Reduction Of Helicopter Internal Noise

Informazioni relative al progetto

RHINO

ID dell’accordo di sovvenzione: AER20046

Progetto chiuso

Data di avvio 1 Gennaio 1993

Data di completamento 31 Dicembre 1995

Finanziato da

• Specific programme of research and technological development in the field of industrial and materials technologies - Aeronautics research -, 1990-1994

Costo totale

Nessun dato

Contributo UE

Nessun dato

Coordinato da

Agusta SpA
Italy

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Risultati sfruttabili

Reduction of helicopter interior noise

The possibility of reducing low frquency interior noise in helicopters by up to 12 dB by active noise control has been validated in flight. In this range of frequencies it is very impractical to apply conventional passive treatment. Methods to identify noise transmission paths and vibratory source descriptors have been validated in flight demonstrating that gearbox noise dominant transmission path is structure borne. The potential benefits of actively controlling the transmissibility of gearbox support struts (as well as passive means such as tuned resonator and elastomeric bearings) and structural panels have been demonstrated. The combination of active control and elastomeric bearings showed a reduction of up to 40 dB in the transmissibility of the strut. A predictive SEA code has been developed and validated on a real helicopter fusilage. A study on the characterization of the most influential parameters (including errors and mis alignements) in noise emission byb gears has been performed.