Correlation of Actual and Analytical Helicopter Aural Detection Criteria. Volume 1
Abstract
This study was conceived as a basic experiment for measurement of helicopter aural detectability, and for assessment of the accuracy of a model developed by Ollerhead for computing aural detection distances. The experiment was conducted over a period of two weeks at NASA Wallops Station utilizing 25 Army personnel as listening subjects, and three different types of helicopters currently in Army service. The effect of the following parameters was investigated: ambient noise level, flight profile, listener attentiveness, atmospheric conditions. Reduction of data was executed using a new procedure for simulating aural frequency decomposition of sound. Correlation with Ollerhead's model confirmed his laboratory-derived detectability criterion as a median case for individual response and allowed extension of the criterion in the context of a measured statistical distribution. Published data included in Ollerhead's model for sound attenuation, other than for atmospheric absorption, was found to be inapplicable and a new comprehensive attenuation model based on measured results was formulated. Comparison of theoretical results, derived using the improved model for predicting helicopter aural detection distances, with measured values provided satisfactory correlation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1975
- Accession Number
- ADB002067
Entities
People
- A. L. Abrahamson