mark wrote in message ...
does anybody know which side of the wing gets the lift.

Mark,

Both sides are necessary. Single surface winds, only found in
Ultralights now I think, are much less effective in creating life, and
they create more drag too.

There's basically two theories about life creation, both of which
describe part of what's happening. Bernoulli's theory says that air
speeded up lowers it's pressure. I.e. there's a fixed amount of
energy at any given time. It either goes into speed or pressure. The
low pressure air is on the top of the wing. Yes, I'm simplifying
greatly, there are much more detailed analysis available online and in
aeronautical engineering books. The air from the top also is
accelerated down after the wing passes due to the shape of the wing
and the air following it.

The other theory is that the air bounces off the bottom of the wing to
push the wing up. (I'm cringing as I write this as I'm simplifying
and dropping out so much). The air also follows this surface and also
can be accelerated down as above.

Basically, the wing works by having a shape that pushes air down, and
thus the wing up. It does this with both the bottom and the top of
the wing. Both surfaces are necessary and have different shapes for
different speed airplanes. There's a picture I remember of a small
jet flying just above a cloud layer in clear air. The air pushed
downward was very visible as it caused an airplane-width trough in the
cloud layer below.

This is a topic which comes up regularly in this group. Most are
tired of it and simply refer you to other sources as there's plent of
information out there. One source I like is:
http://www.av8n.com/how/. Libraries are useful too.

-Malcolm Teas