Sideslip angle

This article is about aviation. For car handling, see slip angle.

Not to be confused with yaw angle.

In figure (a) an airplane flies so that the sideslip angle is zero, in figure (b) it yaws to have a positive sideslip angle. The circular arrow shows the moment needed for directional stability. Credits: NASA

Sideslip angle, also called angle of sideslip (AOS, AoS, $\beta$, Greek letter Beta), is a term used in fluid dynamics and aerodynamics and aviation. It relates to the rotation of the aircraft centerline from the relative wind. In flight dynamics it is given the shorthand notation $\beta$ (beta) and is usually assigned to be "positive" when the relative wind is coming from the right of the nose of the airplane. The sideslip angle $\beta$ is essentially the directional angle of attack of the airplane. It is the primary parameter in directional stability considerations.

Further information: Flight dynamics and Slip (aerodynamic)