# The Axes of an Airplane and Their Purpose

Controlling and steering an airplane is much different than driving a car. For one, stability and maneuvering is vastly different. Boats and cars both two dimensional whereas an aircraft is three dimensional. The three dimensions that determine an aircraft’s stability are its axes. The axes are what control the roll, pitch and yaw.

What are roll, pitch and yaw? Imagine, if you will, three lines. All three lines form intersecting right angles at the airplane’s center of gravity.

Roll: rotation around the front to back axis. Imagine a string running a straight, horizontal line starting from the airplane’s nose all the way to its tail. Now, if the airplane rotated about this string, it would be rolling.

Pitch: rotation around the side to side axis. Imagine another piece of string running in a straight, horizontal line across the wing span from one edge to the other. If you turned or rotated the string, the airplane would be pitching up or down.

Yaw: rotation around the vertical axis. Now, if you take the same piece of string used in the pitch example but instead of rotating, moved it back and forth this would be creating yaw.

The purposes of roll, pitch and yaw.

Roll: Rolling an airplane allows the airplane to make a turn. As covered in the previous lesson, lift is vertical. When an airplane banks or rolls into a turn, the vertical lift becomes horizontal. The horizontal component of lift is what turns the plane. The ailerons rolls the airplane and allows it to turn.

The ailerons can be found on the outer edge of the wing. One on each wing. Both ailerons move in opposite directions. So if the left aileron is up, the right one will be down and vice versa. When an aileron is up, lift is decreased bringing the wing down. When the aileron is down, lift is increased bringing the wing up. This allows the airplane to roll.

Pitch: The elevators control pitch. The elevators can be found on the horizontal tail surface of an airplane. They move up or down. Unlike the ailerons, they move in the same direction in unison. The movement of the elevators decreases or increases lift on the tail which tilts the plane’s nose up or down.

Yaw: The rudder controls yaw. The rudder can be found on the aircraft’s vertical tail fin next to the elevators. It moves from side to side. The rudder’s movement pushes the tail either to the left or right. The rudder is crucial along with the ailerons in turning an airplane smoothly.