On a helicopter, the main rotor or rotor system is the combination of several rotary wings 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.
A Bell AH-1 SuperCobra with a semirigid rotor system with a 2-bladed main rotor
NOTAR helicopter with a rotorless tail
Tail Rotor of a Sea Lynx, the smaller tail rotor counter-acts the force of the spinning main rotor in many designs, although there is other solutions to this, such as having two counter-rotating main rotors
Looking up at CH-53G, which has 6-blades on its main rotor
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of short take-off and landing (STOL) or short take-off and vertical landing (STOVL) aircraft cannot perform without a runway.
A Bell 206 helicopter operated by the Los Angeles Police Department Air Support Division
Cabin view looking out from a helicopter in flight
Bell 412CF looking forward from the tail, showing its twin turbine endinge exhausts
1956 Hiller YROE-1 one-man "Rotorcycle" being tested at NASA Ames Research Center
