Wednesday, March 7, 2012

First Flights in the Winged Tricycle

First Flights in the Winged Tricycle:
On Monday March 12, 1962, NASA research pilot Milton O. Thompson took to the skies in a vehicle he had designed and built himself at the Flight Research Center in Edwards, California. The Paraglider Research Vehicle -- Paresev -- wasn’t a high tech design. It looked more like a winged tricycle than a traditional aircraft. But it was flightworthy. Thompson’s first test flights were successful, but he nearly didn’t live to tell the tale.  


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A Gemini spacecraft mated to a Rogallo wing. NASA.

Thompson first dreamed up the Paresev after attending a lecture by Langley engineer Francis Rogallo in 1961. Rogallo had designed a kite-like sail that NASA was pursuing as the landing system for its Gemini spacecraft. There were doubts about the Rogallo wing’s airworthiness, so Thompson proposed a paraglider research program to Paul Bikle, the head of the FRC. When his request was denied, an undeterred Thompson found an ally in fellow pilot Neil Armstrong. The pair conspired to build a research vehicle themselves out of spare parts. Bikle caught wind of their plan and relented. If he sanctioned the program, he had a better chance of keeping his pilots alive.  

Seven week and less than $5,000 later, the Paresev was finished. In January 1962, Thompson began with ground tow test -- he sat in the Paresev as a truck pulled it across the dry lakebed. The first version had its share of problems. Thompson said his control stick felt about as strong and reactive as a wet noodle. Modification and further ground tow tests over the next two months turned the Paresev into a properly flightworthy vehicle, and by March Bikle was urging Thompson to move on to flight tests.


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Thompson sits inside the open Paresev. NASA.

The plan was for pilot Fred Harris to tow the Paresev to 5,000 feet at which point Thompson would sever the 1,000 foot long nylon tow line and glide to a runway landing. But there was a little more to it. Because the Paresev was so light and entirely without power, Thompson would have to take off before Harris and stay about 50 feet above the airplane; if the Paresev flew in the plane’s wake it risked tumbling through the air. Harris also had to fly to altitude in a wide circle so Thompson would be over a safe landing area at all times. Making an emergency landing in an unpowered homemade aircraft in sagebrush wasn’t anyone’s ideal end to a test flight. 

Thompson quickly ran into problems. Even after modifications, the Paresev was hard to control and the long tow line only added weight and drag. Every slight change to Harris’ airspeed forced Thompson to work twice as hard to keep the Paresev level. To make matters worse, radio reception between the two pilots was so poor Thompson ended up screaming instructions to Harris as he fought to maintain level flight. 

In the half hour it took for the Paresev to climb to 5,000 feet, Thompson’s arms grew tired. He was pleased to find that the vehicle became much easier to control once he severed the tow line and began the free flight. He guided the Paresev to a smooth landing, touching down on the lakebed traveling at just three vertical feet per second. It was, without question, a huge success. 


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The Paresev comes in for landing. NASA.

As soon as the Paresev came to a stop, excited onlookers converged on Thompson. The mood was celebratory with congratulations shouted at the pilot from all sides. Bikle was particularly pleased that the homemade vehicle had performed so well and suggested that Thompson make a second flight right away. Reluctant at first, he eventually gave into the post flight euphoria and agreed despite his mental and physical exhaustion. 

As soon as he was airborne, Thompson realized he’d made a huge mistake. His muscles were more fatigued than he’d realized and he wasn’t sure he had the strength to hold the Paresev steady for another half hour climb. He briefly considered cutting the tow line early, but the prospect of crashing into sagebrush changed his mind. Instead, he wrapped his leg around the control stick to give more power to his steering. 

By the time the Paresev reached 5,000 feet the second time, Thompson’s arms were shaking so badly he was forced to keep his leg around the control stick to help guide the vehicle to a smooth landing. The second wasn’t as smooth as the first, but it was still a successful landing. Thompson was met on the lakebed by the same delighted crowd, but he kept his head this time. He immediately ordered the Paresev be taken to the hangar for overnight storage lest he give into the hype and agree to a third flight. He felt certain that he wouldn’t survive another flight that day. 

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