Control
Elevator
In addition the tailplane helps adjust for changes in the center of lift, and center of gravity caused by changes in speed and attitude, or when fuel is burned off, or when cargo or payload is dropped from the aircraft.
A tailplane normally has a hinged aft surface called an elevator, which allows the pilot to control the amount of lift produced by the tailplane. This in turn causes a nose-up or nose-down pitching moment on the aircraft, which is used to control the aircraft in pitch.
Stabilators or all-moving tails
In transonic flight shock waves generated by the tailplane render the elevator unusable. An all-moving tail was developed by the British for the Miles M.52, but first saw actual transonic flight on the Bell X-1; fortunately Bell Aircraft Corporation had included an elevator trim device that could alter the angle of attack of the entire tailplane. This saved the program from a costly and time-consuming rebuild of the aircraft.
Transonic and supersonic aircraft now have all-moving tailplanes to counteract Mach tuck and maintain maneuverability when flying faster than the critical Mach number. Normally called a stabilator, this configuration is often referred to as an "all-moving" or "all-flying" tailplane.
Read more about this topic: Tailplane
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