AIRFRAME NOISE OF THE DC-9-31
Airframe 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 wind effects, atmospheric attenuation, and spherical divergence, and are normalized to a 1 meter acoustic range. 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 sideline data imply that a significant side-force dipole exists only for the flap- and gear-down configurations; for others, the data imply the existence of only the lift and drag dipoles. The data are compared with airframe noise predictions using the drag element and the data analysis methods. Although some of the predictions are good, further work is needed to refine the methods, particularly for the flap- and gear-down configurations.
Douglas Aircraft Company, Incorporated3855 Lakewood Boulevard
Long Beach, CA USA 90801
- Bauer, A B
- Munson, A G
- Publication Date: 1978-7
- Pagination: 54 p.
- TRT Terms: Aerodynamic lift; Aerodynamic noise; Aerodynamics; Aircraft noise; Airframes; Drag; Effective sound pressure; Flight characteristics; Landing gear; Mathematical prediction; Measurement; Noise
- Identifier Terms: McDonnell Douglas aircraft; McDonnell Douglas DC-9
- Uncontrolled Terms: Noise measurement
- Old TRIS Terms: Aerodynamic configurations
- Subject Areas: Aviation; Data and Information Technology; Environment; Vehicles and Equipment;
- Accession Number: 00185779
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: NASA-CR-3027 Final Rpt.
- Contract Numbers: NAS1-14696
- Files: TRIS
- Created Date: Dec 29 1979 12:00AM