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Old October 8th 07, 01:10 AM posted to rec.aviation.piloting
Le Chaud Lapin
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Posts: 291
Default Backwash Causes Lift?

On Oct 7, 5:54 pm, flightoffancy wrote:
In article ,
says...

The downwash thing is wrong. Yes, there is some dispacemtn of air that
causes lift, but it' only a minor contribution in the bigger scheme of
things.


I admit to being a relative retard on this issue (not as retarded as a
non-pilot probably is, but not as educated as an aeronautical engineer).

I thought I had read in numerous books during training that the primary
component of lift is the air that gets knocked downward by the wing. I
was calling that "downwash". Maybe my concept of downwash is wrong,
maybe it's a separate consideration from the air that gets knocked
downward by the airfoil. Hell I might not be remembering any of that
correctly.


Just wanted to reiterate what I said in my OP and each subsequent post
for you benefit since you just joined the discussion.

If you have an aifoil, and you move it forward, there will be
compression beneath the wing. Newton's law will be at play here, and
there will be downwash. This downwash results from the induced
pressure gradient.

That is not what I was talking about. The books that I have been
reading are talking about downwash that is _on top of_ the wing. The
pictures show air moving at an angle, backward and downward near the
trailing edge of the wing.

Note that these are two "downwashes".

I am saying that downwash on top of the wing does not generate a force
on the wing that causes the wing to move upward.

Anyway you say downwash is minor.

Well okay. But then what are the major contributions that cause lift in
the bigger scheme of things?


-Le Chaud Lapin-