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Author Topic: Human Powered Helicopter Record Attempt  (Read 9894 times)
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fidelio
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« Reply #45 on: May 15, 2011, 11:59 PM »

Physics?
Just a guess.

you're saying if you took those same eight gamera rotor blades and arranged them in a pair of quad bladed rotors in a stacked coaxial orientation you'd generate significantly less lift?

your glib answer didn't help me understand your point.
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Fdeli
zippy8
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« Reply #46 on: May 16, 2011, 12:07 AM »

if you want that 1/4 million, you gotta get WAY outside the box.
I'm assuming "burn them as fuel" is too far out of the box then ?  Wink

TBH I'm underwhelmed by this, no matter how much of an "achievement" it represents. Any kid on a trampoline who spins around will produce a significant fraction of their "air time" and much greater altitude. They appear to have worked very hard to find a solution to an unimportant problem.

Mike.
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Virtual Freestyle - ǝlʎʇsǝǝɹɟ lɐnʇɹıʌ
DWayne
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« Reply #47 on: May 16, 2011, 06:55 AM »

Physics?
Just a guess.

you're saying if you took those same eight gamera rotor blades and arranged them in a pair of quad bladed rotors in a stacked coaxial orientation you'd generate significantly less lift?

your glib answer didn't help me understand your point.

The coaxial unit you posted has half the rotor blades Gamera has. 4 blades rather than 8 blades. So they would have to rotate much faster to create the same amount of lift. Then there's the fact that the upper rotor creates most of the lift as the lower rotor is running in the prop wash of the upper rotor. The purpose of the lower rotor is to overcome the effects of torque, and since torque isn't much of a factor in human powered craft, this design is not really practical.
Now think about the amount of energy a human can create and the amount of drag the drive system would create. (It would take a lot of gearing to get the rotor speed needed. More gearing = more weight = more energy needed to attain flight.) After overcoming the drag of the drive system, there wouldn't be enough energy left to create lift. That's basically the crux of the problem these engineers are trying to overcome.

Denny
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I always wanted to be a procrastinator..........
I just never got around to it.
kiten00b
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« Reply #48 on: May 16, 2011, 07:37 AM »

They need to find a way to use the energy from the feverish typing of Internet Experts.
That, plus the hot air that they're full of should provide plenty of lift.
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indigo_wolf
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« Reply #49 on: May 16, 2011, 07:53 AM »

They need to find a way to use the energy from the feverish typing of Internet Experts.
That, plus the hot air that they're full of should provide plenty of lift.

 Cheesy  Cheesy  Cheesy

ATB,
Sam
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Kantaxel
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« Reply #50 on: May 16, 2011, 01:15 PM »

This is an interesting thread for many reasons.

Sometimes, I think, a fresh perspective is needed. Otherwise, we just keep doing the same old thing, only 10% better.  Smiley

I'm constantly amazed at what we 'flight experts Undecided' think is so important we have to argue about.

Pretty cool that they powered it with a human, but it's all over now, folks Wink

Jim 
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Kant Fly......might just as well buy!
Ca Ike
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« Reply #51 on: May 16, 2011, 02:01 PM »

They need to find a way to use the energy from the feverish typing of Internet Experts.
That, plus the hot air that they're full of should provide plenty of lift.
THe use of hot air is against the rules  Cheesy    I'm no expert, just an aficionado who likes a good puzzle and debate Smiley  Oh and gaining public interest is also part of it and were proof they succeeded in that part at least.
« Last Edit: May 16, 2011, 02:06 PM by Ca Ike » Logged
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