Maryland Team Hopes To Nab $250k Prize For Leg-Powered Copter

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."

Been watching these teams for a while

[Anonymous Coward]

It's fascinating to see the evolution of the teams' designs and efforts. Seeing what functionality was given up for weight / flight power conservation (ability to steer was given up on at least one team's design).

Re:

[Joce640k]

Helicopters can glide, a human-powered helicopter ought to glide quite well because the power to weight ratio will be high.

Re:Leg cramp

[ByOhTek]

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:

[tibit]

Be careful, Gamera is lighter than the pilot :)

Close - to the ground

[Anonymous Coward]

The altitude requirement is probably meant to take the vehicle out of ground effect. A 60s flight at 9ft is not as close to a 60s 10ft flight as the teams may hope.

Re:

[Anonymous Coward]

My argument comes from an observational perspective: If there is no significant difference between hovering at 9ft and at 10ft, then why didn't they just hover one foot higher than they did? Apparently there is an effect which prevented them from attaining the required altitude and maintaining it for the required 60s. The most likely candidate is the ground effect, and overcoming the lift reduction from being out of ground effect is not going to be easy. It's not a small difference in the required power.

Re:Close - to the ground

[ChrisMaple]

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:

[Hentes]

And the parent's point was that they will just increase the rotor diameter so they can hover on ground effect higher.

Re:Close - to the ground

[FatdogHaiku]

It's 1/2 rotor diameter...
http://www.copters.com/aero/ground_effect.html [copters.com]

Re:

[daltec]

The contest rules state that the height requirement has to be reached only momentarily (albeit by the part of the aircraft closest to the ground). So they can cruise at 4 ft, 5 ft, and then really pump it for a one- or two-second flight up to 10 ft, and then come back down. Which even that is proving far easier said than done -- a third requirement is that some reference origin point on the aircraft must stay within a 10 square meter box, for the entirety of the time requirement. Both the Canada and Maryla

Personal Preference

[CanHasDIY]

Personally, I would rather all my aerial screws be leg-powered... much better traction that way.

Re:

[tibit]

They need power from all four extremities -- simply so that they have enough. You'd be surprised at how much power can the glycogen stored in your arm muscles provide. For a crazy spin a couple seconds long, starting "cold", you can push close to a kilowatt IIRC.

OMG THE FLINTSTONES!!

[Anonymous Coward]

YAY!!! Barney's leg-powered copter that he made in one of the first episodes of The Flintstones has finally come true!?!??

Does anyone remember that episode??? He built it and he and Fred used it to go to a bowling alley when they were supposed to be home sick. Then they had to beat WIlma and Betta home when they got caught in their disguises. Their wives drove while Fred and Barney used their leg/arm powered contraption...and the flying machine won!! lol

Okay, Now I'm gonna read the article...

It's a good start

[davidbrit2]

It's a good start, but the real challenge will be finding a sustainable supply of extra legs, and devising a method of reliably delivering them to the combustion chamber.

Oh, and Canada, too

[jfengel]

I find it puzzling that the headline mentions only Maryland, when the summary and TFA talk equally about two teams.

I mean, yay, Go Free State and all that (MD native here) but what gives? Good luck to the Terrapins, but they don't rate special headline mentions until they actually win it, instead of being one of two candidates.

Re:

[daltec]

Maryland is testing today and flying this weekend -- it's entirely possible that they may win the prize tomorrow. AeroVelo made some attempts over the past couple weeks, and came very close, but damage to the aircraft has evidently put them out of commission for at least another couple weeks or so -- no chance of them winning it for a while. Hope that helps! Latest news here [vtol.org].

Oh yes, the well known prize

[thedarkone64]

Ah yes, the well known AHSIISHPHC prize...

I know first hand how hard this is...

[Peter Hudson]

I was the pilot (engine really) of the UBC Human Powered Helicopter project almost 10 years ago. Here's a short video of our attempt [youtube.com]. We were grounded by a flex issue that kept derailing the drive chains that connected my pedals to the overhead transmission. Best of luck to the teams going at it today! It's no small engineering nor athletic challenge.