Static Margin Calculator

The Static Margin is a measure of the longitudinal stability of an aircraft. It represents the distance between the center of gravity  and the aerodynamic center  normalized by the mean aerodynamic chord

• $SM$ is the static margin,
• Xcg​ is the location of the aircraft’s center of gravity,
• Xac​ is the location of the aerodynamic center,
• $c$ is the mean aerodynamic chord

A positive static margin ($SM>0$) typically indicates a stable configuration, where the center of gravity is ahead of the aerodynamic center. A negative static margin ($SM<0$) may indicate an unstable configuration.