The “C”-Launch Technique for High-Altitudes Balloons

BT-1049

The "C"-Launch Technique for High-Ahitude Balloons

Air Force Cambridge Research Labs.

Francis X. Doherty; Chester G.R. Czepyha; Robert J.
Reddy

Dec 1967

■>• ;

AFCRL-67^672

DECEMBER 1967 J*„\,x

INSTRUMENTATION PAPERS, NO. 136

AIR FORCE CAMBRIDGE RESEARCH LABORATORIES

L. G. HANSCOM FIELD. BEDFORD, MASSACHUSETTS

The "C"- Launch Technique
for High-Altitude Balloons

FRANCIS X. DOHERTY

CHESTER G.R. CZEPYHA, LT COL, USAF

ROBERT J. REDDY, MAJ, USAF

This rsseorc

h was supported by the Defense Atomic Support Agency.

OFFICE OF AEROSPACE RESEARCH

United States Air Force

Abstract

During the period from 1961 through 1965, the Air Force Cambridge Research
Laboratories developed the technique for launching high altitude plastic balloons
directly from the manufacturer's shipping crate. This technique was primarily
designed to facilitate the handling, inflation, and launch of large balloons from
small ships at sea. This paper describes the new launch procedure and the spe-
cialized equipment designed to support it.

Contents

1. INTRODUCTION

2. DISCUSSION ^
2.1 "C" -Launch Equipment 2
2. 2 "C"-Launch Operation

3. SUMMARY AND CONCLUSIONS '^
ACKNOWLEDGMENTS ^^

1.

lustrations

Model m "C" Launcher ^

2. "C" Launcher Release Assembly

3. "C" Launch From a Flatbed Trailer

Q

4. Helium Trailer Tie -downs

5. Tank Deck Work Area, LST1178 ^

g

6. Initial Inflation

Q

7. Final Inflation

8. Completion of Inflation 1°

9. Launch at Sea

The "C'-Launch Technique for High-Altitude Balloons

1. INTRODLICTION

A ship at sea provides an ideal launch platform for large high altitude plastic
balloons. By running with the wind a ship can create a highly desirable "zero-
wind" condition during the critical stages of balloon inflation and launch. This
advantage has led to a history of balloon launches conducted at sea. As balloons
and balloon pay loads increased in size, however, the problem of obtaining an ap-
propriate launch vessel became more acute. Such a vessel required the speed
and maneuverability necessary to negate wind effects, a relatively large deck area
to support conventional launch techniques, and an adequate storage area for the
lifting gas, flight system hardware, and balloon launch equipment. These re-
quirements limited ship selection to aircraft carriers, which were costly and of
limited availability.

In 1961, Air Force Cambridge Research Laboratories (AFCRL) was asked to
develop a shipboard launch technique that would circumvent the restrictions of an
aircraft carrier while retaining the highly desirable properties of a shipboard
launch. In accordance with this request, AFCRL developed the "C" -launch tech-
nique, a launch method that is designed for operational use aboard small vessels.

(Received for publication 13 November 1967)

2. UISCLISSION

Balloon design and launch methods invariably reflect ar attempt to minimize
adverse wind effects on the balloon during prelaunch balloon handling and inflation.
These methods, techniques, and devices include reefing sleeves and belts, re-
straiJiing cable systems, protective screens and structures, and use of the "dy-
namic"-launch method. In addition, launch sites and times are carefully selected
to take advantage of natural protection and periods of calm or minimum wind.
Usually, several techniques and devices are used together to protect the balloon
and to control its prelaunch development.

The conventional "dynamic" -launch method restricts the amount of slack bal-
loon material subjected to wind drag or "sail" effect during the critical stage of
balloon inQation. In this launch method, the bulk of the balloon is laid out length-
wise on a suitable launch surface. Very large balloons (26 million cubic foot dis-
placement) have required up to 800 ft of layout space. The top portion of such a
balloon (- 50 ft) is placed under the roller arm of a launch arm vehicle. This ve-
hicle confines the lifting gas to the balloon upper portion during inflation. At com-
pletion of inflation, the launch arm is released and the balloon rises vertically
over its payload release vehicle. This latter vehicle maneuvers to place the bal-
loon directly over the payload for final release and system launch. Use of this
dynamic launch technique is unnecessary in calm or near calm surface winds since
a calm wind will permit inflation of a vertically deployed balloon with little danger
of developing hazardous "sail effects. " Such a calm wind condition exists aboard
a ship running downwind at a speed equal to the surface wind speed.

The "C" -launch technique inflates and vertically deploys the balloon directly
from its shipping crate. Once the erect balloon is fully inflated, it is tethered
over the payload in preparation for launch. This technique has the following ad-
vantages:

1. The need for an expansive launch area is eliminated. Aircraft-carrier
class vessels are no longer requu^ed as launch platforms for large balloons.

2. Much less handling of the balloon is required, so that the risk of dam-
age to the plastic envelope is considerably reduced.

3. The combination of several functions into one deployment launch de-
vice, the "C" launcher, reduces the amount of launch support equipment required.

4. Fewer launch personnel are needed.

2.1 "(i"- Launch Kqui|iinenl

The model III "C" Launcher (Figure 1) is an electrohydraulic device designed
to control the inflation and prelaunch deployment of the balloon. It consists of

a tie-down and release point to which the bottom end litting of the balloon is at-
tached dui-in.u vertical doiiloyment and inflation, a system of rollers th;it controls
the balloon payout rate during initial inflation, a weigh-off system that measures
balloon lift during and at the completion of inflation, a winched -tether system used
to deploy the inflated balloon over its payload and final release point, and a control
panel through which a single operator can control these functions. The launcher
has been used to successfully control the deployment ol 1. IT) million cubic foot
Mylar scrim l)alloons. This balloon is approximately jiOii ft long, weighs an aver-
age of lOdO lb, and is mflated to 6000 lb gross lift.

Figure 1. Model III "C" Launcher

Plavout of the balloon from its crate is controlled with squeeze pressure ap-
plied througli the movable roller of a three -roller squeeze system. A relief mech-
anism in tlie movable roller systeni allows the roller to back off as it maintains
a constant operator -set pressure. This design allows passage of added balloon
bulk wliilc maintaining a constant pressure on the balloon material. The rollers
are all free-wheeling to allow balloon passage with a minimum of friction between

the rollers and the balloon material. It is also possible mechanically to set a
minimum roller clearance to further protect the balloon when maximum squeeze
pressure is applied.

Specifications of the Model-Ill Launcher are as follows:

Release Mechanism
Hydraulic System
Squeeze System

Reservoir

W inch

Tether Line

'A'eigh-off System

Total Weight

Covers

Tie -down Provisions

Gages

Controls

Power Supply

Designed to withstand forces up to 30, 000 lb
3000 lb

At 3000 psi, is designed to deliver 9400-lb squeeze
at the rollers. The squeeze gauge at the operator's
console is direct readout

30 gal. capacity of Mobile DTE # 28-2955SSU hy-
draulic oil

Staffa Hydraulic Motor Mark 4-TU, continuously
adjustable speed of 0-100 rpm with high torque, low
speed capability

400 ft length of 18, 000-lb test dacron over poly-
propylene rope

Martin-Decker SD 12 -0060 tension-load system with
free -lift reading between 0 to 6000 lb with 0. 2 per-
cent accuracy
Approximately 5000 lb
Kydex plastic

Will accommodate 4. 5 in. Navy deck tie -down
chains in order to insure a stable and secure plat-
form under maximum load conditions
System pressure - 3000 psi in operation. Squeeze
pressure - 125 psi normal minimum with squeeze
handle at full decrease. Weigh-off - 0 to 6000 lb
depending upon free -lift.
Power on - Push for on

Roller - UP, DOWN, or neutral center position
Squeeze - Variable between DECREASE /INCREASE
POSITIONS

Reel in - STOP or REEL IN positions
Safety - Lock -on pin

Release - HOLD or RELEASE positions
Payout - Speed of payout is variable between the
STOP and PAYOUT positions

External 220 V, 60 cycle, 3 phase, 10 kV, Diesel
generator

The rt-lease merhanism, picturi'cl in Figure 2, consists oi' a hydraulically
operated bolt which serves to retain a fW' in. BBB coil chain connection to the
Launcher release folate. The Launcher release plate is also connected to the
tether line release fittino. When the balloon is ready for release from the Launcher,
the tether line is drawn m, m order to slacken the Launch.-r release chain. As the
chain slackens, the bolt is withdrawn. This in-ocedure provides a shock-free trans-
fer of the balloon from the launcher to the tetln'r line durins the launcher release
process.

Release
Plate .

n Rod
o Recovery

and Paylood

Fif'ure

"C" Launcher Release Assembly

Use of the "C" -launch techniqu..' required special packaging of the balloon. A
standard manufacturer's shipping crate is modified to |>ermit removal of both the
crate top and one en<h Tlie Ijalloon bottom end fitting is folded back across the
top of the folded balloon so tliat it can be withdrawn readily through the open end
of the crate and attachedto the launcher tie -down. The tr.pmost 40 ft of balloon

is then withdrawn between the "C" -launcher rollers and placed upon a canvas lay-
out cloth for initial inflation. Removal of a protective sleeve from this portion of
the balloon exposes a specially folded and tied inflation tube mounted on a plastic
cylinder. The folded inflation tube is slipped over an elongated gas diffuser which
is attached to the gas storage system with apjjropriate hose. Use of this accordion-
folded inflation tube permits the gas inflation crew to work close-in to the balloon
during tlie early stages of inflation. The entire launch operation can be performed
in a 30 by (;0 ft area. During system development tests, launches were easily
conducted from a flatbed trailer (Figure 3).

Figure 3. "C" Launch From a i'Tatbed Trailer

The XM.SV-001 Mylar scrim balloon designed for use with the "C" Launcher
is encased in a reefing sleeve that extends from the bottom end fitting to a point
40 ft below the balloon apex. This sleeve assists in balloon control during its
passage tlu'ough the launchei' roller system and also during the continuing inflation
process after the balloon is fully deployed vertically. A ripj rope extends the full
length of the reefing sleeve and allows the sleeve to be opened as the balloon ex-
pands dui'ing inflation, thus always maintaining a tight bubble. This protective
sleeve has been designed to release automatically although in (practice it may be
released nianually prior to balloon launch. The undeployed balloon material or
"rudder" is folded in such a manner that it will be on the downwind side of the
deployed poi'tion of tlie balloon which tends to shield the undeployed material from
the wind.

2.2 "C"- Launch Operation

The "C" -launch technique has been successfully demonstrated on land and at
sea. During the land operations natural calm surface winds were required to
simulate the shipboard conditions. The Model III "C" Launcher, which was de-
signed to handle free-lifts up to 6000 lb, has been used to launch sLx XMSV-001
balloons. Although this device has not been demonstrated at sea, the Model H "C
Launcher, which was designed for loads up to 3000 lb, was used to launch 4 com-
plete balloon systems from aboard the USS Wood County LST-1178. These launches
were conducted in the U. S. Navy VACAPES Control Area during the period from
24 to 27 August 1964 in true surface winds ranging from calm to 17 knots. The
ship experienced little difficulty in maintaining the desired zero -wind condition
during these exercises. Ship's motion (as high as 11° of roll) posed no problems
and no limitations were apparent in either the techniques employed or the equip-
ment used. Loading of all balloon operational equipment -the "C" Launcher, bal-
loons and flight system equipment, ground handling equipment, a command -control
instrumentation van, and six helium trailers -to include adequate tie -down and
preparation for sea was accomplished in less than 48 hours. Within 24 hours of
returning to port the same equipment was unloaded. No permanent ship modifi-
cations were required to support the balloon launch operations. It was required,
however, that all major items of equipment be electrically grounded. Storage
space aboai'd the Wood County was plentiful with sufficient area for 16 helium
trailers on the tank deck alone. Figures 4 and 5 show the helium trailer tie -downs
and a portion of the work area available on the tank deck of this class LST. Fig-
ures 6, 7, 8, and 9 show various stages of inflation and launch of a 107 ft diameter,
472, 500 cubic foot displacement, polyethylene balloon. This balloon is capable
of raising an 1800-lb payload to a 65, 000-ft altitude.

3. SUMMARY AND CONCLUSIONS

The "C" -launch technique has enabled conduct of ualloon operations at sea
from small ships. It can also be used on land during periods of low wind in re-
mote areas where appropriate launch surfaces are not available for conventional
launching techniques.

Two "C" -launch devices have been developed and successfully tested. The
Model n Launcher can handle free -lifts up to 2400 lb. It has been used to launch
107 ft diameter polyethylene balloons at sea. These balloons are capable of float-
ing 1800 lb at at 65, 000-ft altitude. The Model HI launcher has a capacity of up to
6000 lb of free-lift and has controlled the vertical deployment of 1. 15 million cubic
foot Mylar scrim balloons, floating a design payload of 4500 lb at an altitude of

Figure 4. Helium Trailer Tic -downs

Figure 5. Tank Deck Work Area, LST llVfi

Figure 6. Initial Inflation

Figure 7. Final Diilation

10

Figtire 8. Completion
of Inflation

Figure 9. Launch at Sea

11

65, 000 ft. With minor modifications, the Model III Launcher could handle larger
balloons and heavier pay loads.

Ship requirements include the following: adequate speed and maneuverability
to neutralize surface winds encountered in the proposed launch area; an uncluttered
deck space approximately 30 ft wide in the beam dii-ection by 60 ft long in the fore
and aft direction; sufficient space to store the required amount of lifting gas, bal-
loon flight system, and related equipment, to prepare flight system equipment, and
to establish a command /control center for flight operations. Equipment can be
placed in position on board ship and removed in one to two day periods without
modification to the ship.

Acknowledgments

The authors wish to acknowledge the assistance of Mr. Sidney Rosenthal of
the Engineering Support Branch of AFCRL for many of the "C" -launch system de-
sign details; Mr. Earl Harrah of AFCRL's shop facilities, who was responsible
for the fabrication of the Model n "C" Launcher; and Mr. Alfred D. DeGii'olamo
of AFCRL, who ably assisted in the design, fabrication, and test of the "C" Launchers
and related equipment.

Unclassified

Security Classification

DOCUMENT CONTROL DATA ■ R&D

(Security ctassiftcation of Citlp, body of abstract and indexing annotation must be entered when the overall report is classified)

I. ORIGINATING ACTIVITY (Corporate authorj

Air Force Cambridge Research Laboratories (CRE)

L. G. Hanscom Field

Bedford, Massachusetts 01730

20. REPORT SECURITY CLASSIFICATION

Unclassified

3 REPORT TITLE

THE "C" -LAUNCH TECHNIQUE FOR HIGH ALTITUDE BALLOONS

4 DESCRIPTIVE NOT ES (Type of report and inclusive dates)

5. AUTHOR(SJ (First niMne, middle initial, last name)

Francis X. Doherty

Chester G.R. Czepyha, Lt. Col., USAF

Robert J. Reddy, Major, USAF

TS. NO. OF REFS

none

6. REPORT DATE

December 1967

7a. TOTAL NO. OF PAGES

16

ea. CONTRACTOR GRANT NO. Supported by DASA

b. PROJECT, TASK, WORK UNIT NOS. 57 10 "Bl. 6-02

C. DOO ELEMENT 76006015

d. DOD SUBELEMENT nOne

9a. ORIGINATOR'S REPORT NUMBEWS;

AFCRL-67-0672

9 6. (^JHER R^POR"^ NC(S) (Arty other numbers that may be
assigned this reportf .^p .^^ j^g

10. DISTRIBUTION STATEMENT

1— Distribution of this document is unlimited. It may be released to the Clearing-
house, Department of Commerce, for sale to the general public.

SUPPLEMENTARY NOTES

This research was supported by the
Defense Atomic Support Agency

12. SPONSORING MILITARY ACTIVITY

Air Force Cambridge Research

Laboratories (CRE)
L. G. Hanscom Field
Bedford, Massachusetts 01730

13. ABSTRACT

During the period from 1961 through 1965, the Air Force Cambridge Research
Laboratories developed the technique for launching high altitude plastic balloons dir-
ectly from the manufacturer's shipping crate. This technique was primarily designed
to facilitate the handling, inflation, and launch of large balloons from small ships at
sea. This paper describes the new launch procedure and the specialized equipment
designed to support it.

DD ''°'"" 1473

1 NOV 6S

Unclassified

Security Classification

Unclassified

Security Classification

KEY WORDS

Balloon launch at sea
Balloon launch technique
Balloon launch equipment

Unclassified

Security Classification