Helicopter Internal Noise Treatment. Recent Methodolgies and Practical Applications

摘要

A methodology including helicopter noise diagnosis, definition of acoustic treatment best adapted for each panel structure, and the development, tests and improvements of internal noise treatments is set up. Noise spectra are obtained at several cabin locations and helicopter speeds. An array of noise transducers placed at 120 locations allows to set the acoustic power radiated by each structure subassembly. It is shown that the method gives a good representation the wave pattern, and it may provide sufficient detail to efficiently reduce the added weight of sound proofing treatments.