In article ,
Beryl wrote:
It's true that the exhaust stream doesn't directly push on the inner
surface of a rocket engine.
Yeah, I like that aerospike design, the inside-out nozzle thing.

wing encounters some unmoving air, and the wing then throws the air
downwards, the velocity of the air has been changed, and the wing
will experience an upwards reaction force. At the same time, a
downwash- flow is created.
The wing, remember, is moving forward. "Downwards" is one component of
circulation.
Those weren't my words.

Yes, but Newton's laws tell us that there is a net force down on the
air. No net force down on the air, no net force up on the plane.

Force is change of momentum with respect to time.
BTW, the man whom you are contradicting is Scott Eberhardt, Bachelors &
I wasn't, but I will now.

"...the wing then throws the air downwards" is just plain wrong.
"Downwards" is not a direction that the air was *ever* thrown.

You are incorrect.

The plane experiences a force upwards from the air, therefore (and this
is inescapable basic Newtonian physics) the air experiences a force
downward from the aircraft.

Up, down, forward, backward.
Lift, weight, thrust, drag.
We always see those four simple arrows.
"If a wing encounters some unmoving air, and the wing then throws the
air downwards" is dumbed down. The air isn't thrown downwards.
Illustrations of the flow around a wing in a wind tunnel are misleading
too. You see all the air going from left to right, every time. No
circulation. Air is pushed the other way, from right to left, under the
wing. Did everyone forget that?

The air is thrown down. It has to be. For the aircraft to experience an
upward force from the air, the air must experience a downward force from
the plane. That downward force isn't balanced by any other force on the
air, so it must result in the air being moved (or "thrown") downward.


Bachelors and Masters from MIT, Ph.D. from Stanford, all in Aeronautics
and Astronautics, but you know better!

"Those weren't my words." You didn't have enough confidence in Mr.
Bachelors and Masters from MIT, Ph.D. from Stanford's words to defend them.

They don't need defense.


LOL

Exactly. Eberhardt's credentials made up your mind for you.

Nope. I understood the situation long before I'd ever even read his
article.

--
Alan Baker
Vancouver, British Columbia
http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg