One of the best descriptions of how a wing works I've heard is that it throws air at the ground (by means of the pressure field about the wing). If you think in terms of a propeller or helicopter which throws air in a particular direction you can make sense of the description. A propeller produces thrust, so does the wing, the wings thrust being equal to the aircrafts weight, all things being equal, in straight and level flight.
A plot of the pressures pertaining to my previous post. Note that negative values of
cp produce arrows pointing away from the airfoil, and positive values point towards the airfoil. In all cases, the formula for
cp is cp=(p−p∞)/q∞
p is the local pressure,
p∞ is the pressure far away from the airfoil, and
q∞ is the dynamic pressure far away from the airfoil.
The dashed line is for inviscid flow, the solid line for pressure with boundary layer effects.
