Many airplanes feature trim devices. A trim device is an adjustable flight control surface that allows pilots to change the aerodynamic forces to which the airplane is exposed. With trim devices, pilots won’t have to constantly apply pressure to control systems. There are many different types of trim devices on airplanes, some of the most common being the following.
#1) Trim Tabs
Trim tabs are adjustable flight control surfaces on the back of an airplane’s elevators or rudders. They are typically controlled by a wheel or crank inside of the cockpit. Pilots can raise or lower the trim tabs by turning the wheel or crank. Like other trim devices, trim tabs change the aerodynamic forces to which the airplane is exposed.
#2) Servo Tabs
Servo tabs are hinge-like devices that allow pilots to control airplanes more easily. Also known as balance tabs, they move in the opposite direction of the control surfaces on which they are attached. Servo tabs work by deflecting airflow so that the control surface is exposed to a greater force. Servo tabs are commonly found on elevators and ailerons.
#3) Anti-Servo Tabs
In addition to servo tabs, there are anti-servo tabs. What are anti-servo tabs exactly? They are trim devices that allow pilots to control airplanes more easily. Anti-servo tabs simply work in the opposite way of their servo counterparts. Servo tabs move in the opposite direction of the control surfaces on which they are attached. Anti-servo tabs, on the other hand, move in the same direction of the control surfaces on which they are attached.
#4) Bungee System
A bungee system is a type of trim device that leveraged a spring-like cord to change the aerodynamic forces to which the airplane is exposed. Most bungee systems are connected to a cockpit lever. Pilots can pull this lever to engage the bungee system. Bungee systems are trim devices that consist of a spring-like cord, which is typically connected to a lever in the cockpit.
#5) Stabilizers
Stabilizers are considered trim devices as well. A stabilizer is simply a moveable control surface that’s designed specifically to stabilize the airplane. Other types of trim devices may or may not stabilize the airplane. Stabilizers receive their namesake from their ability to stabilize the airplane. There are different types of stabilizers. Horizontal stabilizers, for instance, feature a horizontal design, whereas vertical stabilizers feature a vertical and upright design. Regardless, all stabilizers help to stabilize the airplane.
