PARAFOIL REFERENCE TEXT

The parafoil was invented by Domina C Jalbert in 1964. He made a kite using an airfoil-shaped self-inflating canopy. upon review by lawyers, his original patent has been found valid evne though it had some technical shortcomings that prevented it from reaching its full potential. He showed it to Professor John D Nicolaides who was then head of the Aeronautical Engineering Department at Notre Dame University. Dr Nicolaides had some of his students work with the concept. They ran wind tunnel tests and conducted small-scale drop tests. They refined the design. After some work, Dr Nicolaides had man-sized canopies made and was able to find some people who would jump them. Early bugs like an extremely high opening shock were worked out, not without some pain. He managed to convince some members of the US Army's Golden Knights to jump those canopies. They liked them with some reservations. The US Air Force, tested some of these canopies at Wright-Patterson Air Force Base in the late 1960's. The author came close to these canopies while performing a test of the C-5A in the Langley 30ftx60ft wind tunnel in 1968. The parafoils were the next project to go into the tunnel. That sounded like an interesting project at the time. Later, the results of those tests would form the basis for the author's simulation of the parafoil.

the author acquired some canopies from the Air Force after their tests were completed and made a few drop tests at a US Army Facility in Sudbury, MA. The first test was interesting. The author had absolutely no knowlege of parachute packing techniques.  Capt Dimantova, fresh from service in Viet Nam was assiting the author. We went out to the Army's packing facility at Sudbury where the canopies had been delivered expecting the experienced packers to be examining these strange new chutes. The chutes were still in the boxes. "Capt D" and the author pulled them out of the boxes and laid them out on the floor of the packing facilicty. It seemed we were in trouble all ready. All 'proper parachutes' are packed on a long and clean table. The parafoil would not fit on any table. You had to use the whole floor! The chief of the place had someone sweep the floor and Capt D started messing with the canopy. He found and laid out each set of lines. The author helped  a little, trying not to mess anything up. After a while it became clear what the main parts were. All this time the experienced parachute packers stood back with their hands firmly in their pockets not wanting to get involved. Capt D found an old over-size deployment bag that would probably fit and started folding the canopy in a neat way - like folding cloths - and stuffing it in the bag. The author helped. The lines were then straightened as much as possible - they were not laid out like normal parachute lines. Then the lines were zig-zagged and tied into the flap on the pack using rubber binders. A torso dummy weighing 200 pounds volunteered to be the first test subject. With Capt D's help - talking Army to Army - a test drop was arranged for the following day in which the dummy and canopy would be shoved out of the door of a deHaviland Beaver. While it would have been nice to do that at a high altitude, there would have been no control. This scared many people as they though an uncontrolled gliding parachute could fly off that little reservation and land in some civilian's back yard. (The author would later prove them right and do it in front of a visiting general!) Prudence won out and the drop was set for 100 feet - far lower than any previous parachute deployment. Early the next morning a small crowd chased the deer off the meadow of the drop zone. The Beaver came over and dropped the canopy. It opened beautifully about 30 feet from the ground and settled in for a firm but nice landing. The US Army high-performance gliding parachute program was born.  [There had been earlier programs using a single-surface canopy called the parawing with a poor 2;1 glide ratio. It was clear the parfoil offered good potential.

Dr Nicolaides and the author met at a symnposium later. he agreed to sell the Army a pair of canopies with a remote control system. It was a lousy control system but the canopy was very nice and is rep[resented by this FS model. It was later trested with a very good control system and a payload with instruments to measure airspeed, descent rate, altitude, control strokes, and pitch, yaw and roll rates. That system provided a large amount of data used as the basis for further development.

The author spent many years testing this type of canopy in various detail designs in various sizes from a few feet to 80 feet by 32 feet carrying 5000 pounds. Advised NASA, after becoming a NASA employee concerning the use of parfoils to recover objects from space. He spent some time after retirement advising NASA on a parafoil system for use with the X-38 capsule to bring sick or injured astronauts back from the space station. Unfortunately, the application of this type of canopy to very large payloads did not work out. While the canopies deploy and open readily in the size used for a jumper, they do not open reliably in the size needed for large military and space payloads. [The X-38 weighed 29,000 lbs when the program was cancelled.] The last remote-controlled parafoil flight the author made was in a small field next to a NASA parking lot using a mail-order R/C model having a wing span of 5 feet with an electric engine. It worked very well in a strong wind and landed close by without breaking anything.



Have fun.

T. F. Goodrick         4/20/4
goodrick@hiwaay.net

Publications by the author on this subject include:

1. "WIND EFFECT ON GLIDING PARACHUTES WITH NON-PROPORTIONAL AUTOMATIC HOMING CONTROL," TR-28-AD, US ARMY NATICK LABORATORIES, 1969.

2. "ESTIMATION OF WIND EFFECT ON GLIDING PARACHUTE CARGO SYSTEMS USING COMPUTER SIMULATION," AIAA PAPER 70-1193.

3. "ANALYSIS OF VARIOUS AUTOMATIC HOMING TECHNIQUES FOR GLIDING AIRDROP SYSTEMS WITH COMPARATIVE PERFORMANCE IN ADVERSE WINDS," (with A. L. Murphy and A. Pearson), AIAA PAPER 73-462.

4. "THEORETICAL STUDY OF THE LONGITUDINAL STABILITY OF HIGH-PERFORMANCE GLIDING AIRDROP SYSTEM," AIAA PAPER 75-1394.

5. "SIMULATION STUDIES OF FLIGHT DYNAMICS OF GLIDING PARACHUTE SYSTEMS," AIAA PAPER 79-0417.

6. "HARDWARE OTIONS FOR GLIDING AIRDROP GUIDANCE SYSTEMS," AIAA PAPER 79-0471.

7. "COMPARISON OF SIMULATION AND EXPERIMENTAL DATA FOR A GLIDING PARACHUTE IN DYNAMIC FLIGHT," AIAA 81-1924.

8."SCALE EFFECTS ON PERFORMANCE OF RAM AIR WINGS," AIAA PAPER 84-0783.

[NOTE: AIAA refers to the American Institute for Aeronautics and Astronautics.] 