1
Guenter M Schindler: Multi-layered acoustic liner. McDonnell Douglas Corporation, John P Scholl, Walter J Jason, Donald L Royer, April 6, 1976: US03948346 (106 worldwide citation)

This invention concerns a multi-layered acoustic liner which breaks up high amplitude sound and shock waves into several waves of the same type but smaller amplitudes, converting some acoustic energy into heat and shifting part of the acoustic energy to a higher frequency level to achieve better abs ...


2
Guess Arnold W, Schindler Guenter M: Acoustic liner. McDonnell Douglas Corporation, Richardson Robert O, Jason Walter J, Royer Donald L, July 2, 1974: US3821999 (81 worldwide citation)

An acoustic liner consisting of a perforated honeycomb sandwich panel wherein the axes of the honeycomb cells are tilted relative to the outer surface for more effective absorption of high amplitude sound and shock waves over a relatively narrow band of the frequency spectrum. An application is in t ...


3
Philip M Rose, Alojzy A Mikolajczak: Turbofan duct with noise suppression and boundary layer control. Rohr, Patrick J Schlesinger, Frank D Gilliam, Michael H Jester, June 7, 1988: US04749150 (62 worldwide citation)

A boundary layer control device is installed in the acoustically treated inlet duct of a turbofan engine. The device sucks off the turbulent boundary layer of air flowing over the inner or "air wetted" surface of the inlet during aircraft take-off, cruise and approach. The lip of the inlet can thus ...


4
Russell E Motsinger, John W Vdoviak: Closed cavity noise suppressor. General Electric Company, Jerome C Squillaro, July 31, 1990: US04944362 (42 worldwide citation)

An annular acoustic liner for gas turbine engine ducts comprising Helmholtz resonator chambers wherein the resonator's turnable neck length and chamber depth lie on a surface which is concentric to the liner centerline. In another embodiment of the invention the liner is generally rectangular and th ...


5
Marlin D Breer, Ronald F Olsen, Robert K Kunze Jr, Brian L Riedel: Method and apparatus for aircraft inlet ice protection. The Boeing Company, Perkins Coie, February 10, 2004: US06688558 (38 worldwide citation)

An inlet ice protection system, and methods for making and using ice protection systems. In one embodiment, the inlet includes a tapered acoustic liner positioned forward of the inlet throat and has a perforated face sheet, a perforated back sheet, and an acoustic core between the face sheet and the ...


6
Philip R Gliebe: Active low noise fan assembly. General Electric Company, Andrew C Hess, Patrick R Scanlon, December 26, 1995: US05478199 (33 worldwide citation)

A gas turbine engine fan assembly includes an equal number of rotor blades and stator vanes spaced axially therefrom. An annular duct surrounds the blades and vanes and has an inlet for receiving air and an outlet for discharging at least a portion of the air upon compression by the blades. The fan ...


7
Brian W Lowrie: Duct linings. Rolls-Royce, Cushman Darby & Cushman, October 31, 1978: US04122672 (33 worldwide citation)

When fan-blade tips in a turbofan aero engine reach a velocity of greater than about mach 1.1, the regular shock-wave pattern near the blade tips degenerates into an irregular pattern as it moves upstream, thus causing "buzz-saw" noise. An anit-buzz acoustic liner of the spaced-cell type forms part ...


8
Robert E Anderson, Charles A Parente: One-piece engine inlet acoustic barrel. Grumman Aerospace Corporation, Terry J Anderson, Karl J Hoch Jr, December 3, 1996: US05581054 (31 worldwide citation)

An acoustic liner jet engine inlet barrel is formed from a perforated permeable skin, a honeycomb core, and a solid facesheet, each of which is formed in a one-piece configuration such that at most only a narrow single fore-to-aft splice, or no splice at all, is present in the finished product. The ...


9
Marlin D Breer, Ronald F Olsen, Robert K Kunze Jr, Brian L Riedel: Method and apparatus for aircraft inlet ice protection. The Boeing Company, Perkins Coie, October 1, 2002: US06457676 (31 worldwide citation)

An inlet ice protection system, and methods for making and using ice protection systems. In one embodiment, the inlet includes an acoustic liner positioned forward of the inlet throat and has a perforated face sheet, a perforated back sheet, and an acoustic core between the face sheet and the back s ...


10
Kontos Karen Bernadette, Kraft Robert Eugene: Active acoustic liner. Gen Electric, May 15, 1996: EP0712114-A2 (30 worldwide citation)

The active liner comprises the rigid backplate, the piezoelectric panel having a back surface fixedly joined to the backplate, and an opposite face surface for directly facing the noise. The pressure transducer is disposed in the panel for sensing acoustic pressure of the noise being propagated agai ...