English: The proposed National Aerospace Plane (NASP) consists of a long, flexible, lifting-body fuselage and relatively small, highly swept, all-movable, clipped-delta wings. The fuselage flexibility and the all-movable feature of the clipped-delta wings may make the vehicle susceptible to aeroelastic instabilities throughout the flight envelope. A wind-tunnel test of a NASP model was conducted to meet three objectives: to measure the flutter mechanism inherent to this type of vehicle; to examine the effect of parametric variations on the flutter behavior of the model; and to correlate the experimental data with analysis. A tenth-scale representation of an unclassified version of the NASP vehicle was flutter tested in the Transonic Dynamics Tunnel (TDT). This representation was a full-span model with pitch and plunge degrees of freedom simulated with springs in the floor mount. The model had all-movable, clipped-delta wings and cantilevered, clipped-delta vertical fins. The stiffness of the wing actuators was simulated with springs. A photo of the model mounted in the wind tunnel is shown in the figure. A flutter analysis of the model was performed using calculated linear, lifting-surface aerodynamics. The wind-tunnel test of this model showed the NASP-type vehicles employing single-pivot, all-movable wings are susceptible to body-freedom flutter. The test results show that increasing the wing-actuator-pitch stiffness can make the body-freedom flutter instability less critical. The correlation of flutter analysis to the experimental data indicates that the mathematical tools used in this study were sufficient to predict the body-freedom flutter encountered in the wind tunnel.