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Intermeshing twin rotors of a Kaman K-Max Video of K-Max helicopter in flight, showing the meshing main rotors in motion. Intermeshing rotors on a helicopter are a set of two rotors turning in opposite directions with each rotor mast mounted on the helicopter with a slight angle to the other so that the blades intermesh without colliding.
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.
Below, the helicopter rotor has lost power, and the craft is making an emergency landing. Autorotation is a state of flight in which the main rotor system of a helicopter or other rotary-wing aircraft turns by the action of air moving up through the rotor, as with an autogyro, rather than engine power driving the rotor.
[1] [2] Unlike fixed-wing aircraft, of which the stall occurs at relatively low flight speed, the dynamic stall on a helicopter rotor emerges at high airspeeds or/and during manoeuvres with high load factors of helicopters, when the angle of attack(AOA) of blade elements varies intensively due to time-dependent blade flapping, cyclic pitch and ...
In helicopters with coaxial rotors, the two rotor discs rotate in opposite senses. The dissymmetry of lift of one rotor disc is cancelled by the dissymmetry of lift of the other rotor disc. [citation needed] Tandem rotor helicopters such as the CH-47 Chinook still suffer from dissymmetry of lift, because the rotors are offset from one another ...
For a standard helicopter with a single main rotor, maintaining steady flight with a crosswind presents an additional flight control problem, where strong crosswinds from certain angles will increase or decrease lift from the main rotors.
Dissymmetry of lift is an aerodynamic phenomenon caused by the rotation of a helicopter's rotors in forward flight. Rotor blades provide lift proportional to the amount of air flowing over them. When viewed from above, the rotor blades move in the direction of flight for half of the rotation (advancing half), and then move in the opposite ...
During forward flight, if a gust of wind affects the helicopter from the front, increased flapback will decrease the forward speed of the helicopter. This causes the rotor disc to flap forward, leading to increased forward speed, and increasing subsequent oscillations, unless this is corrected by the pilot.