Helicopter Far Field Acoustic Levels As A Function Of Reduced Main Rotor Advancing Blade Tip Mach Number PDF Download
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Author | : National Aeronautics and Space Administration (NASA) |
Publisher | : Createspace Independent Publishing Platform |
Total Pages | : 32 |
Release | : 2018-07-05 |
Genre | : |
ISBN | : 9781722268008 |
Download Helicopter Far-Field Acoustic Levels as a Function of Reduced Main-Rotor Advancing Blade-Tip Mach Number Book in PDF, ePub and Kindle
During the design of a helicopter, the weight, engine, rotor speed, and rotor geometry are given significant attention when considering the specific operations for which the helicopter will be used. However, the noise radiated from the helicopter and its relationship to the design variables is currently not well modeled with only a limited set of full-scale field test data to study. In general, limited field data have shown that reduced main-rotor advancing blade-tip Mach numbers result in reduced far-field noise levels. The status of a recent helicopter noise research project is reviewed. It is designed to provide flight experimental data which may be used to further understand helicopter main-rotor advancing blade-tip Mach number effects on far-field acoustic levels. Preliminary results are presented relative to tests conducted with a Sikorsky S-76A helicopter operating with both the rotor speed and the flight speed as the control variable. The rotor speed was operated within the range of 107 to 90 percent NR at nominal forward speeds of 35, 100, and 155 knots. Mueller, Arnold W. and Smith, Charles D. and Lemasurier, Philip Langley Research Center RTOP 532-06-01-09...
Author | : |
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Total Pages | : 24 |
Release | : 1987 |
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ISBN | : |
Download Helicopter Main-rotor Speed Effects on Far-field Acoustic Levels Book in PDF, ePub and Kindle
Author | : |
Publisher | : |
Total Pages | : 1460 |
Release | : 1991 |
Genre | : Aeronautics |
ISBN | : |
Download Scientific and Technical Aerospace Reports Book in PDF, ePub and Kindle
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author | : |
Publisher | : |
Total Pages | : 440 |
Release | : 1991 |
Genre | : Aeronautics |
ISBN | : |
Download NASA Technical Memorandum Book in PDF, ePub and Kindle
Author | : Louis J. Williams |
Publisher | : |
Total Pages | : 232 |
Release | : 1991 |
Genre | : Aerodynamics |
ISBN | : |
Download NASA Aerodynamics Program : Annual Report 1990 Book in PDF, ePub and Kindle
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Total Pages | : |
Release | : 1992-04 |
Genre | : Government publications |
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Download Monthly Catalog of United States Government Publications Book in PDF, ePub and Kindle
Author | : |
Publisher | : |
Total Pages | : 648 |
Release | : 1992 |
Genre | : Aeronautics |
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Download Aeronautical Engineering Book in PDF, ePub and Kindle
A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
Author | : F. H. Schmitz |
Publisher | : |
Total Pages | : 110 |
Release | : 1983 |
Genre | : |
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Download Helicopter Impulsive Noise: Theoretical and Experimental Status Book in PDF, ePub and Kindle
The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanisms is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanisms of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.
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Total Pages | : 656 |
Release | : 1997 |
Genre | : Aeronautics |
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Download International Aerospace Abstracts Book in PDF, ePub and Kindle
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Total Pages | : 80 |
Release | : 1992 |
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Download Publications on Acoustics Research at the Langley Research Center, January 1987 - September 1992 Book in PDF, ePub and Kindle