Elevator
The elevator is an aerodynamic control surface and is used to turn an aircraft or airship around its transverse axis. In the case of an aircraft, this changes the angle of attack of the wing and thus the dynamic lift .
As a rule, this is a movable horizontal surface in the rear area of the tail fin, which can be moved up or down a transverse axis using the control stick or control horn . The elevator can also be attached to other parts of the aircraft. The Wright brothers' aircraft was a so-called canard construction (duck wing) and had the elevator at the front.
The elevator is adjusted by a trimming device , e.g. B. a trim tab , also used for longitudinal trimming of an aircraft.
If the elevator is no longer flown, it can no longer contribute to the steering ( deep stall ). This can lead to loss of control and, if the flight altitude is low, the aircraft can crash. Since aircraft with a T-tail unit (such as the Boeing 727 or Tupolev Tu-154 ) tend to have a deep stall in critical flight phases, this arrangement of the tail unit is rarely used in new commercial aircraft.
Pendulum elevator
A pendulum elevator is a special embodiment of the elevator. With this design, the entire tail fin is rotated around an axis that runs close to the pressure point . This makes a subdivision into damping fin and rudder flap superfluous. Pivoting around this axis changes the angle of attack and thus the lift. If the rudder halves are mechanically rigidly connected, the steering movement can be on the same side, if the pendulum rudder is also superimposed on the aileron deflection and the halves deflected differently, this is called a taileron .
Since the 1950s, almost all high-performance aircraft, starting with the North American F-86 and the Bell XS-1 , have used a pendulum elevator. It is also occasionally used in gliders , for example the Schleicher ASW 15 .
See also
literature
- Ernst Götsch: Aircraft technology . Motorbuchverlag, Stuttgart 2003, ISBN 3-613-02006-8 .