Shake Test on Light Combat Helicopter

Abstract

This paper deals with the Shake test (Ground Vibration Test) performed on a Light Combat Helicopter (LCH) at Rotary Wing Research and Design Centre, Hindustan Aeronautics Limited, Bangalore. Modal characteristics (frequency, mode shape and damping) and dynamic response characteristics of the prototype LCH have been determined experimentally. Tests are conducted with helicopter resting on landing gear and helicopter in free-free condition. Single input excitation and multipoint output data acquisition is used for determination of modal parameters. Multipoint excitation and multipoint output data acquisition is used for the dynamic response measurement to access the effectiveness of the Anti Resonance Isolation System (ARIS) of LCH. The test setup, instrumentation, data acquisition and analysis procedures are enumerated herein. The modal parameters are comparable to the finite element modal results. It is shown experimentally that, ground resonance condition does not occur and this has been proved during the ground run of the helicopter.