Maryland Team Hopes To Nab $250k Prize For Leg-Powered Copter 33
daltec writes "The $250,000 American Helicopter Society Igor I. Sikorsky Human Powered Helicopter Competition prize, unclaimed since 1980, is now closer than ever to being won. With flights up to ten feet in altitude and lasting over 65 seconds, the prize's strict requirements (thought by many to be impossible to satisfy) have all been met — but not on the same flight. Two teams — AeroVelo in Canada and Gamera II at the University of Maryland — are tantalizingly close to claiming the prize. The Gamera team will be making its latest attempt this weekend."
Re:Leg cramp (Score:4, Informative)
Power to weight ratio, would probably be less than that of a normal helicopter. However the weight, full stop, should be lower. Given the irrelevance of power in gliding, that's what matters anyway.
Re:Close - to the ground (Score:4, Informative)
Ground effect is not a phenomenon which becomes effective at a specific point. It increases as air is blocked from flowing downward, a pressure wave reflecting off the ground, back to the wing (helicopter blade) and out horizontally.
For Ground Effect Machines (Air Cushion Vehicles) the critical factor is the area of the periphery, the height off the ground of the skirt times the skirt's circumference. The pressure differential lifting the vehicle is determined by how much air is pumped in and how fast it escapes under the skirt. This is weakly similar to more air escaping from a low helicopter blade as it gets further above the ground.
Re:Oh, and Canada, too (Score:3, Informative)
Re:Close - to the ground (Score:4, Informative)
http://www.copters.com/aero/ground_effect.html [copters.com]