A
supercritical airfoil is an
airfoil designed, primarily, to delay the onset of
wave drag in the
transonic speed range. Supercritical airfoils are characterized by their flattened upper surface, highly
cambered (curved) aft section, and larger
leading edge radius compared with
NACA 6-series laminar airfoil shapes. Standard wing shapes are designed to create lower pressure over the top of the wing by accelerating the air using the
Bernoulli's principle. The camber of the wing determines the how much the air accelerates around the wing. As the speed of the aircraft approaches the speed of sound the air accelerating around the wing will reach the Mach 1 and shockwaves will begin to form. The formation of these shockwaves causes wave drag. Supercritical airfoils are designed to minimize this effect by flattening the upper surface of the wing.