Following on exploratory developments in flight-testing techniques and data-analysis procedures for helicopter external noise, extensive measurements of noise characteristics and associated flight-path data have been made by RAE on several helicopters in various operational modes, with repeated flight trajectories over longitudinal and lateral arrays of ground-based microphones under quiet airfield conditions. This analysis presents some experimental results from Lynx aircraft with standard rotor configurations, being concerned primarily with the influence of different operating procedures on both main-rotor and tail-rotor noise characteristics and on measurement repeatability during level-flight, oblique landing-approach, and oblique take-off. Some tail-rotor near-field noise signatures have also been derived for correlation purposes, using a microphone mounted with a forward-facing nose-cone just outside the fuselage skin on the tail-boom.
The influence of helicopter operating conditions on rotor noise characteristics and measurement repeatability
Einwirkung der Hubschrauberflugbedingungen auf die Geraeusche des Drehfluegels und Wiederholbarkeit des Messwertes
US Government Reports ; Apr ; 1-63
1982
63 Seiten
Report
Englisch
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