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Comparison of the acoustic characteristics of large-scale models of several propulsive-lift conceptsWind-tunnel acoustic investigations were performed to determine the acoustic characteristics and the effect of forward speed on the over-the-wing externally blown jet flap (OTW), the under-the-wing externally blown jet flap (UTW), the internally blown jet flap (IBF), and the augmentor wing (AW). The data presented represent the basic noise generated by the powered-lift system without acoustic treatment, assuming all other noise sources, such as the turbofan compressor noise, have been suppressed. Under these conditions, when scaled to a 100,000-lb aircraft, the OTW concept exhibited the lowest perceived noise levels, because of dominant low-frequency noise and wing shielding of the high-frequency noise. The AW was the loudest configuration, because of dominant high-frequency noise created by the high jet velocities and small nozzle dimensions. All four configurations emitted noise 10 to 15 PNdB higher than the noise goal of 95 PNdB at 500 ft.
Document ID
19750026206
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Falarski, M. D.
(U.S. Army, Air Mobility Research and Development Laboratory, Moffett Field Calif., United States)
Aiken, T. N.
Aoyagi, K.
Koenig, D. G.
(NASA Ames Research Center Moffett Field, Calif., United States)
Date Acquired
August 8, 2013
Publication Date
October 1, 1974
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
AIAA PAPER 74-1094
Meeting Information
Meeting: American Institute of Aeronautics and Astronautics and Society of Automotive Engineers, Propulsion Conference
Location: San Diego, CA
Start Date: October 21, 1974
End Date: October 23, 1974
Sponsors: American Institute of Aeronautics and Astronautics, Society of Automotive Engineers
Accession Number
75A10278
Distribution Limits
Public
Copyright
Other

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