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Old December 2nd 09, 04:53 AM posted to rec.aviation.homebuilt
Jim Logajan
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Posts: 1,958
Default visualisation of the lift distribution over a wing

Alan Baker wrote:
Because the push is caused by the impact of countless air molecules
with the surface of wing. If those collisions fall to zero (i.e. in a
perfect vacuum) then there is zero push.


I don't see what a change in air density (such as taking the extreme case
of a vacuum) has to do with lift. Unless you are claiming density change as
a requirement?

I believe lift can be reasonably computed using inviscid _incompressible_
flow theory (e.g. as far back as Kutta's 1902 dissertation,) so I don't see
why any change in _density_ - much less the vacuum edge case - needs to be
invoked.