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[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 ...
Retreating blade stall is a hazardous flight condition in helicopters and other rotary wing aircraft, where the retreating rotor blade has a lower relative blade speed, combined with an increased angle of attack, causing a stall and loss of lift. Retreating blade stall is the primary limiting factor of a helicopter's never exceed speed, V NE. [1]
The McDonnell XV-1 could slow its rotor from 410 to 180 RPM. The slowed rotor principle is used in the design of some helicopters.On a conventional helicopter the rotational speed of the rotor is constant; reducing it at lower flight speeds can reduce fuel consumption and enable the aircraft to fly more economically.
Stall speed or minimum steady flight speed for which the aircraft is still controllable. [7] [8] [9] V S 0: Stall speed or minimum flight speed in landing configuration. [7] [8] [9] V S 1: Stall speed or minimum steady flight speed for which the aircraft is still controllable in a specific configuration. [7] [8] V S R: Reference stall speed. [7 ...
Helicopter rotors are designed to operate at a specific rotational speed. The throttle controls the power of the engine, which is connected to the rotor by a transmission. The throttle setting must maintain enough engine power to keep the rotor speed within the limits where the rotor produces enough lift for flight.
The Sikorsky UH-60 Black Hawk is a four-blade, twin-engine, medium-lift utility military helicopter, which can carry 15 people, including two pilots, two crew chiefs and two rescue specialists.
Autorotation is permitted mechanically because of both a freewheeling unit, which allows the main rotor to continue turning even if the engine is not running, as well as aerodynamic forces of relative wind maintaining rotor speed. It is the means by which a helicopter can land safely in the event of complete engine failure.
EVTOL operators like Joby and Archer believe their primary advantage over traditional ride-sharing options like Uber and Lyft is speed. For example, these air taxis can replace car trips in ...