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6figurelenins | 10 months ago

Layman's guess: wings push air down, air pushes wings up.

An everyday experiment is sticking your flat hand out the window of a moving car. With slight wrist rotations, you'll find even slight deviations from neutral (parallel to the ground) cause your "wing" to rise or fall, with a force that seems proportional to the angle.

We can hypothesize that a symmetric wing, with zero angle of attack, should experience no lift:

https://aviation.stackexchange.com/a/35139

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bandrami|10 months ago

That's part of it. But an asymmetric airfoil will in fact generate lift with a 0° angle of attack, so it's not all Newton either.

SAI_Peregrinus|10 months ago

There is a pressure difference with an asymmetric airfoil, and that results in air being directed downward with a resulting upward reaction force. F=ma still holds, the lift force is equal to the mass × acceleration of the air downwards, likewise momentum is conserved as the momentum of the plane up equals that of the air going down.

All of the lift can be explained by Newton's laws, but explaining why the air moves down in the first place can't be explained by Newton's laws.