Abstract
In this paper the author proposes a representation of the longitudinal control, and of the longitudinal static-stability theory of the airplane: (1) By a consistent and exclusive use of the aerodynamic centers of all carrying airfoil bodies and the moment coefficients about these centers; (2) by the reference of all states of flight and of the location of the center of gravity to a basic state of flight with noncarrying tail plane and neutral fuselage orientation, with the characterization of other states of flight by the lift force and an effective angle of attack of the tail plane; (3) by the value of the ratio of static moments of wing and tail about the center of gravity as the measure of stability, which must overcome mainly the destabilizing moment of the fuselage and of the propeller. The analysis shows a relatively great effect of the fuselage and propeller moments on the control and stability. Both effects necessitate a greater force of the elevator and appear as the second important destabilizing terms in the stability condition.
