EFFECTS OF INGESTED ATMOSPHERIC-TURBULENCE ON MEASURED TAIL ROTOR ACOUSTICS

Results from an outdoor hover test of a full-scale Lynx tail rotor are presented, The investigation was designed to further the understandin g of the acoustics of an isolated tail rotor hovering out-of-ground ef fect in atmospheric turbulence, without the effects of the main rotor wake or other helicopter components, Measurements include simultaneous rotor performance, noise, inflow, and far-field atmospheric turbulenc e. Results with grid-generated inflow turbulence are also presented. T he effects of atmospheric turbulence ingestion on rotor noise are quan tified, In contradiction to current linear theories, increasing rotor inflow and rotor thrust were found to increase turbulence ingestion no ise.