What is the primary function of the vertical stabilizer on an aircraft?

The primary function of the vertical stabilizer on an aircraft is to provide stability and control in the yaw axis. The vertical stabilizer, often referred to as the fin, is the upright surface located at the tail of the aircraft. Its main role is to maintain directional stability by preventing unwanted side-to-side motion (yawing). This helps the pilot maintain a straight flight path and assists in controlling the aircraft during maneuvers.

When the aircraft experiences yaw, typically due to crosswinds or asymmetric thrust from the engines, the vertical stabilizer generates aerodynamic force that counteracts this motion. The rudder, which is attached to the back of the vertical stabilizer, can also be used to actively control yaw and make precise turns. By providing this stabilizing effect, the vertical stabilizer is essential for the safe and efficient operation of the aircraft in flight.