CONTRIBUTIONS OF A TAIL

As illustrated in Fig. 7.12, the main effect of q on the tail is to increase its angle of attack by (qlJV) radians. It is this change in at that accounts for

the changed forces on the tail. The assumption is implicit in the following derivations that the instantaneous forces on the tail correspond to its instantaneous angle of attack; i. e. no account is taken of the fact that it takes a finite time for the tail lift to build up to its steady-state value following a sudden change in q. [A method of including this refinement has been given by Tobak (ref. 7.12).] The derivatives obtained are therefore quasistatic.