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Effects of acoustic treatment on the interior noise levels of a twin-engine propeller aircraft - Experimental flight results and theoretical predictionsIn-flight noise level measurements were made within two cabin configurations of a general aviation business aircraft. The Fairchild Merlin IVC twin-engine aircraft was tested with bare walls and fiberglass insulation and in an executive trim configuration. Narrow-band and octave format data were subjected to analyses which permitted identification of the blade passage harmonics (BPH). Cabin noise level reductions (insertion losses) due to added insulation varied with position in the cabin, the BPH number, cabin pressure, and engine torque. The measurements were closely predicted using the propeller aircraft interior noise (PAIN) mode.
Document ID
19850028724
Document Type
Conference Paper
Authors
Beyer, T. B. (NASA Langley Research Center Hampton, VA, United States)
Powell, C. A. (NASA Langley Research Center Hampton, VA, United States)
Daniels, E. F. (NASA Langley Research Center Hampton, VA, United States)
Pope, L. D. (NASA Langley Research Center Structural Acoustics Branch, Hampton, VA, United States)
Date Acquired
August 12, 2013
Publication Date
October 1, 1984
Subject Category
AIRCRAFT DESIGN, TESTING AND PERFORMANCE
Report/Patent Number
AIAA PAPER 84-2331
Distribution Limits
Public
Copyright
Other