Factors affecting the stability of T-tail transports.

Abstract

A wind-tunnel research program has been undertaken by NASA to study the aerodynamic characteristics of T-tail aircraft at high angles of attack. The program was designed to show the effect on longitudinal sLability and control of several configuration variables encompassing horizontal-tail size, vertical position, planfbrm, and incidences; nacelle size, location, and pylon effects; wing section, stall-control devices, flaps, aspect ratio, and sweep; fuselage cross-sectional size, cross-sectional shape, and forebody length. .Results of this program are presented and analyzed to serve as a guide to preliminary design. Nomenclature b = wing span C L = lift coefficient (Cm)oA()r. = pitching-moment coefficient about ().4()c AG\4, = incremental moment due to horizontal tail c = wing mean aerodynamic chord //, = tail incidence A/* = change in tail incidence lt = tail arm M = Mach number S = wing reference area Si = tail area z = tail height a = angle of attack oxtail = angle of attack at wing stall at = angle of attack of horizontal tail