A stabilator is a fully-movable horizontal stabilizer that pivots from a central hinge point, combining the functions of both the fixed stabilizer and the movable elevator. Because the entire surface tilts as one, it offers the pilot more direct and effective control over the aircraft's pitch than do separate elevators, and it is sometimes classified as an all-moving tail.
A conventional stabilizer is fixed in position and carries hinged elevators, while a trimmable stabilizer can slowly adjust its setting via the trim system to maintain pitch balance. Each arrangement therefore presents different benefits and drawbacks in weight, complexity, control power and maintenance.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
What is the difference between a stabilator and a stabilizer?
A stabilator is approximated by a stabilizer for preliminary estimation, yet they differ in both design and function. The stabilizer is fixed, being a non-moving surface that keeps the aircraft stable. It provides stability for the aircraft by generating a down-force whose magnitude is set. Because the stabilizer is fixed and has a separate control surface doing pitching, angle of attack difference of main wing and stabilizer determines static longitudinal stability, making the whole system inherently stable but less maneuverable.
The stabilator combines the stabilizer and elevator into one large, movable surface. Instead of a fixed stabilizer with a hinged elevator, the entire horizontal tail pivots, so altering the angle of attack of the whole airfoil changes the amount of lift generated and the pitching moment directly. This single-surface layout delivers strong control response, which is the reason for the pitch-trim design called anti-servo tab that prevents over-sensitivity. The pilot will not notice difference in handling qualities because the anti-servo system makes the stabilator feel like a conventional control, yet the absence of a fixed stabilizer means static longitudinal stability must be managed through careful area and hinge-moment sizing rather than by the angle of attack difference of main wing and stabilizer.
What is the difference between a stabilator and an elevator?
The difference between a stabilator vs elevator is explained in the table below.
| Term | Description |
|---|---|
| Elevator | Small moving section at rear of stabilizer Connected to stabilizer by a hinge Used to generate and control pitching motion Varies amount of force generated by tail surface Provides precise changes in pitch for maneuvers Attached to each side of fuselage Changes camber of tailplane Changes effective shape of airfoil of stabilizer Active control surface for pitch Primary control surface for pitch on most aircraft Favored for simplicity, cost-effectiveness Generates pitch moment Trim tabs on elevators move opposite of control Work in pairs (right and left elevator move up) |
| Stabilator (all-flying stab) | Offers less pitch effectiveness than stab-and-elevator Tilting the entire surface for pitch control Large commercial airliners have both stabilator and elevators |
| Stab-and-elevator | Changes camber of tailplane More effective than tilting all-flying stab |
| Trim tab | Moves opposite of control surface Acts as anti-servo |
| Lift force | Some distance from aircraft center of gravity |
A stabilator is an all-flying stab whose entire surface pivots. An elevator is the small moving section at the rear of the stabilizer, attached by hinges to the fixed horizontal stabilizer and working as the active control surface for pitch. The stab-and-elevator arrangement changes the camber of the tailplane, making it more effective than simply tilting the all-flying stab. Because the elevator varies the amount of force generated by the tail surface and changes the effective shape of the airfoil, it generates the pitching moment needed for precise changes in pitch required for maneuvers. Elevators are favored for simplicity, cost-effectiveness, and intrinsic stability, and large commercial airliners often combine both an all-moving tailplane and elevators to blend trimming authority with fine pitch control.
How do a Trimmable Horizontal Stabilizer and a stabilator differ?
A Trimmable Horizontal Stabilizer differs from a Stabilator in both structure and control strategy. The THS is a fully-moving horizontal tail surface whose entire horizontal tail assembly moves in response to the trim system. It does not move when the pilot moves the control column or control stick. Because the whole stabilizer pivots to a specific angle that trims the airplane for current weight and speed, it provides strong trimming power over the full speed range and allows smaller elevator deflection angles.
A stabilator is a single-piece, all-moving tail surface that serves as both stabilizer and elevator. The pilot stick input directly pivots the surface, and an anti-servo tab moving in the same direction supplies control and prevents over-controlling. Thus, the THS relies on a separate trim system - often an electrically operated jackscrew - while the stabilator integrates primary pitch control and feel into one surface, making the two systems fundamentally different in operation and pilot interface.
How do a vertical stabilizer and a stabilator differ?
A vertical stabilizer, the upright surface fixed to the aft fuselage, supplies directional stability and curbs aerodynamic sideslip. It is part of the empennage, often called the vertical tail or vertical fin, and its movable aft panel, the rudder, gives the pilot yaw control.
A stabilator is a one-piece, pivoting horizontal surface that merges the functions of stabilizer and elevator. It supplies pitch control, not yaw control. Its anti-servo tab, rather than a rudder, supplies the aerodynamic balance that keeps the aircraft stable.
What are the pros and cons of a stabilator?
The pros of a stabilator include that since increased force is required to move the stabilator, it is less prone to pilot-induced overcontrolling. Longer moment arm means stabilators can be smaller and still have the required pitch moment. Stabilators are used to enhance manoeuvrability. Incorporating the shaft along the structural elements of the stabiliser makes it lighter.
The cons of a stabilator include that it is extremely sensitive to control inputs. The stabilator anti servo tab provides increased hinge moment when deflected, requiring excess pilot effort.
