Bertie the Bunyip wrote:
Dudley Henriques wrote in newsaednT-q-
:

Le Chaud Lapin wrote:
Hi,

Student pilot here, self-teaching using the Jeppensen Private Pilot
Kit after taking ground school.

I read in the book that combustion "creates" energy, which is
technically not true, but I decided to ignore it since the pictures
are sooo pretty.

Now, in Chapter 3, section about airfoils, it actually says:

"In addition to the lowered pressure, a downward-backward flow of air
also is generated from the top surface of the wing. The reaction to
this downwash results in an upward force on the wing which
demnstrates
Newtons' third law of motion. This action/reaction principle also is
apparent as the airstream strikes the lwoer surface of the wing when
inclinded at a small angle (the angle of attack) to its direction of
motion. The air is forced downward and therefore causes an upward
reaction resulting in positive lift."

IMHO, the latter part of this paragraph is correct, but the former
part is wrong.

Obviously, any air above the wing can only result in a force downward
on top of the wing. The only force causing the plane to want to move
upward comes from beneath the wing. The effect of any air above the
wing is to cause rarefication above the wing, resulting in lower
pressure, thereby giving the 14.7lbs/in^2 (plus) to do its work. That
"reaction" coming from downward movement of air seems just plain
silly
to me.

I am also inclined to take issue with the explanations of
Bernouilli's
Principle which I see often in the literature, but that's a different
subject. [Note, I don't doubt Bernouilli's Principle, I just think
there is more to it than the way it is being described in context of
flying.]

-Le Chaud Lapin-

Please don't take this the wrong way but I'm sure you would have
passed
me up as a potential flight instructor.
:-))))



I nominate Anthony!

Bertie


Nah.....Anthony has offered many times to teach me about aerodynamics
and flying but so far at least I've cleverly managed to avoid that
enlightening experience.
:-))

--
Dudley Henriques