Human-powered helicopter

[PMC]

@Blob,

Yep, spot on with the observation comparing a helicopter rotor to a conventional aerofoil.  

One thing though re the Gossamer Condor human powered channel crossing:

Although the Gossamer was propelled by human effort, the aerofoil was partly supported by thermals from the body of seawater.  You only have to see how a sea bird skims the surface of the water for some distance without actually flapping to see that enough lift is being generated to keep the bird aloft without requiring the bird to flap constantly.

You might also notice that the wings of seabirds tend to be longer and narrower than their land bound cousins.

A human powered helicopter would be under constant power to remain airborne, the pilot couldn't stop pedalling and coast because the rotor would cease to generate sufficient lift (constant movement is required), plus the balancing fan (tail rotor) needs it's power modulated to compensate for torque.

I'd love to see the thing fly though...

[PMC]

bloodline wrote:
I remember reading a book all about Lamina air flows and how insects can use Vorticies on the top surface of the wing increase the speed of the air, many years ago (probably about 15!).

when you think about it like that, it's hard to see why any one would think a Bumble Bee can't fly!

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The American P51 Mustang fighter of WW2 was revolutionary because it utilised a laminar flow wing.  This afforded great manoueverability without sacrficing speed and fuel economy through drag because the wing was excessively thick in chord.

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Until the advent of slow motion photography, physics was unable to explain how a four winged dragonfly remained aloft.  Wings that occur in nature have the ability to change shape to suit the conditions.  Insect wings flex to ensure both lift and thrust are delivered on up and down strokes.  Bird and mammal wings are more advanced and can physically change in shape to match the prevailing winds, thermals etc.  This is why a Peregrine Falcon can soar to a respectible altitude which requires an efficient lifting wing and still dive at speeds in excess of 200Mph, simply by folding the wing a certain way.