Graham Warwick Washington

Size can matter when it comes to prizes and, for one of last remaining competitions for human endeavor in flight, a significant boost in the purse has spurred a neck-and-neck race for the finish line.

By the time these words are read, one of the longest-standing prizes in aviation could have been won, with two teams vying for the American Helicopter Society (AHS) International's $250,000 Sikorsky Prize for a human-powered helicopter.

The pursuit of human-powered flight is almost as old as aviation. The first authenticated flight was in November 1961 in the U.K. by Sumpac, the Southampton University Man-Powered Aircraft. The Kremer Competitions for human-powered aircraft had been established in 1959, but it was to take almost 20 years for the first of the prizes to be won.

In August 1977, a team led by designer Paul MacCready took the £50,000 prize for flying a mile-long figure-eight course with the Gossamer Condor, piloted by Bryan Allen. In June 1979, MacCready took the £100,000 prize for crossing the English Channel with the Gossamer Albatross, again flown by Allen. In May 1984, a Massachusetts Institute of Technology team led by John Langford won the £20,000 speed prize for the first flight around a 1,500-meter (4,920-ft.) course in under 3 min., with the Monarch B piloted by Frank Scarabino.

Inspired by the Kremer prizes, AHS in 1980 initiated the Igor I. Sikorsky Human-Powered Helicopter Competition, with a prize of $20,000. The key requirements were to hover for 1 min. and achieve an altitude of 3 meters while staying within a 10-meter-square box. It has proven hard to win.

Several teams tried, and students at California State Polytechnic University at San Luis Obispo built a series of machines that culminated in the Da Vinci IV. Weighing 96 lb., this had a 100-ft.-dia. reaction-drive rotor, powered by propellers at the tips of the two blades. In 1989, the Da Vinci IV flew for 8.6 sec and reached a height of 8 in. to set a record.

In Japan, students at Nihon University developed the Yuri 1—with four 33-ft.-dia. rotors and weighing 89 lb.—that in 1994 flew for 19.46 sec. to set a record. But then the competition stagnated until 2009, when Sikorsky increased the prize to $250,000. This sparked a renewed effort.