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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.
Location of flight controls in a helicopter. Helicopter flight controls are used to achieve and maintain controlled aerodynamic helicopter flight. [1] Changes to the aircraft flight control system transmit mechanically to the rotor, producing aerodynamic effects on the rotor blades that make the helicopter move in a desired way.
For example, when rotor thrust coefficient is assumed to be constant, the weighing function comes out to be: = and the corresponding weighted solidity ratio is known as the thrust-weighted solidity ratio. [2] When rotor power or torque coefficient is assumed constant, the weighing function is:
The rotor system, or more simply rotor, is the rotating part of a helicopter that generates lift. A rotor system may be mounted horizontally, as main rotors are, providing lift vertically, or it may be mounted vertically, such as a tail rotor, to provide horizontal thrust to counteract torque from the main rotors.
Traditional tail rotor of an Sikorsky S-61. The tail rotor is a smaller rotor mounted vertically or near-vertically at the tail of a traditional single-rotor helicopter, where it rotates to generate a propeller-like horizontal thrust in the same direction as the main rotor's rotation.
Airflow through a helicopter rotor. Above, the rotor is powered and pushing air downward, generating lift and thrust. Below, the helicopter rotor has lost power, and the craft is making an emergency landing.
The critical rollover angle is 5°-8°. Once exceeded, main rotor thrust continues the roll, and recovery via cyclic control is impossible. [1] A helicopter is susceptible to a rolling tendency, called dynamic rollover, when close to the ground, especially when taking off or landing. For dynamic rollover to occur, some factor has to first cause ...
In this mode, the wing provides the lift and the rotor provides thrust. The wing's greater efficiency helps the tiltrotor achieve higher speeds than helicopters. An important early tiltrotor in the 1950s, was the Bell XV-3 , which was one of the first aircraft designs to go from vertical takeoff to horizontal successfully.