LYCOS RETRIEVER 
Helicopter: Air
built 649 days ago
Hovering is the most challenging part of flying a helicopter. This is because a helicopter generates its own gusty air while in a hover, which acts against the fuselage and flight control surfaces. The end result is constant control inputs and corrections by the pilot to keep the helicopter where it is required to be. Despite the complexity of the task, the control inputs in a hover are simple. The cyclic is used to eliminate drift in the horizontal plane, that is to control forward and back, right and left. The collective is used to maintain altitude.
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The helicopter had its first significant impact on military operations during the Korean War, but it came of age in Vietnam. Helicopters fielded air-mobile infantry units, evacuated casualties, hauled artillery and ammunition, rescued downed aviators, and served as ground-attack craft.
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Boeing's HH-47 is an advanced derivative of the Chinook helicopter, offering the benefits of the CH-47F and MH-47G upgrades in order to fulfill the Air Force's CSAR mission needs at low-risk and as soon as possible. With the largest cabin size, highest operating altitude, lowest downwash velocity and most lift capacity of all competitors, the HH-47 provides CSAR crews with enhanced flexibility for demanding missions.
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