To understand wingsuit aerodynamics and how the outfit allows its wearer to really fly, you have to understand the basic physics of flight. The first principle to keep in mind is that air is a fluid -- much like water. Try to move your hand, palm flat, through a tub of water or stick your hand out of a moving vehicle. That force resistance you feel is the motion of the fluid (the air or the water) opposing the motion of an object (your hand).
Flight is a careful relationship of four opposing forces. Weight pulls the flying object down. Lift ensues when the downward momentum of the object meets the resistance of the air. If you have a flat surface or airfoil, then the net lift can not only slow the rate of decent, but actually move the object upward through the air.
While lift and weight cover vertical movement in the air, thrust and drag cover horizontal movement. Thrust occurs when flapping wings or an engine push an object forward. Drag, like lift, is the force exerted by the fluid against a horizontally moving object. For more information on the physics of flight, read How Airplanes Work.
A skydiver exiting an aircraft will instantly experience the pull of gravity -- the force of weight. If he or she is wearing a wingsuit, then the suit's airfoil will provide lift. However, the airfoil isn't large enough to accumulate enough lift to push the flyer's weight upward through the air. This is also why wingsuit flyers must use parachutes to land. The small wings simply can't provide enough lift to slow down flyers to a safe landing speed.
Likewise, a wingsuit provides no thrust, and rapidly flapping your arms will only send you into a steep dive or deadly spin. To soar forward through the air, a wingsuit flyer must depend on his or her glide ratio -- the relationship between lift, drag and weight that determines how far a gliding object can travel from a particular altitude. As weight pulls the flyer down, lift allows the flyer to cut horizontally through the air.
How does a wingsuit allow the wearer to achieve the required lift? Read the next page to learn the different parts of a typical wingsuit.