gpsblake

http://rt.com/news/first-human-powered-helicopter-069/

http://www.youtube.com/embed/syJq10EQkog

Rest of article to link above

I wonder what the gear ratio on that bike was?

rm -rf

That's a grade of "infinity" percent...

Metafilter had a discussion of this ride. (There's a lot of confusion in some of the comments, though. Non-cyclists don't know much about bike rider power.)

The wheel seems to be just used as a flywheel to even out the power to the rotors. See the cranks at 1:14 in the video. There's 4 spools, one for each rotor. The cyclist winds up the cables (and unwinds the rotor end). So the flight is limited in time. Pretty ingenious: it's way lighter than a chain and much simpler than a loop of cable to each rotor.

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Quoted from the team:

The problem, of course, is that the human body can produce, at best, about 1 horsepower for a one-minute flight. This is about half the power that it takes to run a good hair dryer!

Is it even possible to build a helicopter that can lift so much weight on so little power? It turns out that it is, but the aircraft will have to be absolutely enormous, possibly even bigger than 30 meters across. As far as the aerodynamics are concerned, it's more efficient to push very lightly on a large mass of air than to push hard on a very small mass of air. So bigger is better. But bigger means heavier, and with human-powered aircraft, weight is the biggest enemy.

A viable Sikorsky Prize helicopter would have to be in the range of 100 pounds or less. For something the size of a Boeing 737, this is a pretty steep challenge!

RyderTheRider

That's pretty awesome!

chaadster

Just to be clear this was NOT the first human powered helicopter flight; most recently, Univ. of Maryland's Gamera craft met duration and height requirements, but lacking a flight control system, was unable to remain within the flight boundaries stipulated by the Sikorsky prize, and so was not awarded.

Other human powered copters have included the Yuri 1 and Da Vinci III, and though obviously less successful, they did achieve human powered flight.

I'd also point out that neither Atlas nor any of the others were 'modified bicycles,' and that it's much more accurate and appropriate to say they were powered by pedaling.

wphamilton

I was glad to see the explanation for leaving the rear wheel on, which I was questioning myself - as a flywheel! I was under the impression that flywheels for storing power were forbidden by the challenge rules but I guess a bike wheel doesn't count, which is a pretty clever design. Like the rest of it, ingenious!

fietsbob 

It was a capstan winding up kevlar cordage that actually turned the Rotary wings.

front wheel less so not really a Bi ke, was hanging from more cordage..

no1mad 

There was a thread about this started two days ago- http://www.bikeforums.net/showthread...e-has-been-won

Bike Rat

The 'copter itself reportedly weighed 120 lbs., and is the second largest helicopter ever built. Very cool!

Jeff Wills

Well, the wheel didn't store any power since it was stopped when the rotors were not moving. Had there been a clutch that allowed the rider to spin up the wheel before starting the rotors, then it would have violated the rules. As I said in the other thread, the wheel is there to modulate power inputs, avoiding unnecessary strain to the cables and various drive fittings.

wphamilton

Obviously whoever is administering the prize thought it was OK. Months ago I was imaging all sorts of potential end-arounds on that restriction, but never thought about simply using the back wheel!