Helicopter rotor

This article is about helicopter main rotor systems. For antitorque control, see tail rotor.
A Bell AH-1 SuperCobra with a semirigid rotor system with a 2-bladed main rotor
NOTAR helicopter with a rotorless tail
Merlin Mk2 helicopter flying. This three-engined helicopter has a single large main rotor and smaller tail rotor

On a helicopter, the main rotor or rotor system is the combination of several rotary wings (rotor blades) with a control system, that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight. Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter tail rotor, which connects through a combination of drive shaft(s) and gearboxes along the tail boom. The blade pitch is typically controlled by the pilot using the helicopter flight controls. Helicopters are one example of rotary-wing aircraft (rotorcraft). The name is derived from the Greek words helix, helik-, meaning spiral; and pteron meaning wing.