Sensitivity of tail rotor noise to helicopter configuration in forward flight

Timothy M. Fletcher, Karthikeyan Duraisamy, Richard Brown

Research output: Contribution to conferencePaperpeer-review

3 Citations (Scopus)
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Understanding the mechanisms that lead to the production of noise by tail rotors across a broad range of flight conditions and helicopter configurations remains an active area of research. Furthermore, designers require numerical models that are able to efficiently and accurately predict the acoustic signature of the helicopter. Predictions made using the Vorticity Transport Model in conjunction with a linear acoustics code, in which the Ffowcs Williams-Hawkings equation is solved for the sound pressure level on a horizontal observer plane beneath a scaled model of the Bo-105 helicopter, have been shown to compare well with measurements made during the HeliNOVI experiments. As the vertical distance between the tail rotor and the main rotor is reduced, the acoustic signature of the tail rotor changes considerably. Both the blade-vortex interactions that occur between the tail rotor blades and their tip vortices, and the interactions between the tail rotor blades and the tip vortices trailed behind the main rotor blades, act as major sources of loading noise. The work presented in the paper suggests strongly, however, that the apparent acoustic advantages of a tail rotor with a particular sense of rotation cannot be considered independently of the vertical location of the tail rotor with respect to the main rotor.
Original languageEnglish
Publication statusPublished - 27 May 2009
Event65th American Helicopter Society Annual Forum - Texas, USA
Duration: 27 May 200929 May 2009


Conference65th American Helicopter Society Annual Forum
CityTexas, USA


  • tail rotor noise
  • vorticity transport model
  • Ffowcs Williams-Hawkings equation
  • loading noise

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