The Quiet Technology Demonstrator Program: Static Test of an Acoustically Smooth Inlet

Abstract

The QTD2 static engine test sought to provide further insight into the noise reduction technologies demonstrated during the 2005 flight test program. One of the technologies demonstrated in the QTD2 program was the Acoustically Smooth Inlet. This technology represented a true zero splice design with the total treated area increased relative to a typical production design. During the flight test, this inlet demonstrated community noise reductions of over 2 EPNdB and significant reductions in forward cabin noise. The static test was successful in identifying key design features that led to these benefits. Multiple pure tone noise reduction was shown to be primarily attributable to increased acoustic area in the inlet. Reductions in BPF tone related noise was shown to be mostly due to the elimination of splices of the inlet. Finally, a detailed investigation into the effects of splices in the forward fan case region was completed.