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)

  • Corporate Authors:

    Bolt, Beranek and Newman, Incorporated

    21120 Vanowen Street
    Canoga Park, CA  United States  91303

    Aerospace Medical Research Laboratory

    Wright-Patterson Air Force Base
    Dayton, OH  United States  45433
  • Authors:
    • Galloway, W J
  • Publication Date: 1979-1

Media Info

  • Pagination: 47 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00198411
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: BBN-3712 Final Rpt., AMRL-TR-78-87
  • Contract Numbers: F33615-76-C-0528
  • Files: TRIS
  • Created Date: Oct 17 1979 12:00AM