Basic airfoil design involves shaping its cross section such that camber, speed, lift and drag are balanced appropriately for the application. The airfoil's chord, or path between the leading and trailing edges, is also designed to shape the wing and improve performance.
Airfoil camber is the asymmetrical shapes on the top and bottom of the airfoil. Airfoils with lower cambers tend to provide less aerodynamic drag to increase speed. These designs, however, provide less lift than deeper camper airfoils. By designing the chord to bend upward or in an "S" shape, the center of pressure under the airfoil moves very little, thus increasing stability. These designs, in turn, reduce lift and increase drag.