Helicopters and Spacecraft

Helicopters also change their attitude by pitch, roll, and yaw motions, but they do it differently from fixed-wing airplanes. Unlike airplanes, helicopters do not have wings, ailerons, elevators, or a rudder. Instead, they use their main rotor, the spinning blades on top, for pitch and roll move­ments. Tilting the whole rotor forward or back­ward changes the pitch of a helicopter. Tilting the rotor to one side or the other makes the air-

POINTING AT THE HORIZON

During daylight, pilots often keep an aircraft’s attitude under control by simply looking out of the window.

To keep an airplane flying straight and level, the pilot keeps its nose pointing at the horizon and the wings level with the horizon. This is called visual flight. If the horizon is not visible because of darkness or clouds, an instrument in the cockpit called the artificial horizon is used instead. It shows an outline of the plane’s wings in front of a ball with the horizon marked on it. Whatever way the plane moves, the ball rotates to keep its artificial horizon in line with the real horizon. A glance at this instrument shows whether or not the plane is level.

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craft roll. Speeding up or slowing down the small rotor in the helicopter’s tail makes the aircraft yaw to the left or right.

The Space Shuttle looks like a delta­wing airplane. It uses elevons in its wings to control pitch and roll. A rudder in its tailfin controls yaw. It also has a hinged panel called the body flap under its tail. No other aircraft or spacecraft has this control surface, which is used to trim the Space Shuttle’s pitch. In space, the Space Shuttle is unable to change its attitude in the same way as a plane
because elevons and rudders do not work in space. Instead, it fires small rocket thrusters in its nose and tail.

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SEE ALSO:

• Aileron and Rudder • Control System • Lift and Drag • Tail

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