Helicopter external noise radiation in turning flight: Theory and experiment

Eric Greenwood, Fredric H. Schmitz, Gaurav Gopalan, Ben Wel C. Sim

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations

Abstract

The external noise radiated by a Bell 206 Helicopter in steady, turning flight is analyzed using two different measurement systems: a boom mounted system attached to the helicopter and a ground measurement system oriented perpendicular to the helicopter's flight path. The resulting data set is unique in that it combines both, simultaneous in-flight noise measurements with ground noise measurements. Noise comparisons are made, using both microphone systems, for a range of flight conditions including: steady straight flight and steady turning flight both in level flight and in descents. It is shown that Bell 206B Blade Vortex Interaction (BVI) external noise gradually increases in level flight at moderate bank angles and with increasing rates of descent. A new analytical procedure is presented to develop Rotor Noise Model (RNM) noise hemispheres for turning flight, for a helicopter following a helical trajectory. The hemispheres are developed using the ground microphone array and depict the directivity of the noise. The method is applied to the Bell 206B data showing the potential of the analytical procedure, but that a more careful placement of the ground microphones is needed to insure well-developed hemispheres. Low ambient winds and careful piloting are also necessary for robust and accurate noise hemisphere development.

Original languageEnglish (US)
Title of host publicationAHS International 63rd Annual Forum - Proceedings - Riding the Wave of New Vertical Flight Technology
Pages1867-1888
Number of pages22
StatePublished - Dec 1 2007
Event63rd American Helicopter Society International Annual Forum 2007 - Virginia Beach, VA, United States
Duration: May 1 2007May 3 2007

Publication series

NameAnnual Forum Proceedings - AHS International
Volume3
ISSN (Print)1552-2938

Other

Other63rd American Helicopter Society International Annual Forum 2007
CountryUnited States
CityVirginia Beach, VA
Period5/1/075/3/07

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Fingerprint Dive into the research topics of 'Helicopter external noise radiation in turning flight: Theory and experiment'. Together they form a unique fingerprint.

Cite this