When oriented at a suitable angle, a solid body moving through a fluid deflects the oncoming fluid (for fixed-wing aircraft, a downward force), resulting in a force on the airfoil in the direction opposite to the deflection.
Foils of similar function designed with water as the working fluid are called hydrofoils. Wings, sails and propeller blades are examples of airfoils. Streamlines on an airfoil visualised with a smoke wind tunnelĪn airfoil ( American English) or aerofoil ( British English) is a streamlined body that is capable of generating significantly more lift than drag.
