A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air.
In the aerospace context, a propeller is a device that converts rotational power into thrust, which propels an aircraft through the air. Propellers are typically used on aircraft with reciprocating engines, such as propeller planes and some helicopters.
The propellers are typically driven by the aircraft's engine and rotate at high speeds. As the propeller blades rotate, they create a difference in air pressure on either side of the blade. This difference in pressure generates thrust, which propels the aircraft forward.
Examples of aircraft that use propellers include the single-engine Cessna 172, the twin-engine Beechcraft Baron, and the de Havilland Canada DHC-2 Beaver bush plane. Some helicopters also use propellers like Bell 206, Robinson R22 and so on.