, as already 
given. It is worthy of remark, en passant, that there is 



very close accord between the figures applying to the gun 
and those which obtain in the gas-engine. In all such 
matters as efficiency, heat lost to barrel (cylinder walls), 
and heat remaining in gases ; the agreement is far 
closer than one would have ventured to expect in view of 
the great disparity of the conditions. 

§ 59. Energy Available and Otherwise. It has 
already been pointed out that under the conditions of 
attack on aircraft there is very little possibility of 
utilising the whole of the energy of the bullet on impact. 
Unless the motor mechanism, or the pilot or gunner, be 
hit, the character of the structure employed in aircraft is 
such that the bullet or projectile will pass through with 
a comparatively insignificant loss of energy and will do 
little or no damage. With the ordinary military bullet, 
and more particularly with the spitzer model, nothing 
less than encounter with a heavy metal part will cause it 
to break up. Any non-metallic structural material, such 
as timber, is bored cleanly through, and if initially 
designed with a reasonable margin of safety, the resulting 
injury to it is negligible. The position is similar to that 
which existed, before the adoption of explosive shell, in 
the attack on the wooden ship by the artillery or cannon 
of a century ago. At close quarters the cannon ball 
would go clean through, often with comparatively little 
injury. It is said that Napoleon, observing this to be 
the case, himself expressed the opinion that explosive 
shell (a then well-known expedient in siege operations) 
could be adopted generally in naval warfare with 
advantage. The situation is considerably more acute 
in the case of the attack on aircraft by rifle-fire, and 
so we are led to consider the possibilities of the ex- 
plosive or expanding bullet, ignoring, for the purpose 
of discussion, the existence of the Declaration of St. 




§ 60. The Explosive Bullet. The simplest form of 
explosive bullet, and one of the most effective, is that 
devised by Mr. Metford about the middle of the last 
century; this, as applied to an Bnfield bullet of the 
period 1860, is illustrated in Fig. 11. An explosive 
charge is inserted in the fore part of the bullet, and 
consists of equal parts of sulphur and chlorate of potash,* 
this mixture acting both as detonator and " burster." 
The hollow-ended form, or " drilled-up " end, has the 
incidental advantage that it alone will determine the 

Fig. 11. 

Fig. 12. 

Fig. 13. 

Fig. 14. 

expansion of the bullet on impact, quite apart from the 
action of the explosive charge. If the Metford system 
were applied to the modern bullet, the section would be 
somewhat as shown in Fig. 12, the basis of which is the 
Service 0.303 Mark VI. Another good form to take as 
the basis of an explosive bullet is the capped bullet, 
Fig. 13, as used in sporting rifles, the space inside the 
cap being conveniently filled with mixture to Metford's 

It is difficult, however the cavity be arranged, to 
devote more than about one-eighth or one-seventh of 

• This mixture being liable to detonate by friction, the ingredients require to 
be separately ground and mixed with due cafe. 



the volume of the bullet to receive the charge, and 
consequently, in view of the relatively low density of the 
explosive (about 1.6 in the case in point), the weight of 
the burster cannot be more than some 2 or 3 per cent, of 
the total. Taking the figure for cordite as representing 
the energy of the burster explosive, this *means, in the 
case of the Service rifle, about 5 or 8 grains, or 1,300 
ft. -lb. energy. But the efficiency of the burster is not 
likely to be higher than that which we associate with the 
main charge — it is at some advantage, inasmuch as there 
is no confined barrel to the walls of which heat is lost, but 
it is at a serious disadvantage, in that the explosion is not 
with any certainty confined to its work. It is doubtful 
whether of the 1,300 ft.-lb. total more than 300 ft.-lb. on 
an average will be usefully expended. 

We are thus led to appreciate the attributes of the 
explosive bullet, and more generally the explosive shell, 
in true perspective. The explosive only adds to an 
initial energy content of 2,000 ft.-lb. as due to velocity, a 
matter of about 300 ft.-lb. in available explosive energy, 
a quantity representing an addition of only 15 per cent. 
It is at once evident that the value of the explosive 
charge is less due to its direct action than to the fact that 
by its spreading or scattering effect on the projectile the 
kinetic energy is used to better advantage. In other 
words, the explosion is effective as a means of initiating 
or causing the expansion of the bullet rather than as 
acting directly by its own destructive power. In the case 
of large shells the proportion of burster charge to total 
weight can be increased, and so the direct effect is 
relatively more important; for armour-piercing projectiles, 
however, the proportion is no higher than in the example 
taken— ^.e., about 3 per cent. It might be imagined that 
the employment of some higher explosive would give a 
capacity of greater direct bursting energy, but the high 



explosive is not so called by reason of any greater total 
energy content, but rather on the effects of its rapidity of 
action ; in brief, its power of detonation. 

It is evident that, for the purpose under contempla- 
tion, the destruction of the less substantial structural 
parts of aeroplanes, etc., if we are able to secure the 
proper and immediate expansion of the bullet on impact 
without the use of an explosive charge, every useful 
purpose will be served. The bullet energy, even reduced 
to about one-quarter of its initial value by 1,000 yards 
flight, is more than sufficient, if definitely expended in 
the impact, to destroy any strut or spar or other light 
constructional part, without any aid from an explosive 
charge. The question is, whether the expansion of the 
bullet can be induced to take place with sufficient rapidity 
by any less drastic device. 

§ 61. The Expanding Bullet. Any bullet is con- 
sidered an expanding bullet if it be so made as to spread 
or mushroom on impact with its objective. But it is 
more usual to restrict the term to bullets having some 
special provision artificially to assist or facilitate their 
expansion, and, generally speaking, the objective is 
assumed to be game or other living quarry of some 
description. Evidently, if the target be hard enough, 
every bullet will expand to some degree. The means 
usually adopted in the case of the solid-lead bullet is 
to drill or form a hollow in the nose, as familiar to all 
who have used the sporting rifle. Another well-known 
method is to split the nose for a short distance by two 
cuts at right angles. In the case of the nickel-covered 
bullet the drilled nose again is sometimes adopted, or the 
nickel sheath at the nose, or point, of the bullet, is 
removed, the lead core being laid bare. All these devices 
have been practised in connection with sporting ammuni- 
tion for many years. The art of designing an expanding 



bullet is so to proportion things that under the average 
conditions the degree of expansion is that found to be 
most desirable ; thus the depth of the hole, or the extent 
of the slits, or the amount of the sheath cut away may 
be varied to whatever extent desired. The object to be 
attained is that the bullet shall expend its whole energy 
in inflicting the maximum possible injury, but at the 
same time it must not go to pieces or spread to such an 
extent that its penetration is lacking. In stopping big 
game it is necessary, not only that the energy should be 
wholly utilised, but also that it should be expended, as 
far as possible, in injury to the deep-seated vital organs. 
More recently Messrs. Westley Richards have brought 
out a modified form of expanding bullet in which the 
sheath is kept intact, but is not wholly filled by the lead 
core, there being an air-space in the fore end ; this type 
(already illustrated in Fig. 13), expands to a moderate 
degree only, and retains a considerable power of 

§ 62. Expansion due to Centrifugal Force. One 
of the main factors contributing to the spreading or 
expansion of a bullet is the centrifugal force of the bullet 
itself; all that is required of the impact is so to break 
down the structure of the bullet as to permit it to expand. 
The direction of motion of the peripheral portions of the 
bullet make at all points an angle with the axis of flight 
at least equal to the angle of the rifling, which is 
commonly about 1 in 10 to 1 in 12. This is the state of 
things when the bullet is discharged, but the actual angle 
rapidly becomes greater owing to the reduction of 
velocity, the speed of rotation being comparatively little 
aff"ected. Thus at 1,000 yards range the velocity is 
reduced by half, and the relative direction of the skin of 
the bullet becomes about 1 in 6 to the line of flight. If 
then by a sudden impact or other means the bullet be 



broken into a number of small fragments at any point in 
its path, these fragments immediately spread out after 
the manner of shrapnel, covering a cone whose base 
is approximately one-third of its height ; moreover, 
the distribution of the fragments in space — that is, 
within the conical surface — will be almost uniform. 
Such a distribution is almost ideal from the point of 
view of the work in hand, A desirable solution to the 
problem would appear to lie in the direction of a bullet 
composed of pellets or shot embedded in a matrix of only 
just sufficient strength to hold together, so that on 
comparatively light impact the component pellets will be 
released, and each will follow its individual direction of 

In every case the degree of expansibility requires, 
finally, to be determined by experiment, though with 
sufficient previous experience, and a proper comprehen- 
sion of the conditions, it is usually possible to hit off the 
right thing without much difficulty. For the destruction 
of wooden struts, spars, etc., it is clearly necessary to 
obtain the most rapid expansion possible (corresponding 
to instant disintegration), since the bullet has to do it*s 
work in a distance rarely exceeding some 3 in. or 4 in. 
Owing to the fact that the " tissue " penetrated is of very 
low density — about 30 lb. or 40 lb. per cubic ft. — it is 
probable that good results would be obtained by drilling 
the nose with a conical aperture of large diameter, at the 
entrance about half the diameter of the bullet, after the 
manner illustrated in Fig. 14. The author is at the 
present time making a series of experiments with 
expansive bullets on a target made up of wooden 
scantlings of cross-section comparable to aeroplane struts 
or wing members. We may form some estimate of the 
latent destructive power of the military Service bullet 
from the fact that it will penetrate some 4 ft. of deal or 



pine, representing 3^ cnbic inches of wood displaced. 
Taking this as a criterion, it is clear that if we can obtain 
the necessary rapidity of expansion, there is ample energy 
in a single hit to sever any ordinary wing or similar 
structural member. 

§ 63. The Light Weight Shell. Apart from the 
question of the explosive or expansible bullet, we have 
already seen that the 14 oz. limit of projectile weight is an 
irksome restriction when we are dealing with aeroplane 
armament. Not only is the gun required weighty and 
cumbersome, but the weight of the ammunition is, save 
for machines of exceptional size, almost prohibitive. If 
we are able to adopt a weight of 6 oz. or 8 oz. in place of 
14 oz., it will be possible to use a gun direct-mounted 
without the elaboration of recoil mechanism, and weigh- 
ing from 40 lb. to 45 lb. In addition to this, the 
cartridges would weigh less than 1 lb. apiece, and 
provision could be made for some 300 rounds in a machine 
of present-day dimensions. For attack on other aero- 
planes, such a shell would be almost as effective as one of 
twice the weight, and, owing to the recoil limit, the rate 
of fire can be doubled if the lighter shell be adopted. 

It is convenient to make a distinction between the 
explosive bullet and the shell, even if the definition be 
considered somewhat artificial. The former is defined as 
containing a single charge, impact fuse and "burster" in 
one ; the latter (the shell) contains, as well as the burster 
charge, an independent cap or detonator, and a fuse or 
mechanism, time or impact, for determining the instant 
of explosion. Many writers refer to the explosive bvillet 
equally as a .shell. 

It is unnecessary to discuss the probabilit}'' or 
possibility of the abandonment of the restriction imposed 
by the Declaration of St. Petersburg. We know that 
the clause in question was framed from humanitarian 



motives, and it is fairly evident that any expanding bullet 
which, from its behaviour, is tantamount to an explosive 
bullet, may be looked upon as infringing the terms of 
the Declaration, even though it contain no actual 
explosive ; the terms of the Hague Declaration (Article 
^0) are virtually an admission of this. It is equally 
clear that neither at St. Petersburg, in 1868, nor at the 
Hague, in 1899, did the matter arise that now confronts 
us ; and so it is actually a question to what extent either 
document will be considered binding under the conditions 
which have arisen. In any case it behoves us to ascertain 
everything there is to know on the subject, and to be 
prepared for all eventualities. 



(November 6th, 1914). 


§ 64. Other Weapons of Ofence. For the fighting 
aeroplane there is no doubt that the gun will prove to be 
the most useful all-round weapon ; however, several other 
means of offence have been suggested and to some extent 
have proved themselves of value. Bombs and hand- 
grenades, both explosive and incendiary, have been found 
to be of considerable service under appropriate conditions. 
Other means of attack have been proposed, such as 
rockets, air-borne torpedoes, etc. ; so far, neither of these 
latter appears to have been successfully utilised. 

The difference between a bomb and a hand-grenade 
is mainly a matter of size and weight, and a corresponding 
difference in the arrangements made for its release. 
Ordinarily, a hand-grenade is a small bomb of some 5 lb. 
or 6 lb. weight or less, containing a high explosive or 
inflammable charge, and is, as its name implies, thrown 
by hand. Requiring no particular provision for its 
storage or discharge, it is a weapon particularly suited to 
employment by scouting and other machines not primarily 
intended for fighting. The judicious employment of a 
few hand-grenades for the scattering of cavalry or the 
stampeding of led horses, or against troops on the march 
or massed in reserve, may by its effect amply justify the 
use of such a device. The bomb is commonly of 
considerably larger dimensions than the hand-grenade, 
and is stored or mounted in a magazine of some kind 



beneath the fuselage of the machine, with some mechan- 
ical device for its release, arranged either to let go a 
single bomb or to empty the magazine as required. It 
may be said that whereas the hand-grenade, in common 
with the machine-gun, is only suitable for injuring 
personnel, the legitimate objective of the bomb is 
fnateriel. Thus the depots, magazines, arsenals, oil 
stores, etc., of the enemy cannot be effectively destroyed 
by gun-fire, at least from present-day aircraft ; but if 
attacked by a few squadrons of aeroplanes, each dropping 
some eight or ten 30-lb. or 40-lb. bombs, irreparable 
mischief might be effected in a very short space of time. 

We may take it that in the future any such points 
will be duly protected by the fighting aeroplanes of 
the enemy. Consequently the bomb-dropping machine 
will need to be also a fighting machine itself, with a 
capacity for rapid fire sufficient to enable it to hold its 
own with the enemy. Or it will need to act in con- 
junction with a supporting fleet of fighting machines of 
sufficient strength to overpower, or at least hold, the 
enemy during the operation. 

It is thus clear that the bomb differs from the hand 
grenade in not being a weapon suitable for casual em- 
ployment by the reconnaissance machine. Further than 
this, it is a weapon which will in future warfare probably 
be found to possess comparatively little value, except 
when used in considerable numbers by machines acting 
in squadrons, or fleets several squadrons strong. The 
use of the incendiary bomb, or petrol bomb, as it is 
sometimes termed, is indicated where the objective is of 
a sufficiently inflammable character. But it is probable 
that in all cases in which an attack is made upon 
buildings of permanent character, such as in the 
destruction of an arms or ammunition factory, or of a 
dockyard, the petrol bomb will be used to complete the 


job by firing the wreckage remaining after high 
explosives have done their work. 

§ 65. The Bomb : Di^culties in Connection with 
Aiming. The accurate directing or aiming of bombs or 
hand-grenades, or of any gravitationally-propelled missile, 
is one of great difficulty, and many suggestions for 
the improvement of the degree of precision attainable 
have been made. The problem, in a sense, is the inverse 
of that of firing at an aeroplane at high altitude. The 
period during which the projectile is at the top of its 
trajectory (the beginning of its fall in the case of the 
bomb), and in which its velocity is low, introduces 
considerable uncertainty as to direction ; it has been 
proposed to minimise this difficulty by giving the 
bomb an initial velocity or " send off," by some form 
of spring or pneumatic gun. The factor affecting the 
aim definitely known to the pilot is the velocity of 
flight (relatively to the air) ; the factors less exactly 
known are the height, the direction and velocity of the 
wind, or, as it must be reckoned by the aeronaut, the 
earth drift, and the direction of the vertical. Previous 
observation may have given the approximate wind allow- 
ance, and the barometric reading (the aneroid) will give 
the altitude, which, in conjunction with a contour map, 
will give the pilot the figure for his height. The 
determination of the vertical, or " plumb," is far less 
simple or certain than may at first sight appear, since 
any pendulum device is affected by acceleration just as 
much as by gravity, and the reading of a damped 
pendulum or a spirit-level gives the apparent plumb, 
which may be literally anywhere. 

In the case of a machine "looping the loop," for 
example, the apparent plumb is, in fact, at one instant 
diametrically opposite to the true plumb, and during the 
whole evolution it " boxes the compass " in a vertical 

97 H 


plane. The lateral deviations of the apparent from 
the true plumb, are no less serious, and, whenever a 
machine is turning and correctly banked, the spirit-level 
records the machine as being on an even keel. In other 
words, an error in the reading under these conditions is 
equal to the angle of banking, and is quite commonly 
as much as 30 deg. or 40 deg. It is precisely on this 
point — the confusion of the true with the apparent 
plumb — that many of the suggestions offered for the 
direction of bomb-dropping are found to fail ; and it is 
quite useless for those having no knowledge of the 
principles involved to attempt to deal with the problem. 
No better way of obtaining a clear conception of the 
difficulty exists than a study of the pendulum 

In the case of a modern aeroplane which virtually 
" flies itself " it is possible to determine the true plumb 
with considerable exactitude under calm atmospheric 
conditions. Such a machine will, just like a gliding 
model, settle down to a definite flight velocity, known as 
its natural velocity, and to a known gliding angle, and 
will maintain a tolerably straight path ; under these 
circumstances the apparent plumb is the true plumb. 
When, however, atmospheric disturbances are present, 
the difficulty once more makes it appearance. 

In view of the above, it is doubtful whether bomb- 
dropping from aeroplanes will ever be found to compete 
with gun-fire on the score of accuracy, and it may be 
anticipated that the utility of this mode of offence will be 
confined mainly to attack on positions or objects that 
present a mark either of sufficient area or size to be 
easily hit, or of sufficient importance to justify a dispro- 
portionate expenditure of missiles. 

• Philosophical Magazine, August, 1905; also Proceed-ngs of the Institution <rf 
Automobile Engineers, vol. iv., page 124. 



§ 66. The Steel Dart. A form of gravitational 
projectile or missile introduced during the present war is 
the steel dart ; this commonly consists of a piece of steel 
wire or rod some 5 in. or 6 in. long by ^^ in. in diameter, 
pointed at the one end and " feathered " at the other. 
In size and shape the missile resembles and ordinary well- 
sharpened graphite pencil, the feathering being done in 
some cases by the milling away of the tail portion to a 
cruciform section ; alternatively the rear two-thirds of 
the missile may be made of thin-gauge tube. The weight 
is about 1 oz. This " pencil dart " is used against the 
personnel of the enemy — i.e., encampments, men ©r 
cavalry on the march, etc. ; the rate of fall, if dropped 
from a few thousand feet altitude, would be little short of 
the limiting velocity, say some 400 ft. or 500 ft. per 
second. The penetration at this velocity should be equal 
to several inches of spruce planking. Steel darts are either 
allowed to fall out of a hopper or may be simply thrown 
out or " sown " by hand. They appear to be quite 
effective when they find their mark, but their discharge 
and direction are subject to the same limitations as to 
accuracy which apply to the throwing of the hand-grenade 
or bomb, with much greater uncertainty as due to air 
resistance. Beyond this the steel dart, to be efifective, 
must be dropped from a height — a very considerable 
height — and so it is not possible to make a sudden 
descent for the purpose of bringing off an attack, 
as is the case when the bomb is the weapon chosen. 
For these reasons the author does not believe that 
the dart will have a very great vogue. Once the 
aeroplane has been satisfactorily adapted to the carry- 
ing of a machine-gun, it is quite clear that the steel 
dart, weighing, as it does, as much - as the ordinary 
Service cartridge, must be regarded as a weapon of 
doubtful utility. 



§ 67. The Rocket and the Air-Borne Torpedo. 
A suggestion which has been made over and over again 
is that of the employment of the rocket in some shape or 
form ; the objective is usually presumed to be a dirigible 
or airship, and the rocket is to be fired from a rocket- 
tube or gun of some kind from an attacking aeroplane. 
There are two replies to this suggestion : firstly, no 
weapon can be contemplated as forming part of an aero- 
plane armament which is confined in its purpose to the 
attacking of the airship. The airship is already being 
regarded as a prospective bonne louche for the aeroplane 
squadron fortunate enough to encounter it in the open, 
and, as the recent exploit at Dusseldorf has shown, it is 
not in a much happier condition when at home. It is 
already recognised that the airship may not expose itself 
to the attentions of hostile aeroplanes, and when the latter 
are able to attack by one-pounder shell fire, in addition to 
bombs (explosive and incendiary), the airship, already 
little more than a name in active hostilities, will cease to 
have any, even verbal, interest. Apart from the above, 
the supposed effectiveness of the rocket, or of other spit- 
fire projectile, is based to a great extent upon a miscon- 
ception. The modern airship is not so easily set on fire 
as is commonly supposed; in the rigid type, as exemplified 
in the Zeppelin, it is reported that the space between the 
gas-bags and the outer envelope is charged with a non- 
flammable gas, and it may be penetrated by any ordinary 
rocket through and through without the smallest chance 
of ignition.* 

The aerial torpedo (proposed by the author in 1897) 
at first sight appears promising. Such a torpedo would 
consist of a gliding model of high velocity adapted to be 

" This feature was actually proposed some years ago to the authorities in this 
country, and was understood to be a matter of secrecy. However, according to 
Navy and Army Illustrated (September 12, 1914), it now appears to be an established 
feature of some of the later German Zeppelins. 



launched from a gun or pneumatic projector of some kind, 
and carrying a charge of explosive and an impact fuse 
actuated by the striking of the aerofoil member on some 
part of the enemy's craft. Again, we are confronted with 
the fact that any such weapon would be of little service 
apart from attack on an airship, and so may be looked 
upon as useless lumber. 

§ 68. The Supremacy of the Gun. The real fact at 
the bottom of the whole question is the vital importance 
of high velocity in any projectile directed against a 
rapidly moving target, and its doubly vital importance 
when the craft from which it is projected is also in rapid 
motion. This is universally recognised wherever the gun 
is to be found, and it is nowhere more important than 
in the attack on aircraft by aircraft, and in particular 
aeroplane on aeroplane. Any lapse of time whilst 
the projectile is in its flight introduces a corresponding 
uncertainty owing to the relative difference of motion 
between gun and mark. Thus a projectile travelling at 
200 ft. or 300 ft. per second, such as a rocket or aerial 
torpedo, would require to be directed at a point so far 
removed from the aircraft it is intended to hit, that, in 
the case of an aeroplane, the chances of success would be 
remote in the extreme. 

In brief, nothing but gun-fire gives the necessary 
rapidity to ensure a reasonable degree of accuracy 
and useful percentage of hits, and it is probable 
that for some time to come the demand will be for 
higher and higher velocity in order that the effective 
range may be increased. This, however, is looking into 
the future ; at present, the problem of mounting a gun in 
a satisfactory manner, and getting the highest possible 
rate of discharge — i.e.., rounds per minute — are the more 
immediate concern of the aeroplane constructor. The 
relation of the ordinary flight velocity to the mean 



velocity of the projectile is round about 12 to 1, and this 
gives the angle of lead necessary to aim in front of the 
objective from a fixed mounting. When . firing from 
another aeroplane moving in the opposite direction, the 
angle of lead will be six to one more or less, a consider- 
ably greater allowance than is known in any other branch 
of gunnery. With the highest muzzle velocity and slow- 
moving aircraft the angle of lead under these conditions 
is about 1 in 15. The angle of lead given by a pigeon- 
shot when the bird is flying fast across the line-of-sight 
is about 1 in 20, and even here the demand, under the 
stress of competition, is for higher and higher velocity. 
This may be taken as a sure indication of what may be 
expected in the eventual future of aeronautical gunnery. 



(November 13th, 1914). 


§ 69. Naval Aircraft. Special Conditions. 'Kie 
position of aircraft in connection with naval warfare 
requires to be studied almost as an independent problem, 
since many of the circumstances and conditions are 
utterly different from those which obtain on land. 
Apart from differences in the constructional features 
which, particularly in the case of the aeroplane, are 
considerable, the questions which arise in the matter 
of attack and defence are so entirely modified, at least 
as affecting the primary function of the arm, as to 
influence fundamentally the question of armament. Thus 
gun-fire, except as against hostile aircraft, ceases to have 
any appreciable value ; no gun capable of being moimted 
in any aeroplane or dirigjible at present built, or contem- 
plated, would be of the slightest service directed against 
even the smallest unit of the enemy's navy. Again, 
when we consider the duties of reconnaisance, we are 
faced with totally altered conditions. In the case of the 
aeroplane, so long as we are confined to bases situated on 
or near the coast, the area which can be reconnoitred is 
limited to a distance of some 300 or 400 miles (possibly 
500 miles) ffom the coast-line, this being at present an 
altogether outside estimate. Since we commonly have to 
regard our frontier as defined by the limit of the enemy's 
territorial waters, it is clear that any such restriction is 



to be considered inadmissible. In the case of tbe large 
airship, especially the rigid type, the range or radius of 
action is usually taken to be considerably greater, possibly 
some 1,000 miles as an extreme. If we admit this 
(crediting the dirigible with more reliability than it has 
yet exhibited), we are still faced with the fact that such a 
machine cannot operate with safety in the presence of, or 
within the zone patrolled by, the enemy's aeroplanes. 

§ 70. Mother-ship or Floating Base. So far as the 
scouting aeroplane is concerned, the obvious solution to 
the difficulty is the provision of a floating aeroplane base, 
capable of accompanying, or acting in co-operation with, 
the fleet on the high seas, or of acting independently if 
required. Various schemes in this direction have been 
proposed; the future appears to lie between a "mother- 
ship " adapted to take on board the necessary complement 
of aeroplanes (or " seaplanes " as they are frequently 
termed when fitted with floats), and to fulfil the functions 
of storage, transport, and supply ; and a more thorough- 
going scheme in which the floating base takes the form 
of a specialised vessel with a clear deck of sufficient area 
to permit of machines being launched or alighting 
without entering the water at all. In the former scheme 
the normal condition is that the machines are lowered 
into the water from which they are required to rise, 
and on which, in due course, they alight ; in the latter 
the machines are not presumed to enter the water at all, 
any immersion is by way of being an accident, for which 
eventuality, however, the machines would be adapted by 
being furnished with floats in addition to the ordinary 
landing gear. To be eff"ective a quite special design of 
vessel would be necessary, with a completely clear and 
flush upper deck. In order to obtain the requisite area it 
would probably be necessary to design something compar- 
able in dimensions to one of the largest of our existing 



battle-cruisers, and in particular the maximum beam 
possible should be provided. A closer study of this 
problem will be given in a later chapter. 

§ 71. The Armament of the Naval Aeroplane. The 
Employment of Bombs. Dealing for the time being 
entirely with the primary function of the Aeronautical 
Arm in the service of the Navy, we have already pointed 
out that the gun, whether the machine-gun or the one- 
pounder, is of no value whatever. Hence, if the aeroplane 
or the airship is to possess any power of offence at all 
against the ships of the enemy, it must be sought else- 
where. A great deal has been said on the subject of 
bomb-dropping as a means of attack on armoured ships, 
but it is not as well recognised as it should be how 
comparatively impotent a bomb, even charged with high 
explosive, may be when used without " tamping " against 
armour-plate. It is quite true that a certain amount of 
mischief would be wrought by a bomb of large size if 
successfully dropped on to the deck of a battleship or 
cruiser, and the effect would certainly be more disagree- 
able still if the recipient were a destroyer or some still 
smaller craft. The effect, however, would in no degree 
be comparable to that of a torpedo, where the inertia of 
the surrounding water plays an important role. It would, 
in any case, take a vast number of hits to put a first-class 
battleship or cruiser out of action. Further, the diffi- 
culties of aim, as pointed out in the preceding chapter, are 
considerable, and with the counter-aircraft armament 
with which warships are now being fitted, it will not, 
generally speaking, be possible for an aeroplane to 
descend to low altitude with impunity. The dropping of 
bombs from an airship is a matter of somewhat less 
difficulty; moreover, the bombs employed may themselves 
be of really formidable dimensions ; but here the author 
is of opinion that an airship will not in the future be able 



to approach a warship of any kind by daylight without 
certain destruction, and it may be little or no better ofiF 
by night. 

§ 72. Torpedo Attack by Air. Some experiments 
reported as having been made in Germany appear to 
indicate a direction in which aircraft may become an 
actual source of danger to even the most formidable 
battleship or cruiser. It is said that a Zeppelin has 
recently been fitted with means of discharging a White- 
head torpedo with complete success. We may presume 
that the airship is brought down close to the sea-level, 
and then fires the torpedo, just as is done from the deck- 
tube of a torpedo-boat. In view of the great range of the 
modern torpedo — at the present day over 2 miles — 
this form of attack cannot be ignored. It is evident 
that what is possible to the airship in this direction 
is also possible to the aeroplane, provided that the 
latter be built of sufficient carrying capacity; and 
whereas the airship would find it difficult to approach a 
battleship or cruiser within 2 miles without detection and 
destruction, the aeroplane would rarely find this either 
difficult or dangerous ; the matter is mainly one of 
choosing the proper time and direction of attack. In the 
haze of the early morning, or in the dusk after sunset, an 
aeroplane at the distance in question is quite invisible ; 
or again, it is frequently possible for an aeroplane to 
approach in broad daylight against a landscape back- 
ground without being observed, especially if assisted by 
suitable protective colouring ; much depends also upon 
the direction of the sun's rays. Night attack would also 
in many instances be possible, although the absence of 
light may be a greater hindrance than help to the 
aeronaut ; added to this there is the not inconsiderable 
risk of being located by searchlight. The aeroplane for 
the duty in question will need to be somewhat larger and 



of greater carrying capacity than the present standard ; 
the modern 21 -in. torpedo, for example, weighs approxi- 
mately 1 ton, and would require a machine of about 4 tons 
gross lifting power. The older model, the 18-in. weapon, 
weighs about 12 cwt., and would require a machine with 
a gross lifting-power of 2i tons, the latter being not very 
much in excess of the largest machines already in service. 
§ 73. Aeroplane as ajfected by Discharge of 
Torpedo. It might be thought, considering the matter 
superficially, that the dropping of one-quarter of the 
gross weight of a machine whilst in flight would be a 
dangerous and risky business. But closer investigation 
shows that this is not the case ; the resulting disturb- 
ance is one which can be quite easily rectified by the 
pilot. In the case of the modern machine, whose flight 
path is stable (the dynamically-stable machine), and 
which is said to be — and undoubtedly is — capable of 
flying itself, the disturbance calculated as due to the 
release of the torpedo is well within the permissible 
limit. The only condition to be observed is that the 
centre of gravity of the machine shall not be thrown 
forward or backward by the discharge ; in other words, 
the centre of gravity of the torpedo, as carried, must be 
approximately in the same vertical line as that of the 
machine. If this condition is complied with, the result- 
ing disturbance, assuming the torpedo as constituting 
one-quarter of the gross weight, is shown by the diagram 
Fig. 15. The torpedo being dropped at point />„ the 
path of flight py p^ becomes undulatory, the undulations 
dying out, as indicated in the figure, at a rate depending 
upon the degree of dynamic stability provided. The 
extent of the initial undulation is correctly represented 
to scale in the figure, and is the same as would be 
produced in a 70-mile-an-hour machine by an adverse 
wind gust of 10 miles per hour, a thing of everyday 


Plate VIII. 

Built by Messrs. AVHi'nc & Thomi'Sox. 

Pkath IX. 

HYDRO-AEROPLANE H.R.E.3. R. A. F. Design for 
the "Naval Wing" (Now R.N. Air Service) in 1912. 


experience. The patti of the torpedo is indicated by the 
dotted line p^ p^. It is even possible to diminish the 
disturbance still further by arranging the torpedo some- 
what behind the position above assumed, so that on 
discharge the centre of gravity moves forward. This 
would in some degree compensate for the loss of weight 
as giving a less net change in the natural velocity. In 
the opinion of the author, however, it is not to be 
recommended, since it would result in the machine being 
catastrophically unstable (prior to the discharge of the 
torpedo), or would at least tend in that direction. 

§ 74. Aeroplane and Submarine. It is well known 
that the submarine, although when submerged invisible 
to an observer or " look-out " on the deck of a warship or 
other vessel, is clearly visible, and may be readily located 
by an aeronaut from a sufficient altitude. The conditions 
are similar to those frequently noticed when fish in a 
river are seen clearly from a bridge, but are invisible 
from the river-bank. The torpedo-boat or destroyer 
when operating against the submarine is at a considerable 
disadvantage, inasmuch as when the latter is submerged 
the only visible sign of its presence is its periscope — a 
pole of a few inches in diameter, projecting some few 
feet out of the water. Ordinarily it is the point where 
the periscope " rips " the surface that forms the most 
conspicuous visible indication. Thus we may anticipate 
that, in the future, operations directed against the 
submarines of an enemy will involve the employment of 
aircraft, at least as a means of reconnaissance. It is an 
important fact that in this particular service the enemy 
(the submarine) has no power of offence ; hence it is 
possible that the dirigible may prove itself as well suited 
to the work as the aeroplane. It is true that the modern 
submarine is being fitted with guns of light calibre, but 
these are only available after the vessel has come to 




the surface. We may presume that in any operations of 
the description contemplated, one or more destroyers or 
light cruisers will accompany the aircraft scout, and the 
conning-tower of the submarine will be blown away 
within a few seconds of its appearance. 

§ 75. Attack on Submarine by Aeroplane. Destruc- 
tion by Bomb. It is not in any sense certain or likely 
that the operations of aircraft in relation to the submarine 
will be confined to observation. In the opinion of the 
author, aircraft, whether aeroplane or dirigible, will prove 
to be the submarine's most dangerous enemy, the 
submarine being attacked by bombs charged with high 
explosive while submerged. Owing to the absence of 
any danger of counter-attack the aeroplane may fly as 
low as deemed desirable to obtain the necessary accuracy 
of aim, and much of the difficulty commonly associated 
with bomb-dropping will accordingly vanish. Such an 
attack is depicted (somewhat diagrammatically) in Fig. 
16, in which, for the purpose of illustration, the machine 
is shown as flying at a quite low altitude of about 60 ft., 
and when at the point A to drop a bomb, which, having 
the velocity of the machine in flight, describes the 
trajectory A B whilst the machine is travelling to the 
point C ; the motion of the submarine in the intervening 
time is indicated by the dotted outline. It is not to 
be anticipated that in practice it will be found necessary 
to come down to as low an altitude as that shown in 
order to ensure the degree of accuracy required. 

The type of bomb appropriate to the duty in 
question, although not greatly diflferent from that 
required in connection with land service, will need a 
certain amount of consideration. In view of the fact 
that the size of the hole blown in the skin of the sub- 
marine is not important, the charge of explosive may be 
quite moderate ; probably 10 lb. or 15 lb. of wet gun- 


cotton will be ample. A bomb of torpedo-like form, 
about 6 in. in diameter, and fitted with a sheet-metal 
cruciform tail, as shown diagrammatically in Fig. 17, 
would probably be found suitable ; it would be furnished 
with a positive impact or contact fuse at its nose. The 
usual way of dropping a bomb of this type is broadside 
on, pointing in the direction of flight ; the axis then 
remains tangent to the trajectory throughout the fall, 
the tail acting in the manner of the feathering of an 

A bomb of the t3'^pe described in the preceding para- 
graph will travel through water under the influence of 
gravity at a no inconsiderable velocity. Taking its 
weight to be (immersed) about half a hundredweight, its 
limiting velocity in water will be about 50 ft. per second. 

Fig. 17. 

which is ample to ensure the certain action of the contact 
fuse. Thus it will be impossible for a submarine to 
escape by deep immersion, presuming it to remain suffi- 
ciently visible to permit of attack. 

§ 76. Submarine Activity as Affected by Aircraft. 
In brief, the aeroplane, and to some degree other aircraft, 
suitably armed, may be expected to prove an eff"ective 
check on the unbridled activity of the submarine. With 
a properly-equipped naval aeroplane service, supported by 
a few fast, light cruisers, such as the type known as 
the " destroyer leader," the enemy's submarines will be 
unable to roam at large or to make unexpected attacks on 
our cruiser patrols. They will need to operate under the 
protection of a supporting force, and will only leave that 



protection at the risk of almost certain destruction. Or 
they will require to confine their activities to raiding by- 
night — a form of activity in which their radius of action 
is essentially limited, and, save under exceptional 
circumstances, of doubtful promise. It must not be 
assumed, however, that the service necessary for the 
eifective patrolling of the seas by aeroplane will prove at 
all a simple or easy matter. The provision of the needed 
bases, coastal and floating, alone will be a formidable 
matter, and as the radius of action of the submarine is 
increased, and the field of operations is thereby widened, 
the work will become more and more arduous. Again, 
the enemy's aircraft will always have to be reckoned with. 
Thus, although the air service may be looked to to 
provide an eff"ective limit to the power of the submarine, 
we can never expect or anticipate that the value or 
utility of the latter will be by any means nullified. 



(November 20th. 1914). 


§ 77. The Duties of Naval Reconnaissance. The 
work of scouting, or reconnaissance, will undoubtedly 
be the first and most important duty of aircraft in the 
service of the Navy. Whether it be in connection with 
the work of coast defence, in giving timely warning of the 
approach of hostile vessels of war, or in searching out and 
reporting the whereabouts of an enemy's battle fleet, in 
locating the enemy's commerce-destroyers on the high 
seas, or in directing gun-fire during a bombardment or a 
fleet action, the employment of aircraft cannot fail to be 
of signal value. 

So far as coastal work is concerned, there appears to 
be no present difficulty in eff"ectually patrolling the 
whole of the home waters to a distance of some 200 or 
300 miles from our shores, other than the want of the 
necessary machines and the requisite organisation — 
that is to say, there is no difficulty of a technical or 
engineering character. To some extent, as touching more 
especially points of strategic importance, aircraft are 
already occupied in this duty ; the extension of the 
system is mainly a matter of increase in materiel and 
personnel. Unfortunately the demand and pressure for 
increase are felt in all branches of the aeronautical 
services, and it cannot but take some considerable time 
to build additional machines, apart from the time which 



must be expended in the training of the personnel and in 
accumulating the experience necessary to determine what 
types and establishment are really necessary. 

§ 78. Type of Aircraft as imposed by Extraneous 
Conditions. In connection with the work of reconnais- 
sance in home waters, where the " base " is a station 
situated on or in the region of a coast-line, it is well 
understood that the length and extent of the coast-line 
is a matter of considerable importance. If, on the one 
hand, the base be situated on a small island or promon- 
tory in the vicinity of hostile or neutral country, a 
dirigible or other similar low-velocity machine is clearly 
unsuitable. In the event of a high wind it woiild 
frequently be impossible for it to return to its base ; 
tersely, it would be blown away. If, on the other hand, 
the base be situated on a long stretch of coast-line (such 
as the Hast Coast of Great Britain) with a number of 
well-placed stations, the risk is comparatively small ; 
since, unless the wind is directly off shore (or nearly so) 
it will always be possible to make some other " port " 
than that of origin ; the chance of its being lost will be 

When the operations in contemplation are far 
removed from home, beyond the radius of action of 
aeroplanes operating from a coast station or from friendly 
territory, we find ourselves confronted with difficulties of 
a kind for which there is no parallel in land operations. 
As pointed out in the preceding chapter, two solutions are 
possible. Either the machine must be capable of alight- 
ing on, and rising from, the water, and of riding in safety 
on the surface of the sea or ocean under ordinary weather 
conditions, and so be able to accompany and act as an 
auxiliary to a warship or squadron at sea ; or some kind 
of sea-going pontoon vessel must be devised from which 
machines can be launched and on whose deck they may 



alight. Both these schemes are evidently practicable, and 
each has its advantages and difficulties. 

§ 79. Advantages of Flying-Boat Type. For the 
former scheme the most suitable type of machine would 
appear to be the " flying boat " — that is to say, the type 
in -vrhich the flotation, when riding at anchor, is derived 
from a hull of boat shape and of seaworthy design, with 
the usual "hydroplane" stepped bottom to give the 
necessary lift to cause the craft to rise on the water and 
skim whilst acquiring the speed necessary for flight. 
It is by no means certain that this single hull or boat 
will oust the double float at present more generally 
adopted, but for the larger naval aircraft, weighing pro- 
bably upwards of two or three tons, the single boat may 
be reasonably expected to prove the more seaworthy, 
especially in heavy weather. In discussing the question 
recently* the author made the suggestion that, for the 
sea-going aeroplane (such as now under discussion), it 
may be found advantageous to make arrangements for 
the abandonment of the flight organs, and to provide a 
marine propeller, so that in case of emergency the hull 
may be navigated as an ordinary motor-boat. The flying 
boat will thus, it is anticipated, be found the most con- 
venient type of machine to act as sea-going air-scout to 
the cruiser or battleship. It is a type which may be so 
designed as to be readily stripped and carried in davits, 
the flight organs being fitted, and the boat otherwise 
made ready for air service, when required. For the 
commerce-raider, or the cruiser or cruiser squadron 
detailed for the destruction of the hostile commerce- 
raider, an air-scout capable of being carried in this 
manner would prove of the greatest value. In really bad 
weather it would not perhaps be possible to launch or fly 
a machine of this type ; but so far as present experience 

* James Forrest Lecture, Institution of Civil Engineers, 1914. 



^ -2 

CI- S 


goes, it is impossible to fly any aeroplane which has to 
rise from the water under such conditions. However, 
if it should prove possible to fly, as an average, on but 
half the total days in the year, the extended range of 
vision obtained (even by such limited use of the air 
scout) would frequently prove of decisive value. In the 
case, for example, of the recent pursuit of the Bmden 
and Konigsberg, if our cruisers had been able to sweep a 
belt of some 200 or 300 miles in width (instead of about 
one-tenth of that amount), the result might have been 
achieved in far less time. A cruiser, well served by its 
air scouts, in pursuit of an enemy (if not fast enough or 
strong enough to give battle), would be able, having 
located the enemy, to warn merchantmen of their danger 
and at the same time to call for the requisite reinforce- 
ments. It would also be no longer possible for an enemy 
cruiser to secure concealment amongst the islands of an 
archipelago or in a river mouth or estuary. 

§ 80. Points in Favour of the Double- Float. For 
the duties of bomb and torpedo air-craft, discussed in 
detail in the preceding chapter, the boat type of machine 
is ill-suited; the conditions are such as would indicate the 
two-float type as necessary. The latter admits of the 
bomb-magazine or torpedo-cradle being arranged centrally 
beneath the fuselage, from which position, by suitable 
release mechanism, the missile or torpedo can be readily 
let fall. It is doubtful, on the other hand, whether the 
two-float type will prove as convenient to handle aboard 
a vessel not especially fitted out for its reception, 
and it is further doubtful whether it will prove as sea- 
worthy when compelled to depend on its own resources. 
However, there are authorities who are disposed even to 
give it preference on the latter count, and certainly for 
the smaller craft there is something to be said in favour 
of the fact that, so long as the floats are intact and 



uninjured, the machine is virtually unsinkable — it cannot 
be swamped, as is the case with the boat-type. 

A serious disadvantage under w^hich the sea-going 
aeroplane at present labours, whether it be of the single 
boat or double-float type, is that its speed is essentially 
limited by the fact that it has to alight and take off from 
the water, and this involves designing to a comparatively 
low minimum flight velocity. Whilst not necessarily 
limiting the mean or maximum in like degree it tends 
in that direction. 

§ 81. The Ocean-Going Aeroplane Pontoon Base or 
Pontoon Ship. Passing now to the alternative scheme — 
the aeroplane pontoon-ship, we find opened up possi- 
bilities of quite a different kind. We are no longer 
concerned of necessity with the limitations imposed by 
rising from or alighting on water, and the vessel will 
be expressly designed to suit the aeroplane service, 
instead of the aeroplane requiring to adapt itself to 
the vessel. Any land type of machine could be used 
from the pontoon-ship, but by preference floats would 
be fitted, and so far as practicable, machines would be 
rendered amphibious. Whilst it is evidently desirable 
that all machines in the service of the Navy should be 
able to rise from the sea, the conditions are evidently 
altered when an immersion is to be regarded as an 
accident rather than as part of the regular routine. 

For the primary function of the aeronautical arm 
in the Navy, whether it be scouting, or attack on the 
submarine, or torpedo work, there is no outstanding ad- 
vantage in the employment of machines in great numbers. 
For the latter duty (when the machine for this class of 
work has been developed), it may be found desirable to 
attack by squadrons or flights rather than by individual 
machines. But even this is doubtful, since the advantage 
gained by simultaneous attack from different points of 



the compass, as preventing the enemy from concentrating 
his fire on any one machine, may be more than out- 
weighed by the greater risk of the impending attack 
being detected and reported by the enemy's air service 
or torpedo craft. When, however, we have to consider 
the demands which will be made on the naval air-service 
for the performance of its secondary function, in addition 
to the occasions when it will be required to act in 
connection with land operations, it is evident that 
provision must be made for transporting and handling 
machines in large numbers, and this, so far as can be 
made practicable, irrespective of ordinarily bad weather 
conditions, and independently of any land station or base. 
It is here that the need for the floating base or pontoon- 
ship will be felt. 

We may anticipate that, apart from such mechanical 
detail as alighting gear, relative petrol capacity, etc., the 
requirements of the naval and military machines for the 
destruction of hostile aircraft will not differ greatly. 
Bach will rely mainly on the gun in some shape or form 
for its power of offence, and will depend upon its speed 
to force the enemy into engagement. Both types will be 
sent into action in the greatest numerical strength that 
circumstances permit, or as limited by the number that can 
be handled or manoeuvred without undue danger to them- 
selves, in order to bring the heaviest fire concentration 
upon the enemy, and to take full advantage of the n-square 
law. To this end the whole subject of formation flying 
will need to be studied exhaustively and practised assid- 
uously both in time of peace and in time of war. For the 
time being, however, we are concerned with the question 
of the floating base — whose object is to render it possible 
to mobilise an air fleet, as contemplated (complete with 
repair depot and supplies of every kind) at an}'- point 
required, in the shortest possible space of time. 



§ 82. Conditions to be fulfilled. The conditions 
which it is desirable that the air-service pontoon-ship 
shall fill are, briefly, as follow : — 

(1) To act as storage and transport for a fleet of 
at least three squadrons, say fifty or sixty machines, 
complete with spares, fuel and oil supplies, and personnel, 
together with all guns, ammunition, bombs, torpedoes, 
etc., necessary for complete equipment. 

(2) To carry a workshop fully equipped, together 
with the necessary mechanical staff to deal with repairs, 
etc., such as are reasonably required to maintain the 
said air fleet in fighting order. 

(3) To provide an upper deck of sufficient area to 
act as an " alighting ground " completely free from 
obstruction — i.e., there may be no masts, funnels, 
ventilators, cranes, searchlight platform, or wireless 
apparatus such as would form a permanent projection 
above the flying-deck level. The conditions as to deck 
area, etc., must be such as to give ample room for 
alighting or getting ofi" to a pilot of ordinary skill. 

(4) It must have a speed exceeding 20 knots in 
order that it may be able to accompany a battle fleet at 
sea, or to render it able to save itself by flight from an 
enemy battle squadron. 

(5) It must have a gun armament of sufficient power 
to protect it from attack by the light fast cruisers of 
the enemy. 

(6) It must be of comparatively shallow draught, as 
light as is consistent with its sea-going qualities and 
other requirements, in order that it may be able to act 
in rivers, harbours, or estuary regions in support of land 
operations, and incidentally to enable it to evade pursuit 
and destruction by war vessels of heavy draught and gun 
power (such as the battle-cruiser) by taking refuge in 
shoal water. 



§ 83. Tlte Pontoon-Ship, Specification. The above 
list of requirements indicate at once that the pontoon 
vessel will need to be a ship of very large size, com- 
parable to that of a first-class battleship, at least as ta 
length and beam. Beyond this, taking the requirements 
in order, there appears to be nothing really difficult or 
impossible of fulfilment. Thus, conditions (1) and (2) 
could be met without difficulty by a specially-designed 
vessel of a few thousand tons displacement. Condition 
(3) is more exacting, and requires that the vessel should 
be of the maximum beam admissible — say 90 ft. — with a 
water-line of not less than 500 ft. ; also the need for 
doing away with funnels probably means that the 
internal-combustion engine will have to be considered as 
the means of propulsion. This, for the horse-power 
required — about 15,000 indicated — is rather beyond any- 
thing yet attempted ; however, it can be bj'^ no means 
deemed impossible. The conditions could be met by 
employing six propeller-shafts, each driven by a Diesel 
unit of 2,500 indicated horse-power ; this is not regarded 
as by any means beyond the limits of commercially 
sound engineering. The present day uses of the masts 
of a warship are mainly for signalling (by wireless and 
otherwise), to serve to carry searchlight and lookout 
platforms, and as an anchorage for jib-cranes. All these 
various requirements will need to be met without hamper- 
ing the flying-deck with any permanent obstructions. 
Thus it is well understood that the " aerial " for a wire- 
less installation may be arranged horizontally ; in the 
present case it could be carried on spar outriggers, some 
10 ft. or 15 ft. away from the gunwale, being shipped 
and unshipped as needed. Searchlights could, without 
difficulty, be mounted on telescopic pillars dropping flush 
into the deck, operated by hydraulic power or other 
means, and taking but a few seconds to raise or lower ; 



cranes also can be provided in such form as to be 
rigged only when needed. Altogether there is nothing 
in these detail requirements likely to prove of insuper- 
able difficulty. Condition (5) would be adequately met 
by a powerful broadside armament of 6-in. guns, in 
addition, perhaps, to guns of heavier calibre mounted 
in a single turret astern, all arranged below the level 
of the flying-deck. With a ship of the size con- 
templated there should be no difficulty in providing a 
sufficient weight of armament for the purpose specified. 
The gun-deck would be the main upper structural 
deck of the vessel, with only the comparatively light 
flying-deck above it. 

§ 84. Advantage of Pontoon-Ship as Aeroplane 
Base. The pontoon-ship as an aeroplane base possesses 
certain and obvious disadvantages ; an area for alighting 
such as is presented by the deck of a ship, although it 
may be, say, 90 ft. beam by 400 ft. or more in length, is 
none too large under really bad conditions of weather for 
even a skilled pilot, especially if the vessel be rolling 
in a heavy seaway. Without doubt, under extreme 
conditions operations will become frankly impossible ; 
but, under similar conditions, it will be also impossible 
to employ a machine designed to rise from the water. 
The conditions in the case of the pontoon-ship, however, 
are not really so unfavourable as might be thought ; the 
vessel can always be brought head to wind, when the 
relative velocity of the machine on alighting will be 
reduced by the velocity of the wind ; it may also be still 
further reduced by maintaining the vessel under power ; 
these two effects in combination, assuming the wind to 
be 40 miles per hour and the vessel at full speed, will 
result in a machine, flying through the air at 60 miles 
per hour, taking the deck without any relative motion 
whatever — a most favourable state of things, permitting 



it to be instantly secured and made fast. Beyond this, 
under the said condition — i.e.^ head to wind^it is only 
in the exceptional case of a heavy cross sea that the 
rolling could be serious, and with the modern methods of 
steadying sea-going vessels (gyroscopes and ballast- tanks) 
it would require a quite exceptional state of weather to 
keep the air fleet imprisoned. There is one construc- 
tional point worthy of mention ; the flying-deck 
will require to " run-out " at the bows of the ship in 
easy lines, to avoid setting up eddies or dead regions, 
such as might aff'ect the stability or buoyancy of machines 
landing or leaving the deck ; to some extent it may be 
found necessary to extend this precaution to where deck 
joins gunwale abeam. 

It is also worthy of note that the proposed pontoon- 
ship, being of comparatively light draught and great 
beam, will possess naturally the type of stability of a raft 
rather than that of an ordinary ocean-going vessel, and 
will thus tend in a seaway to follow the changing slope 
and motion of the long ocean waves. Now this slope 
and motion, as is well known, are so co-ordinated that 
the normal to the wave slope is always the apparent 
plumb, and so it may even turn out that the flying- 
machine, on taking the deck of a vessel studied as a 
raft rather than as a ship, will (even when the motion is 
severe) have no tendency either to side-slip overboard or 
turn turtle. 

The same conditions which are favourable to alight- 
ing, as from the point of view of relative motion, are also 
favourable to the machine when getting away. Thus, 
with a 40-mile-per-hour wind and a vessel at full speed, 
head to wind (as already assumed), a machine will be 
able to leave the deck with a relative motion of only 
some 10 or 20 miles per hour and a flight velocity of 70 
or 80 miles per hour. Taking all the possibilities of the 



situation into account, it is probable that the machines ta 
operate from a pontoon will, on the whole, be constructed 
as faster fliers than those designed for rising from the 
water, and to that extent at least will be better fitted for 
combatant duties. 




(November 27th, 791'^. 

§ 85. Air Power as Affecting Combined Tactics. 
Some indication has been given in the preceding articles 
of the influence that the advent of aircraft may be 
expected to have on the tactical value and employment 
of the other Arms of the Services ; more particularly 
attention has been called to the changes that will almost 
inevitably be found necessary in the employment of 
cavalry. Certain writers, basing their views too exclu- 
sively on. the experience of the present war, have 
expressed the opinion that the aeroplane, and, more 
broadly, aircraft, though of the greatest service and 
utility as a new means of reconnaissance (and, to some 
extent, of offence), will not have any material influence 
on the tactical employment of the older Arms, either 
Infantry, Cavalry, or Artillery. In the opinion of the 
author this view is fallacious, and the present war, at 
least so far as developed, cannot be taken as a criterion. 
It may be thought overbold thus to give preference to 
purely theoretical deduction in place of actual experience, 
but a little consideration will show that the experience, 
such as it is, cannot be regarded as a serious indication 
of the future. It is an undeniable fact that the aeroplane 
has, in the present war, been able to give information of 
the positions and movements of the enemy such as would 
have been otherwise unobtainable, and in a few cases it 
has enabled points to be attacked which could not have 



been reached by any other means. To this extent it 
may be said to have invented or originated new dnties 
not overlapping those of the older Arms. It is equally 
true that, so far, it has not seriously encroached by its 
employment on the duties of the other Arms — it has not 
replaced cavalry in any measurable degree, neither has 
aeroplane bombardment been found effective as a .sub- 
stitute for gun-fire. There is, however, one important 
consideration that should prevent us from drawing too 
hasty a conclusion from these facts. The number of 
aeroplanes at present in service (as already pointed out) 
is small in comparison with the size of the armies in the 
field, so much so that we can only afford to employ our 
aeroplanes for work for which they are pre-eminently 
suited ; that is to say, to perform mainly those duties 
which cannot be done by other means. 

The position is perhaps most easily illustrated by 
means of an analogy. Some years ago, when the milling- 
machine was first introduced into our general engineering 
shops, it was not an uncommon thing to see one such 
machine installed (more or less experimentally) in a large 
machine-shop alongside some hundred or so lathes and 
other machine-tools ; such a machine usually had allotted 
to it a number of odd jobs that could not be done 
conveniently or cheaply on any other machine. Any 
superficial observer asked to report on the innovation 
might have been tempted to say, " By means of this new 
machine work may be undertaken which could not, 
commercially speaking, be done previously ; it does not, 
however, show any promise of replacing to an}'^ extent 
the older forms of machine-tool, and can only be regarded 
as useful for doing the special work for which it has 
shown itself of unique value." Such a view would, we 
know, have been utterly wrong. The milling-machine 
to-day is doing a multitude of jobs formerly looked upon 



as essentially work for the lathe or planing-machine, but 
it had no opportunity of demonstrating its full capacity 
until installed in sufficient numbers. The above is 
merely an illustration chosen from innumerable examples 
which might be cited. 

§ 86. General Influence on Combined Tactics. 
Aircraft as affecting Attack and Defence. Without 
attempting to discuss fully the influence of the develop- 
ment of the Fourth Arm on questions of " grand " or 
" combined " tactics, mention may be made of one salient 
fact which has already become manifest ; the influence 
of aircraft as a means of reconnaissance has greatly 
increased the power of defence without, it would appear, 
conferring a commensurate benefit on the attack. It is 
possible that the fighting power of the aeroplane may in 
the future be found to redress the balance of advantages \ 
but, so far, there is no definite indication that this will 
be the case. 

It may be stated tersely that the equilibrium 
between forces conducting respectively an attack and 
defence is normally maintained by a balance between 
strategic and tactical advantages. Thus the tactical 
advantage lies with the defender, in so far that he may 
be presumed to occupy chosen positions carefully prepared 
and fortified in advance, so that to place the attack on 
terms of equality the force employed must (locally at 
least) be numerically stronger ; a numerical superiority 
many times that of the defending force may be required. 
The strategic advantage is with the attacking force, 
owing to the fact that the general in command can select 
any one of a number of possible points at which to deliver 
his assault. By exerting pressure at other points, by 
way of feint, he can keep the enemy in ignorance of his 
intentions whilst he is concentrating at the point chosen 
for the main attack, and so prevent him (the defender) 



taking steps to reinforce his lines. Thus an attacking 
army can always ensure a local numerical superiority at 
the decisive moment, and the issue will largely depend 
on whether this advantage is sufficient to outweigh the 
tactical advantage of the defending force as due to its 
choice of position and entrenchments and other defensive 
works. Clearly much, if not everything, depends upon 
the general in command of the attack being able success- 
fully to conceal his movements until the moment arrives 
for delivering his blow. But the veil of secrecy has been 
lifted by the advent of aircraft. It is for this reason that 
the power of aerial reconnaissance has proved so valuable 
a weapon to the defending force, and of comparatively 
little value to the attack. It is quite true that the air- 
craft of the attacking force may be of considerable use in 
reporting the nature and strength of the defences, and so 
may disclose the points ofweakness at which the chances 
of successful assault are the greatest : but this will only 
in a very small degree compensate for the premature 
disclosure of the whole plan of attack to the defenders, a 
disclosure which, if we may judge from experience so far 
gained, appears to be little short of complete. 

The foregoing applies more particularly to warfare 
in which large bodies of troops are engaged over a great 
extent of territory ; evidently where fighting is on a 
small scale, and the whole of the movement constituting 
a concentration and attack can be executed between 
sunset and sunrise, the operations can be considered to 
be of a purely tactical character. It may be emphasised 
that it is by destroying the strategic advantage hitherto 
enjoyed b}^ the attack that aeronautical reconnaissance 
gains its especial value as an aid to the defence. Thus, 
so far, the advent of aircraft in the field of battle has had 
the effect of tending to produce a deadlock, or position of 
stalemate, such as we are able to witness at the present 



time in the north-west of France and on the Belgian 

§ 87. Previous Improvements in Weapons and 
Armament. Question of Depth of Fighting Line. It is 
of interest to note that, previously to the arrival of the 
aeroplane, most of the improvements of weapons and 
armament have tended to favour the attack and to render 
defence more difficult. During the last three or four 
centuries we have seen the value of permanent defences 
gradually diminish, as constructional improvements and 
scientific methods of usage have rendered the Artillery 
Arm more and more deadly. Of more recent times we 
have witnessed the result of the increased effectiveness 
of fire-arms generally in the greater concentration that 
can be effected on any given point in a field of battle. 
In other words, the depth of the line has been increased 
by the greater range of small-arms, and it may to-day 
be increased almost indefinitely by the employment of 
artillery of heavier and heavier calibre, with correspond- 
ingly increased range. Such increase in the depth of the 
line only becomes of general value when, as in the 
present war, the number of men per mile of front is 
great, and more men are available than can be effectively 
employed in the trenches or infantry supports. Any 
additional numerical strength must then be assigned to 
the Artillery Arm, and the greater the supply of men 
(in other words, the greater the density of the line), the 
greater becomes the relative importance of Artillery : 
then the heavier and longer range should be the artillery 
brought into action, in order to ensure that the weight of 
numbers shall tell, in some degree at least, in accordance 
with the n-square law. It would seem that this is a 
point which has been very fully realised by the German 
Staff. In our own experience it is certain that the Boer 
War, owing to the comparative openness of the country 

129 K 


and less density of the fighting-line, did not fully 
demonstrate the importance of artillery from the stand- 
point of modern Buropean warfare. 

§ 88. The Command of the Air. It is probable 
that in the future the employment of aircraft in large 
numbers, tactically in a combative capacity, may, in effect, 
still further deepen the fighting-line. Without attempt- 
ing to predict exactly what role the aeroplane will take 
in this regard, it is safe to say that if, during a battle, it 
is found practicable to conduct air raids and air attacks 
systematically over a considerable belt of territory in the 
rear of an enemy's lines, this belt will require to be 
defended, and (if the air forces employed are of numerical 
strength comparable to the other Arms) the belt will 
actually become a measure of the depth of front. The 
permanent defeat of the enemy's air fleet and, as we may 
express it, the capture of his air will then become the 
first and most important duty of the Aeronautical Arm. 
It is difficult to gauge what the total consequence of 
defeating the enemy in the air will be. It is unlikely 
that it will entirely prevent his aerial reconnaissance ; 
his scouts will doubtless manage to run the gauntlet and 
continue to keep him sufficiently informed. On the 
other hand, he will be deprived of all those uses of the 
Aeronautical Arm in which some more direct and definite 
purpose is involved, such as the direction of gun-fire, 
defence of stores, protection of cavalry, etc. He will 
require to submit to aeroplane attack without possibility 
of effective counter ; he will be subjected to long-range 
gun-fire (directed by aeroplane) without means of return- 
ing it ; his cavalry will be continually harassed by 
machine-gun fire and explosive grenades, and will cease 
to be of service ; his railways, convoys, and mechanical 
transport will be nowhere safe ; and he will need to 
expend an undue proportion of his resources in patrolling 



his lines of communication and guarding points of 
strategic importance. The command of the air opens up 
possibilities in the direction of raiding of a kind and with 
a scope not hitherto known in warfare. To what extent 
it will be found possible for aircraft to detach themselves 
from their base, and execute extended raids in territory ' 
held by the enemy, only the future can determine. It 
would certainly appear that if the inhabitants are friendly, 
and the enemy's aircraft are no more a force to be 
reckoned with, tactics of this kind may be quite feasible. 

Once again the author would point out that the 
experience of the present war is no guide ; the Aeronau- 
tical Arm qua Arm cannot at present be said to exist. 
The Flying Corps, excellent though it be, is scarcely 
more than necessary to constitute an armed recon- 
naissance service. 

§ 89. Total Defeat in the Air an Irreparable 
Disaster. From the foregoing it would appear to be at 
least doubtful whether in future warfare an army which 
has been deprived of its aircraft, or has to admit the air 
supremacy of an enemy, will find itself in a position to 
carry on a campaign. It is, in any case, certain that it 
will only be able to do so at a very grave disadvantage. 
It is the author's opinion that the time will come when 
the total and irretrievable loss of the command of the 
air to an enemy will be regarded as a disaster of an 
altogether irreparable and decisive kind, and although 
there may be a great deal of fighting still before the end, 
nothing less than an overwhelming superiority in the 
other arms will save an army deprived of its air service 
from ultimate defeat. We are thus led to the considera- 
tion of a branch of the subject of extreme importance — 
namely, aeroplane tactics. 

§ 90. Employment of Aircraft in Large Bodies. 
Air Tactics. In some of the previous Chapters (Chapter 



VII., et seq.) the question of aircraft fighting — i.e., 
aeroplane versus aeroplane — has been considered, and 
matters such as armament have been fully discussed. 
We shall now deal with the employment of the armed 
machine in its fighting capacity, not as a single unit, 
but as part of a force whose function is the destruction 
of the armed air fleet of the enemy, and the crippling 
of his reconnaissance service. It is evidently necessary 
to assume that the enemy in his turn has prepared an 
armed air fleet, and that the problem to be studied is 
the handling and bringing to battle of the two air 
fleets in their struggle for supremacy. 

The various factors that enter into the problem, 
apart from the personnel are those of speed, climbing 
power, armament, and last, but not least, numerical 
strength. These, together with that all-important item — 
the tactical scheme — are the more weighty of the 
material factors on which the question of victory or defeat 
will turn. The relative importance of the different items 
is not by any means always the same. It may, for 
example, usually be assumed that one or the other of the 
combatant forces is seeking, and the other endeavouring 
to avoid, battle, or at least is only willing to accept 
battle under conditions deemed favourable ; thus it may 
be that the enemy can be only brought to battle b}' 
virtue of superior speed. In other cases it will be 
possible to force the enemy to give battle by attack upon 
some vulnerable point connected with his land forces ; 
all this is strictly analogous to the similar problems of 
naval warfare. Given the main conditions, all that can 
be accomplished by a tactical scheme is to ensure 
engaging the enemy in the most favourable manner 
possible, and, as in the problems studied in Chapters V. 
and VI., bringing the greatest weight of numbers possible 
to bear on lesser numbers of the enemy, in order to reap 



the advantage of the n-square law. The object of the 
practice of tactical exercises will be to enable an air fleet 
to manoeuvre to defeat the enemy in detail, and, if his 
numbers are superior, to prevent him from bringing his 
whole concentrated fire to bear by the adroit handling of 
the weaker numbers, and so to neutralise the advantage 
of his numerically superior force. 



(December 4th, 1914). 


§ 91. Need for an Independent Combatant Air 
Fleet. The subject of aeroplane tactics, or air tactics, 
may be said to lie wholly with the future. Hitherto the 
aeroplane has acted in its combative capacity as an 
individual unit ; there has been no systematic co-opera- 
tion between a number of machines for the organised 
destruction of the enemy aircraft, such as could be 
described as tactics in the military sense. 

Before we can usefully discuss the present branch of 
the subject we must look forward to the time when air 
fleets or squadrons will be organised for the purpose of 
operating together according to some well-understood, 
or prearranged, scheme as combatant units. We have 
already defined the duties of attack and defence by air 
against the air forces of the enemy as constituting the 
secondary' function of the Aeronautical Arm. This 
being the mainspring from which the tactics of the air 
must derive its motive, we require to take for our 
foundation the material provided by our previous con- 
sideration of the primary function of the Arm. 

The initial condition of the problem, then, is that 
both combatant armies are provided with reconnaissance 
machines of two types, namely, the long-distance or 
strategic scout — an unarmed machine built for speed and 
endurance, and the tactical scout, probably mounting a 



machine-gun, and protected by light armour from attack 
from below. Possibly also there will be a type more es- 
pecially designed for lending support to ordinary military 
operations, on the lines already foreshadowed, protected 
beneath by heavier armour or by point-blank-proof 
shields, and mounting a multiple machine-gun, or a 
mitrailleuse having three or four barrels, and capable of 
firing 2,000 to 3,000 rounds per minute. Further than 
this, there will without doubt be machines expressly 
constructed for bomb-dropping, in addition to specialised 
naval types ; these, however, do not require particular 
consideration, since, in view of the weight they have 
otherwise to carry, their power of offence against hostile 
aircraft (as measured by their gun-power) will of necessity 
be feeble. 

In the absence of any organised air fleet intended 
for the destruction of the types as above defined, there 
will take place, indeed as is already the case, a certain 
amount of desultory fighting of a local character ; at one 
point the aircraft of one belligerent will secure the 
advantage, and at some other point the reverse may be 
the case. So long as neither air force possesses any 
marked superiority in the matter of speed, and so long as 
neither army has at its disposal more machines than are 
reasonably necessary for the reconnaissance and other 
services mentioned, we cannot anticipate that the results 
of such aerial combat will be decisive in any sense. 
We may assume that numbers may combine in order to 
overweight the enemy locally, and drive him out of 
action ; the advantage obtained, however, will only be 
temporary. In such desultory air warfare there will be a 
continual wastage of men and machines, but these losses 
can be made good by new units and new formations. 

In order to effect anything decisive, an organisation 
of an entirely new character is required : an air fleet 



absolutely free from any routine or other set duties, 
whose one and only object is to seek out the enemy's 
aircraft wherever reported, and effect their destruction 
with the utmost swiftness and despatch ; in brief, an 
independent air fleet, whose unchallenged existence 
alone stands for the command of the air. 

§ 92. The Independent Air Fleet. Air Tactics. 
It may be laid down that the independent air fleet, in 
order that it shall be capable of fulfilling the duties 
assigned to it, must be strong by virtue of numbers. In 
order to destroy — i.e.^ not merely to drive away — the 
active aircraft of the enemy, it must be of decisively 
higher speed, so that the enemy, whether reconnaissance 
or fighting machines, will be compelled to surrender or 
give battle. An exception may be made in the case of 
the strategic scout, which, being designed purely for 
speed and being burdened with neither armour or 
armament, may be taken as, within reason, faster than 
anything that can be brought against it. This need for 
superiority in the matter of speed means evidently that 
the air-fleet type must suffer in some degree in the 
matter of armament ; alternatively it must be a heavier 
type machine for machine. Closely allied to the question 
of speed is that of climbing power. Other things being 
equal, whether for increased speed or for increased 
climbing power, a greater horse-power per unit weight is 
necessary. If we assume some given value for the horse- 
power per unit weight, then a machine may be designed 
either to develop the highest flight speed possible or to 
obtain the greatest rate of altitude increase — i.e.., vertical 
Telocity. Any actual design is of the nature of a com- 
promise ; maximum flight speed is kept as high as 
possible consistently with obtaining a sufficient rapidity 
of ascent. The independent air fleet must be, without 
question, the master of the service machines whose 



destruction it is required to encompass, both in the 
matter of speed and climbing capacity. Thus it will 
require to possess a considerable superiority in the 
essential matter of horse-power; it must be made 
impossible for its prey to escape either by horizontal 
flight or by putting on altitude.* 

§ 93. Tactical Importance of Altitude. This 
question of altitude is one of really vital consequence 
in connection with the tactics of the air. The service 
machine designed to fulfill the primary function of the 
Arm must evidently carry its protective plating or 
armour distributed in such manner as best to resist 
gun-fire from below. Also the armament is necessarily 
directed mainly to the downward projection of missiles, 
by gun-fire or otherwise. Hence to obtain the " upper 
berth " in an air-fleet action is at the outset to secure 
a great tactical advantage. It might be supposed that 
these considerations will lead to an increase in the 
protection accorded — that is to say, that the service 
fighting-machine will be fitted with a complete panoply 
of steel plate, above as well as below. This, however, is 
improbable, since any such measure would, by reason of 
the additional weight, so reduce the general mobility of 
the machine as to constitute too serious a handicap. It 
would appear to be only possible to ameliorate the 
conditions under which a machine will have to fight when 
resisting an attack from above by arranging the gun 
armament with as great a capacity for upward fire as 
possible. A further advantage in the possession of the 
upper berth or " gage " lies in the fact that the potential 
energy, represented by the difference of altitude, may, 
at any time, be used to augment the velocity of flight 

• Perhaps the above is asking too much. When a fleet is of sufl5cient numerical 
strength it may be that a definite superiority in climbing power will not be necessary. 
Thus sections of the fleet may be told ofiFto operate at various different altitudes, so 
that escape from one section will mean engagement by another. If the choice of 
aliitude is thus left to the enemy, it is clear that the numerical superiority will need 
\9 be OTcrwhelming. 



above normal, a power which cannot fail to be of real 
tactical value. 

§ 94. Air Fleet must he Homogeneous. It is a fact 
which cannot be too strongly stated that the independent 
air fleet must be homogeneous. It must be composed of 
units of approximately the same capacity of speed and 
climbing power ; the range of its weapons also should be 
the same. As a counsel of perfection, the fleet should be 
of one design^ mounting one standard type of gun, using 
one kind of ammunition. Owing to the need for 
aeronautical ascendancy, we have seen that the armament 
cannot be of the heaviest ; it may more often than not 
be individually less powerful than that of its opponent. 
The independent air fleet must therefore base its strength 
on its numerical superiority. It is precisely here that 
the need for homogeneity becomes manifest. Properly 
to assert the power of numbers, the whole fleet must 
come into action as nearly as possible as a single unit ; 
in brief, it must concentrate the whole power of its 
combined fire on the numerically inferior enemy, and so 
take full advantage of the n-square law. No fleet can 
accomplish this unless its components are able to move 
and act in concert ; thus the slowest vessel in a fleet 
must regulate its speed, and that which has the weakest 
armament the battle range.* In the case of the air fleet 
also we have the slowest climber determining the rate 
of ascent. 

§ 95. Air Tactics. Formation Flying. In order 
that the air fleet shall be brought into action as a single 
unit, it is not only necessary that it should be in its 
constitution homogeneous, as already pointed out, but it 
must also be handled in some definite formation. Where 
the numbers are moderate, as, for example, in the 
handling of a single squadron, the formation adopted 

* The range of the armament in an aerial engagement ia mainly a question of 
muzzle velocity, not calibre. 



may evidently be fairly elastic, and there will be no 
difficulty in bringing the tail of the formation promptly 
into action. When, however, as we may suppose will 
some day be the case, the numbers become great the 
whole question cannot fail to become one of the first 
magnitude. The actual importance will again be greatly 
increased when air fleet meets air fleet, for in view of 
this eventuality, numbers will be augmented to an extent 
that we have as yet no means of gauging, perhaps beyond 
anything that we can at present imagine. 

It would not serve any useful purpose in the present 
state of knowledge and development to attempt to discuss 
too closely the types of formation that may or may not 
be found suitable. We have the same, or an analogous, 
tactical problem in each of the older arms of the military 
organisation, and in the Navy, and in every case, in spite 
of the store of practical experience available, there is still 
a deal of controversy, different ideas being represented 
by diff"erent "schools" of thought; even in the case of 
the oldest Arm of the Service — the infantry, there is no 
unanimity of opinion. This being so, it would clearly be 
futile to attempt to lay down any scheme for an arm 
which cannot yet be said to exist. However, in spite of 
all this, there are certain outstanding facts that cannot 
fail to have some bearing, and will assuredly act as 
controlling influences. 

§ 96. Formation Flying. Airmanship and Sig- 
nalling. When the numbers become great a point will 
inevitably be reached when the accuracy and closeness of 
the formation will be a matter of first importance to the 
tactical scheme, since the only way in which the whole 
force can be brought to bear at once will be by a studied 
plan, in which each machine will have its allotted place. 
In other words, the number of machines from the point 
of view of the n-square law will no longer be the number 



brought into the field by the strategic plan, but rather 
such portion of it as can be brought to bear simultane- 
ously on the enemy ; it will become a battle of airmanship. 
One of the difficulties which exists to-day, and probably 
will always be a matter of anxiety, is that of signalling ; 
and to whatever extent this remains a difficulty, the 
flexibility of the formation will be impaired. The air 
fleet with the most perfect system of signalling will be 
the best able to take advantage of any opportunity that 
may arise in the course of an engagement by adapting 
its tactical scheme to the needs of the moment. In 
order to render it possible to control large numbers, it 
would appear to be evident that the unit command will 
be a small group, or what is at present termed a " flight " 
(some four or five strong), and that the individual 
machines will act on the plan of follow-my-leader ; in 
other words, they will have instructions to keep station. 
It may be found desirable to extend the same system to 
larger units, as tending to avoid possible confusion. 

§ 97. The " y " formation and its value. There 
is a point in connection with the pattern or character 
of these unit formations which may turn out to be of 
importance. It has for long been observed that certain 
birds, flj^ng numbers strong (as in migration), are in 
the habit of assuming definite formation, and that this 
formation is of the shape of a letter V travelling point 
first ; each bird, besides being some distance behind its 
leader, is also somewhat on one or the other flank. The 
reason for this is almost certainly one of aerodynamics ; 
the air immediately in the wake of a bird in flight has 
residuary downward motion, and so is "bad" air from 
the point of view of the bird following. On the other 
hand, the air to the right and left of the leader has 
residuary upward motion owing to the vortical character 
of the wake disturbance, and so is " good " air ; con- 



sequently the V formation arises naturally from each bird 
seeking the air which gives the best support, a matter in 
which most birds show consummate skill. There is very 
little doubt but that, by this manner of flight (formation 
flying in fact) a flight of birds is able to cover the ground 
with a material saving of work done. If the point in 
question is as important as it appears, it will certainly 
have to be taken into consideration in connection with 
aeroplane tactics, and more particularly formation flying. 
The follow-my-leader formation will evidently be on 
a V or diagonal plan rather than in line ahead. 

§ 98. Formation Flying. Machines disabled. What- 
ever formation plan be adopted, it is evident that 
provision must be made for machines shot down or 
disabled to be able to leave the lines without creating 
confusion ; evidently the closer the formation the more 
danger there will be of a real mix up and debacle in case 
of any confusion arising. Similarly, it is important that 
the enemy shall not be able, by ramming tactics or other- 
wise, to throw the formation out of gear ; once more the 
** upper berth " clearly has every advantage. 

§ 99. Conditions in Aerial and Naval Tactics 
Contrasted. The conditions, both as to armament and 
otherwise, which obtain in the Navy and in the Air Fleet 
offer many striking contrasts, the disparity is such as 
should preclude too much reliance being placed on 
analogies between the Services, except where the issue 
under consideration is of the broadest description. 

The range of the gun-fire of an aeroplane (or other 
aircraft) is less a matter of the ultimate range of the gun 
employed than it is of the angular magnitude of the 
objective and of those other factors, such as speed and 
light, which contribute to render accurate shooting more 
or less difficult. In this the conditions diff'er remarkably 
from those which obtain in the Navy, where the useful 



range is, roughly speaking, the ultimate effective range 
of the weapon employed. Thus in air warfare the craft 
carrying the heavier guns will in nowise possess the 
advantage that accrues in the corresponding case in the 
Navy. To a certain degree the larger aeroplane (or 
airship) will be penalised by the fact that it offers a 
target of greater area, and hence it will be more vulner- 
able. It may therefore be anticipated that the trend of 
design in the fighting machine will not be in the 
direction of very heavy units analogous to the battleship, 
but rather in the construction of machines of moderate 
size and weight, with the maximum possible rate of fire. 
As pointed out in one of the earlier articles, this rate of 
fire will be measured by the number of projectiles per 
second, rather than by their weight or striking energy. 
Whilst pointing out that the large aeroplane does not 
possess the marked advantage over the smaller, which, 
in the Navy, has led to the development of the Dread- 
nought and the super-Dreadnought, the author does not 
wish it to be inferred that his opinion is against the 
reasonable development and growth in the weight and 
dimensions of the fighting-machine. It may, indeed, 
be found when the size of air fleet becomes great, that, 
owing to the numbers becoming unwieldy, the only way 
in which the fighting strength can be increased will be 
by increasing the power of the individual unit — i.e., 
by employing larger machines, mounting more guns. 

Again, the larger machine, owing to its less relative 
body resistance and other well-understood causes, has a 
lower coefficient of traction, and so, where the speed is 
important (as we may always assume to be more or less 
the case), the advantage is with the larger machine. 
Alternatively, the larger machine, speed for speed, will, 
with equally good design, be the better climber ; these 
points have already been discussed to some extent ; it is 



only necessary here to draw attention to their influence. 
It would thus appear that there is nothing to be gained 
at the present time by attempting anything heroic in the 
direction of aeroplane design ; the large machine will 
come (if it does come) by a natural process of evolution. 

In contrast to the large machine the present author 
has frequently expressed the opinion that the single-man 
machine for many purposes would be able to effect all 
that is required of it (chiefly reconnaissance), and 
in this he has found himself opposed by the official 
specifications of the Departments concerned. However, 
the experience of the present war seems to indicate 
that there is something in this view, and it is more 
than probable that in the future the single-man machine 
will become a recognised t3rpe for military purposes. 
The advantage of the single-man type is that the 
machine can be altogether smaller and more compact, it 
can be designed to possess, speed for speed, a higher 
degree of inherent stability, and so will fly itself^ leaving 
the pilot quite free to make observations and notes. Be- 
yond this it is more difficult to hit and may more easily 
escape observation ; it is also better to manage when it 
comes to alighting in a difficult situation. Needless to 
say, the single-man type is not a fighting type, although 
for bomb-dropping and such like duties it seems clear 
that the weight of a second man in extra bombs would be 
of far more value than the man himself. 

§ 100. Aircraft bases at High Altitude. Aeronau- 
tical tactics will present many fascinating problems and 
opportunities to the air-fleet commander of the future, 
entirely without parallel in the pre-existing Arms of 
the Service, and there will be ample scope for originality 
and resource. Take, for example, the operations of 
aircraft in a mountainous country such as the Alpine 
regions of Europe ; the selection of aeroplane stations or 



bases at high altitude, and their employment to determine 
an ascendancy over an enemy less fortunately situated ; 
the utilisation to their full extent of air-currents, etc. 
It must be remembered that an advantage in altitude 
can be always turned to account to give a temporary 
advantage in speed, as in the swoop of a bird of prey. 
We may look confidently to the wide employment of 
such swooping tactics in the future of aerial warfare. 
The advantage possessed by an air fleet having its base 
at high altitude, sometimes even some 6,000 ft. or 8,000 ft. 
above sea-level, will be very great ; it will have the 
initial advantage of the upper berth, and this under some 
circumstances may result in the enemy fleet, or sections 
of it, being kept flying for long periods together at 
high altitude in order to avoid the possibility of being 
engaged in action at a disadvantage. Such a process 
might conceivably result in the wearing away of a 
hostile air fleet to such a degree as to determine its 
ultimate defeat. 



(December 7 7th, 7974). 


§ 101. The Command of the Air, and its Limita- 
tions. The term " command of the air " can never be 
taken to carry a meaning so wide or far-reaching, or in 
any sense so comprehensive, as that understood when we 
speak of the " command of the sea." Sea-power has its 
origin and secret in the fact that (as rightly insisted by 
Mahan) the seas control the main highways of inter- 
national commerce and communication ; thus sea-power 
is necessarily world-power. It would not, strictly speak- 
ing, be true to say that the command of the sea essentially 
involves world-wide supremacy ; but so far as a navy is 
provided with fully equipped bases, so far will its power 
extend in its plenitude. It has sometimes been rashly 
assumed by writers that in the future air-power is not 
only going to exercise an influence as wide-spread and 
decisive as sea-power, but is, in fact, about to take a 
superior position, and that the latter will lose some of its 
present character and importance. No such conclusion 
can at present be justified. It is, of course, to-day 
considered bad form to call any engineering project 
impossible; but in view of the fact that, after making 
every reasonable allowance for possible developments, the 
maximum distance that can be flown by an aeroplane 
without replenishment is less than 2,000 miles, it is clear 
that the range or radius of action of an air fleet must be 

145 L 


regarded as permanently imposing strict limitations on its 
employment. The large airship, even should it be found 
to be of greater military or naval importance than 
suggested in the present volume, is scarcely likely to be 
better situated, and suffers from the not inconsiderable 
disadvantage of requiring accommodation of an elaborate 
and expensive kind. Hence we see that the " command 
of the air " is, from a world standpoint, a local condition. 
It might conceivably be secured and asserted by a 
Kuropean Power over half the continent of Europe, or 
the whole of the south and east of the African continent 
might be dominated by air fleets having their bases in 
Hgypt and other territory in British occupation. Hven 
this, however, is looking a great way ahead. For the 
time being we may take it that the policy of any one 
of the Great Powers in time of peace will be to secure 
unquestioned supremacy within its own territorial 
limits, with such bases in the vicinity of its coast lines 
and frontiers as will suffice to ensure the respect of 
hostile aircraft in the event of an outbreak of war. 
When a state of war exists, the task of an air fleet will be 
to maintain its air supremacy at home, and to extend and 
carry the command of the air over land or water in 
support of the Army and Navy, wherever operating. 
Hence the Aeronautical Force is not to be considered as 
a new kind of Navy, or otherwise as a self-contained 
Service to which large-scale independent duties can be 
assigned ; it is definitely, in the words of our title, a new 
or Fourth Ann. 

§ 102. Neutral Aircraft. International Regula- 
tions. It has been believed from the earliest days of 
the modern aeronautical movement that the military, 
(and naval) uses of the flying-machine would prove to 
be one of the most important of its initial applications. 
This view has been more than justified, so much so 



that to-day there is scarcely a machine that *' takes the 
air" in Europe which is not on Service duty. This 
fact probably the most ardent supporter of the military 
usage of the flying-machine would have scarcely 
ventured to predict prior to the outbreak of hostilities. 
Certainly, if five or six years ago anyone had been 
bold enough to assert that at the beginning of the 
year 1915 there would be scarcely a machine flying in 
Europe on other than military duty, it would have 
sounded incredible. That the present situation is not 
representative of the future in this respect we may take 
for granted. On the other hand, it is becoming clear 
that we may quite dismiss from our minds any general 
usage of the air as a commercial highway; the traffic 
in merchandise which will be air-borne will never become 
a great percentage of the world's total. 

We may anticipate that lines will be established for 
the rapid conveyance of mails, and to some extent we may 
look to the development of passenger services in diff"erent 
parts of the world. But for the time being the incon- 
venient (and, in the case of shipping, contentious) 
question as to the rights of neutrals in the air can 
scarcely be said to have been established ; commercial 
usage of the air is virtually non-existent. 

The obligations imposed by international law and 
convention on both belligerents and neutrals are, at 
the best, of an arbitrary and makeshift character ; it is 
doubtful whether anything is to be gained by attempting 
to lay down a code or set of rules to control a form of 
locomotion, in its application to warfare, when so little 
experience is available. However, the author has had a 
book placed in his hands (published early in 1914) on 
" Aircraft in War," in which the whole contents, from 
cover to cover, relate to nothing but the international 
aspect of the subject and to rival codes of proposed 



" legislation." It seems, therefore, that this side of the 
subject requires discussion. Without wishing to belittle 
work of the type in question, it may certainly be said 
that the discussion of anything more than the barest 
generalities of the subject can only be time and effort 
wasted. A new Arm requires to work out its own 
salvation in warfare, and the machine which has won for 
itself and mankind the freedom of the air is not to have 
its future proscribed or fettered by the scratchings of 
an unofficial quill. 

§ 103. Belligerent Aircraft and the Rights and 
Obligations of Neutrals. A question which appears 
likely to lead to great trouble in practice is the 
propriety of belligerent aircraft operating over the 
territory of a neutral Power. Without discussing such 
academic subjects as the territorial sovereignty of the 
air, it seems clear that eventually neither belligerent 
can be prevented from passing over neutral territory 
except by the air forces and counter-air forces of the 
neutral Power in question. If such Power should elect 
not to use his forces to prevent such violation of his 
territorial air, it will be impossible in practice to make 
him do so or hold him responsible. Beyond this, if the 
neutral Power should subsequently make claim against a 
belligerent for using his air, it is difficult to see how 
any such claim could have more ground than an ordinary 
civil claim for trespass, in which the only admissible 
basis of an award is for damage done. If the aircraft 
has flown at reasonable altitude and has done no injury 
by dropping anything, or by gun-fire, it is difficult to 
see how any claim could be substantiated. If the 
neutral Power should elect to employ his aircraft and 
counter aircraft artillery to assert a presumed right to 
his territorial air, he not only puts himself to very 
considerable expense and inconvenience, but at the best 



his efforts are unlikely to be wholly effective ; in thick 
weather the whole of a belligerent air fleet might pass 
over his territory without once being sighted. Hence 
it will be possible that at any time he may be plausibly 
accused of favouring one side or the other, and thus 
find himself in difficulties of a diplomatic kind far 
worse than would have been possible had he left his 
air undefended. A host of other difficulties spring into 
one's mind in connection with the defence of territorial 
air by a neutral Power ; aircraft may encounter above 
the clouds: a belligerent fleet and the neutral air-sentry 
force. How shall they decide in what way to act ? They 
cannot stand still and hold a palaver whilst the matter 
is tested by a plumb-line. Clearly any attempt to 
enforce neutrality in territorial air would be more likely 
to drag the neutral Power into the war on one side or 
the other than a rigid abstinence from interference ; and 
since this is one of the most important contingencies 
to be guarded against,* it seems evident that, as a matter 
of expediency^ the rights (if they be admitted) of neutrals 
over their territorial air should be regarded as not 
involving any obligation of action against belligerent 
aircraft. On the other hand, it is equally clear that the 
ordinary powers of enforcing restrictions in such matters 
as flying over prohibited areas, etc., will in nowise be 
weakened by the existence of a state of war, and neither 
belligerent will have cause for complaint if his aircraft, 
after due warning, should be fired upon. In brief, whilst 
it would appear to be impossible to deny the right to 
a neutral of chasing away — or, if necessary, even of 
destroying — belligerent aircraft if found in occupation 
of territorial air, it would appear to be equally impossible 
to impose the duty of doing so as an obligation. A 

• It is, in fact, one of the main benefits of an international code that the friction 
between neutrals and belligerents should be minimised. 



corollary to this would appear to be that the use of a 
neutral's territorial air will only become a violation of 
neutrality if persisted in in the presence of aircraft or air 
forces of the neutral Power.* Put in a few words, the 
position, as above, is in every way analogous to the 
ordinary law of trespass ; the owner is entitled to turn 
the trespasser off, using only such force as is necessary, 
and can claim damages only on account of actual 
injury sustained. 

§ 104. Other International Questions Relating to 
Aircraft. Distinctive Marks.- It has been suggested, 
or stated, by most previous writers on the subject that 
aircraft will be required to carry a distinctive mark or 
colours, indicating their nationality and their character 
as military or belligerent — i.e., not civilian — machines. 
This view is clearly based on the practice which is 
presumed to obtain in the case of ships-of-war, and which 
is, to some extent, necessary owing to the fact that the 
ocean being the common highway of all maritime nations, 
some declaration of nationality is obligatory, or at least 
desirable, from the point of view of neutrals as well as 
of belligerents. History has shown again and again that 
when a state of war exists, no rules, codified or otherwise, 
will compel a war-vessel or fleet to display its national 
flag, or prevent it from using the flag of any other 
nation that may commend itself at the moment ; and if 
it were not for the interest of neutrals, the practice of 
employing any distinguishing flag or mark in war-time 
might fall into desuetude without aff"ecting anything or 
anybody. Now, in the case of aircraft, it is not only 
improbable, but quite inconceivable, that civilians or 
neutrals will be permitted to fly at all in or near the zone 

* If this view be accepted, the recent action of the British naval airmen in passing 
over Swiss territory is quite permissible and in no way irregular. Switzerland, 
had she so willed, could have employed aircraft to police her frontiers, in order 
to prevent the "borrowing" of her territorial air. Failing this, and not having 
suffered actual, i.e., material, injury, she has no ground of complaint. 



of hostilities. It is even probable that on the declaration 
of war all private aircraft will be requisitioned or 
impounded (as now done in the case of wireless tele- 
graphic apparatus), and that neutrals will be advised that 
they will use the territorial air of the belligerent countries 
entirely at their own risk and peril ; in fact, that they 
will be shot down if detected. We cannot for an instant 
admit a state of things such as would arise were neutral 
or private aircraft (with war correspondents and suchlike) 
allowed to fly in any area in which fighting might be 
in progress ; there would be continual uncertainty as to 
the nationality of such alien aircraft, and no means of 
checking the abuse of a neutral flag by spies or imposters. 
The position is totally diff'erent from that which obtains 
at sea. There is no possible means of investigation, and 
no time to ask questions ; if there is any doubt, instant 
action is imperative. It is only too evident that even if 
distinguishing marks were agreed, no reliance would be 
placed upon their genuineness in real warfare, and their 
disuse, sooner or later, may be considered to be a 
foregone conclusion. 

It will be part of the business of the airmen and 
gunners of both belligerent armies to be fully conversant 
with the peculiarities of the various types of aircraft in 
their own service and in that of the enemy, and to be 
sufficiently "fly" to detect any attempts at disguise or 
deception. It is, of course, always open to the aircraft 
of either army to carry a distinguishing mark or sign 
which can be displayed at will, and the nature of this 
may either be known or unknown to the enemy ; it may, 
to ensure secrecy, be changed from time to time like a 
'' pass-word." This, however, is an entirely diff'erent 
matter to the compulsory wearing of a badge, like a 
uniform or a national flag, by which the nationality 
will be openly declared as a matter of obligation. 



§ 105. Aircraft landing in Neutral Territory. 
Other questions of an international character relating to 
aircraft do not appear to present any serious difficulty. 
Bvidently a belligerent aircraft descending into neutral 
territory will be interned, just as would a cavalryman or 
an armoured motor-car. To treat an aeroplane or airship 
according to the rule established in the case of a warship 
would clearly be to admit its right to have been in 
the territorial air of the neutral Power concerned, which, 
we may assume, will be considered quite inadmissible. 
Already, in the course of the present war, we have seen 
the hospitality of neutrals greatly abused. It certainly is 
not just or expedient that the cruisers of a nation which 
has ceased to possess any coaling stations, or bases, of its 
own should be allowed to roam indefinitely at lar-ge, 
interfering with the commerce of an enemy, when such 
action would have been impossible without neutral 
assistance. The proof of the inexpediency of the existing 
rule in such a case is to be found in the fact that the 
difficulty could be soon ended by a few declarations of 
war against some of the minor neutral Powers, with the 
bombardment of the ports by which the enemy is served. 
The very fact that this becomes the logical reply, which, 
but for humanitarian considerations, would without doubt 
be pursued, demonstrates an inherent deficiency in the 
present international code, and one which perhaps may, 
in due course, be remedied. Any rule by which aircraft 
would be enabled to utilise neutral territory or neutral 
resources for repair, refit, or replenishment would almost 
certainly be the cause of great friction, and might result 
in a position so impossible as to drag the neutral Power 
into the conflict, the precise eventuality that it should 
be an object of international convention to avoid.* 

In other respects there would seem to be no reason 

* Footnote page following. 



to treat the flying-machine or dirigible differently from 
arms or armament of other kinds, or belligerent airmen 
differently from other combatants. It is at least clear 
that any modifications in the accepted code which 
may eventually be found necessary may well be left 
to come as the natural outgrowth from experience in 
warfare. With regard to the manufacture and supply 
of aircraft by neutrals to belligerents, or the granting of 
facilities of transport, the same considerations will govern 
the decision of the neutral Power as are at present 
involved where arms and munitions of other kinds are 
concerned. The Power affected requires to consider in 
what way its own interests and those of neutrality are 
best served. 

* It would often appear from the framing of clauses and debates in connection with 
the various international conferences that the above (in the author's opinion the most 
important object of achievement of international conventions) is almost lost sight of 
in a quagmire of dangerous and namby-pamby sentimentality. In many cases the 
desire seems to be vaguely to do something that will be thought humane ; no clear idea 
seems to exist as to right and proper grounds on which regulations of restrictions 
should be based. Thus, for example, in the Brussels Conference of 1874, Article 13 e, 
andin the Hague Conference of 1899, Article 23 e (already cited, Chapter VII. )■ the same 
restriction appears for the prohibition of bullets of the dum-dum or expanding type ; 
in the first (the abortive Conference of 1874) the prohibition is worded : — " The use of 
arms, projectiles, or material of a nature to cause unnecessary suffering ; the wording 
adopted at the later conference is " . . . of a nature to cause superfluous injury." 
At the 1874 Conference the assembly was, it appears, imbued with feelings of horror 
for pain and suffering, but in 1899 this seems to have become changed for a dread of 
disablement and death — a totally different matter. The suggested prohibition of 
bombs or missiles from aircraft is an illustration of the same infirmity of purpose 
that appears to reign supreme at peace conferences and the like ; again we see the 
dictates of fear mistaken for those of benevolence. There is, and was, no evidence 
that bombs from aeroplanes or balloons are any more barbarous or inhumanly 
destructive than the shells from artillery or howitzer batteries, yet clauses were 
debated and framed, and (with a time-limit restriction) were actually signed by certain 
of the representatives of the Powers. The fear of the unknown is without doubt more 
widespread and potent than its victims realise. A cavalryman is killed in peace time 
by a fall from his horse, it scarcely excites comment ; an army airman falls and is 
killed and a thrill of horror goes through the country — it is a new kind o death. 



(December 24th, 1914). 


§ 106. The Fourth Arm in Peace Time. The 
problems connected with the maintenance of the Fourth 
Arm in time of peace are numerous, and present 
difficulties which will certainly be found to increase as 
the numerical strength of the Arm is augmented. It is 
not easy to form any real conception of what the future 
may have in store in the direction of numbers, but as a 
matter of guesswork it is difficult to believe that, sooner 
or later, the strength of the Flying Corps will not reach 
or exceed 1 per cent, of the number of bayonets. Thus 
a considerable part of the work formerly allotted to 
cavalry will in the future be assigned to the new Arm, 
and the cavalry ordinarily represents from 5 to 10 per 
cent, of the number of bayonets. Also, the guns will 
require the assistance of aircraft, probably one or more 
machines being attached to each battery or group. Beyond 
this there will be specialised fighting-machines of differ- 
ent denominations. Taking everything into consideration, 
the suggested 1 per cent, does not look like an over- 
estimate ; it is probably too low. 

Assuming 1 per cent, as a basis, the numbers are 
already formidable. Thus, for the British regulars on 
home service prior to the outbreak of war, the number 
would need to be at least some 1,000 machines. In the 
case of the large Continental armies — say, the French — 
with over 700,000 men (peace footing), it may be 



anticipated that a total of about 5,000 machines will 
be required.* 

The peace training of these vast numbers of 
flying-men would represent an organisation of immense 
proportions, especially if the author's anticipations in 
such matters as aeronautical tactics, formation flying, etc., 
come to be realised. The multiplicity of flight-grounds, 
training-schools, workshops, sheds, etc., with the necessary 
staff of instructors, mechanics, and other non-combatant 
members of the organisation, will render the whole 
matter a very big undertaking. 

In view of the probable magnitude of the business, 
it is to be feared that the question of peace-time casualties 
in the Flying Corps will inevitably become a matter of 
the most serious importance. It is quite certain that 
everything possible must be done to minimise the 
dangers of military flying in peace time ; this looks like 
a self-evident proposition, but apparently it is not. The 
author has frequently passed comment on the seriously 
defective nature of some of the existing flight-grounds, 
and has found himself met (quite unofiicially) by the 
argument that since the men will have to alight upon 
pasture land, or even ploughed fields, when on service, 
it is best that they should have plenty of experience of 
rough ground when at home ; further, that it is necessary 
to test the strength of the machines by using them in 
peace time under service conditions. So far as the 
machine is concerned, this kind of argument is altogether 
unsound. If the type is one which has been thoroughly 
tested in the first instance before adoption, and if the 
machines are properl}^ inspected during manufacture, 
they will be far more reliable in the battlefield if they 
have not been knocked about by rough treatment over 

* The fact should not be lost sight of that Great Britain may require to regulate 
the strength of her Flying Corps by that of her neighbours rather than by the 
strength of her own Army. 



bad ground in peace-time flying. Testing to destruction 
is good in its way, but the particular article so tested 
must not be subsequently used. With regard to the men 
themselves, the argument that a bad ground is better 
than a good one is almost as gravely at fault. One 
hundred alightings on a good ground (with a fair surface 
and without obstructions) will carry less risk than, say, 
20 or 30 on a poor or bad ground, and the man who has 
made his 100 alightings, with, if we wish, imaginary 
obstacles, is a better man than the one who has only done 
his 20 or 30, especially if the latter is disabled or dead. 
A man who practises jumping uses a light lath, which 
will do him no injury if he falls, in spite of the fact that 
his object may be to join a club of harriers and jump a 
five-bar gate. 

The need for improvement in our flying grounds is 
very much emphasised, when the importance of night 
flying is taken into consideration. With bad or indif- 
ferent flight grounds, such as existent at the time of the 
outbreak of war, alighting by night is an operation of 
extreme risk, and is only possible for a pilot of great 
experience. There is no real reason why alighting by 
night should be unduly dangerous ; flight grounds of 
adequate area, properly drained, and of good surface, are 
however essential. There are many ways, by means of 
artificial lights, by which the difficulty of judging the 
distance from the ground may be overcome. 

It is more than possible that, in some respects and 
from certain points of view, flying by night may become 
less hazardous than by daylight, just as, for example, 
there are many conditions under which navigation at sea 
is actually safer by night than by day. 

The military importance of night flying is in part 
due to the need for countering the activity of the larger 
dirigible or Zeppelin, but the question is far wider than 

156 . 


this. At present all raids, reconnaissances and other 
duties entrusted to the aeroplane are subject to the con- 
dition that the operation must be completed in time to 
return to headquarters before dark ; infraction of this 
condition is prone to result in serious losses, both of 
machines and men. It is abundantly clear that no such 
restriction should be tolerated, and the solution of the 
difficulty is to be sought in the provision of flight 
grounds, worthy of our present day aircraft. It is a 
serious reflection on our conduct as a nation that we have 
so far shown ourselves prepared to spend more money in 
the provision and upkeep of cricket fields, than we are 
ready to do for the safety of our flying men and the 
efficiency of the Aeronautical Arm. 

Even before the outbreak of the present war, the 
author had more than once given expression to the 
opinion that our flight grounds stood more in need of 
immediate improvement than the machines themselves. 
Thus the following is quoted from the author's recent 
"James Forest " lecture (1914) :— 

" There is, moreover, another factor (quite extraneous 
to flying conditions proper) that at present puts a definite 
handicap on high speed and prevents the aeronautical 
designer from doing himself justice in that direction ; 
namely, the backward condition of existing accommodation 
in the way of alighting-grounds. Owing to quite well- 
understood conditions, it is necessary, before rising, to attain 
a speed on the ground not very much less than the normal 
flight-speed of the machine, and so, in the case of a machine 
designed for 120 miles per hour maximum flight-velocity, it 
would be necessary to acquire a speed round about 80 miles 
per hour before leaving the ground, which would necessitate 
a straight-line run of about 300 yards. To comply with this 
condition, and to give safe room otherwise for handling the 
machine, a flight-ground of at least half-mile length should 
be provided, having a surface far better than is now custo- 
mary. Beyond this, since in bad weather it is undesirable 



either to start or to alight across the direction of the wind, 
it would appear that a ground of not less than some lOO or 
150 acres in extent would be desirable. At the present time 
the Author believes that the provision of well-appointed 
flight-grounds of the area stated in different parts of the 
country would do more to further the cause of aviation than 
an equal expenditure of money in any other direction. 

" It is possible that at some future time the landing-gear 
of machines may be so far improved that it may be found 
possible to alight on the ordinary high road ; also it may be 
that sections of the high road will be specially widened and 
freed from adjacent obstruction to serve in cases of emer- 
gency. It is clear, however, that the general use of the high 
road for this purpose would in any case be open to very 
grave objection. 

" It might be thought that the setting apart as flight- 
grounds of such considerable areas of land as above indicated 
would impose too serious a financial burden on flying, at 
least for some time to come, to be commercially possible. 
It is, however, to be borne in mind that with proper manage- 
ment such grounds could, especially if duplicated, be 
utilized for grazing purposes : thus, if an area of 200 acres 
were available, a herd of some few hundred head of cattle 
could be grazed, being transferred from one section of the 
ground to another from time to time. It is therefore evident 
that, under favourable conditions, the commercial aspect of 
the problem is by no means outrageous, even during the 
period that must intervene before flying as a mode of loco- 
motion can become in any sense popular. Beyond this, 
assuming that the flying-machine is able to justify its exist- 
ence apart from its employment by the Services, there seems 
no reason to suppose that the returns of a well-equipped 
flying-ground might not easily become far greater than the 
agricultural value of the land concerned, which at the best 
is but a few pounds per annum per acre." 
§ 107. The Fourth Arm in Peace Time. Depre- 
ciation and Obsolescence. A somewhat knotty point is 
that of the duration of the service life of aircraft. 
So far no definition has been generally accepted. The 


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truth is that any machine may become " superannuated " 
either owing to depreciation or to obsolescence ; in the 
former case the number of miles covered will be the 
determining factor, coupled, perhaps, with other facts 
relating to its history or usage ; in the latter, it is the age 
of the machine which determines its unfitness for service, 
considered, of course, in relation to the advance which has 
been made in the art of construction since the date of 
building. Thus a machine may be unfit for service 
either because it is, according to some accepted definition, 
worn out and incapable of repair, or because it is obsolete 
in design. In some cases obsolescence may be absolute, 
as when a design is so out of date that by comparison 
with the best available it is to be considered unsafe or 
uneconomical ; in this case it is only fit to be destroyed ; 
or its obsolescence may be relative, as when it is out- 
classed by the machines of corresponding type in the 
service of some neighbouring Power ; in this case it is fit 
to be sold out of the Service or to be transferred to some 
distant part of the Empire, where competition is not 
equally severe. The questions of depreciation and obsoles- 
cence and the disposal of condemned machines have not 
yet received due consideration. On continuous active 
service it would appear that the life of a present day 
aeroplane is about three or four months. 

The foregoing may be taken merely as samples of 
the many questions which have to be faced before the 
training of army pilots and aeroplane gunners and 
signallers can be attempted in the thousands, or tens of 
thousands, for which the warfare of the future ma}'- 
call. Without adequate consideration of these questions, 
coupled with appropriate measures, progress in the direc- 
tion of increase of numbers and the practical development 
of aeroplane tactics on a large scale will be most seriously 



§ 108. Present Position. British Superiority. The 
reports as to the performance of the air-craft, and more 
particularly the aeroplanes, of the different belligerent 
armies are at present very meagre and incomplete. How- 
ever, it would appear from the observations of those best 
qualified to judge that the British machines are by no 
means backward, and in many important respects are 
superior both to those of the enemy and to those of our 
Allies. The features in which we at present possess 
the advantage are those in which the flying capacity 
of the machine, rather than its more essentially 
fighting quality, is concerned. Thus superiority may be 
claimed for the British aeroplanes : firstly, as being better 
aerodynamically — that is to say, for given horse-power 
and weight they possess a greater speed and climbing 
power ; secondly, they are more stable — in fact, our 
present-day machines are definitely automaticall};' or 
inherently stable ; thirdly, they have a higher factor of 
safety than any of their Continental rivals and are far 
more robust as to alighting gear ; and, fourthly, they are 
more weather-proof. In short, they are better fitted to 
service conditions. Beyond this, one of the latest 
models turned out by the Royal Aircraft Factory is by 
far the fastest machine in the world, being some ten or 
twenty miles per hour faster than anything the Continent 
can show. On the other hand, on the outbreak of 
hostilities we found ourselves without a thoroughly 
satisfactory fighting or gun-carrying type of machine — 
it is one matter to be able to mount a gun on an 
aeroplane, and quite another to design and construct 
machines expressly for that purpose. It is, indeed, doubtful 
whether at that date any really satisfactory gun-carrying 
aeroplane existed at all; it is in any case precisely in 
this direction that our own air service has found itself 
most lacking. In brief, it may fairly and undoubtedly 



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"be claimed that so far as the reconnaissance machine is 
concerned, the British aircraft are more than able to 
hold their own with those of the other European nations. 
In the main the "proprietary" machines built by- 
private firms have lacked the all-round qualities of those 
turned out by the Government factory, or under contract 
to the Royal Aircraft Factory specification. In some 
cases they have failed from a constructional standpoint ; 
under the exacting conditions of service the alighting 
chassis have sometimes proved inadequate ; in other 
cases the weather-proof qualities of the " proprietary " 
machines have been found deficient. These defects have 
not only shown themselves amongst British-built 
machines, but also some of the best known of the French 
makes have failed, or at least are reported to have cut 
a very sorry figure when submitted to the rigorous test 
of service conditions in real warfare. Possibly it was 
not anticipated (as it appears is the case) that machines 
would be required to remain permanently in the open 
night and day, shelter being the exception rather than 
the rule. It is under these conditions that our own 
Aircraft Factory machines have exhibited an unrivalled 
robustness of constitution. On behalf of the " pro- 
prietary " makes of machine, however, it must be said 
that some of the most notable of the exploits performed 
by the Naval Air Service (such as the raids on Diisseldorf 
and Friedrichshafen) have been performed by such 
machines,* which proves that, from the point of view of 

* The execution of these sensational feats of arms by our naval airmen must 
not be taken to mean that they could not have been performed equally well by 
members of the Royal Flying Corps, but rather that the latter are fully occupied by 
their regular daily work of military reconnaissance, and are certainly no more than 
numerically sufficient for the needs of our Army in the field. In the Navy, the 
routine or " business " employment of aircraft (more especially aeroplanes) is not yet 
understood ; the efficient patrolling by aircraft of the seas in which a state of war 
exists — mainly the North Sea, in the present instance — should be considered by the 
Air Department of the Admiralty to be its most important duty ; this will require the 
systematic employment of a considerable fleet of aeroplanes, which should, if 
jjiossible, be machines of 16 or 18 hours' capacity and at least capable of 80 miles per 
hour. The large airship, until recently in contemplation for this duty, provides, 
in the author's opinion, a doubtful solution, without recapitulation of its other 

161 M 


flying, they are fully worthy of the Service and a credit 
to their designers and constructors. 

§ 109. Causes which have Contributed to British 
Ascendancy. The position of the British in the matter 
of military aeronautics — more particularly aviation — 
to-day, which, subject to the limitations stated, may 
properly be described as " ascendancy," is not to be 
attributed to any one definite cause ; the results achieved 
in the field have been contributed to both • by the 
personnel of our Flying Corps and Naval Air Service, 
and by the sound qualities of the machines employed. 
In view of the peace-time exploits of the airmen of the 
three leading Western Powers, in which it may fairly be 
said that honours have been divided, it would appear 
that, without belittling the magnificent performance and 
daring of our flying men, it is in the matter of material — 
i.e., actual machines, etc. — that our superiorit}^ is most 

In discussing the influences which have led to the 
development of the present-day types of service machine 
it must be borne in mind that these influences have been 
at work in the factories of the private firms engaged 
equally with the Government factory at Farnborough. 
There has in the past been little or no secrecy in 
connection with the Royal Aircraft Factory — private 
builders and the designers attached to private firms have 
virlually had the "run of the place," and all possible 
assistance has been rendered them ; in brief, the private 
firm has been at all times kept thoroughly up-to-date 
in the matter of technical information. 

deficiencies, it is too slow ; the key-note in matters of military or naval advancement 
is mobility, tlie measure of which is flight speed. As in certain other fields of 
employment, the dirigible might prove better suited to the work in question than 
the aeroplane, weie it not for the fact that sooner or later, the aircraft of the enemy 
will have to be faced. The inherent weakness of the slow and vulnerable balloon 
type cannot fail to place it at a disadvantage. 

•In time of peace the opportunities for public demonstration accorded to Service 
machines are limited. Since the time of writing it has become apparent that our 
superiority is no less due to our men and organisation than to the merits of our 



The main factors that have contributed to the 
production of the machines of outstanding merit, which 
are upholding our reputation in the field to-day, are 
unquestionably the greater scientific knowledge possessed 
by our designers, and the conspicuous ability shown by 
the staff of the Royal Aircraft Factory in making 
practical use and application of the latest and best 
information at their disposal, and in their own full-scale 
experimental work and study of the many practical 
problems outside the range of purely scientific research. 

The machinery set up by the Government for dealing 
with a new and difficult question of the greatest national 
importance, has, so far as its allotted scope is concerned, 
worked with singular smoothness and undeniable effect. 
In brief, we have the Royal Aircraft Factory, which may 
be regarded as the headquarters of the national sources of 
production, and in itself of the character of an experi- 
mental or pioneer department rather than a national 
manufactory. Behind this we have the Advisory 
Committee for Aeronautics, a body whose functions are 
mainly concerned with scientific and technical questions, 
and at the disposal of the Advisory Committee a 
large and growing department forming part of the 
National Physical Laboratory. In addition to this, there 
exists the Naval side, consisting of constructional works 
and depot at Aldershot, which has taken over in its 
entirety the Dirigible (Balloon) section of the work. 

The secretarial headquarters of the Advisory 
Committee is permanent^ located at the National 
Physical Laboratory, the Director of the latter, Dr. R. T. 
Glazebrook, F.R.S., being the Chairman of the Committee 
under the presidency of Lord Rayleigh, O.M., F.R.S. ; 
the Army being represented b}^ the Director-General 
of Military Aeronautics, Major-General Sir David 
Henderson, K.C.B., the Navy by the Director of the 



Air Department of the Admiralty, Captain Murray F. 
Sueter, and the Royal Aircraft Factory by the Super- 
intendent, Mr. Mervyn O'Gorman, C.B. In a sense the 
Advisory Committee may be said to act as a " clearing- 
house " for information, inasmuch as its functions are to 
ensure, on the one hand, that the information obtained 
from the work done at the National Physical Laboratory, 
and collected from other sources, is duly made available 
to the Royal Aircraft Factory and to the Services, and, on 
the other hand, to hear and dispose of the difficulties and 
demands of the said parties. This latter may be a matter 
either of tendering immediate advice or of appropriately 
employing the resources of the National Physical Labora- 
tory, or requisitioning any such other assistance as may be 
deemed expedient. The work is carried out in the main 
on an annual programme framed on a sufficiently elastic 
basis to allow of all possible contingencies being dealt with. 
In addition to the foregoing, the Committee receive and 
publish a considerable number of new investigations, also 
abstracts of most of the work of importance done on the 
Continent ; in these latter respects the work accomplished 
by the Committee can be best judged from a perusal of 
the Annual Report presented to Parliament.* It is by 
these means that those responsible for the design, 
specification, and construction of our aircraft, whether 
military or naval, have been, and are, kept fully informed 
of all that concerns them from both technical and 
scientific standpoints, and have been able to employ the 
somewhat limited resources granted them by the 
Treasury to the best possible advantage. Beyond this 
the staff of the Royal Aircraft Factory includes men of 
exceptional resource and ability, who have proved them- 
selves again and again more than competent in the 
execution of the duties entrusted to their care. It is 

• Reports 1909-10, 1910-11, 1911-12, and 1912-13, at present published. 




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impossible in this connection to pass over without 
mention the great loss which the factory (and the 
country, it may be said), has suffered in the death of Mr. 
H. T. Busk, who recently lost his life in the execution of 
his duties, being burnt to death in mid-air whilst person- 
ally carrjdng out investigations of an experimental 
character. Mr. Busk combined with exceptional abilit}^ 
as an experimenter a very thorough knowledge of his 
work ; he was largely responsible for the design and 
construction of many instruments and appliances which 
have proved of the greatest service in the development of 
the present-day machine. 

There are many of the less-informed members of the 
public who believe that the flying-machine has been 
developed, and is to-day being designed, by empirical 
methods, and that the scientific man has had nothing to 
do with it, except, perhaps, late in the day, to give 
plausible explanations of the " whys and wherefores." 
Nothing is further from the truth. The work relating 
to the design and construction of the modern aeroplane 
is quite as much the result of careful and scientific 
calculation, in fact, rather more so, than in the case of 
shipbuilding. All matters connected with the flying 
properties of a machine, whether it be lifting power, 
propulsion, or stability, are amenable to rigorous scientific 
treatment, and are as carefully founded on scale-model 
and wind-channel experiment as the analogous problems 
in ship design. 

In scientific work connected with flight (as pointed 
out by the author in his recent James Forrest Lecture), 
the work which has been done in this country is far in 
advance of that done on the Continent ; more especially 
is this the case in connection with stability : it is fair to 
take it that the advantageous position in which Britain 
finds herself to-day in the matter of aircraft is legitimately 



to be regarded as a reflection of this fact. No one 
acquainted with the history of the development of our 
Service machines can have the slightest doubt as to the 
truth of this statement. 



(December 24th, 1974). 


§ 110. Maintenance of British Supremacy. The 
maintenance of the present superiority of the British 
reconnaissance machine and the development of different 
types, and, in short, the building up and consolidation 
of the Aeronautical Arm, both as to quality and quantity, 
in order to ensure our capacity to hold our own with the 
other great Powers, is a task of national importance, and, 
as such, one of the first magnitude. In order that our 
Aeronautical Arm may be raised and maintained as a 
whole at the necessary high degree of efficiency, more 
will be needed than merely the technical superiority of 
our machines ; many other questions of vital consequence 
will require to be adequately dealt with. However, the 
basis of strength lies in poSvSessing the right types of 
machine in adequate numbers. Hence there must be no 
relaxation of effort ; we must retain our technical 
ascendancy by every means in our power. 

There is much to be said at the outset in favour of 
the exercise of greater secrecy in the matter of technical 
information. At present a great deal of work of an 
important character is done at the public expense which 
is of the utmost value to the aeronautical constructor, and 
forthwith it is given complete publicity ; one has only to 
glance through any one of the annual reports of the 
Advisory Committee to realise the extent to which this 




is the case. There is, it is true, also a certain amount 
of work which is not published, being considered as of a 
confidential character. The question arises whether the 
main body of the work, or, at least, some of the more 
important sections, should not be held back, and treated 
as confidential for a certain period, possibly one complete 
year, in order to give our own designers a twelve months' 
lead. The difficulties in the way of any such scheme are, 
firstly, that, to be efi"ective, the first twelve months' 
output of any new design would require to be met as 
output from the Government factory ; the conditions 
issued with designs and specifications for tenders, though 
nominally intended to ensure secrecy, can never be really 
effective. Secondly, in a branch of Governmental 
activity as little understood by the public as that of aero- 
nautical construction, the public and Parliament expect 
to see something for their money, and for those entrusted 
with aeronautical development to have shrunk from 
publicity would have been equivalent to committing 
suicide. In spite of any disadvantage which may have 
resulted from publicity in the past, the net result has been 
highly satisfactory. It is more than probable, however, 
that the Continental Powers have somewhat underrated 
the importance of the work which had been done in this 
country, and have taken no particular pains to follow or 
study that work ; this neglect is not likely to be repeated. 
Certain it is that, technically, the Continental nations 
are, without being aware of the fact, some way behind us 
in aeroplane design. The author is disposed to think 
that, all things considered, it will be found advisable in 
the future to restrict publication somewhat, and consider- 
ably to strengthen the Aircraft Factory, to enable full 
control to be exercised over new models, and otherwise 
to take steps to ensure secrecy where, in the national 
interest, it may be deemed wise. 



§ 111. Government versus Private Manufacture. 
In every problem of production in quantity, otherwise 
that which is termed " manufacture," the essence of true 
economy is continuity. The whole of the organisation of 
a modern factory is based on the work in progress being 
of the nature of a *' flow," rather than a succession of 
jerks. In actual practice it is only in the case of certain 
industries in which the goods manufactured are not 
liable to change from year to year, and in which the 
demand is not of a fluctuating character, that the " flow " 
can be maintained under ideal conditions — that is to say, 
with perfect uniformity. In other cases fluctuations are 
inevitable ; changes in design necessitated by the stress 
of competition and the advance of knowledge prevent the 
condition of perfect continuity from being realised. 
Under these conditions a not inconsiderable part of the 
duties of the organisation is that concerned with 
negotiating the necessary irregularities and changes. 
The work still is dealt with on the theory that it remains 
a flow, but it is actually a succession of batches, the flow 
being comparable to that of a river subject to seasonal 
fluctuations, periods of flood alternating with periods of 
slack. The system of organisation requires to be framed 
to deal with the consequent unavoidable breakages of 
continuity, and it is the business of the works and 
engineering staff so to regulate the progress of work that 
the resulting disorganisation is minimised, and the 
economy of production is not too seriously impaired. 
The possibilities of the situation, so far as the manage- 
ment staff" is concerned, are very much circumscribed by 
considerations of finance and the exigencies of the 
market. These latter questions are, or should be, 
dominated by the prevision of the directorate ; they are 
matters governed by the policy of the company, for which 
the board of directors (directly or through their managing 



director) should be definitely responsible. The policy 
thus includes such questions as the market or markets 
to be attacked ; the quantities and dates at which it 
is estimated sales can be effected ; the financial needs, 
whether it be for building or plant extensions or for 
stock-in-trade ; and the provision of, or the raising of, 
the necessar}' finance. 

In brief, in a well-managed concern the Board may 
be said to control that which is in military parlance the 
strategy of the company, whilst the management staff 
look after the tactics. Clearly, just as in military affairs, 
success must depend very largely upon the strategic 
scheme being accommodated to the tactical resources, 
and the tactical work being skilfully adapted to the 
strategic scheme. 

Now, in the case of a Government factory, there 
is no real board of directors. The financial side is 
controlled by the Treasury, whose interests are not 
concerned with the prosperity of the concern in the least 
degree ; it is equally satisfactory from a Treasury stand- 
point whether the " grant " can be reduced by the most 
arbitrary and expensive "cheeseparing," or whether it is 
done by legitimate and proper means — by the exercise of 
true economy. The result is that anyone acquainted 
with the working of Government manufacturing institu- 
tions could cite innumerable cases of gross extravagance 
resulting from so-called Treasury economy. Again, there^- 
is no one to formulate in advance a proper manufacturing 
programme with the least assurance that there will be the 
means available in order to carry it to a successful 
conclusion ; even ironwork of a part-finished structure 
has been known to be denied the wherewithal for a coat 
of paint ! The cast-iron system of closing the programme 
at the termination of each financial year without carry 
forward is destructive of good management. Thus the 



position of a Government factory is equivalent to that of 
an army with no Minister of War, no strategic scheme, 
and a capricious and fitful transport and supply. The 
larger institutions, such as dockyards, etc., represent a 
national interest of sufficient magnitude to escape some 
of the disadvantages of Government control, but here the 
circumstances are exceptional. 

Manufacturing by private firms under contract, 
therefore, has considerable advantages ; but even here 
the want of regularity in the placing out of orders is not 
conducive to higl^economy ; a private firm, however, is 
able to work in one job with another, and execute a 
Government contract in lieu of other work for which 
there may happen to be a lull in the demand. This is 
especially the case in war time, when (as at the present 
moment) a large proportion of our engineering works 
and factories, having little demand for their regular 
products, are mainly occupied in turning out munitions 
of war. Whatever the state of preparedness may be 
before war is declared, it is almost certain that the needs 
of the country, whether for aeroplanes, guns, or other 
items of armament, will be increased many times during 
the period of hostilities. The employment of private 
enterprise under these conditions is clearly desirable, and 
may be looked upon as imperative. 

Once admit the above, the propriety of widely 
utilising the ordinary manufacturing resources of the 
country during peace time follows as a corollary, for it is 
only by this means that these resources can be brought 
promptly into operation when the need arises. A firm 
which has once executed contracts for any given article 
is always in a better position than one to whom the work 
is new ; this is true in any case, but is more especially 
so where the preparations for manufacture involve the 
duplication of gauges, tool outfits, etc. 



When work is done by contract it is absolutely- 
necessary that it should be first standardised in every 
detail. The rigid methods of gauging and viewing 
which have definitely to be adopted when aeroplanes (or 
other implements of war) are being manufactured to 
Government specification and contract, render anything 
in the way of ambiguity or alteration during manufacture 
intolerable. Therefore, whatever be the relative merits 
or demerits of private and Government manufacture, the 
former can only properly be resorted to for work which 
has passed its experimental stage, anj has been finall}'- 
standardised in every detail. This involves, in the case 
of anything so progressive as an aeroplane, that the 
Government will of necessity carry the manufacture of 
every new design up to a certain point ; we may say up 
to that point at which it has become, after due tests and 
trials, an officially accepted type. This is almost exactly 
the position as it has come about : the Royal Aircraft 
Factory is directlj^ responsible for the initial develop- 
ment of every new model (with the exception of 
some few *' proprietary " types which have been taken 
into service) : the only difficulty at present is that the 
resources of the factory are not sufficient fully to cope 
with even this preliminary work, and, in consequence, 
private enterprise is being called upon to do more than 
ought to be the case : the standardisation is having to be 
effected whilst manufacture is under weigh. 

In view of the present position and the enormous 
development which may be anticipated in the course of 
the next few years, it will, in the author's opinion, be 
necessary very greatly to strengthen and increase the 
establishment of the Aircraft Factory in the near future. 

§ 112. Future Maintenance of British Supremacy. 
Continuity of Policy. The supremacy of British aircraft 
can only be maintained by the adoption of a thoroughly 

172 <r 


progressive constructional policy, guided constantly by 
the most recent scientific discovery and research, and 
by utilising to the full information and experience gained 
in the Services. The day is past when technique or 
craftsmanship can be permanently bottled, and the trade 
or craft in question monopolised by any one nation, as 
was at one time the case. Under present-day conditions 
the lead can only be obtained and held by mobility and 
progress in which the motive power is derived by the 
combination of brains, energy, and material resources. 
The most that can be hoped is to obtain a lead of two or 
three years in advance of other nations, and to keep it. 
The task is not beyond the power of the country ; we 
have both the men and the money, and an Bmpire whose 
preservation demands that nothing shall be left to chance. 
The key to the whole situation lies in the proper 
organisation and control of the manufacturing resources 
of the Government, as at present represented by the Royal 
Aircraft Factory. This must be based on a clear con- 
ception of the duties of the factory as the birthplace of 
new types and the nursery for their development, also as 
the headquarters of full-scale experimental work, that is 
to say, tests and investigations engineering in character, 
or those in which actual flying is involved, as distinct 
from laboratory experiment. The deficiencies at present 
existing are due, firstly, to the fact that the Treasury has 
too much control over the Factor}^, and the Factory not 
enough control over the Treasury ; secondly, there is no 
one upon whom definitely devolves the duty of initiating 
any departure in advance of immediate requirements ; 
thirdly, the resources of the factory have been insufficient 
for the needs of the Services ; it has been necessary to 
send out drawings and specifications to contractors before 
the designs have been standardised or even thoroughly 
established, with all the little attendant difficulties in the 



matter of minor alterations, ambiguities as to gauging, 
etc. ; also with the loss of any real pretentions to secrecy. 
Lastly, there is a tendency to divorce the aircraft develop- 
ment of the two Services — the Army and Navy ; this 
the author considers to be bad. The main supplies of 
established types may certainly be obtained by the two 
Services from independent sources or from different 
contractors, but to separate the experimental or develop- 
mental phase of construction appears to have nothing to 
commend it. 

The deficiencies of the present regime, such as they 
are, in no way reflect adversely on the existing staff and 
personnel of the Royal Aircraft Factory as it stands ; in 
fact, it is undeniably greatly to the credit of all concerned 
that so much has been done. It is, however, hard to say 
who is supposed to be responsible for supplying initiative 
and foresight. That initiative has not been lacking is 
evident, but it is an open question whether anyone could 
have been accused of neglect of duty if the factory had 
never developed or constructed a solitary aeroplane. 

Actually that which is lacking is something analogous 
to a directorate, a Board whose existence would ensure 
continuity of policy, and whose members would be 
definitely responsible for the sufficiency of the construc- 
tional programme so far as its developmental side is 
concerned, and for securing the needed Treasury support. 

§ 113. A Board of Aeronautical Construction. 
The duties adumbrated in the preceding paragraph would 
be best deputed to a Board of Aeronautical Construction, 
in which both Army and Navy are represented by the 
responsible heads respectively of the two branches of the 
Arm — namely, the Director-General of Military Aero- 
nautics and the Director of the Air Department of the 
Admiralty, in addition to a strong civilian contingent 
selected for their eminence or attainments in such 



directions as aeronautical or mechanical engineering, 
manufacturing, naval architecture, business management 
(organisation), finance, etc., and including the Superinten- 
dent of the Factory. In view of the fact that the future 
of the new Arm has yet to be determined, and in view of 
the vital importance of this future, it would seem 
desirable that certain Cabinet Ministers, such as the 
Minister of War and the First Lord of the Admiralty, 
should ex officio be members of the Board. This may 
possibly appear to be- giving unnecessary importance to 
the idea, but it must be remembered that the existing 
Arms of the Services, during the earlier stages of their 
history, were considered of sufficient importance for the 
most minute and detailed attention of kings and princes, 
and the new Arm might almost claim as its right similar 
solicitude from those on whom the burden of office has 

The duties and functions of the proposed Board 
would be in nowise limited to the aircraft themselves, but 
would extend to aircraft and counter-aircraft armament, 
and, further, to all questions of materiel ancillary to the 
employment of aircraft in the Services, including aero- 
plane vessels or ships. 

The duties and constitution of the Advisory 
Committee for Aeronautics would remain as at present, 
being in no way affected. In some few cases it is 
possible that questions touching the work done at the 
Royal Aircraft Factory would be referred to the new 
Board in place of the Advisory Committee. 

The arrangements regulating the Board in the 
matter of expenditure would need to be, on a basis com- 
patible with the responsibilities ; a refusal or a cutting 
down by the Treasury of the requisitions by the Board, 
either annual or supplementary, should be rendered next 
to impossible. It would suffice for the purpose if, in case 



of such eventuality, it were made incumbent upon the 
civilian section of the Board to resign en bloc. Parlia- 
ment and the public would thus be advised that something 
had gone wrong with the " machine." To create this 
position it is only necessary for a public statement to be 
made by a responsible Minister of the Crown that the 
Board has at its disposal whatever funds it deems 
necessary ; this is virtually the footing on which the 
present Advisor}^ Committee is placed.* 

The alternative to the creation of a Board, such as 
suggested in the present chapter, would be an extension 
of the powers of the Advisory Committee. The present 
functions of that Committee are strictly advisory ; 
and they are, to all intents and purposes, confined 
to the scientific and technical side of the subject ; 
the personnel of the Committee also has obviously 
been chosen on the basis of this being the 
intention. The Committee expends no money directly, 
but controls grants on account of aeronautics so far as 
relating to research work and the like. It would be 
impossible without destroying the whole intention and 
character of the Committee, to assign to it those duties 
in relation to the national programme of aeronautical 
construction for which the author is advocating the 
formation of a Board of Aeronautical Construction ; 
hence any such change may be regarded as out of the 

* House of Commons, May 5th, 1909. 







§ 114. Scope and Limitations of the Present Work. 
lu the present work it has been the author's endeavour 
to give an account of the existing position and the future 
possibilities of aircraft in its Military and Naval usage ; 
in so far at least as present day knowledge permits of a 
reasoned forecast. There remains considerable ground 
however, to cover which no attempt has been made ; 
thus we have the whole subject of aeronautical photo- 
graphy in its present relation on which much might 
have been said ; also many quasi-technical questions 
connected with aeronautical signalling, by wireless and 
otherwise, might legitimately have been introduced. 
Beyond this the whole subject of aeroplane design, as 
affected by the various kinds of usage in warfare, is 
itself one of vast and intricate interest, — this has been 
barely touched upon. In these matters considerations of 
secrecy have necessitated reticence ; the author had 
obviously to steer clear of much that was known to him 
on the subject of our aeronautical equipment, and to 
confine himself for his facts to such material as was 
common property before the date of hostilities, or had 
become so since. As an indication that the position 
has not been without difficulty, it may perhaps be 
mentioned that (contrary to what might be expected) it 
is not always permissible to reproduce matter which has 

177 N 


already been published in the press ; should it thus 
appear that the author has not taken full advantage 
of material already published elsewhere, it will be fair 
that he should be credited with an adequate reason. 
Certain digressions from the main subject have on the 
other hand been made, and here and there speculative 
incursions into the unknown have been ventured. The 
most important digression is without question that con- 
stituting the subject matter of Chapters V. and VI., 
involving the demonstration of the n-square law. The 
author believes that this law will, in due course, be 
recognised as fundamental even in relation to ordinary 
military operations where its application is commonly 
masked by conditions extraneous to the hypothesis. 
Still more readily will its importance be recognised in 
Naval warfare, as already exemplified bj^ the Battle of 
Trafalgar.* The clearest and cleanest application of the 
law, however, will unquestionably be in connection with 
aerial warfare, here the author predicts that, other 
things being equal, it will be found to operate with 
almost mathematical precision. 

§ 115. Then-square law as affected by the Tech- 
nique of Gunnery. In the application of the principle of 
concentration and the n-square law to Naval warfare 
under modern conditions, a difficulty occurs which has 
not so far been adequately dealt with, and which is 
worthy of full discussion. This difficulty mainly concerns 
existent methods of range finding, and is to the effect 
that when the fire of more than one vessel is brought to 
bear on a single ship of the enemy, the same accuracy — 
as evidenced by the percentage of hits — is not attainable 
as in ship-to-ship combat. 

It is to be understood that after the range has been 
found as accurately as possible by the, instrument known 

• Chapter VI. §§ 40, 41 and 42. 


as a range-finder, the final corrections are made by firing 
salvos, each salvo being observed, and our appropriate 
correction given. When the range has been thus 
determined, firing by salvos may be discontinued and 
independent firing resorted to, the main advantage of 
the latter being an increased rapidity of fire. If it be 
observed that the firing is becoming wild, that is to say, 
if the range has been lost, firing by salvos may be 

The objection to more than one battleship making 
a target of a single vessel of the enemy is that it is 
difficult to avoid uncertainty as to whose projectiles are 
going wild, and so when independent fire is the order 
of the day, it is impossible for the gunnery officer to tell 
whether his own gunners have lost the range or whether 
the bad shooting is from the co-operating vessel. It 
then becomes necessary for both ships in turn to resort 
to salvo firing, in order to check their range and correct 
their aim, and thus at the best the speed of fire is 
unavoidably reduced at intervals during an engagement. 

The objection no doubt is valid, but, like other 
objections, the question is one of degree. The loss of 
speed of fire when salvo firing is adopted depends to a 
great extent upon the type of vessel, and more especially 
upon the armament. Thus if the vessel be one of the 
pre-dreadnought period having in its primary' armament 
guns of various calibre and of different rapidity of fire, it 
is clear that in salvo firing the lighter guns (also the 
more rapid) -either will not be employed or will have their 
speed of fire regulated by that of the guns of heavier 
calibre. In the case however, of the all-big-gun ship — 
as dating from the original " Dreadnought " — the loss 
is not so great, and the objection of proportionately less 

It is to be remembered that at modern ranges, some- 



times amounting to a distance of 8 or 10 miles between 
opposed fleets,* the time of flight of the projectiles is 
very great. It may amount to some 20 or 30 seconds, 
and thus if two vessels are concentrating their fire on one 
of the enemy and firing by salvos, it will frequently be 
the case that two salvos of projectiles are in flight at 
the same time, and the uninitiated would not be certain 
which salvo belongs to which vessel : for the professional 
gunner however, the matter is different. Although the 
correct range may not be known or may be wrongly 
determined in the first instance, the gunner, or the officer 
responsible for the control, knows precisely the range for 
which he has set his elevation, and consequently he 
knows to a fraction of a second the interval which 
will elapse between the discharge of the salvo and the 
time the projectiles strike the water ; thus unless two 
salvos are actually fired to strike the water within say a 
second of one another there will be no reasonable doubt 
which is which. 

It may fairly be urged that the troubles of observa- 
tion and of gun fire direction in naval actions tend to 
increase, and at the best the conditions are already 
sufficiently exacting. It is, for instance, not uncommon 
when combatant vessels are separated by some 8 or 10 
miles, for destroyers and torpedo boats to be told off to 
create clouds of smoke, by which the difficulties of obser- 
vation may be indefinitely increased. It is probable, in 
fact it is almost certain, that in the future the aeroplane 
will come to the rescue of naval gunnery, just as it is 
already employed in co-operation with long range artil- 
lery on land. The author believes that in future naval 
warfare much of the observation work and fire control 
will be corrected by aircraft, either dirigible or aeroplane 
being used ; under these conditions it will be necessary 

• Perhaps even 12 miles as a maximum estimate ; so far battle experience is lacking. 
Tie 4 or 5 miles given in § 36 is (from the context) an ordinary minimum. 



for the battleship to notify to its associated aircraft 
the range of each salvo, so that when the fire of two or 
more vessels is concentrated on one, the aerial observer 
will be able to locate the position of any given salvo with 
certainty. There are many ways in which this might in 
eflfect be accomplished ; for example, a smoke or flash 
signal could be fired on board the battleship at a pre- 
arranged one or two seconds' interval before the salvo is 
due to strike the water. The observer or airman will 
note the said signal and pick out the corresponding 
salvo from the splashes of independent fire or of salvos 
from other vessels, signalling in reply whether too short, 
too long, or right, or left, according to a pre-arranged 

It will be quite clear from the foregoing discussion 
that although undoubtedly two or three ships concen- 
trating their fire on one of the enemy may be detrimental 
to accurate shooting, the difficulties are such as can be 
met, and that with only a moderate loss of fire efficiency. 
Now, if the advantage shown to accrue from fire con- 
centration, as exemplified by the n-square law, were 
something trifling or negligible, in comparison with the 
difficulties involved, then, without doubt, it might be 
judged that in practice the ship-to-ship combat would be 
the best, even when a numerical superiority exists. But 
the advantage of concentration as exemplified by the 
n-square law is not negligible or trifling, it is overwhelm- 
ing, and of such a character as to entirely outweigh any 
objections which can be raised from the gunnery stand- 
point.* In brief, the controversy (so far as it is so) is 
a conflict between a fundamental principle and a matter 

• Discussing the present subject with the author, a Naval officer of high rank not 
only expressed the opinion that the concentration of the fire of two ships on one is 
impracticable under modern conditions, but further stated that if he were fightingr 
two ships against two ships of an enemy, he would bring one of his ships into action 
first, and only throw the other into tlie 5ght when the fire control mechanism of the 
enemy, i.e., observation and fighting tops, telephones, etc., had been carried away 
or disabled. This view is the opposite extreme to that held and advocated by the 
author. In any case it is not thus that Nelson fought. 


§ 115 


of technique, and we know that in all cases when such 
a conflict takes place, it is the technique which has to 
adapt itself to meet the fundamentall}^ important 
condition. The technique in the present case is the 
technique of gunnery and fire control, and the author 
believes that it cannot be put too strongly that it is " up 
to " the gunnery officer (whenever possible) to carry into 
practice the concentration of the larger force on the 
lesser and to adapt his methods, cost what it may, to 
meet the requirements of the case ; he cannot afford to 
flout a fundamental principle for the sake of simplifying 
the technique of his profession. 



§ 1 16. The n-square law and Partial Concentration. 
In § 42 it was shown that if the whole of the "combined" 
fleet of 46 ships had been concentrated upon the British 
40 ships the annihilation of the latter would have been 
complete, leaving the combined fleet victors with the 
equivalent of 23 whole ships to the good; this is now 
represented graphically in Fig. 18. By inadvertence 
this was referred to (quoting Villeneuve) as " the usage 
of former days." This is not strictly accurate, at least 
it requires qualification. 

According to the said "usage of former days" 
34 of the British vessels would have been opposed 



to 34 of the enemy ship to ship, and the remaining 6 
British would have been opposed to 12 of the enemy, 
these conditions are represented graphically in Fig. 19. 
Thus it will be seen that the numerical surplus is 
reduced to 10.4 ships, the case being one of partial 
concentration. Of course in actuality the scheme, how- 
ever carefully planned, would never result in the perfectly 
well ordered doubling of the excess of one fleet on 
the rear ships of the other ; the construction, however, 
given in Fig. 19 is quite elastic, and any departure may 
be readily dealt with. Thus Fig. 19 may be taken as the 

•0 * UO ^ io * '30 * 40 

Pig. 19. 

appropriate general graphic construction for the repre- 
sentation of any case of partial concentration in 
accordance with the n-square law. 

It is worthy of remark that in cases of partial 
concentration there may always be a second or after 
phase in the battle when the residue of the superior 
force concentrated on the " tail " of the enemy having 
done its work, will throw its weight into the main 
combat, the final conditions will then be more nearly 
the same as if the initial concentration had been com- 
plete, as assumed in § 42. 

§ 117. Air Raids: The Value of Numbers. The 
importance of numbers in duties other than actual fight- 
ing does not, generally speaking, follow the n-square 
law; it is nevertheless by no means negligible. 

The reason here is that the object attacked is, 
ordinarily speaking, not an actively hostile force. Thus 



even where, as in the attack on an arsenal or magazine, 
the position is protected by counter aircraft artillery, it 
is fair to assume that the latter is mounted at a sufficient 
distance from the main object of attack not to be en- 
dangered unless bombs are wilfully diverted from their 
objective. Under these conditions a numerically great 
attacking force of aeroplanes will manifestly possess an 
advantage in that they will divide the limited fire 
capacity of the defending batteries and so suffer less 
individual punishment ; we may take it that the actual 
injury inflicted on the attacking fleet will be constant and 
independent of its numerical strength. If, by the nature 
of the attack, the period during which the air fleet is under 
fire is lessened by a numerical increase, there is a gain 
to an extent proportional to the reduction of time the 
defending batteries can be brought to bear. 

In any case the gain is clear, as for example if 
10 machines can do in a given time 10 times the 
mischief of one machine, and if this is done at the 
same average total loss it is done 10 times as economic- 
ally. In other words, if a given weight of bombs have 
to be dropped and this be done by 10 separately 
attacking aeroplanes, the protecting batteries will be 
able to "get off" a 10 times greater number of shells 
than if the attack were planned and executed by the 
10 machines simultaneously. 

It is of some interest to remark that in § 64 
(originally published Nov. 6th, 1914) the suggestion 
is made of an attack by a " few squadrons " of aero- 
planes as constituting a reasonably effective concentra- 
tion ; this is an almost exact forecast of the practice 
as it obtains to-day, since a "Squadron" may be taken 
as from 16 to 20 machines and in recent air raids it 
is reported that about 60 or 70 machines have been 
employed. We may confidently look to a substantial 



numerical increase in the air raids of the future. 

The author is inclined to believe that the tendency 
of the future will be towards machines of not too 
great size each dropping a comparatively few bombs, 
possibly no more than one large bomb being carried 
by each machine. This conclusion arises as a deduction 
from the fact that when machines are acting in great 
numbers it will not be possible (neither will it be politic) 
for any given machine to pass more than once over 
the object of attack, hence if a large number of bombs 
be carried they will need to be released almost simul- 
taneously. Under these conditions a single large bomb 
of equal weight will possess a far greater potential 
capacity of destruction. 

§ 118. Aircraft v. Submarine. DiscuSvSing the 
value of Aircraft as countering submarine activity in 
Chapter XI., the subject has perhaps been handled too 
much in detail, and some of the broader considerations 
have not been given sufficient prominence. It is not 
to be supposed that it will always be found possible on 
locating a submarine, to follow it up and immediately 
effect its destruction, since in the turbid waters of the 
Channel and parts of the North Sea (especially in 
rough weather) a submarine, by diving deeply and 
steering by gyro-compass, could frequently effect its 
escape. Quite apart from the method of attack it is the 
author's view that with a sufficiently numerous air recon- 
naissance, the enemy submarine will be subject to 
continuous and unremitting pressure to such an extent 
that, even where it may escape destruction, it will 
commonly fail in its object. Thus, taking the case of the 
large submarine having a great radius of action, it is 
impossible to make a long passage such as an incursion 
into the Atlantic from the Heligoland Bight round Cape 
Wrath, without steaming on the surface for a consider- 



able proportion of the distance. Under these conditions, 
once located by an efficient air scout service, it will be 
tracked from day to day if need be, and, sooner or 
later, either by aircraft or destroyer, it will be brought 
to book. It is not suggested that under no circum- 
stances could a submarine escape, it would, however, 
only do so by radically altering its course or by some 
other manoeuvre involving the temporary abandonment 
of its purpose ; ultimately the influence of aircraft on 
the high seas will be to keep the submarine submerged, 
under which condition its radius of action is greatly 
circumscribed. Thus persecuted, it will be reduced to 
surface running by night, and even then, unless favoured 
by the elements, will be liable to attack by fast light 
cruisers or destroyers which will be informed with con- 
siderable exactitude as to the whereabouts of their quarry. 

Beyond the above, a submarine or submarines tracked 
by aircraft will have great difficulty in keeping a pre- 
arranged rendezvous, and any "neutral" vessel or fishing 
craft used for fuel supply and revictualling will be far 
more liable to detection than is at present the case. 

The author believes that it is by continuous pressure 
of this kind, backed up bj'^ direct attack when occasion 
serves, that submarine activity will eventually be curbed. 
It has already been pointed out that the capacity of 
aircraft to warn merchantmen of danger will alone be 
sufficient to render the submarine threat quite inefifec- 
tive, apart from any question of destroying the craft 

Such work as contemplated can only be effectively 
performed by aircraft if sufficiently numerous, operating 
in units of flights or squadrons. It will be found com- 
paratively useless to endeavour to carry out the duties 
in question by single machines, since it will often be 
necessary to sweep considerable areas of the ocean in 



order to pick up the trail or get on the track of a 
submarine that has been temporarily lost. It is thus only 
when the number of machines and the organisation 
is sufficiently developed that the power of aircraft as 
controlling submarine activity will be fully realised. 

§ 119. The Strategic Employment of Aircraft on a 
Large Scale. It is becoming more and more clear as time 
goes by that the future of Aircraft in Warfare is a subject 
of such vast potentiality that we may to-day consider our- 
selves only on the outer fringe of developments destined 
ultimately to carry us far beyond anything yet conceived. 
We are at present only on the threshold of a revolution 
which aircraft will ultimately bring about in the conduct 
of warfare. 

Thus, in the existing phase of the present war, were 
our aircraft of sufficient numerical strength, it would no 
longer be a matter of individual and isolated raids on 
selected places at which the maximum of injury could be 
inflicted, but rather a continuous and unrelenting attack on 
each and every point of strategic importance. Depots of 
every kind in the rear of the enemy's lines would cease to 
exist; rolling stock and mechanical transport would be des- 
troyed; no bridge would be allowed to stand for 24 hours ; 
railway junctions would be subject to continuous bombard- 
ment, and the lines of railway and roads themselves broken 
up daily by giant bombs to such an extent as to baffle all 
attempts to maintain or restore communication. 

In this manner a virtually impassable zone would be 
created in the rear of the enemy's defences, a zone vary- 
ing, perhaps, from 100 to 200 miles in width. Once this 
condition has been brought about, the position of the 
defending force must be considered as precarious ; not 
only will the defence be slowly strangled from the 
uncertainty and lack of supplies of all kinds, but ulti- 
mately retreat will become impossible. The defending 



force will find itself literally in a state of siege under 
the worst possible conditions, for the position will be one 
in the form of an extended line along which the forces of 
all arms will be definitely immobilised, for the lateral 
communications will suffer no less than the lines from 
the rear. Such a position of affairs presents all the 
elements conducive to complete and irreparable disaster. 

Thus, in the extended employment of aircraft, we 
have the means at hand of compelling a bloodless victory; 
for, once admit the truth of the present conclusions, the 
serious and comprehensive threatening of the communi- 
cations of the enemy by aircraft on the lines indicated 
can only be answered by his retirement. If he neglects to 
take this step until too late, he pays the penalty in anni- 
hilation or surrender; the matter thus stated becomes one 
involving the ordinary logic of military necessity. 

The magnitude of the aeronautical forces and estab- 
lishment necessary to effect the present purpose must not 
be under-estimated. In order to prove a decisive factor 
the devastated zone will need to be of very great area, a 
belt of from 50 to 100 miles in width probably represents 
the minimum, and the destruction wrought over the said 
zone must be complete and thorough in every important 
respect. The accomplishment, however, is commensurate 
with the magnitude of the means, for an operation on 
the scale stated must be met by the enemy by a with- 
drawal of corresponding magnitude ; no ordinary retreat 
of a few miles to a second line of defence can avail him. 
From the time his aircraft and air defences are over- 
powered and his communications placed in jeopardy, he 
must prepare to fall back on new lines established beyond 
the zone of devastation, that is to say, if the work is 
effectively done his retirement can be but little short 
of 50 or 100 miles. In the present war, this would 
mean virtually the evacuation and abandonment of the 



whole of the allied territory at present occupied in 
Flanders and in the North and West of France. Once 
the captured territory has been organised and the neces- 
sary preparations have been made, the attack would be 
repeated, and, presuming the continued supremacy of 
our air fleets, no resistance or defence by the enemy of a 
permanent character can be sustained. 




§ 120. National Defence. Air Raids- In considering 
the more far-reaching ejffects of iVircraft in Warfare, it is 
more than ever necessar}' that we should substitute in 
our minds for what we may see to-day, a picture of what 
may reasonabl}" be expected in the not very distant future. 
Thus from the military standpoint and even from the 
standpoint of the Nation, the effect of the raids by German 
aircraft has been a negligible quantity ; it has moreover 
cost the enemy no small expenditure of energy (which he 
can ill afford to squander) to effect this relatively micro- 
scopic injury. Tersely put, air-raids on Great Britain by 
Zeppelin do not pay. We have no reason, however, to 
assume that this condition of affairs will last ; on the 
contrary, we must make provision against future possi- 
bilities, when air-raids will be conducted in so effective a 
manner that, if not successfully opposed and beaten back, 
they will pay. 

§ 121. The Defence of London. A broad question 
at once arises : will it be possible in the future to entirely 
and effectively defend from aerial attack a city of the size 
of London situated within so short a distance of the 
enemy's frontiers ? For the purposes of the proposition 
we must assume the whole of the continental coastline as 
hostile territory; on this basis the distance is no more 
than one hour's flight. 



There is uo doubt that so long as the weather con- 
ditions are favourable to defence, anything in the nature 
of a daylight attack on London could be rendered im- 
possible by a sufi&cient defending force of aeroplanes, but 
here even, in the event of an attack in great force, it is by 
no means certain that some measure of success might not 
be achieved ; it would at least require an immense pre- 
ponderance of power, if every hostile aeroplane is to be 
beaten back or otherwise accounted for. 

When, however, the weather conditions are favour- 
able to attack, also in the case of attack by night, there 
is no means of defence at present known to the author 
which w'ould prevent the enemy from inflicting enormous 
damage if he attack in sufficient numerical force and is 
prepared to act with determination in spite of an}'' losses 
he may sustain; no reasonable superiority in the defend- 
ing aircraft, either individually or numerically, can be 
entirely effective. Neither can we pin our faith to 
counter-aircraft artillery ; under the conditions in question 
it may prove to be useless. 

We have so far not witnessed an attack by aircraft on 
an important city on a grand scale, such as, without doubt, 
the future has in store. The " raids " which have hither- 
to been carried out are quite trivial and ineffective affairs 
compared with what in due course will become possible. 
The critical point, and the point to be aimed at as an act 
of war, is that at which the fire-extinguishing appliances 
of the community are beaten or overcome. Up to this 
point the damage done may be taken as roughly propor- 
tional to the means and cost of its accomplishment; 
beyond that point the damage is disproportionately great : 
the city may be destroyed in toto. 

There will always be the sentimentalist who has 
implicit faith (in spite of experience) in the omnipotence 
of peace conferences and the like and the unalienable 



rights of humanity, who will decline to believe that after 
the present war Nation will need to defend itself against 
Nation by brute force. To these the destruction of a city 
of 5,000,000 peaceable inhabitants by fire with the scenes 
of horror that would inevitably ensue, will be looked upon 
as the figment of a diseased imagination, to these the 
author does not address himself ;* he regards the possi- 
bility as one which it behoves us to consider and meet as 
a matter of ordinary military precaution, not regarding it 
as any more improbable or unexpected than any other 
hostile act of which an enemy might be capable. 

§ 122. Justification for Attack upon Capital City. 
It is futile to attempt to disguise the self-evident fact 
that a serious attack on the capital city of an enemy, con- 
taining in its heart the administrative centre both of 
his Army and Navy, in addition to the headquarters of 
his Government, cannot be regarded other than as a 
legitimate act of warfare. No international agreement 
or convention can make it otherwise. Once war is 
declared the successful waging of war becomes the first 
duty of a belligerent Government, it obviously cannot do 
or countenance any act, or the neglect of any act, which 
could by any possibility compromise the issue, without 
thereby proving false to its trust. There is really no 
escape from this. Unquestionably, the destruction of a 
capital city such as London, with the administrative 
centres aforesaid, would be a military achievement of the 
first order of magnitude ; it would be, from an enemy 
standpoint, an achievement of far greater potential value 
than any ordinary success or victory in the field of battle. 

We may then disabuse our minds of the popular 
notion that the raiding or attacking of London by air- 
craft is to be regarded as something contrary to the 

•A certain cynic once defined a fool as a man who could only learn by 
experience. The author prefers the more benevolent definition that a fool is one to 
whom the teaching of experience is of no avail. 



established ethics of warfare ; we recognise that we are, in 
the protection of our capital, face to face with a necessary 
problem of national defence of the first magnitude. Let 
us admit that, given a determined enemy in the posses- 
sion of the French and Belgian littoral, the problem in 
future will be increasingly difficult. Let us go further, 
and, for the purpose of argument, assume that it may be- 
come impossible. We have no assurance in all the cir- 
cumstances that this is not the truth. What then will be 
the measures by which the new situation can be met ? It 
is wholesome to consider the position on this basis. 

§ 123. The Incentive to Attack. The Real Source 
of Weakness. It is evident that if the administrative 
headquarters of the Army and Navy were removed to some 
less accessible position, and in fact if London were to 
cease to be the centre of Government, the main incen- 
tire to attack, as a military operation, would be destroyed, 
and the danger in question disposed of. Obviously 
London as a city would be no less vulnerable than before, 
and it would be open to be wantonly raided unless 
adequate means of defence were provided. Measures of 
defence, however, to be effective have always to be propor- 
tioned to the incentive to attack, and to reduce the incentive 
to a minimum is to make the most of such means of pro- 
tection as are available. Putting this in other words, we 
have it that the enemj^ would not be prepared to pay so 
high a price or take the same risks for the privilege of 
destroying private property and murdering civilians, as 
he would if. he were able at the same stroke to disorganize 
the whole administrative machinery of the State. Also, 
so long as any act of aggression has admittedly no 
military value, it may be answered by appropriate 

• A reprisal to be effective must be delivered with promptitude like the riposte of 
a skilled fencer. A reprisal which is too long delayed possesses no moral weight 
and has every appearance of an independent act of aggression ; it may even plausibly 

193 o 


The possible need for abandoning the present capital 
as the centre of administration in wartime carries with it 
as a corollary its abandonment equally in time of peace, 
at least so far as the control of the Army and Navy is 
concerned ; since, on the declaration of war, or even 
without a formal declaration, the aircraft of the enemy may 
already be mobilised for an attack. Of course our 
premises are hypothetical, we have no proof yet that the 
adequate defence of London from hostile aircraft will 
actually become impossible, but equally it is clear that 
the contingency may have to be faced, and therefore 
it is one that must be taken seriously. 

§ 124. The Question of Fire Risk. Apart from 
the active defence provided by a numerically strong and 
vigilant air fleet, the most important factor in the protec- 
tion of a city from hostile aircraft is to be sought in the 
prevention of fire. Thus a city in which fire-proof or 
fire-resisting construction is extensively employed, and in 
which a town-planning scheme has been adopted with a 
view to the localisation of any conflagration that may get 
out of hand, will be far safer and more easily defended 
than one in which these precautions are not taken. It 
goes without saying that all the usual appliances for 
dealing with the outbreak of fire should be liberally pro- 
vided in any case. The greater and more thorough the 
precautions, the less probability will there be of the 
enemy attack being successful, and the larger the scale 
on which it will have to be conducted to have any hope of 
success; conversely the easier will be rendered the effective 
defence. It is to be understood that the word success as 
here used is measured by whether or no the extent of 

be given as an excuse for a subsequent repetition of the original oflFence. It is thus 
detrimental to the cause of humanity to tie the hands of a belligerent by inter- 
national convention. Such conventions result in delays whilst law oflScers are 
consulted and whilst committees are called and decisions are reached ; also they 
result in no preparations being made for counter measures such as comprehended by 
the word reprisal. The power of reprisal and the knowledge that the means of 
reprisal exists will ever be a far greater deterrent than any paeudo-legal document. 



«[irect injury is sufficient to cause a general conflagration, 
as already laid down. 

§ 125. The Question of Radius of Action. A point 
of great importance in the present connection is the 
radius of action of the aircraft by which attacks such as 
under discussion will be carried out. Evidently it is the 
aeroplane or flying machine which chiefly concerns us, 
and due allowance for possible improvement over existing 
performance must be admitted. 

When we are discussing the range or radius of 
action of a battleship or cruiser we are dealing with some- 
thing definite, such vessel can either reach a given des- 
tination with its power of aggression unimpaired, or it 
cannot get there at all ; not so with the aeroplane. In 
the aeroplane the power of aggression and the range 
•r radius of action are alternative quantities, which, 
measured by the weight of bombs and the weight of fuel 
(*'.«., petrol) respectively, represent a definite amount in 
sum. Thus if one-third of the maximum gross weight of 
the machine be taken to represent its combined petrol 
and bomb capacity, the maximum distance which can be 
flown by an aeroplane is about 1,200 miles, or 600 out 
and home, if the whole of the said capacity be devoted 
to petrol. When part of the capacity is devoted to the 
carrying of bombs the range of flight is proportionately 
lowered, so that the position of affairs may be represented 
as in Fig. 20, in which it will be seen that as the range of 
flight is increased the value of the machine for the 
purposes of attack is diminished till at a maximum out- 
and-home radius of 600 miles it falls to zero: the machine 
has ceased to be capable of offence. 

It is not only in its power of offence that the long- 
distance aeroplane is at a military disadvantage ; it is so 
in respect of all other attributes which are involved in the 
problem of weight. For example, any machine built 



expressly for long distance raiding, will be essentially 
a relatively slow machine, since speed means engine 
weight ; it must be, comparatively speaking, a relatively 
poor climber for the same reason. Again, it cannot 
afford to carry shield or armour, neither can weight be 
spared for a defensive gun armament. All these facts 
mean that as the distance to be raided becomes greater, 
defence will become more and more easy, and point to 
the conclusion that in actual warfare the maximum 
distance which can be effectively raided by aeroplane 
will be far less than the theoretical maximum aforesaid. 
Beyond this the opportunities for defensive counter 



'500 MILE& 

measures become greater, and the possibility of taking 
advantage of favourable weather conditions less, the 
greater the distance involved in the raid. Taking every- 
thing into account, the author thinks it improbable that 
raids over territory held by an enemy exceeding 300 
orl'400 miles will be found practicable, and in the face 
of opposition it would be rare for an attempt of this 
magnitude to succeed unless conducted by a force of 
overwhelming numerical strength. 

§ 126. The Danger to Aircraft Factories and 
Production. There is a further point in respect of which 
the position of aircraft is without exact parallel in the 
other arms of the Services ; in a war of any magnitude 
or duration the manufacture during the period of hos- 



tilities is vital to the maintenance of the Arm at its 
initial strength, and the manufacture is itself threatened 
if the enemy once obtain, aeronautically, the upper hand. 
Thus the life of an aeroplane in active service is a 
matter of only some three or four months, and the 
manufacturing resources of the country must thus be 
capable of replacing the whole active force of aeroplanes 
three or four times over in every year. On the other 
hand, our sources of supply, or those situated within 
raiding distance of hostile territory, would be seriously 
imperilled were the enemy to obtain, even for a short 
time, a sufficient preponderance of air power. The 
intention of thus making use of aeronautical ascendency 
to extinguish the enemy's sources of supply has been 
clearly manifested in the present war, as witness the 
raids executed against Friedrichshaven and other Zep- 
pelin bases ; the reason that such tactics have not been 
pushed to the extreme and followed to their logical con- 
clusion is clearly that the raiding aeroplane, in respect of 
type, numerical strength, and organisation, is yet in its 

For the above reason it is the author's opinion that 
the main aeronautical manufacturing resources of any 
country will eventually be established out of effective 
reach of hostile territory ; in the case of Great Britain 
this indicates the selection of a position some three or 
four hundred miles from the continental littoral. The 
circumstances point ultimately to the industrial districts 
of Belfast and the Clyde, as appropriate centres for the 
production of both aeroplanes and so-called " seaplanes " 
in the quantities the future will demand. Such a position 
is out of range of existing hostile aircraft, and will probably 
remain so for many years to come. Looking beyond this 
it is a position giving such great possibilities of defence, 
that so long as we assume the motive power engine subject 



to its known restrictions as a form of heat engine, it may be 
regarded as safe for all time. The position of Belfast is such 
that, even if we assume the whole Netherlands, Belgium 
and the French littoral to be in the hands of an enemy, 
the distance to be flown is approximately 400 miles,* 
during almost the whole of which distance enemy air- 
craft will have to run the gauntlet of our air defence, both 
aeroplane and counter aircraft artillery. 

§ 127. Comparison with Navy. It is true that the 
Aeronautical Arm is not alone in requiring manufactur- 
ing facilities during the period of hostilities, and in being 
liable to the dislocation of these facilities hy its own kind. 
The same is true, but in far less degree, of the Navy; in 
the latter these facilities (in the form of our Naval building 
yards and dockyards) are quite essential to the proper 
upkeep of the Fleet, although the amount of new con- 
struction (in comparison with aircraft) is relatively small. 
It is nevertheless regarded by the Naval authorities as 
essential that our dockyards, etc., shall be so placed as to 
be capable of effective defence against naval raids, and 
any situation which cannot be made to comply with this 
condition has sooner or later to be abandoned, or at least 
new bases have to be created to take over its more 
important functions. The position of the Aeronautical 
Arm, however, is unique in the relatively great impor- 
tance of the daily output of new machines, and in the 
relative ease with which this may be interfered with by 
enemy enterprise if due precautions are not taken. Thus 
the present recommendation may be regarded as the 
extension of a principle, admitted in the selection for 
the site of a ship-building yard or dockyard, to the choice 
of a headquarters for aeronautical construction. 

It is extremely doubtful whether we shall witness 

• Compare Appendix 11. In the present war the position is far more favourable ; 
the Midlands and West of England are reasonably safe from attack. 



during the present war raids extending to anything 
approaching 300 or 400 miles out and home over enemy 
territory, so that the recommendation suggested above is 
probably more drastic than necessitated by present con- 
ditions; however, all depends upon the duration of the 
war, the technical difficulties in the way of the production 
of suitable machines can be surmounted at any time with- 
out great difficulty. Beyond this there is no reason to 
suppose that during the present war the French littoral 
will be in other than friendly hands, whereas in the fore- 
going discussion the broader basis has been assumed, 
namely, that all territory not actually British must be 
considered as potentially hostile. 

§ 128. Air Raids mid the Naval Outlook. The 
possibility of air raids on a large scale on the Naval out- 
look will certainly be far-reaching in its effects. All dep6ts, 
dockyards, etc., within easy range of alien territory, such 
as those situated on our southern coast, can no longer be 
regarded as secure from bombardment; the defence of 
such places as Portsmouth and Devonport from attack by 
air may prove an almost if not quite impossible proposition ; 
the weather conditions may be such as to let the enemy 
through even in face of a numerically superior defensive 
force. Thus it may be confidently anticipated that these 
southern depots will become points of subsidiary import- 
ance, useful enough in times of European peace, but 
forming no really essential part of the scheme of National 
defence in the event of a great European war. The 
*' centre of gravity " of the bases on which the Navy will 
rely for its support is bound to move northward and still 
further north as the power of the aeronautical Arm is 
uncoiled, and eventually the strategic centre of our 
defences, both Naval and Aeronautical, will perforce be 
located in the region of the Irish Sea and North Channel; 
it will then be in the neighbourhood of Belfast on the one 



hand and the Clyde on the other, that our main Naval 
building yards, dockyards and important depots will be 
established, and our largest and most important aircraft 
factories will be installed. 

If the above conclusions are sound it may be found 
necessary, for reasons of Naval strategy, to cut a ship 
canal through from the Clyde to the river Forth. This 
would be an engineering feat of considerable magnitude, 
involving, besides the actual cutting itself, the deepening 
of the Clyde for a distance of some 12 or more miles 
between Clydebank and Greenock, in addition to extensive 
dredging of the River Forth. The existing Forth and 
Clyde Canal is an ordinary inland navigation, with 
numerous locks, fit only for lighters or barges of length 
not exceeding 68 feet. The height of the " divide " is 
about 160 feet. 

A real ship canal for the purpose intended — to be 
navigable by the largest of our battleships — would be an 
undertaking of the same order of magnitude as the 
Kaiser Wilhelm or Kiel Canal, and we may assume would 
involve an expenditure probably not less than forty 
millions sterling. Such a canal would bring the Naval 
base at Rosyth within a few hours steaming of the Clyde, 
or roughly within twelve hours of Belfast Lough. 

§ 129. Aeronautical and Naval Defence indisso- 
lubly associated. It is evident that the whole scheme 
for aeronautical defence must and will be closely related 
to the distribution of our Naval bases. In fact it is our 
Navy and defensive aircraft which henceforward will 
jointly constitute Britain's first line of defence. It is for 
this reason that the control of our defending air forces 
falls naturally to the Admiralty rather than the War Office. 
The most important objectives of an enemy air-raid, 
apart from attack on our centre of government, will be 
without doubt our Battle Squadrons, our Naval bases and 



dockyards, and our aircraft and shipping centres, for it is 
here that, apart from any question of invasion, Great 
Britain is most vulnerable. The problem of giving 
adequate protection to these is manifestly a work which 
only the Admiralty is competent to undertake. As 
already pointed out there are geographic positions which 
in no way lend themselves to aeronautical defence, it will 
be incumbent upon the Naval Authorities to determine 
when and under what conditions these will need to be 
abandoned. Generally speaking, a point can only be 
defended from hostile aircraft when its approach neces- 
sitates a considerable length of flight over British terri- 
tory. Alternatively a point may also be considered 
defendable if the total distance from hostile territory is 
sufficient, provided that the intervening sea is effectively 
patrolled ; thus again the intimate relation of aeronautical 
to naval defence becomes manifest. 

§ 130. The Future of the Aeronautical Arm a 
National Question. It is more than probable that before 
the termination of the present war we may witness and 
experience aerial raids on a scale immeasurably greater 
than anything so far attempted, either by the enemy or 
by our own airmen ; it is also probable that the strategic 
employment of the aeronautical Arm on the lines laid 
down in the preceding chapter (§ 119) will become 2. fait 
accompli. The extent of realisation depends upon the 
duration of the war and the numerical strength of the air- 
fleets which will become available before the conclusion of 
hostilities. , 

In the author's opinion it is vitally necessary, both 
with a view to ensuring speedy victory and to our future 
as a nation, that our manufacturing resources in the pro- 
duction of aircraft should be developed to the utmost; 
aeroplanes and still more aeroplanes will be needed, aero- 
planes in the maximum possible quantities of every useful 



type, whether reconnaissance, bomb-dropping, or fighting 
machines ; our total present capacity for production is 
petty in comparison with what we have evidence the 
future will demand. 

The question of the future of the Aeronautical Arm 
is not purely the concern of the Army and Navy, it cuts 
deeper; it is essentially an affair of the Nation. It is 
national because it concerns both Services. It is national 
because it is of wider and more far-reaching moment 
than comprised by its relation to either. It is national 
because it depends upon our national industrial resources, 
and may tax these to the uttermost ; national because it is 
the Arm of greatest potential development in the present 
war, and in future warfare may decide the fate of Nations. 
Finally, it is national because it is the Arm which will 
have to be ever ready, ever mobilised, both in time of 
peace and war : it is the Arm which in the warfare of the 
future may act with decisive effect within a few hours of 
the outbreak of hostilities. 

§131. In Conclusion. That we have temporarily the 
upper hand in military aeronautics there is no doubt, but 
this is due more to our technical prescience than to the scale 
or magnitude of our national preparedness. In other words, 
our present lead is only in part due to our own effort, it is 
largely due to the mistake made by the enemy prior to the 
war in devoting altogether disproportionate attention to 
the large dirigibles : Germany backed the wrong horse. 
The Zeppelin, from the military standpoint, has proved a 
complete failure. If the resources thus diverted into 
a useless channel had been devoted to the development of 
the aeroplane and strengthening of the enemy flying 
corps, the position from our point of view might have 
been nowise so satisfactory. Having been thus favoured 
with the advantage by what may almost be regarded as a 



" chance of war," we must make up our minds to maintain 
it by any and every means in our power. 

Let us not delude ourselves by supposing that the 
enemy will be content to allow us to retain our advantage 
without a keenly contested struggle ; he is probably ere 
this fully alive to his past mistake, and will strain every 
nerve to rectify matters ; there is already evidence of 
strenuous effort in that direction. The chief factor in the 
coming contest in aeronautical armament will undoubtedly 
prove to be the relative manufacturing resources available 
respectively to the two belligerent groups ; here Great 
Britain and her Allies have an undoubted advantage. 

In concluding the present work, the author claims 
that a clear case has been made out for an immediate and 
thoroughgoing overhaul of our programme and adminis- 
tration as touching the future of, the Aeronautical Arm, 
and to this end urges for immediate consideration the 
following : — 

(1) That in view of the potentialities of the Aero- 
nautical Arm, a comprehensive scheme of construction 
should be forthwith prepared, in which provision shall be 
made for organizing, utilizing, and developing every 
available source of manufacture and supply. 

(2) That if possible certain of our present types of 
aeroplane be virtually adopted " for the duration of the 
war," and existing manufacturing facilities should be 
utilised for their uninterrupted production to the utmost 
of their capacity.* 

(3) That where it is decided that new types are 
required, new sources of production should so far as 
possible be tapped or new works equipped, in order that 

• A given type of aeroplane may not be the best we know how to make, but the 
same may be said of our small arms, or our field pieces ; it does its work, however, 
and is understood by the men who handle it in the field : these are points worth a 
great deal. It is not realised by those who are not intimately connected with manu- 
mcture the extent to which alterations or improvements during quantity manufacture 
are detrimental to output ; especially is this the case when working at high pressure. 
Fixity of design should be looked upon as a sine qua non once manufacture has been 
embarked upou. 



output should not be made to suffer. In other words, the 
policy should tend in the direction of establishing each 
new type with the factory for its production as a complete 

(4) That more adequate provision be made for the 
development of improved models and new types, both as 
regards initial manufacturing facilities and finance. 

(5) That a Board of Aeronautical Construction* be 
formed on the lines adumbrated in the present work, to 
deal with the needs of the Services and to settle specifica- 
tions and approve the designs for new types, and gener- 
ally to assume control and responsibility for our National 
Aeronautical Programme, both as to sufficiency and 

• Under the Presidency of a responsible Minister. 




The Lewis Machine Gun* has features which render 
it especially suitable for employment as an aeroplane arm. 
These are in brief : — 

The absence of water jacket. 

The lightness obtained by the adoption of pres- 
sure in place of recoil actuation. 

The self-contained magazine. 
The abandonment of the water jacket is effected by 
resort to direct air cooling, a gilled jacket being applied to 
the barrel ; the problem is closely analagous to that of the 
air cooled petrol motor. In aeronautical fighting a 
machine gun is never required to work continuously for 
any length of time, and the problem under these condi- 
tions presents no difficulty : in other fields of usefulness 
the reverse is the case, and calculations given later in the 
present appendix give some idea of the real difficulty of 
the problem, the solution of which has been achieved by 
the inventor of this weapon. 

The advantage of pressure actuation in place of recoil 
actuation lies in the fact that if the former be adopted 
the total weight of the weapon can be designed to the 
minimum possible, whereas in a recoil actuated gun the 
mass of the portion which acts as " abutment " to the 
recoil mechanism has to be far greater than considerations 
of strength alone would warrant : thus the total weight is 

*For description see "Engineering," November 8th, 1912. 


1pp. I. APPENDIX. 

greater in the older recoil actuated gun than in the 
Lewis t5rpe. 

The importance of the self-contained magazine in a 
weapon to be handled from aircraft is obvious, and is so 
great as to make this feature almost a sine qua non. In 
the Lewis Gun each magazine contains 47 rounds, and 
can be replaced with but a few seconds pause in the dis- 
charge of the weapon. The resulting "breaks" in the 
continuity of discharge do not seriously affect the value of 
the arm in general usage, and in aeroplane fighting they 
count for nothing. The advantage, on the other hand, of 
a gun with no " appendages," which can be directed 
upward or downward or to any point of the compass at 
will, is one of real and decisive value. 

The Problem of Direct A ir Cooling. A Study of the 
Lewis System. Some Approxim^ate Figures. The cool- 
ing of the barrel of a machine gun by air in place of the 
more usual water jacket is a problem of no mean difficulty. 
It is not ordinarily realised how great is the output of a 
machine gun in continuous firing expressed in horse 
power. Thus in the case of the M.VI service ammunition 
the muzzle energy is 2,000 ft. lbs.,* and the power repre- 
sented by the energy of the stream of projectiles is 
approximately 0'06 horse power per shot per minute. At 
a maximum rate of fire of 800 per minute this gives 
48 h.p. or at a normal speed of fire — say 480 per minute — 
29 h.p. The problem of air cooling a machine gun then, 
is comparable to that of air cooling an internal combustion 
engine, of roughly 50 b.h.p., approximately the power of 
an aeronautical motor such as until recently in general 

The comparison with an ordinary petrol motor is 
closer than might be supposed, since the energy and heat 
account, in the rifle barrel and the motor cylinder respec- 

* M. VII ammunition is higher. 


lively, is almost identical, in spite of the diversity of the 
conditions. Thus the thermal efficiency in the region of 
25%, in other words, about one quarter of the heat energy 
of the fuel on the one hand, or explosive on the other, is 
converted into mechanical work.* 

Now we know how formidable is the difficulty of air 
cooling in the case of the petrol motor ; the difficulty in 
the machine gun is augmented by the fact that the sur- 
face of the barrel on which to attach the cooling fins or 
gills is only about half a square foot, as compared with say 
two or three square feet or more in the petrol motor of 
equivalent output. On the other hand the condition as to 
temperature is not so exacting in the case of the gun 
barrel, and the degree of durability demanded is incom- 
parably less. 

The approximate energy account of the service rifle 
and ammunition is as follows : — 

Kinetic energy of bullet .... .... 28% 

Friction as heat imparted to bullet 5% 

„ „ „ ,, „ barrel 5% 

Heat directly imparted to barrel.... 25% 

Kinetic and heat energy of " ex- 
haust " powder gases .... .... 37% 

Total barrel 
heat 30%. 


Thus thirty per cent, of the total heat equivalent of 
the charge is imparted to the barrel and has to be 
dispersed by the cooling means employed. The actual 
heat equivalent of the service charge is approximately 
7,000 ft. pounds, therefore the barrel heat per charge 
represents 2,100 ft. pounds, and taking the ordinary 
maximum rate of continuous fire as 600 per minute — 
10 per sec. — we have 21,000 ft. pounds per sec. as the 

* Compare § 58. 


equivalent rate of heat loss ; this may otherwise be 
expressed as 

37 Fah. H.U. per sec. 
or 15 Centigrade H.U. per sec. 

or 6,600 (gram) calories per sec. 

or 38 horse power. 

Now, the actual form taken by the Cooling surface 
in the Lewis Gun is that of a number of radial gills of 
aluminium, whose aggregate surface is approximately 


6 sq. ft., hence we have to dispose of the equivalent of -^ 

or, say, 6 h.p. per square foot. 

Following the method laid down in the author's 
recent " James Forrest " Lecture, the above betokens 
both a very considerable temperature difference and a 
high velocity of air over the cooling gills ; the product of 
these (deg. Fah.) being 84,000. Thus the temperature is 
currently given (under the conditions in question) as 
about 440 deg. Fahrenheit, which means a temperature 
difference of 400 deg. Fahrenheit ; this corresponds to a 
velocity of the air through the jacket, say, 200 ft. per 
second, in order that the heat shall be disposed of with 
sufficient rapidity by the surface of the gills. 

This appears unexpectedly high, but there are two 
ways in which the figure may be checked. Firstly, it is 
clearly necessary that the total mass of air passing shall 
be adequate, and more than adequate, to carry off the 
waste heat ; in other words, the air entering the jacket at 
the one end at atmospheric temperature must be able to 
absorb the whole of the waste heat before leaving the 
jacket, and this without its temperature being raised to 
such an extent as to prevent its being active as a cooling 
agent. Secondly, we may compare the calculated resis- 
tance of the jacket to the passage of air, with the known 
recoil as due to the powder gases ; since the former is 



overcome by the momentum of the latter, it is manifest 
that the jacket resistance can never exceed the mean 
recoil force as due to the gases : thus we have a limit to 
the possible velocity of the air blast. 

As to the first of these, we have the combined area 
«f the air passages, about 5 square inches, or volume per 

o.^^ r J 200 X 5 ^ , . ^ 

second at 200 rt. per second = — tjj — = 7 cubic rt. = 

0"54 lbs., equivalent in heat capacity to 0'13 lbs. of water. 

Now, the heat units to be taken up = 27, hence the air 

will be increased in temperature Tyy^ = 208 Fahrenheit. 

This result is concordant. Evidently no velocity much 
less than 200 ft. a second will pass the volume 

Next as to the recoil calculation. If we take the 
resistance of the jacket as calculable on the basis of skin- 
friction we may fairly assume the single surface co- 
efficient as '005, and at 200 ft. per second this gives 
0*3 lbs. per square foot, or, on a total surface of 6 square 
feet, the resistance is 1*8 lbs.; this is the mean force 
which must be applied by the exhaust blast of the powder 
gases to maintain an air current of 200 ft. per second 

It has been established by experiment that the mean 
recoil as due to the powder gases in the service cartridge 
is 0'28 that of the projectile ; now the latter already 
calculated ainounts to 2 lbs. per shot per second, or 20 lbs. 
at 10 shots per second. Thus the mean force due to the 
momentum of the powder gases is '028 x 20 = 5'6 lbs. 
But the air leaving the jacket muzzle retains approxi- 
mately its mean velocity, and this represents by its 
momentum a force of 0*54 x 200/32*2 = 3*35 lbs., so the 
account becomes : 

209 P 

1pp. I. APPENDIX. 



Recoil due to pow- 

Resistance of 

der gases 

5-6 lbs. 

jacket ... ... 1*8 lbs. 

Efflux momentum 

of air 3'351bs. 

Total 5-15 lbs. 

Credit Balance .... '45 lbs. 

5-6 lbs. 5'6 lbs. 

There is, consequently, nothing inconsistent in the 
velocity of 200 ft. per second, though the margin of 
driving force as due to the momentum of the powder 
gases seems narrow. It is to be remembered, however, 
that the figure taken for the gas momentum is based on 
experiments made with the ordinary service rifle ; it is 
without doubt considerably augmented by the special 
nozzle with which the barrel of the Lewis Gun is fitted, 
so that in reality there should be an ample margin. 

It is worthy of note that the work done by the blast 
represents approximately 2 horse power, and the actual 
work done against the skin-friction on the gilled surface 
is about two-thirds of a horse power ; an appreciable and 
valuable return for so simple an expedient as the muzzle 

Summarising the foregoing, we have, under con- 
ditions firing, at 600 rounds per minute : — 

1. The mean velocity of the induced air current 
in the cooling jacket is approximately 200 feet per 

2. The temperature difference has a mean value 
of about 420 degrees Fah., that is to say the ordinary 
temperature of the gills is in the region of 500 Fah. 

3. The momentum represented by the exhaust 
powder gases is a measure of the force available for 



impelling the induced air current, and is consistent 

with the above. 

In any actual measurements the jacket temperature 
recorded will depend very much upon where the bulb of 
the thermometer is placed, for there is a very steep 
temperature gradient from the surface of the bore of the 
barrel outward. Rough calculation shows that there must 
be a difference of about 200 degrees Fah. between the 
inner and outer surfaces of the barrel alone, apart from 
the difference in the gills themselves ; thus it is impro- 
bable that the temperature of the rifled surface of the 
barrel when the gun is in continuous usage can be less 
than 700 Fah., but this does not seem to have any marked 
effect on its durability. Bven in the case of a water 
cooled gun, when the water is on the boil, the internal 
temperature of the barrel at a high rate of fire is probably 
not less than 400 Fah. 

The aggregate sectional area of the aluminium gills 
taken normal to the radius is approximately 250 sq. c. m., 
and the quantity of heat being 6,600 gram calories, we 
have the mean temperature gradient about 52 deg. C. per 
centimetre,* or 240 Fah. per inch (measured radially) : 
this means a difference between the root of the gills and 
the outer casing of roughly 300 Fah. Hence the total 
difference of temperature between the outer casing and 
the rifling, under conditions of continuous fire, will be 
about 500 Fah. This is quite sufficient to give rise to 
uncertainty when jacket temperature is under discussion; 
the portion of the jacket must be specified. 

* The conductivity of aluminium has been taken at 0-5 in C.G.S. Units ; this is a 
fair average value. It is on the safe side. 



The discussion of tlie radius of action of aeroplanes 
presented in § 125 and 126, and as affecting the Naval 
outlook in § 128, may be helpfully illuminated by the 
aiccompanying sketch map (Fig. 21). 

This map gives in outline the British Isles and the 
nearest adjacent portions of the Continental littoral ; a 
few towns and places, important from the present stand- 
point, are indicated by their initial letters (block capitals) 
from which there will be no difficulty in identification. 

Positions have been chosen on salient points of the 
Continental coast, and indicated by circles identified by 
numerals, thus : — 

Cherbourg is denoted by .... 1 

The region of Calais ,, .... 2 

North Holland or Texel ,, .... 3 

Heligoland „ .... 4 

Stav anger (Norway) ,, .... 5 

From the above points as centres, arcs of circles 
hare been struck of 400 miles radius, as indicating the 
probable extreme radius or limit of raid by aeroplane. It 
is to be understood that raids by aeroplane at so great a 
radius in the face of reasonably good defensive measures 
will rarely be pushed home, and still more rarely success- 
ful. We may take it that any point or place in or beyond 
this radius is to be regarded as out of the effective reach 
of the enemy, and points 50 or 100 miles within this as 
reasonably safe. Thus, referring to the figure, station 5 
may be ignored as not seriously threatening any point of 
importance not otherwise imperilled. The only station 



App. II. 

which brings any portion of Ireland within danger is 
number 1, that is to say, the French coast from Cher- 
bourg westward. Under all conditions the region of the 
North Channel, including Belfast and the Clyde, and 
extending as far as the Naval Station at Rosyth (R on 
the map) may be taken as out of range. 

Fig. 21. 

In addition to the above, the nearest point situated 
on the German frontier, taken to be Dusseldorf (D), has 
also been considered a centre of danger, and an arc of 
400 miles inscribed. This brings such important centres 
as Newcastle, Liverpool and Manchester, Bristol and 
Weymouth, almost, but probably not as an actual fact 



within danger. Such centres as Southampton and Ports- 
mouth, Birmingham and the Midlands, and last but not 
least, London, are, however, clearly threatened. 

As representing more closely the conditions of the 
moment, a point (B) has been taken as representing 
Belgian territory at present in enemy hands. From this 
point arcs have been struck at radii 100, 200 and 300 
miles, the latter representing the probable present-day 
limit of raiding distance. The degree of the existing 
danger to our Midland and South-East Counties can be 
fairly judged from these indications, taken in conjunction 
with the discussion in the text. 

The suggested ship canal from Clydebank to the 
Forth River is indicated in the map by the heavy line C 
Apart from its strategic import, such a canal could not 
fail to be of great value as a commercial asset, though 
from that point of view alone it could not be justified to a 
greater extent than a mere fraction of its probable cost. 
Whether from a National point of view the need will 
justify its being carried out is a question which the 
future alone can determine ; its strategic value would be 
considerable in any case, but if at any time the French 
littoral were to fall into enemy hands the importance of 
a canal such as proposed would be greatly increased. 

At the moment of going to Press it has come to the author's notice that the 
proposal for a Ship Canal from the Firth of Forth to the West of Scotland haM 
already been seriously considered ; both the route herein suggested and an alter- 
native route through Loch I<omond and Loch Long having received attention. 
For full particulars vide Royal Commission on Canals and Waterways ; Fourth 
and Final Report ; England, Wales and Scotland ; page 183. The computed cost 
given in the said report, viz., twenty millions sterling, is decidedly optimistic. 



AdTisopy Committee for Aeronaatics, personnel, § 109 ; work of 

the, § 109. 

Aeronautical Arm, essentially a National responsibility, § 130; 
future development, importance of, § 131 ; in peace time, 
§ 106 ; must be ever ready, § 130 ; primary and secondary 
function of, § 2 ; strategic and tactical uses of, § 8. 

Aerial and Naval Tactics contrasted, § 99. 

Aeroplane, auxiliary to tactical operations, § 10 ; for directing 
artillery fire, § 10 ; types of machine, differentiation of, § 10 ; 
protection by armour, § 12 ; fighting type and its future, 
§ 17 ; offensive against cavalry, § 18 ; attack by aeroplane 
on aeroplane, § 43 ; fighting machine as specialised type, 
§ 44 ; the one-pounder as armament, § 46 ; attack on aero- 
plane, the gun supreme, § 68 ; aeroplane or seaplane for 
torpedo attack, §§ 72, IZ ; aeroplane and submarine, § 74; 
as affecting submarine activity, §§ 76, 118 ; present numeri- 
cal weakness, §§ 1, 85 ; naval floating base, §§ 81, 82, 83, 84; 
seaplanes, the double-float and flying-boat types, §§ 79, 80 ; 
worn-out and obsolete, § 107 ; conditions governing size 
and number of bombs carried, § 117 ; see also Aircraft* 

Aeroplane and Dirigible, speed limitations, § 3 ; range and dura- 
tion of flight, § 4 ; analogy between air and naval forces 
,^ refuted, § 5 ; in armed conflict, § 6 ; means of attack and 
defence, § 7 ; in naval reconnaissance, § 78 ; range and 
radius' of action compared, § 69. 

Air Fleet, need for independent combatant air fleet, § 91 ; must 
be homogeneous, § 94. 

Air Power, as affecting combined tactics, § 85. 

Air Raids, danger from, § 120; against city, the criterion of 
success, § 121 ; important objectives from military stand- 
point, § 129. 

Air Tactics, § 90 ; formation flying, § 95. 



Aircraft, present numerical weakness, §§ 1, 85 ; comparison with 
cavalry Arm, § 1 ; directing artillery fire, §§ 1, 10; in co- 
operation with cavalry, § 9 ; methods of signalling, § 10 ; 
differentiation of type, § 10 ; attack by rifle and gun-fire, 
§ 11 ; protection by armour, § 12; offensive against cavalry, 
§ 18 ; in the service of the Navy, § 69 ; as affecting attack 
and defence in combined tactics, § 87 ; in naval reconnais- 
sance, relative advantages of aeroplane and dirigible, § 78 ; 
general influence on combined tactics, § 86 ; aeroplane 
bases at high altitude, § 100 ; landing in neutral territory, 
§ 105 ; estimate of future numerical strength, § 106 ; merits 
of British machines discussed, § 108 ; for directing gun-fire 
in naval warfare, § 115 ; as countering submarine activity, 
§§ 74, 76, 118 ; strategic employment on large scale, § 119; 
see also Aeroplane. 

Airship, see Dirigible. 

Altitude, in reconnaissance work, §§9, 12; as effective against 
small arms fire, §§ 11, 12; difficulty of hitting aircraft by 
rifle or gun-fire as due to, § 11 ; meaning of term high 
altitude, definition, § 12 ; tactical value of, § 55, 93, 100 ; 
bases at high altitude, importance of, § 100 ; low altitude 
flying, § 13 ef seq. 

Amphibious Type of Aeroplane, utility of, § 81. 

Armament, miscellaneous weapons, § 64 et seq. ; the machine 
gun, §§ 15, 47, 48, 53; one-pounder, § 46; light weight 
shell, § 63; the bomb, §§ 64, 65; supremacy of the gun, 
§ 68 ; treaty restrictions as affecting, § 45 ; in its relation to 
armour, § 54 ; of naval type, § 71. 

Armour, and Altitude, § 12 ; as defence against attack from 
below, § 12 ; thickness of, § 12 ; penetrative power of 
different weapons, § 12 ; for low altitude and point blank 
range, § 14 ; in its relation to armament, § 54 ; pros and 
cons, § 56 ; and shield a distinction, § 57. 

Artillery, direction of fire by aircraft, §§ 1, 10, 115 ; counter- 
aircraft, difficulties pertaining to, § 11. 

Attack, from below by gun-fire, § 11 ; by aeroplane on other 
arms of the service, § 15 ; aeroplane on aeroplane, § 43 ; 
from above, § 56 ; attack and defence, balance between 
strategic and tactical advantages, § 86 ; by bomb, § § 64, 65 ; 
on submarine, § 75 ; general on communications, § 119; on 
London or capital city, § 121 et seq. 

Ballistics, the energy account, § 58. 
Balloon, see Dirigible. 



Balloon Hall, an unmistakable landmark, § 4. 

Base, importance of altitude, § 100. 

Battle Range, in naval warfare, §§ 36, 115. 

Belfast and the Clyde, future importance of as seat of aero- 
nautical and naval construction, § 126, App. II. 

Board of Aeronantical Gonstrnotion, advocated, §§ 113, 131. 

Bomb, as a weapon of offence, § 64 ; difficulties of accurate 
aiming, the true and apparent plumb, § 65 ; attack on 
submarine by, § 75 ; use of in the Naval Air Service. 

BFitish Aeroplanes, points of superiority, § 108 ; ascendency ,^ 
causes contributing to, § 109 ; supremacy, maintenance of, 
§ 110. 


Canal, proposed strategic ship canal, § 128, App. II. 

Cavalry, as affected by Aeronautical Arm, §§9, 17, 18, 85; 
numerical strength of, §§1, 106; reconnaissance, difficul- 
ties of, § 2 ; future limitations of, § 18. 

Clerk, (1780) writings quoted, § 39. 

Clyde and Forth ship canal, suggestion for, § 128, App. II. 

Combatant Air Fleet, independent air fleet and its duties, § 91. 

Command of the Air, §§ 85, 88 ; limitations concerning, § 101 ; 
meaning of in contrast to command of the sea, § 101 ; 
strategic use of, § 119. 

Communications, vulnerable to air power, § 119. 

Concentration, principle of, § 19 et seq. 

Continuity of policy, importance of, §§ 112, 131. 

Counter-aircraft Artillery, facts and gunnery difficulties, § 11. 

Danger Zone, as determined by Radius of action, § 125, 
App. II. 

Dart« the steel dart as an aeroplane weapon, § 66. 
Declaration of St. Petersburg, as affecting aeroplane armament, 

§§ 45, 63. 
Defeat, total in air and its consequences, § 89. 

Defence, aerial and naval essentially one, § 129 ; as affected by 
proximity to enemy territory, §§ 121, 125; concerning a 
Capital city, § 121, et seq. 

Depreciation, and obsolescence, § 107. 

Differentiation of Type, § 10. 



Dirigible, essentially not a fighting machine, § 4 ; gross weight! 

of Zeppelins, naval and military, § 4. 

Dirigible and Aeroplane, see Aeroplane and Dirigible. 

DistinctiYe National Marks, § 104. 

Divided Force, weakness of, § 23 et seq. 

Doable Float Type, naval sea-plane, § 80. 

Damdnm or Expanding Bollets> prohibition of, § 45 ; types of, 

§ 61. 
Duration and Range of Flight, aeroplane and dirigible, § 4. 
Dusseldorft raid on, § 108. 

Energy Utilised and Lost, as determined for different weapons, 

§§ 58, 59. 

Expanding Ballets, §§ 45, 61, 62, 63 ; advocated for attack on 
aeroplanes, §§ 45, 62; prohibition of, § 45; part played by 
centrifugal force in expansion, § 62. 

Explosive Ballets and Projectiles, §§ 45, 50, 59, 60, 63. 

Fighting type of Aeroplane, need for, § 2 ; future of, § 17 ; ai 
a specialised design, § 44. 

Fire, the great danger from air raid, prevention of, §§ 121, 124. 

Flight Grounds, present provision unsatisfactory, § 106 ; night 
flying and, § 106. 

Flight Speed, importance of, §§9, 92. 

Floating Base, for aeroplanes and sea-planes, § 70. 

Flying Boat, type of naval sea-plane, § 79. 

Formation Flying, importance of, § 81 ; airmanship and signal- 
ling, §§ 95, 96; the "V" formation, § 97; machinal 
disabled, § 98. 

FriedrichshaYen, raid on, § 103 (foot note), § 108. 

Fuse, sensitive, need for, § 46. 

Gage or Berth, advantage of upper, §§ 55, 93. 
Government Manufacture, advantages and otherwise, § 111. 
Gravitational Weapons, §§ 64, 65, 66. 
Grenades and Bombs, § 64. See Bomb. 



Gnn-fire, ballistics of, § 58 ; defence from, § 12 ; in naval 
warfare difficulties of control, § 115 ; direction by aircraft, 
§§1, 10, 115 ; rapidity of fire, its importance and measure, 
§§ 47, 48, 49 et seq. ; rapidity of, in relation to the 
n-square law, §§ 29, 30. 

Gun, supremacy of, in attack by aircraft on aircraft, § 68. 

High AltitadOt military meaning of, § 12 ; bases at, value of, 
§ 100. 

Hostile Raids, defence against, §§ 120, 121 ; legitimate 
objectives, §§ 122, 129; diagram illustrating danger zone, 
App. II. 


Independent Air Fleet, combatant, need for, §§ 91, 92; air 
tactics, §§ 92, 95; constitution of, § 94. 

International Law, proper subject for, §§ 102, 103, 104; 
misguided views on, §§ 45, 63, 102, 105 (foot note), 123 
(foot note). 

Ireland, mainly out of range of hostile aircraft. National 
importance of Ulster industrial area, § 126, App. II. 


Lee Gage, in naval tactics, § 39. 

Lewis Gun, as an aeroplane Arm, § 15, App. I. ; cooling system, 
calculations relating to, App. I. 

London, as a capital city a legitimate object of attack, § 120; 

defence of, §§ 120, 123, 124. 
Low Altitude Flying, advantages and disadvantages of, § 13 ; 

extreme low altitude, points in favour of, § 16. 


Machine Gun, in the service of the Aeronautical Arm, §§ 15, 47 
et seq. ; importance of rapid fire, §§ 15, 47, 48; multiply 
mounted, § 41; weight of projectiles thrown by, §§ 51, 52; 
ammunition for, §§ 47, 48; manner of employment from 
aircraft, § 47 ; present advantages of, § 53 ; the Lewis gun, 
App. II. 

Manufacture, goverment and private, § 111. 

Mobilisation of Air Fleet, pontoon ship as a means for, § 81. 

"Mother Ship," for aeroplanes, § 70. 




N-Square Law, § 26 et seq.; demonstration of the, § 27; 
graphically represented, §§ 34, 35, 37; application to a 
heterogeneous force, § 33 ; examples from military history, 
§ 32 ; in naval strategy and tactics, ^ 36 et seq. ; at 
Trafalgar, § 42 ; virtual basis of Nelson's tactics, §§ 41, 42; 
the basis of future air tactics, §§ 81, 90, 92, 94, 95; its 
influence on gunnery, § 115 ; operation in cases of partial 
concentration, § 116. 

Napoleon at Yerona, exemplifying the n-square law, § 32. 

National Defence, considerations relating to, § 120 et seq:, App. 

National Physical Laboratory, importance of aeronautical work 
of, § 102. 

National Programme, recommendations respecting, § 131. 

Naval and Aerial Tactics, a contrast, § 99. 

Naval Aircraft, § 69 e^ seg. ; armament of, §71; reconnaissance, 

Naval Air Service, raids carried out by, § 108. 

Naval 'Tactics, as exemplifying the n-square law, §§ 39, 41, 42. 

Navy, as affected by danger from hostile aircraft, § 128. 

Nelson, memorandum as defining tactical scheme, § 41 ; his 
tactical scheme analysed, § 42 ; tactics at Trafalgar as 
illustrating the n-square law, §§ 41, 42. 

Neutral Aircraft, rights and obligations, §§ 102, 103. 

Neutral Territory, violation of by belligerent aircraft, §§ 103, 

104, 105. 
Night Flying, § 106. 
Number of Aircraft, importance of numbers see n-square law ; 

too small to permit of general conclusions being drawn, §§1, 
85 ; in air raids, §§ 64, 117. 

Numerical Strength, aircraft and cavalry compared, §§1, 106; 
and air tactics, § 90. 

Obsolescence and Depreciation, § 107. 
One-pounder, as aeroplane arm, §§ 46, 53. 

Peace Time, conditions as affecting the aeronautical arm. 
Flight grounds and training, § 106. 



Pontoon Ship, or ocean-going floating base, §§ 81, 82, 83, 84; 

conditions to be fulfilled by, § 82 ; specification of, § 83 ; 

advantages as an aeroplane base, § 84. 
Primary Function, definition of, § 2 ; of the aeronautical Arm, 


Radias of Action, dirigible and aeroplane compared, §§4, 69; 
as affecting danger from hostile raider, § 125, also App. II. 

Raids, by air as affecting the security of the Navy, § 128 ; 

value of numerical strength, § 117 ; the criterion of success, 

§ 121. 
Range, see Radius of Action. 

Range Finding, aircraft of known size, § 10; naval, § 115. 
Rapidity of Fire, importance of, see Gun-fire. 
Reconnaissance, by aircraft, § 1 ; tactical and strategic, § 8 ; 

by aircraft and cavalry, § 9 ; Naval, §§ 69, 11 . 
Resistance, laws of, aeroplane and dirigible, § 3. 
Retreat, compelled by strategic employment of aircraft, § 119. 
Rocket, considered as aeroplane weapon, 64, 67. 
Rodney, early naval tactics, § 39. 
Royal Aircraft Factory, work of the, § 109. 
Royal Flying Corps, ascendency of the, § 108. 


Saints, battle of, tactics at, § 39. 

Scientific Investigation, importance of in aircraft development, 

§ 109. 

Sea-plane, see Aeroplane. 

Secondary Function, definition, § 2 ; of the aeronautical Arm, 

Shell, light weight, advocated by author, § 63. 
Shield and Armour, comparison, § 57. 
Signalling, from aircraft, §§ 10, 95. 
Size, influence on resistance, § 3. 
Speed, limitations, aeroplane and dirigible, § 3 ; as dependent 

upon weight per horse power, § 3. 
IStability, importance of inherent stability, § 65. 
Storage, aeroplane and dirigible compared, §4. 
Strategic and Tactical Uses of the Aeronautical Arm, § 8. 
Strategic Scout, its duties, § 9. 



Strategic Advantage of Attack, diminished by advent of aircraft, 

Strategic Employment of Aircraft, operations on a large scale, 

§ 119. 
Strategy, naval, and the n-square law, § 38. 
Submarine, activity of, as affected by aircraft, §§ 75, 76, 118. 
SufTren (Admiral), on naval tactics, § 39. 

Tactical Importance of Altitude, § 93. 
Tactical Operations, aircraft associated with, § 10. 
Tactical Reconnaissance, § 10; conditions associated with, §§ 10, 

11, 18, 44 ; aeroplane in the double rdle of scout and fighter, 

Tactical Scheme, importance of in aerial warfare, § 90. 
Tactical Uses of Aeronautical Arm, §§8, 10, 13 et seq. 

Tactics, birds of prey as illustrating advantage of upper gage or 
berth, §§ 55, 93 ; naval tactics and the n-square law, § 39; 
aerial and naval contrasted, § 99 ; combined, as affected by 
aircraft, §§ 85, 86; of the air, future of, §§ 91, 92. 

Torpedo, air-borne, proposed as weapon of offence, §§ 64, 67. 

Torpedo, attack by air, § 72 ; discharge of as affecting aeroplane 
stability, § 73. 

Trafalgar, tactical scheme as laid down in Nelson's memo- 
randum, § 41 ; battle of, as illustrating the n-square law, 

Treaty Restrictions, as affecting aircraft armament, §§ 45, 63. 


Upper Gage, tactical importance of, §§ 55, 93. 


"Y" Formation, its value, § 97. 

YilleneuYe, memorandum disclosing British tactical method, 
§ 40. 


Warfare, ancient and modern conditions contrasted, § 20. 
Weight, dirigible and aeroplane compared, § 4. 


Zeppelin, a failure from a military standpoint, § 131 ; also see 




Vol. I. Vol. II. 


21/. net. 21/- net. 

Translated into French by 

COMMT. BENOIT: Gauthier-Villars, Paris. 

Translated into German by 

PROF. CARL RUNGE: Teubner, Leipsig. 

" The Times," November 4th, 1908. 

"A distinct step forward in the campaign 
for the conquest of the air is marked by the 
publication of Mr. Lanchester's two volumes." 

" The Morning Post," October 27th, 1908. 

" Mr. Lanchester seems to be the first man 
who has considered and mastered the fact and 
theory of every phase of the subject before 
sitting down to write." 


(Reprinted by permission of the Institution of Civil Engineers). 



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