A team of student engineers at the University of Maryland are closing in on the American Helicopter Society's $250,000 Sikorsky Prize, which has remained unclaimed for over thirty years. The requirements of the prize sound simple enough. The winner must build and demonstrate a human-powered helicopter that can lift off the ground vertically and hover for one minute, reaching a height of three meters (about 10 feet) without drifting from a 10-square-meter area. But as this video from the NPR "Radio Pictures" series explains, those parameters test the limits of light-weight aircraft design. After four years of trial and error, the Maryland team has satisfied two of the three requirements. In one recent flight they kept their helicopter, the Gamera II, in the air for a world-record 65 seconds while staying within the required 10-meter area--but only reaching a height of two feet. In shorter flights they've approached the 10 foot goal. To learn more about the project you can read and listen to Adam Cole's story at NPR, "Human-Powered Helicopter: Straight Up Difficult."