On this day in 1977, Bryan Allen becomes the first person in 18 years to claim the US$100,000 Kremer prize for human-powered flight when he completes a figure-eight course piloting aerospace expert Paul MacCready’s Gossamer Condor, the first human-powered aircraft capable of controlled and sustained flight.
The challenge was set in 1959 when British industrialist Henry Kremer offered a prize for a successful human-powered aircraft. To win the prize, a person had to pilot a human-powered aircraft around a figure-eight course in which the turning points where about .8 kilometres apart. The craft also had to clear a 3-metre hurdle at the beginning and end of the course. The challenge seemed simple enough and more than 50 attempts were made to claim the prize.
But for 17 years the prize went unclaimed as pilots debuted sleeker, faster, and more complex aircraft. But as the aircraft grew faster and sleeker, they also tended to grow heavier, which meant they needed more power to become airborne. Because power was supplied by a single person piloting the plane, however, most aircraft were simply too heavy and power-hungry to complete the course.
Aerodynamicist Paul MacCready observed the failed human-powered flights—and successful bird-powered flights in nature—and came up with his own, creative solution. One day, while watching vultures lazily circle a kill, MacCready decided to build a very lightweight craft that would fly so slowly that extra drag wouldn’t be a problem. The result was the Gossamer Condor, a pedal-powered craft made of an aluminium frame covered with a very thin layer of Mylar. With a wingspan of nearly 30 metres, the delicate Condor weighed only 30 kilograms. MacCready and his team used wing warping instead of traditional—and heavy—control elements like ailerons or vertical rudders, to allow the plane to make coordinated turns without adding to its weight. During practice sessions, the ultra-lightweight aircraft flew at a jogging pace only 3 to 4 metres above ground, making crashes a minor problem: the team fixed tears in the Mylar with lots of Scotch tape. After hours of test flights, metres of Scotch tape, and a redesign that left the plane nearly 3 kilograms lighter, the Gossamer Condor was ready for competition.
On 23 August 1977 pilot Bryan Allen began to peddle the Condor for its 223rd flight in Shafter, California—it’s most important. Seven minutes and 27 seconds later, Allen had successfully completed the figure-eight course and the Gossamer Condor had won the now-$100,000 Kremer Prize.
MacCready went on to win a second Kremer Prize for human-powered water travel with the Gossamer Albatross, which crossed the English Channel, as well as a wide range of aircraft including solar-powered planes. MacCready died of brain cancer in 2007. He is considered one of the most creative and innovative aircraft designers in history.
Credit: Image courtesy of NASA
Caption: The Gossamer Condor takes flight.