Accession Number:

ADA014640

Title:

A Comprehensive Review of Helicopter Noise Literature

Descriptive Note:

Final rept.

Corporate Author:

FEDERAL AVIATION ADMINISTRATION WASHINGTON DC SYSTEMS RESEARCH AND DEVELOPMENT SERVICE

Report Date:

1975-06-01

Pagination or Media Count:

188.0

Abstract:

This report summarizes the state-of-the-art in helicopter noise. It includes a bibliography of reports on all components of helicopter noise including main rotor, tail rotor, engine and gearbox. Literature on helicopter noise reduction and subjective evaluation of helicopter noise were also included. Capsule summaries of important reports are included which describe the purpose of the report, summarizes the important results, compares the report with others on the same subject, and provides a critical evaluation of the work presented. It is concluded that the available prediction methodology provides a means for estimating helicopter sources on a gross basis. However, the mechanisms of noise generation are still not fully understood, although the experimental and theoretical tools are now available to conduct the definitive experiments and establish the mathematical models needed for accurate definition of helicopter noise generation mechanisms. Spectrum analyses of helicopter noise show that main rotor, tail rotor, and engine sources contribute significantly to annoyance. In cases where these sources have been heavily suppressed, gearbox noise will also appear as a significant contributor to annoyance. Therefore, quieter helicopters must include suppression of all of these components. For certification, the liter

Subject Categories:

  • Helicopters
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE