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Noise propagation from a four-engine, propeller-driven airplane
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Willshire Jr., William L. |
| Copyright Year | 1987 |
| Description | A flight experiment was conducted to investigate the propagation of periodic low-frequency noise from a propeller-driven airplane. The test airplane was a large four-engine, propeller-driven airplane flown at altitudes from 15 to 500 m over the end of an 1800-m-long, 22-element microphone array. The acoustic data were reduced by a one-third octave-band analysis. The primary propagation quantities computed were lateral attenuation and ground effects, both of which become significant at shallow elevation angles. Scatter in the measured results largely obscured the physics of the low-frequency noise propagation. Variability of the noise source, up to 9.5 dB over a 2-sec interval, was the major contributor to the data scatter. The microphones mounted at ground level produced more consistent results with less scatter than those mounted 1.2 m above ground. The ground noise levels were found to be greater on the port side than on the starboard side. |
| File Size | 5733091 |
| Page Count | 41 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19870008049 |
| Archival Resource Key | ark:/13960/t6rz4574k |
| Language | English |
| Publisher Date | 1987-02-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Noise Propagation Flight Tests Acoustic Measurement Research Aircraft Acoustic Scattering Research Facilities Attenuation Arrays Ground Effect Communications Elevation Angle Microphones Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
