Engine inlet deep acoustic liner section

摘要

An inlet of an aircraft nacelle having an acoustic barrel configured to reduce engine fan flutter by attenuating various frequencies. The acoustic barrel may comprise an acoustic panel of a honeycomb configuration sandwiched between a first back sheet and a face sheet and extending from a forward bulkhead to an aft bulkhead of the inlet. The acoustic barrel may further comprise a deep liner section bonded to and sandwiched between the first back sheet and a second back sheet. The deep liner section may have a narrower width than the acoustic panel and may be located proximate the aft bulkhead. The sections of the first back sheet, the face sheet, and a septum of the acoustic panel may be perforated and may contain additional holes formed in portions aligned radially inward of the deep liner section.