Posted for "James H. Keyworth" <jhk@clearwire.net>:

 Paul says: The air inside the wing pushes up on the top surface at 40 PSF
 while it pushes down on the bottom surface at 20 PSF.
 
 Hey, c'mon Paul.  How can a gas in a closed container decide which way it's
 going to exert more pressure.  Can you blow up a round balloon so its bottom
 is a flatter curve than its top?
 
 JHK