A Comprehensive Review of Helicopter Noise Literature

摘要: Abstract : This report summarizes the state-of-the-art in helicopter noise. It includes a bibliography of reports on all components noise including main rotor, tail engine and gearbox. Literature reduction subjective evaluation were also included. Capsule summaries important are included which describe purpose report, results, compares with others same subject, provides critical work presented. is concluded that available prediction methodology means for estimating sources gross basis. However, mechanisms generation still not fully understood, although experimental theoretical tools now to conduct definitive experiments establish mathematical models needed accurate definition mechanisms. Spectrum analyses show contribute significantly annoyance. In cases where these have been heavily suppressed, gearbox will appear as significant contributor Therefore, quieter helicopters must include suppression components. For certification, liter