engleski

Comparative helicopter noise analysis in static and in-flight conditions

Rotary-wing aircraft is a source of a intense noise, external and internal alike, in conclusion becoming serious environmental and health issue. The generated noise is in some aspects similar to propeller noise in fixed wing aircrafts, while differing in main noise source alignment in respect to the relative airflow: in helicopters, both rotors, i.e. main and tail, that produce force s necessary for flight, and inline with the direction of flight, while the airplane rotor(s) are perpendicular to it. Another distinctive noise in helicopters, well known as 'slapping' comes from the rotor cutting its own wake/wortexs, especially while descending. In this article main helicopter noise sources will be discussed and most significant results of various static and in-flight noise measurement on two different types of helicopter will be presented and analyzed.

helicopter; noise measurement

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