stabilisatorflater

Stabilisatorflater are trailing-edge surfaces located on the horizontal stabilizer (tailplane) of an aircraft. They are movable fins or flaps designed to modify the lift and aerodynamic moment produced by the tail, contributing to pitch control and trim.

Purpose and function

The primary role of stabilator flaps is to adjust the tail’s lift and thus the aircraft’s pitch attitude and stability. By deflecting the flaps, pilots or automatic flight control systems can achieve nose-up or nose-down moments, reduce control forces on the elevator, and improve handling across different flight regimes such as takeoff, landing, high angles of attack, or changes in weight and center of gravity. They may work in conjunction with trim systems to maintain a desired pitch without continuous control input.

Mechanisms and control

Stabilisatorflater are typically hydraulically powered, but can also be electric or mechanically actuated. They are controlled directly by the flight control system or via trim controls, allowing for adjustments independent of the primary elevator. In some aircraft, the entire horizontal stabilizer is a moving surface (a stabilator) rather than having fixed surfaces with separate flaps; in these cases the term stabilator flaps may refer to supplemental trailing-edge devices or may be less common.

Design considerations

Use of stabilator flaps involves trade-offs among lift generation, drag, and structural loads. Excessive flap deflection can increase drag and risk of tailplane stall or flutter under certain conditions. Reliability of actuators and proper calibration are essential, as with other tailplane control surfaces.

See also: Horizontal stabilizer, Elevator, Trim tab, Stabilizer, Stabilator.