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When a rotor blade is hunting leading and lagging it is?
Lead-lag or leading and lagging is the horizontal movement of the rotor blades forwards and backwards along a vertical hinge. Leading and lagging is a capability designed into a fully-articulated rotor system to reduce the stress on the rotor system due to blade flapping.
What is helicopter blade hunting?
The drag brace or drag damper resists the movement of the blade around its lead-lag hinge on a semi-rigid rotor system. In the same plane, we have also the hunting, defined as the tendency of a blade to oscillate ahead of or behind a position which would be determined by centrifugal force alone.
What is rotor flapping?
Flapping is the vertical movement of a blade up or down to increase or decrease lift in order to compensate for dissymmetry of lift. To equalize lift across the rotor disc, the advancing blade flaps up and the retreating blade flaps down. When the retreating blade flaps down, it moves with the induced flow.
What is the purpose of the helicopter main rotor flapping hinge?
The horizontal hinge, called the flapping hinge, allows the blade to move up and down. This movement is called flapping and is designed to compensate for dissymmetry of lift.
What does the tail rotor do on a helicopter?
The tail rotor is used to control the heading of the helicopter while hovering or when making hovering turns, as well as counteracting the torque of the main rotor. Hovering turns are commonly referred to as “pedal turns.”
What causes a helicopter to turn in the opposite direction?
With a single main rotor helicopter, the creation of torque as the engine turns the rotor creates a torque effect that causes the body of the helicopter to turn in the opposite direction of the rotor.
How do helicopter blades Hunt forward and backwards?
The blades will hunt forward and backwards from the neutral position in a sine wave as the rotor rotates. Lead/lag dampers reduce the force of this hunting. A variation of flapping hinges (independent hinges for each blade) is a teetering hinge on 2 blade helicopters where the hinge is connected to each blade.
How does a helicopter maintain a constant rotor speed?
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. The swash plate is two concentric disks or plates. One plate rotates with the mast, connected by idle links, while the other does not rotate.
What happens to the blade as the rotor rotates?
Since the rotor is turning at a constant speed, the blade must move forward around the lead/lag hinge. In a similar way, the blade flapping down slows down so lags. The blades will hunt forward and backwards from the neutral position in a sine wave as the rotor rotates.