Investigation of Gearbox Design Modifications for Reducing Helicopter Gearbox Noise
Final technical rept.
MECHANICAL TECHNOLOGY INC LATHAM NY
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Results presented were obtained in a continuing effort to control, through development of vibration and acoustics technology, noise produced by helicopter geared power trains. The results achieved, while not all inclusive, represent a significant step in understanding the generation of gearbox noise. Efforts undertaken, directed at both the UH-1D main and CH-47 forward rotor- drive gearboxes, included predictions of lateral natural frequency and forced response vibration characteristics of the spiral bevel gear shafts, thin-shell predictions of natural frequency and forced-response vibration characteristics of the planetary ring gear casing, general and analytical modeling of gearbox mounts and adjoining airframe structure, and collection and evaluation of existing helicopter internal noise and vibration data from helicopter manufacturers and users.