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Old October 8th 07, 05:58 AM posted to rec.aviation.piloting
Le Chaud Lapin
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Posts: 291
Default Backwash Causes Lift?

On Oct 7, 11:02 pm, flightoffancy wrote:
Did you mess with NASA's online simulations of airfoils?


Yes, 15 minutes ago, in fact after taking a break from my very tedious
work.

Those suggest that the air both "on top" and "on the bottom" of an
airfoil get turned as the airfoil's AoA changes. Those have to be put in
quotes since an aircraft (with the proper engine) can be flown upside
down and in other orientations.


I did notice the turning. The article is claiming that the upper
surface of the wing "turns" the upper flow.

Link: http://www.grc.nasa.gov/WWW/K-12/airplane/right2.html

I must admit that I am having problems with this explanation. It is
extremely vague? What is the turning? How, exactly, does the wing
"turn" the flow. The air is made up of molecules. If it is upper
surface of the wing that is turning does air molecules so that they
have a velocity component that is downward, how is this happening?
Since when, could one body, A, of any kind, that does not involve
gravitational or electrostatic fields, induce another body B, to move
in a direction that has a component vector that is aimed directly at
B?

Also NASA does not just explain why the longer length theory, the
Newtonian theory, and Bernoulli theories are incorrect, they also
elaborate what the correct equations to properly calculate observed lift
are, though I didn't see an example calculation. So they do say what is
correct, as well as what is not.- Hide quoted text -


True.

This "turning" theory of NASA makes me suspicious. If anyone else has
any qualtitative explanation of what they mean by the upper surface of
the wing foil turning the air so that it has a downward component in
its velocity, I would like to see it.

Finally, I do agree that the geometry, AoA, etc...interacts with the
atmospher in such a way that the net result of the flow on the top
surface of the wing is back and downward. What I don't see is the how
the wing itself is "turning" that flow.

-Le Chaud Lapin-