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The Paresev (Paraglider Research Vehicle) was the first flight vehicle to use the "parawing," which was a simple, delta wing design patented by Francis Rogallo of the NASA Langley Research Center. This little glider was designed, built, and flown at Dryden to evaluate the parawing concept and determine its suitability for Gemini spacecraft. The parawing was envisioned as a replacement for the space capsule's parachute landing system, so it could be landed more like an airplane instead of making "splash downs" in the ocean.
The Gemini parawing was to be inflated for rigidity after deployment, and connected to the spacecraft by wires that would be used to control roll and pitch by shifting center of gravity of the capsule. The Paresev was used to gain in-flight experience with the parawing, and was not used to develop the more complicated inflatable deployment system.
The Paresev "fuselage" was an open framework fabricated of steel tubing. The keel and leading edges of the wings were constructed of 2 1/2 -inch diameter aluminum tubing. The leading edge sweep angle was held constant at 50 degrees by a rigid spreader bar. Additional wing structure fabricated of steel tubing ensured structural integrity. To minimize fabrication time, off-the-shelf hardware was used as much as possible. For instance, the shock absorbers for the Paresev-1A were Ford automotive parts, the wing universal joint was a 1948 Pontiac part, and the tires and wheels were from a Cessna 175 aircraft.
A sailmaker was brought in to sew the wing membrane according to the planform developed by Dryden personnel. He suggested some improvements to the fabrication, but yielded to the engineer's specifications. Flight tests proved this wing too flexible. It flapped and bulged in alarming ways. Paresev pilot Milt Thompson put it this way, "Thus, the sailmaker was asked to construct a wing the way he wanted to. The resulting wing membrane had excellent contours in flight."
The Paresev was controlled by manually shifting the center of gravity with respect to the center of pressure. The Paresev 1-A originally had a control bar that hung in front of the pilot's seat, but this was soon replaced with a stick and pulley arrangement that operated more like conventional aircraft controls.
The Paresev 1-B was a 1-A fuselage with a smaller parawing used to evaluate its handling qualities with lower lift/drag values. One project engineer described its gliding ability as "pretty scary."
The Paresev 1-C was the 1-A fuselage with a half-scale version of the inflatable, Gemini parawing. The results were not encouraging, and the rest of the inflatable parawing tests were undertaken by its contractor, North American Aviation, Downey, California.
The first Paresev flights began with auto tows across the dry lakebed. Eventually aero tows were done using a Stearman biplane, and a Piper Super Cub. Speed range of the Paresev was about 35 to 65 miles per hour.
Nearly 350 flights were made with the Paresev during a research program from 1962 until 1964. Despite its looks, the Paresev was a useful research aircraft that helped develop an new way to fly. Although the Rogallo wing was never used on a spacecraft, it revolutionized the sport of hang gliding, and a different but related kind of wing was tested on the X-38 technology demonstrator.