Rohr Industries, Inc.

Aeronautic Development Corporation, Ltd.

Philip M Rose

Frank J Riel

Thomas W Carr

Jia Yu

Alan H Marsh

Alojzy A Mikolajczak

A double layer structural honeycomb sandwich noise suppression panel for use in severe environments such as aircraft turbine engine housings. Two honeycomb core sheets having multiple cells transverse to the sheets are sandwiched around and bonded to a septum sheet consisting of a wire cloth sheet alone or bonded to a sheet of perforated material. A thin sheet of impervious material is bonded to one surface of the sandwich and a facing of thin perforated sheet material is bonded to the other sandwich surface. The panel has improved simplicity, structural strength with unusually light weight.

Honeycomb noise attenuation structure

A quiet nacelle system for jet aircraft engines includes a nose cowl and nose dome having a sound-attenuating liner, a concentric ring between the nose cowl and nose dome, and fan duct components having a sound-attenuating liner. The system is particularly suitable for JT3D-3B and JT3D-7 engines for use with DC-8 aircraft. The components may be combined as a hush kit for retrofit in existing nacelle systems.

Quiet nacelle system and hush kit

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 be made thinner to reduce drag during cruise without degradation of fan performance during take-off. The acoustic liner of the inlet comprises a microporous honeycomb sandwich structure through which air may be sucked at various locations through headers and conduits connected to an onboard pump.

Turbofan duct with noise suppression and boundary layer control

A quiet nacelle system for jet aircraft engines includes an elongated nose cowl and nose dome of the nacelle and a sound-attenuating liner applied to the nose cowl, nose dome and fan duct components. The system is particularly suitable for JT3D-3B and JT3D-7 engines for use with DC-8 aircraft. The components may be combined as a hush kit for retrofit in existing nacelle systems.

A sandwich type acoustical absorbing panel for use adjacent to high speed gas flow areas in and around the engines of high speed aircraft. The panel in one embodiment comprises an imperforate facing sheet including having upright side and end walls, the inner volume of the panel and upright side and end walls are divided by means of partitions into a plurality of individual cavities or cells, each of the plurality of individual cavities or cells are filled with a bulk absorber material having many small torturous air passages, such as, open celled foam, fiberglass, felts or the like, the bulk absorber filling each cavity or cell is encapsulated in a membrane of thin limp material for preventing bulk absorber contamination and a perforated sheet overlay for attaching to the side, end walls and partitions for containing the bulk absorber within the cavities or cells.

Encapsulated bulk absorber acoustic treatments for aircraft engine

A method of manufacturing a double degree acoustic attenuation sandwich panel having a plurality of stacked components adhered together to form a unitary sandwich structure. The structure comprising an impervious facing of thin sheet material, a first honeycomb core with end wise directed cells, a first perforate facing of thin sheet material, a first thin layer of porous fibrous material, a second perforated facing of thin sheet material, a second honeycomb core with end wise directed cells, a third perforate facing of thin sheet material, the second perforated facing sheet having substantially larger perforations than the first and third sheets, and a second layer of porous fibrous material. The resulting sandwich panel has a pre-determined flow through resistance between the outer surface of the first and second layers of porous fibrous material and the cells of the first and second honeycomb cores. The cells of the first and second honeycomb cores may be of equal or different volume and may be constructed of similar or dissimilar materials.

Method of manufacturing double layer attenuation panel with two layers

A double degree acoustic attenuation sandwich panel having a plurality of stacked components adhered together to form a unitary sandwich structure. The structure comprising an impervious facing of thin sheet material, a first honeycomb core with end wise directed cells, a first perforate facing of thin sheet material, a first thin layer of porous fibrous material, a second honeycomb core with end wise directed cells, a second perforate facing of thin sheet material and a second layer of porous fibrous material. The resulting sandwich panel has a predetermined flow through resistance between the outer surface of the first and second layers of porous fibrous material and the cells of the first and second honeycomb cores. The cell of the first and second honeycomb cores may be of equal or different volume cells and may be constructed of similar or dissimilar materials.

Double layer attenuation panel

A sandwich type acoustical absorbing panel for use adjacent high speed gas flow areas in and around the engines of high speed aircraft. The panel comprises a pan type base having an imperforate base member and upstanding sides and end walls, an acoustic absorbing medium is disposed within the pan type base, a rigid perforated plate is secured to the distal surfaces of the upstanding sides and end walls for enclosing the acoustic absorbing medium and a sheet of fine woven mesh is secured to the outer surface of the rigid perforated plate. The outer positioned fine woven mesh enhances acoustic properties of the panel and substantially prevents entry of water, dust, chemicals and similar foreign matter from penetrating into the panel structure and reduces the aerodynamic drag loss normally encountered by high speed gas flows across perforated material, such as, that normally used for the outer surface of acoustic panels.

Bulk acoustic absorber panels for use in high speed gas flow environments

A double degree acoustic attenuation sandwich panel having a plurality of stacked components adhered together to form a unitary sandwich structure. The structure comprising an impervious facing of thin sheet material, a first honeycomb core with end wise directed cells, a first perforate facing of thin sheet material, a first thin layer of porous fibrous material, a second perforated facing of thin sheet material, a second honeycomb core with end wise directed cells, a third perforate facing of thin sheet material, the second perforated facing sheet having substantially larger perforations than the first and third sheets, and a second layer of porous fibrous material. The resulting sandwich panel has a pre-determined flow through resistance between the outer surface of the first and second layers of porous fibrous material and the cells of the first and second honeycomb cores. The cells of the first and second honeycomb cores may be of equal or different volume and may be constructed of similar or dis-similar materials.

Growing community of inventors

Chula Vista, CA, United States of America

Philip M Rose