The general name "airscrew" will be used throughout for the organ of propulsion of aircraft.

When the airscrew is in front of the main lifting surfaces it is called a tractor, when behind them a propeller.

When it turns clockwise, as seen by an observer standing in the blast (i.e., behind the aircraft) it is called right-handed and, when anti-clockwise, left-handed. Airscrews are thus classified as :— Propellers or Tractors. Right-handed or Left-handed.