Definition
An adjustable trim system that applies a steady corrective input to the rudder, relieving the pilot of having to hold continuous rudder pressure to keep the airplane flying straight. It is typically used to offset yaw caused by engine torque, propeller effects, or asymmetric thrust.
Plain English
A control that holds the rudder slightly deflected for you, so your feet don't have to keep pushing on the pedals to stop the nose from drifting left or right.
Context Anchor
Seen in trim control discussions and used in flight when the airplane needs steady rudder pressure, such as during climb, cruise, or power changes.
Derivation
Rudder' comes from Old English rother, meaning a steering oar or paddle used on early boats. 'Trim' originally meant to put something in proper order or balance — as in trimming a ship's sails. Together the term describes setting the rudder in its balanced position so the airplane flies straight without constant pilot effort.
Why Pilots Care
It reduces fatigue and control workload, especially during long flights, engine-out conditions, or crosswind operations where constant rudder pressure would otherwise be required.
Intuition Check
Rudder trim is not a separate steering control for turning the airplane. It is an adjustment that reduces steady rudder pedal pressure.
Example Sentence 1
After leveling off in cruise, the pilot adjusted rudder trim to eliminate the slight left yaw caused by engine torque.
Example Sentence 2
With the right engine shut down the pilot used rudder trim to keep the airplane straight without fighting the controls.