Airfoil
An airfoil (in American English, or aerofoil in British English) is the shape of a wing, or blade of a propeller, the blade of a ship's screw or the shape of a sail as seen in cross-section. When moving through a fluid it will provide lift and drag. Lift is not only up, it may be in other directions depending on what it is used for. The airfoil has a rounded leading edge (front edge of the wing) to make the airfoil more insensitive to the angle of attack.
Airfoil Media
Examples of airfoils in nature and in or on various vehicles. The dolphin flipper at bottom left obeys the same principles in a different fluid medium; it is an example of a hydrofoil.
Streamlines on an airfoil visualised with a smoke wind tunnel
Streamlines around a NACA 0012 airfoil at moderate angle of attack
Lift and drag curves for a typical airfoil
Different definitions of airfoil thickness
An airfoil designed for winglets (PSU 90-125WL)
An airfoil section is displayed at the tip of this Denney Kitfox aircraft, built in 1991.
Airfoil of a Kamov Ka-26 helicopter's lower rotor blade
