THE DERIVATIVE CA(tji

This derivative gives the change of aileron hinge moment due to rolling. It occurs because of the change in wing angle of attack at the ailerons, and because Ghx of the ailerons is usually nonzero. Let ya be the spanwise co­ordinate of the right hand mid-aileron section. Then the approximate change in angle of attack at the right hand aileron is

A

V

THE DERIVATIVE CM

The change in vertical-tail angle of attack brought about by p produces a change in the rudder hinge moment. This is given by

When ChTx is negative, as for a simple flap control, then a positive roll produces a positive rudder hinge moment.