N 62 12819
PARAGLIDER RECOVERY SYSTEMS
By Francis M. Rogallo
NASA Langley Research Center
Langley Station, Hampton, Va.
For Presentation at IAS Meeting
on Man's Progress in the Conquest of Space
St. Louis, Missouri
April 30, May 1-2, 1962
PARAGLIDER RECOVERY SYSTEMS
By Francis M. Rogallo
NASA Langley Research Center
The flexible- wing concept, which may be as old
as the pterodactyl and was given serious considera-
tion by Leonardo Da Vinci, was apparently ignored
by the Wright Brothers, Glen Curtiss, and others
whose rigid-wing structures followed established
bridge and roof- truss design. Today’s airplanes
have evolved from these early rigid- wing designs.
The thin cantilever wings of modern high-speed air-
planes are not completely rigid, but they are elas-
tic rather than flexible. They can not be folded
up like a balloon or parachute.
In 1945 it occurred to the writer that if we
could discover how to make flexible wings that
could be packaged and deployed somewhat like a
parachute, such wings would have many new applica-
tions as well as replacing some parachutes and
rigid wings. Previous uses of flexible materials
in aerodynamic surfaces - parachutes, kites, boat
sails, and wind mills - were reviewed, and some
crude experiments were performed with gliders and
kites. Before the end of 1948, the device now
generally called a paraglider was evolved and
developed sufficiently to merit a patent applica-
tion 1 . The study was continued privately as time
permitted, and in 1954 & short paper on the sub-
Ject was presented to an audience of about
50 Reserve Air Force Officers. This paper was
given rather wide distribution, although it suffers
from lack of the many kite and glider demonstra-
tions of the original presentation. Little serious
interest was shown by the aeronautical community,
however, until about a year after Sputnik I. In
December 1958 the flexible- wing concept was pre-
sented to the Langley Committee on General
Aerodynamics with the aid of the hurriedly pre-
pared charts shown in figure 1 , faithfully repro-
duced here for historical purposes.
Of the many configurations and applications
shown in figure 1 , it was decided that the two-
lobe, single- curvature, suspended- load design that
had already shown much promise ' should be
investigated as a possible reentry glider. While
preliminary work of this nature, which is reported
in references 3 to 7 > was ± n progress, Information
pertaining to other applications was requested.
The parawing was shown to be a very effective high-
lift device for aircraft 0 . It was demonstrated as
a wing for a powered aircraft and an air-drop
glider, both radio controlled^. It was considered
for the recovery of rocket boosters 1 ^, and for the
terminal glide and landing of manned space cap-
sules 11 . And to support such applications, basic
information on pressure distribution was
obtained 12 ' 1 ^. The aerospace industry, partic-
ularly Ryan, North American, and Goodyear, has
also contributed paraglider information and has
made feasibility studies of the recovery of
boosters and space vehicles by paraglider. These
studies indicated that such recoveries were
Because NASA work on flexible wings prior to
1961, including Langley Film L-593, was well
received at the January 1961 New York IAS Meeting,
it was thought that a brief mention of NASA work
done since then and continuing, in addition to that
listed in the references, might be of interest.
Langley Film L-688 shows some of this work.
A wide range of wing geometric variables is
being investigated with static wind-tunnel setups
such as those shown in figure 2. Line loads and
complete glider static forces and moments are
determined by the setup of figure 3 . Stability
and control characteristics of gliders in flight
are determined by tests of remote- control models,
such as are shown in figures 4 and 5* Space cap-
sule (fig. *0 and booster (fig. 5) models were
flown in the full-scale tunnel and also by radio
control after being dropped from a helicopter.
Deployment of the folded wings after dropping was
an important part of the investigation by the
Outdoor Test Unit of the Recovery Systems Branch
In figure 6 is shown a propeller- powered model
being flown in the full-scale tunnel, and in fig-
ure 7 is a roughly similar gas- powered radio-
controlled model with which some impressive flight
demonstrations were made. Figure 8 is a static
wind-tunnel model for force test in the 7- by
10- foot wind tunnel, and figure 9 is the Ryan
Aircraft being statically tested in the Langley
The glider shown in figure 10 Just after lift-
off by a helicopter is 50 feet long and has 32 - inch-
diameter inflated fabric tubes at the leading edges
and keel. It has been towed to an altitude of sev-
eral hundred feet and released for free glide with
weights of about 700 , 1 , 300 , and 1,900 pounds with
the small capsule shown. A standard sized Mercury
Capsule will be used next, and weight progressively
In figure 11 is shown a glider built and flown
by the NASA Flight Center at Edwards Air Force
Base, California. This glider has been towed to
altitude and then released for glide and landing.
1. United States Patent Office, Patented March 20,
1951, no. 2,5^6,078. Flexible Kite, Gertrude
Sugden Rogallo and Francis Melvin Rogallo,
2. Rogallo, Francis M. : Introduction to Aero-
flexibility. Presented April 21, 1954 to
ARDC Reserve Unit at Langley Field, Virginia.
3 . Rogallo, Francis M., and Lowry, John G. : Flex-
ible Reentry Gliders. For Presentation at the
Society of Automotive Engineers, 485 Lexington
Ave., New York 17 , New York. April 4-8, i 960 .
Preprint no. 175C.
4. Rogallo, Francis M., Lowry, John G., Croom,
Delwin R., and Taylor, Robert T. : Preliminary
Investigation of a Paraglider. NASA TN D-443,
1 960 .
Taylor, Robert T., Judd, Joseph H., and Hewes,
Donald E.: Flexible Gliders. Joint Conference
on Lifting Manned Hypervelocity and Reentry
Vehicles. April 11- 14, i 960 , p. 215, N- 82529 .
6 . Taylor, Robert T.: Wind-Tunnel Investigation
of Paraglider Models at Supersonic Speeds.
NASA TN D- 985 , 1961 .
7« Penland, Jim A.: A Study of the Aerodyn ami c
Characteristics of a Fixed Geometry Paraglider
Configuration and Three Canopies With Simulated
Variable Canopy Inflation at a Mach Number of
6 . 6 . NASA TN D- 1022 , I 96 I.
8 . Naeseth, Rodger L.: An Exploratory Study of a
Parawing as a High-Lift Device for Aircraft.
NASA TN D- 629 , i 960 .
9. Hewes, Donald E.: Free-Flight Investigation of
Radio-Controlled Models With Parawings. NASA
TN D-927, 1961.
10. Hatch, Howard G., Jr., and McGowan, William A.:
An Analytical Investigation of the Loads, Tem-
peratures, and Ranges Obtained During the
Recovery of Rocket Boosters by Means of a
Parawing. NASA TN D-1005, 1961.
11. Hewes, Donald E., Taylor, Robert T., and Croom,
Delwin R. : Aerodynamic Characteristics of
Parawings. NASA- Industry Apollo Technical Con-
ference, Washington, D.C., July 18, 19 , 20,
1961. Part I, p. 423.
12. Fournier, Paul G., and Bell, B. Ann: Low Sub-
sonic Pressure Distributions on Three Rigid
Wings Simulating Paragliders With Varied Canopy
Curvature and Leading- Edge Sweep. NASA
TN D- 983 , 196 I.
13. Fournier, Paul G., and Bell, B. Ann: Transonic
Pressure Distributions on Three Rigid Wings
Simulating Paragliders With Varied Canopy Curva-
ture and Leading- Edge Sweep. NASA TN D-1009,
WHY A MEMBRANE WING ?
1. VERY LIGHT WING WEIGHT PER UNIT AREA
MAKES POSSIBLE VERY LOW WING LOADING
2. ABILITY TO BE ROLLED UP OR FOLDED LIKE
3. RADIATION FROM BOTH SURFACES REDUCES
AERODYNAMIC HEATING AND FLEXIBILITY
REDUCES THERMAL STRESS
4. VERY THIN WINGS REDUCE WAVE DRAG AT
2. SPACE SHIP LANDING
3. SOLAR SAILING
4. HIGH ALTITUDE CRUISE (POSSIBLY
DISSOCIATED OXYGEN PROPULSION)
5. PERSONNEL AND/OR CARGO GLIDING
PARACHUTE AS SUBSTITUTE FOR
6. WINGS FOR STOL (COULD BE ROADABLE)
7. LANDING AID FOR CONVENTIONAL
AIRPLANE (LIFT ADVANTAGE OVER DRAG)
Figure 1.- Flexible- wing concept as presented to Langley Committee on General Aerodynamics,
December 19, 1958*
L- 62- 1682
L- 61- 3167
Figure 2.- Typical wind-tunnel setup for systematic investigation of the
effect of wing geometry on the static aerodynamic characteristics of
L- 62- 8l6
Figure 3.- Wind-tunnel setup for determination of line loads and com-
plete glider static aerodynamic characteristics.
Figure 4.- Remote-controlled model of a paraglider recovery system for
space capsules, shown flying in the Langley full-scale wind tunnel.
L- 61-16 53
Figure 5*- Paraglider booster- recovery model that was radio-controlled
after drop from a helicopter by the Langley Recovery Systems Branch.
Figure 6.- Remote-controlled model of a manned flexible- wing vehicle
flying the Langley full-scale wind tunnel.
Figure 7 • - Radio-controlled gas- powered model of a manned flexible-wing vehicle being prepared
for flight by the Langley Recovery Systems Branch.
Figure 8.- Static wind-tunnel model of a manned flexible- wing vehicle in a Langley 7- Ly
10- foot tunnel.
L- 62- 6 31
Ryan flexible- wing vehicle setup for force tests in the Langley full-scale
Figure 10.- Fifty-foot inf lated- frame paraglider immediately after lift-off by a helicopter.
Figure 11.- Paraglider research vehicle built and flown at NASA Flight
Research Center, Edwards, California.
LOADING CONDITIONS VERSUS TIME OF FLIGHT
time of flight
3.7i“' t ? +<> '
SATURN CONSTRUCTION DETAILS
FIRST VIBRATION MODE
MAX Q WEIGHT
(SAD - 1)
SECOND VIBRATION MODE
x , 0 3 DUE TO WINDS
M b ,IN.-LB
30 32 34 36xl0 3
20 30 40
SATURN GROUND- WIND INDUCED LOADS
I5 r xi0 6
EMPTY- VEHICLE OVERTURN MOMENT
M b ,IN.-LB
! O STEADY* DRAG M b
□ MAX. OSCILLATORY
LATERAL M b
WIND VELOCITY, FPS
WIND-VELOCITY MEASUREMENTS „/
OF MODEL AND FULL
/ZA #-o° * . .- KiftSA-LANQlgy,
O 300 , 600
FREQ., CPS (MODEL)
/'/-// -OO O