Far be it from me to take an opposing position, but how does this concept explain the operation of a propeller where we can consider the thrust it creates as simply lift in the horizontal plane?  I know I've got to be missing something here.

   <Marv>


"Paul Lipps" <elippse@sbcglobal.net> wrote:
"""
 A strongly held concept is that the bottom of a wing has positive pressure
and the top of the wing has reduced pressure, and this is where lift comes
from. Any wing with curvature on the bottom, such as the NLF1 0215F on Lancair
235,320,360 has reduced pressure both on the top and on the bottom; its just
that the reduced pressure on top is lower than on the bottom, so the there is
a net upward force. Since lift is a force due to a pressure difference across
a surface, it may come as a shock to most of you that the pressure difference
is across the top skin and the bottom skin. That's right, Ladies and germs,
lift on a hollow wing is due to the air inside pushing up on the top skin and
pushing down on the bottom skin, but the top skin wins, hopefully!
"""