Backwash Causes Lift?

On Oct 8, 5:18 pm, Phil wrote:
I think you are really describing Bernoulli. If you agree that the
pressure on the top of the wing is lowered by the wing's progress
through the air, then that is just what Bernoulli suggests.

This is true...but even if you do, there seems to be a lot of people
who do not realize the implications of what you just wrote. Yes it's
Bernoulli, but the Bernoulli that is taking place has nothing to do
with the Bernoulli that is being described in flight education texts.
And no it is not a matter of style, or equivalent models that are
interchangeable, or anything like that. There is a fundamental
difference in perception going on.

If you
don't like the concept that the top of the wing is being sucked upward
by that lower pressure

It is not a matter of whether I like it or not. It is something that
simply does not happen. There is no sucking force.

then think of it this way. Imagine a cross-
section of the wing. The top surface of the wing forms a line. The
air just above this line has lower pressure. The air below this line
(inside the wing) has normal pressure.

So the air below the line is
pressing upward against it with more force than the air above is
pressing down.

Right...I have been saying this all along. Then the net force on the
wing is upward.

This is lift, and since the upper surface of the wing
is attached to the ribs and spars, this lift is imparted to the
airplane.

Yes, and the all the upward force that is being imparted comes from
the bottom surface of the wing.

The upper surface of the wing can only help by *not* imparting a
downward force.

The upper surface of the wing does not impart and upward force on the
wing.

-Le Chaud Lapin-

Le Chaud Lapin wrote:

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.


You really need to look at some video of Tuft testing.

Here's one to start with.

http://www.youtube.com/watch?v=zrwlpHE7P8Q