Concepts for long-range air travel are characterized by airframe designs with long, slender, relatively flexible fuselages. One aspect often overlooked is ground-induced vibration of these aircraft. This paper presents an analytical and experimental study of reducing ground-induced aircraft vibration loads by using actively controlled landing gear. A facility has been developed to test various active landing gear control concepts and their performance, The facility uses a Navy A6 Intruder landing gear fitted with an auxiliary hydraulic supply electronically controlled by servo valves. An analytical model of the gear is presented, including modifications to actuate the gear externally, and test data are used to validate the model. The control design is described and closed-loop test and analysis comparisons are presented.Horta, Lucas G. and Daugherty, Robert H. and Martinson, Veloria J.Langley Research CenterACTIVE CONTROL; CONTROL THEORY; LANDING GEAR; SERVOMECHANISMS; VALVES; VIBRATION; MATHEMATICAL MODELS; CONTROL SYSTEMS DESIGN; DYNAMIC CONTROL; DYNAMIC TESTS; AIRCRAFT TIRES; FUSELAGES; LAPLACE TRANSFORMATION; EQUATIONS OF MOTION...