T o d d P a t t i s t wrote:

I'd say it's the other way around: Lift creates the pressure differential.

The pressure differential is caused by the motion of the air
as the wing moves through the air.

Well how will that work. The air on top is set into motion as a result
of the wing pulling on it and the air on bottom is set into motion as a
result of the wing pushing on it. How can the motion of the air on the
top and bottom of the wing cause a pressure differential? It can't.
The pressure differentials are actually caused by the wing pulling and
pushing on the air and the air pushing and pulling back. Low pressure
does very little to generate lift directly. Example. A ball will
suspend in an upward airflow from an air hose. This causes the not to
bright people at the NASA web sight to jump to the large and mostly
inaccurate conclusion that it is sucked in to the low pressure flow or
pushed into it by the higher atmospheric pressure. This is disproved
by the fact other shaped object do not seem to be sucked into the flow
at all.


The shape of the wing,
particularly, the upper surface, strongly affects the motion
of the air and thereby strongly affects the amount of lift
and drag produced.



The shape of the wing (the top or bottom) strongly affects the
direction of the motion of influenced air. Thereby strongly affecting
the amount of lift produced. Example One of the airfoil shapes that
generates the most lift at zero degrees angle of attack is the under
cambered. It uses shape on top and bottom to divert the low-pressure
air.