chieftiff said:
For spoilers look here
http//www.grc.nasa.gov/WWW/K-12/airplane/spoil.html
For a good basic description of flight theory look here
http//www.physics.ubc.ca/~outreach/phys420/p420_99/sarah/welcome.htm
I could have written it all out but my diagrams would have been c*ap, 70 words isn't a great deal! I would concentrate on the fact that wings are designed to create a pressure differential between the upper and lower surface, this happens because air is forced to increase in velocity over the upper surface (reducing it's pressure relative to the ambient) It's all there in the physics tutorial.
Sorry to disagree with you chieftiff. Wings, or any airfoil for that matter, do NOT generate lift by making air go faster over the top than the bottom thus creating a pressure differential. Airfoils create lift by obeying Newtons Laws of Motion, specifically, "for every action there is an equal and opposite reaction". Simply, what airfoils do, is divert air downwards, the equal and opposite reaction being to move the wing (and whatever is attached to it), upwards. How do they make air do this? A combination of Coanda effect (basic fluid mechanics - a moving fluid will tend to 'stick' to a surface and follow it) and fluid viscosity (i.e. layers of a fluid will tend to follow each other to a diminishing degree proportional to the distance they are from the airfoil).
If what you say is true, how does a perfectly symmetrical wing generate lift (e.g. on a Pitts Special)? Or, if a curved upper surface is required to make the air go further and therefore faster, what happens when you turn it upside down? Will such a wing 'pull' the aircraft into the ground? Answer, no. You can go to the NASA website where they have film of smoke injected into fluid flows over all sorts of airfoils. What you will see is the fluid passing over the top of a curved airfoil actually arrives at the trailing edge well before the same timeframe fluid which passes beneath - therefore scotching the further/faster argument.
Preesure drops, like lift in fact, are just a by-product of the mechanical processes of making the air change direction.
Boy, have I got too much time on my hands..........!
Regards
Greenking