A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) and 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 a swashplate connected to the helicopter flight controls.The vast majority of helicopters maintain a constant rotor speed (RPM) during flight, leaving the angle of attack of the blades as the sole means of adjusting thrust from the rotor. Cyclic controls are used to change a helicopter's roll and pitch while the collective controls the entire swashplate moving up or down along its axis without changing the orientation of the cyclic controls

This blade tip is from a full metal blade, originally mounted when we received of our sea king's in 1976. These were filled with an inert gas with an indicator on the main rotor head to detect possible damage. These blades can be recognized by the olive green color on the bottom and the black color on top. Later they were replaced by a variant made of composite, these are completely gray.