concept

Static margin

The distance between a flyer's centre of mass and the point where an added gust of lift acts - the neutral point - measured in wing chords. A positive margin (mass ahead) makes the flyer self-righting: knock the nose up and the geometry pushes it back down. But that same restoring force fights every deliberate turn, so stability and manoeuvrability sit at opposite ends of one dial. Modern fighters deliberately run the margin near zero or negative - relaxed static stability - to get a fast-pitching nose, then hand the job of staying pointed to a flight-control system correcting continuously.