Human-Powered Helo - Mission Possible?

The two leading teams competing for the $250,000 AHS Sikorsky Prize for human-powered helicopter flight are regrouping after back-to-back unsuccessful assaults on the challenge, which remains unclaimed after three decades. A respected rotorcraft academic, meanwhile, says the lack of success shows the prize is unwinnable. Its organizer disagrees. Established in 1980, the AHS Sikorsky Prize for the...