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But they are able to adjust the shape of the airfoil and the wing plan as they fly... so a stall will probably never happen with a bird. They will feel it coming on and adjust accordingly.

Cheers,

Hugh
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That's true, Hugh. Birds are marvelous devices that we are yet to match in flying ability. Some birds even have automatic feathers on their leading edges which pop out when their angle of attack reaches a point where stall is imminent.

But if thick airfoils were of any advantage at low Reynolds Numbers, wouldn't at least some birds have them ? If they had thicker wings, it sure would make for more space for additional muscle tissue and bones.

The stall with a thin airfoil isn't necessarily any worse than for a thick airfoil. I've flown some full scale 1920's era thin wing airplanes (Tiger Moth, Travelair, for instance) that have very benign stall characteristics. And I've flown some thick wing airplanes that have terrible stall characteristics.

Dick