초록 ▼

A hush kit for jet aircraft engine includes a respaced inlet guide vane to provide an increased space between the fixed guide vanes of the inlet and the rotating fan blades of the fan connected to the core engine, a mixer for mixing hot exhaust gas from the core engine with colder bypass fan air, an

A hush kit for jet aircraft engine includes a respaced inlet guide vane to provide an increased space between the fixed guide vanes of the inlet and the rotating fan blades of the fan connected to the core engine, a mixer for mixing hot exhaust gas from the core engine with colder bypass fan air, and an acoustic barrel to reduce the noise generated by the mixed air flowing through the thrust reverser downstream of the core engine. The acoustic barrel includes an outer imperforate layer, an inner perforate layer and a multi-cellular core sandwiched therebetween. The ratio of the thickness of the multi-cellular core to the open area defined by the holes in the inner perforate skin of the acoustic barrel is designed to reduce noise of a particular frequency range generated by the aircraft engine. In combination, each of the components of the hush kit described herein reduce noise generated by the jet engine for compliance with Federal Aviation Administration noise reduction requirements.

대표청구항 ▼

A noise reduction assembly for a jet engine having a core engine generating axial exhaust gas flow through a downstream end thereof, an inlet having a plurality of fixed guide vanes at an upstream end of the core engine, an outer casing defining an annular bypass duct surrounding the core engine, a

A noise reduction assembly for a jet engine having a core engine generating axial exhaust gas flow through a downstream end thereof, an inlet having a plurality of fixed guide vanes at an upstream end of the core engine, an outer casing defining an annular bypass duct surrounding the core engine, a fan positioned downstream from the inlet for generating axial fan air flow through the bypass duct, a thrust reverser for selectively converting axial flow of exhaust gas and fan air into reverse thrust, and a tail pipe disposed to axially receive and discharge the exhaust gas and fan air, the noise reduction assembly comprising: an annular ring positioned between the inlet and the fan of the core engine, said annular ring providing an increased axial spacing between the guide vanes and the fan to thereby reduce noise generated by the jet engine; a mixer assembly having a plurality of cold ducts being radially inwardly directed and a plurality of hot ducts being radially outwardly directed, said cold ducts diverting the fan air from the bypass duct inwardly toward an axial centerline of the jet engine and said hot ducts diverting the exhaust gas from the core engine outwardly away from said axial centerline; and an acoustic barrel within the thrust reverser, said acoustic barrel having a sandwich configuration with an outer imperforate skin, an inner perforate skin having a plurality of holes therein and a multi-cellular core positioned between said inner and outer skins, the exhaust gas from the core engine and the fan air from the bypass duct being mixed in said mixer assembly and passing through said acoustic barrel prior to being discharged through the tail pipe to thereby reduce noise generated by the jet engine.