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Active wing/store flutter suppression systems were demonstrated in 1977 in a series of wind tunnel tests on a YF-17 scale model. In order to substantially improve the suppression system performance, new control laws were developed based on multiple feedback loops, multiple control surfaces, or both. For test safety, a flutter sensing unit and a new store, functioning as a flutter stopper, were designed and fabricated. Test monitoring programs were organized on a Hewlett-Packard 5451C Fourier Analyzer that permitted a real time assessment of the control law effectiveness. One of the monitoring programs generated the aircraft open loop transfer function and Nyquist plots in the supercritical region while the flutter suppression loop was closed. In the tests performed in late 1979, the new control laws were applied to suppress a severe flutter condition to 70% above the uncontrolled flutter dynamic pressure. Postanalysis of the test data indicated the potential to increase the dynamic pressure to an even higher level. Nomenclature= constants used in the pseudo-integrator a lt . c,c' G,Gj,G 2 ,G A M Q Qf R!>* s a. J IN,LÊ IN^TE 02 = accelerometer outputs (g) = damping coefficients = critical damping coefficient = pseudo integrators (Fig. 2) = feedback loop transfer functions (Fig. 4) = transfer functions of aircraft model response and the servo-actuator system = open loop transfer functions of aircraft model response (/) due to control servo input (/') = corresponding closed loop transfer functions of Gfj = Mach number = dynamic pressure (psf) = flutter dynamic pressure (psf) = potentiometer settings = Laplace operator = typical transducer signal = inputs to leading edge or trailing edge surface servos = responses to noise = model responses = frequency and natural frequency (rad/s)

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