Helicopter rotor

A rotating assembly of blades that generates aerodynamic lift and, in helicopters, helps control flight by changing blade pitch and rotor thrust.

Rotor blade: An airfoil-shaped blade that rotates around a hub to generate aerodynamic force. Each blade contributes lift as it sweeps through the air.
Rotor hub: The central assembly that connects rotor blades to a helicopter’s mast or drive system. It supports the blades and transmits forces between them and the aircraft.
Coaxial rotor: A rotor arrangement with two counter-rotating rotors mounted on the same axis. It cancels torque without a tail rotor but requires a more complex rotor system.
Main rotor: The primary rotor that provides most of a helicopter’s lift and often its directional control. It is the principal lifting rotor in conventional helicopter designs.
Retreating blade stall: A loss of lift on the retreating side of a rotor when its blades exceed critical angle of attack. It limits forward speed as the retreating blade encounters lower relative airflow.
Collective pitch control: A helicopter control that changes the pitch of all main rotor blades together. Changing every blade’s pitch together varies total rotor thrust.
Swashplate: A mechanical assembly that transfers stationary control inputs to rotating rotor blades. It converts pilot control movement into collective and cyclic blade-pitch changes.
Tandem rotor: A helicopter arrangement with two large rotors mounted fore and aft. Its two lifting rotors balance torque and allow a long cabin without a tail rotor.
Tail rotor: A small rotor mounted near a helicopter’s tail to counter main-rotor torque and control yaw. It supplies anti-torque thrust in the conventional single-main-rotor layout.
Dissymmetry of lift: The unequal lift between advancing and retreating rotor blades in forward flight. The rotor must compensate for this imbalance as one side moves faster through the air.

Linked from 9 pages