What is 'rudder trim' used for in aircraft?

Rudder trim is a crucial aerodynamic feature in aircraft that assists pilots in achieving and maintaining coordinated flight. Its primary purpose is to relieve the pilot from the necessity of applying continuous pressure on the rudder pedals to counteract yaw, which can arise from various factors, such as asymmetrical thrust or torque effects during flight. By adjusting the rudder trim, a pilot can set the aircraft's rudder in a way that offsets these tendencies, allowing for more comfortable and efficient flight management, especially during prolonged flight segments or when flying straight and level.

This function is particularly beneficial during long flights or in conditions where the aircraft is subjected to consistent and steady forces that would otherwise require constant rudder input. By effectively trimming the rudder, pilots ensure that the aircraft maintains coordinated flight, which is essential for optimal performance and passenger comfort.