Helicopter Noise Reduction Design Trade-Off Study.

摘要

A study was performed to determine the noise reduction benefits and economic costs associated with applying state-of-the-art noise reduction methods to future design civil helicopters. As part of this study, a survey of the make-up of the civil fleet was performed,and this fleet make-up was projected to the 1980time frame. Analytical methods were developed and/or adopted for calculating helicopter component noise,and these methods were incorporated into a unified total vehicle noise calculation model. Analytical methods were also developed for calculating the effects of noise reduction methodology on helicopter design,performance and cost. The analytical methods were used to calculate baseline noise and cost characteristics of several existing civil helicopters. These methods were also used to calculate changes in noise,design,performance and cost due to the incorporation of engine and main rotor noise reduction methods. All noise reduction techniques were evaluated in the context of an established mission performance criterion which included consideration of hover ceiling,forward flight range/speed/payload and rotor stall margin. (Author)