Helicopter Non-Unique Trim Strategies for Blade-Vortex Interaction (BVI) Noise Reduction

Abstract

An acoustics parametric analysis of the effect of fuselage drag and pitching moment on the Blade-Vortex Interaction (BVI) noise radiated by a medium lift helicopter (S-70/UH-60) in a descending flight condition was conducted. The comprehensive analysis CAMRAD II was used for the calculation of vehicle trim, wake geometry and integrated air loads on the blade. The acoustics prediction code PSU-WOPWOP was used for calculating acoustic pressure signatures for a hemispherical grid centered at the hub. This paper revisits the concept of the X-force controller for BVI noise reduction, and investigates its effectiveness on an S-70 helicopter. The analysis showed that further BVI noise reductions were achievable by controlling the fuselage pitching moment. Reductions in excess of 6 dB of the peak BVI noise radiated towards the ground were demonstrated by compounding the effect of airframe drag and pitching moment simultaneously.

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Document Details

Document Type
Technical Report
Publication Date
Jan 22, 2016
Accession Number
AD1015586

Entities

People

  • Ben W. Sim
  • Carlos Malpica
  • Eric Greenwood

Tags

Communities of Interest

  • Air Platforms
  • Space

DTIC Thesaurus Topics

  • Acoustics
  • Aerodynamic Configurations
  • Aircraft Equipment
  • Aircrafts
  • Airfoils
  • Airframes
  • Blade Tips
  • Control Systems
  • Flight Paths
  • Flight Testing
  • Helicopter Rotors
  • Horizontal Stabilizers
  • Noise
  • Rotary Wing Aircraft
  • Standards
  • Wind Tunnel Tests
  • Wind Tunnels

Fields of Study

  • Engineering
  • Physics

Readers

  • Acoustics.
  • Aerodynamics.
  • Aerospace Engineering