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Abstract:

Wind-tunnel measurements of the aerodynamic damping and oscillatory in pitch and yaw for a 1/22-scale model of a proposed carrier-based variable-sweep fighter airplane have been made by using a small-amplitude forced-oscillation technique. Tests were made with a wing leading-edge sweep angle of 68 deg at angles of attack from about -1.5 deg to 15.6 deg at a Mach number of 1.60 and at angles of attack from about -3 deg to 21 deg at Mach numbers of 2.02 and 2.36. The results of the investigation indicate that the basic configuration has positive damping and positive oscillatory stability in pitch for all test conditions. In yaw, the damping is generally positive except near an angle of attack of 0 deg at a Mach number of 1.60. The oscillatory stability in yaw is positive except at angles of attack above 16 deg at Mach numbers of 2.02 and 2.36. The addition of external stores generally causes increases in both pitch and yaw damping. The oscillatory stability in pitch is reduced throughout the angle-of-attack range by the addition of the external stores. The effect of adding stores on the oscillatory stability in yaw is a function of angle of attack and Mach number. The effect of changing horizontal-tail incidence on the pitch parameters is also very dependent on angle of attack and Mach number.

Author(s):
R.A. Kilgore; J.B. Adcock