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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]
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
When the blade retreats, the blade falls downward again, increasing the AOA and therefore generating greater lift. There are three general designs. The earliest, and by far, least common design today, is the fully rigid rotor system; the blades are rigidly fixed to the rotor hub but made of a flexible material that allows some degree of flap ...
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 rotor consists of a mast, hub and rotor blades. [citation needed] The mast is a cylindrical metal shaft that extends upwards from the transmission. At the top of the mast is the attachment point for the rotor blades called the hub. Main rotor systems are classified according to how the rotor blades are attached and move relative to the hub.
[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 ...
Static Rollover is a rolling action when the helicopter blades are not in rotation. When the rotor blades stop, the helicopter has the same principles of any other object and will roll if the static rollover critical angle is exceeded. Each helicopter has its own critical angle; this is a byproduct of its center-of-gravity.