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Blade pitch control is a feature of nearly all large modern horizontal-axis wind turbines.It is used to adjust the rotation speed and the generated power. While operating, a wind turbine's control system adjusts the blade pitch to keep the rotor speed within operating limits as the wind speed changes.
Most helicopters have a single main rotor but require a separate rotor to overcome torque. This is accomplished through a variable-pitch antitorque rotor or tail rotor. This is the design that Igor Sikorsky settled on for his VS-300 helicopter, and it has become the recognized convention for helicopter design, although designs do vary. When ...
[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 ...
Phase lag may vary depending on rotor tilt rate, ratio of aerodynamic damping to blade inertial forces (Lock number), offset of flapping hinge from axis of rotation (e/R ratio), and coupling of blade flap, drag, and feather motions, and often results in cross-coupling between the aircraft control axes. Phase lag is a property of all rotating ...
If a helicopter suffers a power failure a pilot can adjust the collective pitch to keep the rotor spinning, generating enough lift to touch down and skid in a relatively soft landing. [ 3 ] The collective pitch control in a Boeing CH-47 Chinook is called a thrust control , but serves the same purpose, except that it controls two rotor systems ...
The helicopter rotor is modeled as an infinitesimally thin disk with an infinite number of blades that induce a constant pressure jump over the disk area and along the axis of rotation. For a helicopter that is hovering, the aerodynamic force is vertical and exactly balances the helicopter weight, with no lateral force.
The tail rotor system rotates airfoils, small wings called blades, that vary in pitch in order to vary the amount of thrust they produce.The blades most often utilize a composite material construction, such as a core made of aluminum honeycomb or plasticized paper honeycomb, covered in a skin made of aluminum or carbon fiber composite.
The rotorhead is where the lift force from the rotor blades act. The rotorhead is connected to the main drive shaft via the Jesus nut, and houses several other components such as the swash plate, flight control linkages and fly-bars. [1] The rotor hub is also where the centre of gravity acts on the helicopter. The rotor head of a Sikorsky S-92