Cars and air.

When driving cars, especially at high speed while cornering, you want to be sure that your car will remain stuck to the ground. Of course, the tires are doing thier best to help out in that regard, but when you need more "stick", and wider/softer tires just *aren't* enough, you can resort to using a wing. Now, a wing as used on a car, is not used in the same manner as an airplane. In fact, the wings (sometimes called spoilers or airfoils/aerofoils) are attached exactly opposite to the way they are on planes. Instead of providing aerodynamic lift , the press down on the car at speed, helping to hold the car tighter to the ground. This is called downforce .

An interesting solution to the grip/downforce problem was the use of a Lexan skirt attached to the bottom edge and two powerful fans attached to the rear of a car. This was used in the Chaparral 2J . The fans pulled air out from beneath teh car, and vented thm behind. This pulled the car tightly to the ground, and improved grip and corner speed by quite a bit. This innovation in racing cars was imitated by some other groups, but almost all racing federations now disallow this sort of aerodynamic augmentation.