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Old October 10th 07, 02:49 AM posted to rec.aviation.piloting
Le Chaud Lapin
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Posts: 291
Default Backwash Causes Lift?

On Oct 9, 7:51 pm, Phil wrote:

Maybe there was a misunderstanding. Your original posts implied that
you were thinking that there was some kind of suction force. Most
importantly, it appear that you were thinking that the molecules on
the overside of the top surface of the wing were somehow pulling up on
the wing.

This last post of yours, is, technically acceptable, but if you look
at it closely, it's like someone asking you if you have $20 in your
pocket, you say, "No, I have a $2, a $5, 3 $1's, and a $10."

Physicists generally don't arbitrarily pick apart an object the way
you are saying. With the point of view you just gave, I could just as
well say that there really is no pressure on the upperside of the
bottom surface of the wing, but 10,000 "mini-pressures", each to be
taken individually and added up.

Then how do you explain what happens when a wing stalls? When a wing
reaches a high enough angle of attack to stall, the bottom surface is
still deflecting air downward. Yet when the airflow over the top of
the wing detaches and becomes turbulent, most of the lift of the wing
is destroyed. If the attached airflow over the top of the wing is not
generating lift, then why does the lift disappear when that airflow
detaches?


If you look at this paragraph that you wrote before, it seems at first
glance that you are not aware that the air, doing good-stream
conditions, is doing nothing more than not pushing down as hard as in
a stall or standstill.

Because the turbulent air on top of a wing during a stall pushes down
on the wing harder than does when the airflow non-turbulent.


-Le Chaud Lapin-

You can also see from the falling line that you imply that there
should be research to support my "theory", but there is no theory or
all.

Do you know of any research that supports that theory?


Perhaps there was just a misunderstanding.

-Le Chaud Lapin-