SVX spoiler = downforce?!

Those images definitely help illustrate the function of a wing. The typical "teardrop" airfoil shape is not all that crucial. The Wright flyer had wings of an equal length on top and bottom. The important factor is the angle of the trailing edge. The image that ssnsltd posted actually shows a condition of absolutely zero lift. In order to create lift, the wing must deflect air downwards. This engages Newton's third law, and the force hurling that air down is going to push right back up on the wing. The whole high/low-pressure rubbish is very much secondary to angle of attack. Why should the air traveling over the top of a curved wing be accelerated? What compulsion is there for it to keep up with the air below? None.

Don't believe me? Apply your own logic:

If the whole curved/flat thing [like the diagram above] were the main contributor to lift, how would an airplane fly upside down? Wouldn't that high-pressure zone be shoving it toward the ground?

NapaBavarian's images very clearly show the air being diverted downward. If you move beyond the 2D representation there, you'll find that the ends of the wings induce spinning vortices, just like lee mentions. Airplanes fly by chucking big spinning masses of air down...

[Chiketkd]

Originally posted by deruvian
Chike, remember that "impact" forces are much different than forces applied more slowly. Did you push down on the trunk quickly or slowly?

It was a gradual push down on the trunk...

-Chike

[dcarrb]

Originally posted by ThetaReactor
If the whole curved/flat thing [like the diagram above] were the main contributor to lift, how would an airplane fly upside down? Wouldn't that high-pressure zone be shoving it toward the ground?

Exactly. As I've read someplace, given an appropriate powerplant and control surfaces (elevators, rudder), a barn door will fly.

Spoilers (not wings), simplified: Ever make a paper airplane and fold little "flaps" on the trailing edges of the wings (which, it's worth noting, are rarely "airfoil" shaped)? Fold these surfaces upward and the plane's nose will rise, because the airflow forced over these elevators creates downward pressure on the rear of the plane. Now consider the spoiler on a NASCAR racer. Same principle. With the race car, the trick is to balance to downforce by routing airflow over the nose of the car, rather than beneath it or through the grille openings.

I think if you look at most "winged" race cars (such as the example early in this thread) you'll see the trailing edge is angled sharply upward. And think of the size of these wings relative to the car. They're huge. Now look at the wing on the SVX.

dcb

[ssnsltd]

How stuff works article

Talks through both sides of the airfoil creating lift.