Yaw (dynamics)

Yaw is a type of motion of an object around its vertical axis, so that the longitudinal axis changes direction in the horizontal plane. The yaw angle is the angular value between the current longitudinal axis of a moving object, and the direction of travel of the object.

Yaw is the basic turning movement of an aircraft, ship, or projectile. The basic aerodynamic or hydrodynamic means of changing yaw is the rudder. Ailerons affect both yaw and roll.

While the term is not often used for ground vehicles, one can think of changing the yaw of a car or truck by turning the angle of the tires.

Spacecraft make changes in yaw with reaction motors that are at an angle to the longitudinal axis, usually angled toward the longitudinal axis but in the horizontal plane. Some aircraft also have reaction controls, especially STOVL such as the AV-8 Harrier or Harrier (fighter).