Measurement of Rotor Noise Levels and Evaluation of Porous Blade Tips on a CH -47A Helicopter

Abstract

Two sets of acoustical data were correlated. Relative blade tip-path plane positions influence noise levels more than other operating parameters such as rotor speed or gross weight. Porous blade tips were installed on the test aircraft. The tips reduced noise levels in hover but had no consistent effect in forward flight. However, the tips tended to decrease the sharpness of the acoustical signature at all airspeeds.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1969
Accession Number
AD0864116

Entities

People

  • Harry Sternfeld Jr.
  • Robert H. Spencer

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aircrafts
  • Airframes
  • Army Aviation
  • Computer Programs
  • Fuselages
  • Geometry
  • Government Procurement
  • Governments
  • Helicopters
  • Mach Number
  • Measurement
  • Recording Systems
  • Rotary Wing Aircraft
  • Statistical Analysis
  • Tape Recorders
  • Test And Evaluation
  • Waveforms

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Aerospace Engineering