What is the primary function of the rudder in an aircraft?

The primary function of the rudder in an aircraft is to control yaw, which refers to the left and right movement of the aircraft's nose around the vertical axis. The rudder is located on the vertical stabilizer (tail fin) and is operated by the pilot using foot pedals. When the pilot pushes on the left pedal, the rudder deflects to the left, causing the aircraft’s nose to move left, and similarly for the right pedal.

This capability is essential for maintaining coordinated flight and enabling smooth turns. During maneuvers, especially when banking, the rudder helps counteract adverse yaw, which is the tendency of the aircraft to turn opposite to the intended direction due to differential lift on the wings. Thus, the rudder plays a crucial role in ensuring stability and control in the yaw axis, making it an integral part of an aircraft's control system.