What is the primary function of the rudder?

The primary function of the rudder is to control yaw, which refers to the left and right movement of an aircraft’s nose around its vertical axis. The rudder is typically located on the vertical stabilizer at the tail of the aircraft. When the pilot deflects the rudder left or right by using the rudder pedals, it creates a side force on the tail of the airplane, causing the nose to turn in the desired direction.

Controlling yaw is crucial for maintaining coordinated flight, especially during maneuvers and turns. Effective rudder usage helps to counteract adverse yaw, which occurs when an aircraft rolls in one direction but yaws in the opposite direction due to the difference in lift and drag between the wings. By using the rudder properly, pilots can ensure that the aircraft maintains a straight flight path and responds correctly to control inputs.

In contrast, other functions mentioned in the choices, such as increasing lift, controlling pitch, and controlling roll, involve different flight control surfaces (e.g., ailerons for roll, elevators for pitch). Understanding the unique roles of each control surface contributes to overall aerodynamics and flight safety.