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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]
In aeronautics, a swashplate is a mechanical device that translates input via the helicopter flight controls into motion of the main rotor blades. Because the main rotor blades are spinning, the swashplate is used to transmit three of the pilot's commands from the non-rotating fuselage to the rotating rotor hub and mainblades.
Collective angle of attack for the rotor main blades via the swashplate: Increase/decrease pitch angle of all main rotor blades equally, causing the aircraft to ascend/descend Increase/decrease torque. In some helicopters the throttle control(s) is a part of the collective stick. Rotor speed is kept basically constant throughout the flight.
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
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.
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Overhead view of helicopter rotors. The rotor tips travel much faster than the inner sections, so produce more lift. (For the purposes of this article, the demarcated circular regions are irrelevant and should be ignored.) A helicopter rotor blade is an airfoil, which is driven through the air to create lift. The lift generated is proportional ...