Human-Powered Helicopters...
The concept is simple -you pedal, the rotors turn,... ...re chasing one of aviation's last milestones: the Sikorsky Prize . The American Helicopter Society (AHS) has promis... ...box.Turns out, that's harder than it sounds. The prize has been unclaimed for more than three decades.Ma... ...cent designs are get...
https://www.neatorama.com/2012/10/17/Human-Powered-Helicopters/
