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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]
However, when the helicopter starts to move forward its speed is added to the speed of the blades as they advance towards the front of the aircraft, and subtracted as they retreat. For instance, if the helicopter is flying forward at 100 km/h, the advancing blades see 300 + 100 km/h = 400 km/h, and for the retreating ones its 300 – 100 km/h ...
This situation, when not immediately recognized can cause a severe loss of aircraft controllability. Retreating blade stall is a factor determining the maximum forward speed of the helicopter, the never-exceed speed (V NE). At very high forward speeds, the advancing blade may go supersonic. This is another factor determining the never-exceed speed.
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 ...
A helicopter crash off the coast of Kauai, Hawaii on Thursday has left one person dead and two people missing, according to authorities.. The crash was reported around 1.20pm, a quarter of a mile ...
The U.S. Army described the helicopter as a UH-60 Blackhawk based at Fort Belvoir in Virginia. The helicopter was on a training flight. Military aircraft frequently conduct training flights in and around the congested and heavily-restricted airspace around the nation’s capital for familiarization and continuity of government planning.
Propeller slipstream reduces the stall speed by energizing the flow over the wings. [26]: 61 Speed definitions vary and include: V S: Stall speed: the speed at which the airplane exhibits those qualities accepted as defining the stall. [26]: 8 V S0: The stall speed or minimum steady flight speed in landing configuration. [27]