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An example of the effect of rotor blade number is the UH-72 (EC145 variant); the A model had four blades, but the UH-72B was changed to five blades which reduced vibration. [24] Other blade numbers are possible, for example, the CH-53K, a large military transport helicopter has a seven blade main rotor. [25]
As the blades rotate, the speed of the blade-tips relative to the air remains constant. Now imagine the helicopter in forward flight, at v meters per second. The speed of the blade-tip at point A in the diagram relative to the air is the sum of the blade-tip speed and the helicopter forward-flight speed: rω+v.
A rotor blade produces more lift in the advancing half. As a blade moves toward the direction of flight, the forward motion of the aircraft increases the speed of the air flowing around the blade until it reaches a maximum when the blade is perpendicular to the relative wind. At the same time, a rotor blade in the retreating half produces less ...
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
An intermeshing-rotor helicopter (or synchropter) is a helicopter with a set of two main rotors turning in opposite directions, with each rotor mast mounted with a slight angle to the other, in a transversely symmetrical manner, so that the blades intermesh without colliding.
1. Non-rotating outer ring (blue). 2. Turning inner ring (silver). 3. Ball joint. 4. Control (pitch) preventing turning of outer ring. 5. Control (roll). 6. Linkages (silver) to the rotor blade. In aeronautics, a swashplate is a mechanical device that translates input via the helicopter flight controls into motion of the main rotor blades.
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.
The Sikorsky CH-53K King Stallion (Sikorsky S-95) [2] is a heavy transport helicopter designed and produced by Sikorsky Aircraft.The King Stallion is an evolution of the long running CH-53 series of helicopters which has been in continuous service since 1966, and features three up-rated 7,500 shp (5,590 kW) engines, new composite rotor blades, and a wider aircraft cabin than its predecessors.