Wikipedia:Sandbox

Introduction

An airfoil is a device that uses air flowing over its surface to generate [lift]. Airplane wings, propellers, tail surfaces are all examples of [airfoils]. Airfoils designed for [subsonic speed] flights are characterized by having rounded leading edges to flow separation. (1) If an airfoil of such characteristics was used under supersonic speeds a detached shock would from in front of the leading edge, as a consequence an increase in wave drag will create a significant impact on the aerodynamics of a supersonic flight. This is why most supersonic airfoils consist of two arcs forming a relatively thin section with sharp leading and trailing edges without fear that the flow will be detached at the leading edge. (2) Thin airfoils’ thickness, camber and angle of attack of the section are designed so the local flow direction at the surfaces of the airfoil has a slight deviation from the free-stream direction. (3) To obtain high lift at low speeds the advanced fighter wing sections incorporate a plain leading-edge flap and a slotted trailing edge flap, as can be seen in Figure 1. The two most common designs of a supersonic airfoil are the “double wedge airfoil & the Biconvex airfoil” see Figures 2 (a), (b) & 3.