Re: 15 minute classroom version...

[Ludwik Kowalski <KowalskiL@MAIL.MONTCLAIR.EDU>]

I support this naive point of view. Why is it a "misconception"?
What happens to the air encountered by the bottom of the wing?
How can the absence of "bouncing down" be demonstrated?

OK, I see. You are not denying bouncing, you are saying it is
not the cause of the lift force. In my opinion it is also the cause.
The faster air from above should contribute more than slower
air from below but that is a different story. The statement "air
pushed down  cause the lift" simply avoids this issue.

William Beaty wrote:

> ... The idea that lift occurs because air bounces off the bottom of the wing
> is a typical misconception that children aquire (I myself figured it out
> as a kid from experimenting with hands out the car window, also by analogy
> with sprayers on hoses deflected from the hand.)  In reality, most of the
> lift appears because the flow of the air "attaches" to the upper surface
> of the wing and is guided downwards because the trailing edge of the wing
> is angled downwards.  It's called "flow attachment", also "the Coanda
> Effect." The air "bounces off" the upper surface of the wing, but the
> "bounce" is reversed, it is like an attraction, and when the air is thrown
> down, the wing must experience an upwards-directed force. ....