Airframe noise of the DC-9Airframe noise measurements are reported for the DC-9-31 aircraft flown at several speeds and with a number of flap, landing gear, and slat extension configurations. The data are corrected for atmospheric attenuation and spherical divergence, and are presented for an overhead position normalized to a 1-meter height. The sound pressure levels are found to vary approximately as the fifth power of flight velocity. Both lift and drag dipoles exist as a significant part of the airframe noise. The data are compared with airframe noise predictions using the drag element and the data analysis methods. Although some of the predictions are very good, further work is needed to refine these methods, particularly for the gear-down and flaps-down configurations.
Document ID
19770068183
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Bauer, A. B. (Douglas Aircraft Co., Inc. Long Beach, CA, United States)
Munson, A. G. (Douglas Aircraft Co., Inc. Long Beach, Calif., United States)
Date Acquired
August 9, 2013
Publication Date
October 1, 1977
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
DOUGLAS-6658AIAA PAPER 77-1272
Meeting Information
Meeting: Aeroacoustics Conference
Location: Atlanta, GA
Start Date: October 3, 1977
End Date: October 5, 1977
Sponsors: American Institute of Aeronautics and Astronautics