Rotation (aeronautics)

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Not to be confused with Autorotation.
An Aeroflot Il-96 rotating.

In aviation, rotation refers to the action of applying back pressure to a control device, such as a yoke, side-stick or centre stick, to lift the nose wheel off the ground during the takeoff roll. Proper rotation is important for safety reasons and to decrease takeoff distance.[1] This is when the aircraft lifts up from the runway and takes off whenever it reaches the optimal takeoff speed for a safe takeoff, which is called the VR speed. Certain planes like Boeing 727, Boeing 767, and Concorde require a high degree of rotation during takeoff, but not all planes require a lot of rotation; if too much rotation is added for takeoff, the plane can face a tailstrike, or, in the worst cases, will stall and crash.

Rotation is a flight concept which is integral to the design of many tricycle gear aircraft and is not at all applicable to conventional gear aircraft. At the design phase of tricycle gear aircraft there is a selection of the on ground angle of attack of the wing. Such is created in the mains and nose gear leg length design which creates a negative angle of attack relative to the ground. The effect of this idea is that during the takeoff roll the wing will have negative lift until the pilot commands the nose skyward to create a positive angle of attack of the wing. At the end of the flight the concept is reversed where at the touchdown all tires touch the runway and the wing is instantly moved to a negative angle of attack which causes the wing to stop lifting. At one time Cessna Aircraft featured this idea as "Land O Matic" so noted on all of their tricycle gear aircraft.

References[edit]

  1. ^ Christopher L. Parker. "Normal Takeoff and Climb". AOPA. Retrieved 10 July 2010.