A flutter investigation of the T-tail of a currently projected multijet cargo airplane has been conducted in the Langley transonic dynamics tunnel at Mach numbers up to 0.90. The tail and aft fuselage of the model employed were geometrically, dynamically, and elastically scaled, whereas only the mass and stiffness characteristics of the forward fuselage, wings, and nacelles were simulated. This study included variations in flow density, stabilizer-pitch-actuator stiffness, fin-spar stiffness, roll and yaw stiffnesses of fin-stabilizer joint, rotational stiffnesses of elevators and rudder, stabilizer mass and yaw and roll inertias.nWithin the ranges of the tests, no flutter occurred for the design configuration with control surfaces locked, with design elevator rotational stiffness, or with a simulated rudder-free condition. However, severe reductions in stabilizer-pitch-actuator stiffness or in elevator rotational stiffness did result in symmetric flutter. Increasing stabilizer mass and yaw and roll inertias by adding large weights to the stabilizer tips led to symmetric flutter which was studied over wide ranges of Mach number and flow density. Two antisymmetric flutter points were obtained for a configuration having stabilizer tip weights and a weaker-than-design fin spar.
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