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Re:Why we don’t understand heavier-than-air flight by graderjs on Saturday June 26, 2021 @06:12AM (#27640666)
Isn't it because planes are continually falling (because gravity), and this leads to two things:

1) wings increase the surface area pushing down (gravity) on the air below, which pushes back (air pressure), and

2) as wings are falling toward ground (gravity), they create vortices above the wing, which lowers the pressure, increasing the push up effect of the air below, and

at a certain speed, the vortices are stabilized into low pressure regions above the wings, and in a certain "envelope" region, of speed, plane shape, air pressure, all of these forces are equalized to give you level flight, so long as the dial you turn to get into the envelope region, "speed", keeps up.

That's how I understand it. Happy to hear a physicist / aerospace engineer guide me in how to think about this clearly.

Re:Why we don’t understand heavier-than-air flight by tomsto on Saturday June 26, 2021 @06:33AM (#27640756)
This is not how it works, no falling or positive angle of attack is required for an asymmetrical aerofoil. Imagine swinging a bucket of water over your head - the force your arm feels is similar to what the top surface of the wing feels.
Re:Why we don’t understand heavier-than-air flight by bbojan on Saturday June 26, 2021 @06:40AM (#27640789)
Is that so? I thought that for asymmetric airfoil, zero angle of attack is by definition the angle where it creates no lift. So, tautologically, if it's creating lift a (positive) angle of attack is required.
Re:Why we don’t understand heavier-than-air flight by tomsto on Saturday June 26, 2021 @06:56AM (#27640847)
For a symmetric aerofoil, 0 angle of attack is 0 lift. For an asymmetric - there is (some) lift, which comes entirely from the suction side.

https://www.wolframalpha.com/input/?i=NACA+6409+airfoil&assu...

Re:Why we don’t understand heavier-than-air flight by robotresearcher on Saturday June 26, 2021 @02:40PM (#27644630)
A defining characteristic of a plane is that it is not continuously falling. Falling can’t really be the explanation, since they don’t.