Helicopter Noise Level Functions for Use in Community Noise Analyses.

Abstract

Acoustical data obtained from helicopters in level flight and during 6 degree approaches are used to obtain the variation of A-weighted sound exposure level and effective perceived noise level with distance. These functions are normalized to a reference airspeed which differs for individual helicopter types. Sound level functions at airspeeds different from the reference airspeed, either higher or lower, are obtained by adding a decibel increment to the reference functions. This increment is obtained by multiplying a constant, different for each helicopter, times the square of the difference between the airspeed of interest and the reference airspeed. These data are provided for the following aircraft: CH-3C, CH-47C, CH-54B, HH-53B/C, OH-6A, TH-55A, UH-1N, UH-13. Maximum A-weighted sound levels and perceived noise levels at a distance of 76 meters (250 feet) are also provided as a function of angle around the aircraft during stationary hover conditions. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1979
Accession Number
ADA068455

Entities

People

  • William J. Galloway

Organizations

  • BBN Technologies

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Air Force
  • Aircraft Equipment
  • Aircraft Noise
  • Aircrafts
  • Airframes
  • Fixed Wing Aircraft
  • Flight
  • Flight Paths
  • Helicopter Rotors
  • Helicopters
  • Level Flight
  • Measurement
  • Military Aircraft
  • Noise
  • Rotary Wing Aircraft
  • Turbofan Engines
  • United States

Readers

  • Acoustics.
  • Aerospace Engineering
  • Geodesy