Encyclopaedia of Aerospace Engineering, Volume 5
Static Longitudinal Stability


Encyclopaedia of aerospace engineering book cover

A Filippone
John Wiley & Sons Ltd
Dec 2010, Chapter 252

This article deals with the static longitudinal stability of fixed-wing aircraft having a conventional configuration consisting of a wing and a horizontal tailplane with elevator and trim tab. The aircraft is considered as a rigid body. We provide a definition for the mean aerodynamic chord and show its role in the longitudinal stability problem. Then the pitching moment equations are written for the wing alone and the full aircraft. Trim equations are derived for stick-fixed and stick-free conditions; the corresponding stability points are calculated. Finally, the pull-up up manoeuvre is described under steady-state conditions; stick-free andstick-fixed manouvre points are derived.