Most foil shapes require a positive angle of attack to generate lift, but cambered airfoils can generate lift at zero angle of attack. This force is known as aerodynamic force and can be resolved into two components: lift and drag.

When oriented at a suitable angle, the airfoil deflects the oncoming air (for fixed-wing aircraft, a downward force), resulting in a force on the airfoil in the direction opposite to the deflection. The lift on an airfoil is primarily the result of its angle of attack. Foils of similar function designed with water as the working fluid are called hydrofoils. Airfoils can be designed for use at different speeds by modifying their geometry: those for subsonic flight generally have a rounded leading edge, while those designed for supersonic flight tend to be slimmer with a sharp leading edge. An airfoil is a streamlined shape that is capable of generating significantly more lift than drag. The component parallel to the relative freestream velocity is called drag. The component of this force perpendicular to the relative freestream velocity is called lift. Streamlines on an airfoil visualised with a smoke wind tunnelĪn airfoil ( American English) or aerofoil ( British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.Ī solid body moving through a fluid produces an aerodynamic force.

Wing and airfolil geometry x 21