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A practical approach to helicopter internal noise prediction
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Levine, L. S. Defelice, J. J. |
| Copyright Year | 1978 |
| Description | A practical and well correlated procedure for predicting helicopter internal noise is presented. It accounts for the propagation of noise along multiple paths on an octave by octave basis. The method is sufficiently general to be applicable to conventional helicopters as well as other aircraft types, when the appropriate structural geometry, noise source strengths, and material acoustic properties are defined. A guide is provided for the prediction of various helicopter noise sources over a wide range of horsepower for use when measured data are not available. The method is applied to the prediction of the interior levels of the Civil Helicopter Research Aircraft (CHRA), both with and without soundproofing installed. Results include good correlation with measured levels and prediction of the speech interference level within 1.5 db at all conditions. A sample problem is also shown illustrating the use of the procedure. This example calculates the engine casing noise observed in the passenger cabin of the CHRA. |
| File Size | 2346614 |
| Page Count | 44 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19790002686 |
| Archival Resource Key | ark:/13960/t6838m74h |
| Language | English |
| Publisher Date | 1978-08-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Effective Perceived Noise Levels Engine Noise Noise Reduction Aircraft Noise Helicopters Noise Intensity Aircraft Compartments Speech Prediction Analysis Techniques Auditory Perception Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
