An Investigation of Noise Generation on a Hovering Rotor

Abstract

This report presents the results of a program of helicopter rotor noise measurement. The program was carried out using a 60-foot diameter CH-47B 3-bladed rotor on the Boeing-Vertol engineering rotor whirl tower. The primary objectives were: to obtain acoustical data over a frequency range wide enough to define all elements of rotor noise under well-documented ambient conditions, to measure the tip vortex position with respect to a trailing blade using high- speed cameras and smoke to visualize the tip vortex and to relate blade-vortex separation distance to noise level, to determine the propagation characteristics of rotor noise, and to evaluate two current analytical procedures for predicting rotor noise against the measured data. Tipspeeds ranged from 600 to 900 fps and thrusts ranged from 6300 to 32,000 pounds (disk load 2.2 to 11.3 pounds per square foot).

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1971
Accession Number
AD0721312

Entities

People

  • H. Sternfeld
  • J. O. Schairer
  • R. H. Spencer

Organizations

  • Boeing Rotorcraft Systems

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Accuracy
  • Air Force
  • Aircrafts
  • Cameras
  • Combustion
  • Coordinate Systems
  • Engineering
  • Frequency Response
  • Helicopter Rotors
  • Mach Number
  • Measurement
  • Mobile Laboratories
  • Recording Systems
  • Smoke Generators
  • Test And Evaluation
  • Three Dimensional
  • Waveforms

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Aerospace Engineering
  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.