The noise transmission loss characteristics of the sidewall treatment in the propeller plane of a twin-engine turboprop aircraft are experimentally investigated in the NASA Langley Research Center Transmission Loss Facility. The sound attenuation properties of the individual elements of this treatment are evaluated showing least noise transmission loss in the low frequencies (below 500 Hz) where the excitation levels at the propeller blade passage frequency and the first few harmonics are highest. It is shown that single and double wall resonances play an important role in the noise transmission loss values of the treatment at these low frequencies suggesting that a limp mass with a very low resonance frequency serves better as a trim panel than a trim panel having a high structural stiffness. It is indicated that the window structures might be a potential noise control problem.
Noise transmission through sidewall treatments applicable to twin-engine turboprop aircraft
American Institute of Aeronautics and Astronautics, Aeroacoustics Conference ; 1983 ; Atlanta, GA
1983-04-01
Conference paper
No indication
English
Analysis of store separation from a generic twin-engine turboprop aircraft
British Library Conference Proceedings | 2007
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