A proprotor is a spinning airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....

 that is used as both an airplane-style propeller
A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...

 and a helicopter-style rotor
Rotor may refer to:*A rotating part of a mechanical device, for example in an electric motor, generator, alternator or pump.In engineering:...

 during the same flight. Proprotors are typically used on vertical takeoff and landing (VTOL) aircraft.

The dual-role airfoil is accomplished by one of several design approaches:
  • changing the angle of attack of the wing that the proprotor is attached to, from approximately zero degrees to around ninety degrees: a tiltwing
    A tiltwing aircraft features a wing that is horizontal for conventional forward flight and rotates up for vertical takeoff and landing. It is similar to the tiltrotor design where only the propeller and engine rotate. Tiltwing aircraft are typically fully capable of VTOL operations.The tiltwing...

  • changing the angle of attack of only the rotor hub, and possibly the engine that drives it, as on a tiltrotor
    A tiltrotor is an aircraft which uses a pair or more of powered rotors mounted on rotating shafts or nacelles at the end of a fixed wing for lift and propulsion, and combines the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft...

  • changing the angle of attack of the entire aircraft, as on a tailsitter
    A tailsitter is a type of VTOL aircraft that launches and lands on its tail. One of the most famous examples of this type of aircraft is the Ryan X-13 Vertijet. Among the propeller-driven versions were the Lockheed XFV, and the Convair XFY Pogo. Studies and wind tunnel models were made of a...

    , which launches and lands on its tail.

See also

  • Convertiplane
    A convertiplane is an aircraft that converts in flight to change the method to obtain lift, and is capable of vertical take-off and landing. The most common example uses a standard wing in horizontal flight and proprotors for takeoff and landing; the proprotors could be in a tilt rotor or tilt wing...

  • Puffin personal aircraft
    Puffin (aircraft)
    |-See also:- External links :* , 2010-02-08.*, Charles Q. Choi, Scientific American, 2010-01-19*, Discover Magazine, 2010-01-20.*, Jason Paur, Wired, 2010-01-21.*, computer graphic video....

  • VTOL
    A vertical take-off and landing aircraft is one that can hover, take off and land vertically. This classification includes fixed-wing aircraft as well as helicopters and other aircraft with powered rotors, such as cyclogyros/cyclocopters and tiltrotors...

  • V-22 Osprey
    V-22 Osprey
    The Bell Boeing V-22 Osprey is an American multi-mission, military, tiltrotor aircraft with both a vertical takeoff and landing , and short takeoff and landing capability...

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