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The Bell Boeing Quad TiltRotor (QTR) is a proposed four-rotor derivative of the Bell Boeing V-22 Osprey developed jointly by Bell Helicopter and Boeing.The concept is a contender in the U.S. Army's Joint Heavy Lift program (a part of Future Vertical Lift program).
A quadcopter, also called quadrocopter, or quadrotor [1] is a type of helicopter or multicopter that has four rotors. [ 2 ] Although quadrotor helicopters and convertiplanes have long been flown experimentally, the configuration remained a curiosity until the arrival of the modern unmanned aerial vehicle or drone.
If the engine fails, the freewheeling unit automatically disengages the engine from the main rotor, allowing the main rotor to rotate freely. The most common reason for autorotation is an engine malfunction or failure, but autorotation can also be performed in the event of a complete tail rotor failure, or following loss of tail-rotor ...
The higher the loading, the more power needed to maintain rotor speed. [3] A low disk loading is a direct indicator of high lift thrust efficiency. [4] Increasing the weight of a helicopter increases disk loading. For a given weight, a helicopter with shorter rotors will have higher disk loading, and will require more engine power to hover.
Unlike single- and double-rotor helicopters which use complex variable pitch rotors whose pitch varies as the blade rotates for flight stability and control, multirotors often use fixed-pitch blades; control of vehicle motion is achieved by varying the relative speed of each rotor to change the thrust and torque produced by each.
In a zero airspeed hover the rotor blades, regardless of their position in rotation, have equal airspeeds and therefore equal lift. In forward flight the advancing blade has a higher airspeed than the retreating blade, creating unequal lift across the rotor disc. A fuller treatment is provided in dissymmetry of lift.
Rotor syndrome is a benign disease requiring no treatment. [2] Jaundice is a lifelong finding, but the disease is not associated with morbidity or mortality, and life expectancy is not affected. [2] Most individuals with Rotor syndrome are born to consanguineous couples and its diagnosis may coincidently identify consanguinity. [2]
Pages in category "Engine problems" The following 13 pages are in this category, out of 13 total. This list may not reflect recent changes. B. Back-fire; C.