SOURCE DIRECTIVITY OF NOISE FROM HELICOPTERS.A DISCUSSION OF MEASUREMENT METHODS

摘要

Unlike fixed-wing aircraft; helicopters are extremely complicated noise sources with respect to both spectrum and directivity. Much effort has been put into the description of measurement methods and collecting noise data during operation. A working party has been set up under the auspices of the NATORCMS follow-up group on aircraft noise. Investigations and measurements were carried out by the working party [l]. Still essential work remains before the goal is fulfilled: to describe a measurement methodology for the collection of a database fit for use when noise exposure calculations need to be carried out as basis of environmental planning.