A FLIGHT INVESTIGATION AT TRANSONIC SPEEDS OF A MODEL HAVING A TRIANGULAR WING OF ASPECT RATIO 4

摘要

Free-falling recoverable-model tests have been conducted at transonic speeds on a model having an aspect-ratio-4 triangular wing and a 45 sweptback tail located in the extended wing-chord plane. Static and dynamic-stability and load-distribution data were obtained at maximum angles of attack of about 8 to 21, depending on the Mach number. As angle of attack was varied, at subsonic values of Mach number, the aerodynamic center of the complete model moved one-half the mean aerodynamic chord as a result of the reduced stability contributions of both wing and tail at low angles of attack. Lowered values of horizontal-tail effectiveness for values of Mach number above 0.99 are believed to result from losses of dynamic pressure in the wing wake. Large losses of damping in pitch at high angles of attack, noted at Mach numbers less than O.92, were probably due to nonlinear variations with angle of attack of the downwash angle at the tail.