Armstrong and Thompson's Flying Tricycle
In 1961, Milton Thompson was working at NASA’s Flight Research Center at Edwards Air Force Base, Calif., when he attended a talk by Francis Rogallo. Rogallo was an engineer working with paragliders, and the system he presented that day was called the Rogallo wing.
It was the two-lobed paraglider NASA was developing to land the Gemini spacecraft. Thompson was intrigued. The pilot in him wanted to know how it feel be to fly the Rogallo-Gemini configuration while the engineer in him wanted to build it a test vehicle.
When his request was denied by the Center’s director Paul Bikle, he sought and found and ally in Neil Armstrong.
Thompson and Armstrong, though both career pilots, were first and foremost engineers. They agreed that building a Rogallo training vehicle was the right thing to do. After all, NASA’s astronauts would have to learn to pilot the Rogallo wing somehow. Who better to build the trainer than two pilot-engineers?
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They set off to build the vehicle themselves, discreetly collecting material from around Edwards to re-purpose into their homemade trainer. Bikle eventually found out and relented; he created a formal paraglider research vehicle program at Edwards. Thompson suspected Bikle’s change of heart was really an attempt to save him and Armstrong from killing themselves in a homemade vehicle.
In just seven weeks, a small team of engineers and builders constructed a paraglider research vehicle — Paresev — from chalk lines Thompson and Armstrong had drawn on a workshop floor. It cost just $5,000, and hardly looked like it would fly.
The Paresev looked more like a large steel tricycle with a fabric wing draped over top than a test aircraft. It had no electronics or fuel — it wouldn’t need any since the Gemini-Rogallo landings it was designed to mimic were unpowered glides. All it had was an altimeter and airspeed indicator in the open cockpit so pilots could monitor their rates of descent. Tests of the Paresev’s integrity were equally rudimentary; they dropped it three and a half feet on to the ground to see if it would break.
Flying the Paresev came down to shifting the vehicle’s center of gravity. The wing pivoted on a mast that the pilot controlled with a center stick. Pitching the sail forwards and backwards generated or decreased lift, and altering the angle of the sail yielded directional control.
Building momentum from small movements gave the pilot enough control to land safely. If it all went wrong, the pilot had a parachute to help him to the ground. Bikle had the Paresev checked out by the Federal Aviation Administration before he let his pilots take it for a test flight. Unconventional as it was, it was flight worthy.
Thompson took the Paresev out for its first spin in January 1962. It was a simple ground tow test. Strapped into the cockpit wearing a helmet, a truck pulled him along the dry lakebed so he could get a feel for the controls. On the next test, the truck sped up giving Thompson enough speed to generate lift. He rose about 20 feet off the ground.
After two months of ground tow tests, Thompson embarked on the first free flight in March 1962. Towed behind a small airplane, he rose in a circular pattern above the lakebed for a physically taxing half hour climb. At 500 feet, he cut the towline and maneuvered the Paresev to a landing. It took considerable physical effort but it worked. He landed to cheers from other test pilots and engineers, including Bikle, who urged him to make a second flight. Thompson went back up immediately, and he immediately regretted it. His arms were so tired he had to wrap his legs around the control stick to ease the strain on his upper body. He made another successful landing, but took the Paresev right into storage lest he get carried away and attempt a third.
Thompson had worse experiences in the Paresev on later flights. At one point an engineer suggested he deploy a smoke bomb during the gliding to make the vehicle more visible in photographs. The idea was to help engineers plot and understand the Paresev’s landing characteristics. Thompson tried it, deploying the smoke bomb only to find himself flying blind in an acrid cloud cursing the engineer.
On another flight, Armstrong flew the towplane for Thompson with disastrous results. The radio connection between pilots failed, so when Thompson noticed he was losing speed he had no way to tell Armstrong. He tried yelling to Armstrong to increase he speed. Armstrong did, but misinterpreted Thompson’s goal. He flew the towplane faster including on the turns, which had the effect of letting the tow line go slack. With a slack line, Thompson lost more speed and more altitude. Before long, Thompson realized he had no recourse but to sever the tow line and try to land. He didn’t make it; he crashed in the Joshua trees on the lakebed’s edge. Armstrong only found out that Thompson had bailed when he landed the plane and didn’t see the Paresev behind him. The Paresev was totaled in the crash but Thompson was fine.
Armstrong didn’t fly the Paresev himself until September 1962, the month he joined NASA’s astronaut corps. As one of NASA’s second group, he was a likely candidate to land a Gemini mission with the Rogallo wing so needed practice. Mercury astronaut Gus Grissom was the only other NASA astronaut to fly the barebones trainer.
The Paresev program ended midway through 1963. And while the Gemini-Rogallo never flew, Thompson and Armstrong’s homemade trainer demonstrated that had it flown it would have been fully pilotable.
Image credit: NASA