Abstract: A panel for attenuating noise is disclosed comprising a face skin having a first inner surface, a base skin having a second inner surface, a cellular core connected to and forming a plurality of cells between the face skin and the base skin, wherein the cellular core is defined by a cell structure having a plurality of cell walls extending between the face skin and the base skin defining each of the plurality of cells and a septum disposed within each of the plurality of cells, the septum defining an upper chamber proximate the face skin and a lower chamber proximate the base skin, wherein the face skin comprises a plurality of perforations fully through the face skin and in fluid communication with the upper chamber.

Abstract: A panel for attenuating noise is disclosed comprising a face skin having a first inner surface, a base skin having a second inner surface, a cellular core connected to and forming a plurality of cells between the face skin and the base skin, wherein the cellular core is defined by a cell structure having a plurality of cell walls extending between the face skin and the base skin defining each of the plurality of cells and a septum disposed within each of the plurality of cells, the septum defining an upper chamber proximate the face skin and a lower chamber proximate the base skin, wherein the face skin comprises a plurality of perforations fully through the face skin and in fluid communication with the upper chamber.

Abstract: A panel for attenuating noise is disclosed comprising a face skin having a first inner surface, a base skin having a second inner surface, a cellular core connected to and forming a plurality of cells between the face skin and the base skin, wherein the cellular core is defined by a cell structure having a plurality of cell walls extending between the face skin and the base skin defining each of the plurality of cells and a septum disposed within each of the plurality of cells, the septum defining an upper chamber proximate the face skin and a lower chamber proximate the base skin, wherein the face skin comprises a plurality of perforations fully through the face skin and in fluid communication with the upper chamber.

Abstract: A panel for attenuating noise is disclosed comprising a face skin having a first inner surface, a base skin having a second inner surface, a cellular core connected to and forming a plurality of cells between the face skin and the base skin, wherein the cellular core is defined by a cell structure having a plurality of cell walls extending between the face skin and the base skin defining each of the plurality of cells and a septum disposed within each of the plurality of cells, the septum defining an upper chamber proximate the face skin and a lower chamber proximate the base skin, wherein the face skin comprises a plurality of perforations fully through the face skin and in fluid communication with the upper chamber.

Abstract: An acoustic liner may include a core with a plurality of resonator chambers, a perforated top sheet coupled to the core, and a backskin coupled to the core. A thermoacoustic speaker including nanomaterials may be coupled to at least one of the core, the backskin, and the perforated top sheet. A voltage may be applied to the thermoacoustic speaker. The thermoacoustic carbon nanotube speaker may create a dynamic excitation within a resonator chamber in the core. The dynamic excitation may change the liner acoustic impedance to achieve optimum noise attenuation over a wide range of frequencies or engine operating conditions.

Abstract: An acoustic liner that may be for a turbofan engine includes a first panel that may be non-permeable and a permeable panel spaced from the first panel. A non-permeable wall located between the first panel and the permeable panel faces in a first direction away from the first panel and a non-permeable wall, also between the panels, faces in a second direction away from the first panel and traversing the first direction. The liner may further include a plurality of sidewalls spaced from one-another, extending between the panels, and through the walls.

Abstract: An acoustic liner has a honeycomb layer disposed between a first panel and a permeable panel and includes a plurality of serpentine walls spaced apart from one-another. Adjacent serpentine walls outline in-part a first region carried by the first panel and an opposing second region carried by the permeable panel. The first and second regions are offset such that a centerline distance extending between the regions and centered between adjacent walls is greater than a distance measured directly between the panels, enabling the design of thinner acoustic liners. The regions and adjacent walls further define a cell having a constricted portion communicating between an end portion and an entry portion such that the constricted portion creates a frequency shift.

Abstract: An acoustic liner may include a core with a plurality of resonator chambers, a perforated top sheet coupled to the core, and a backskin coupled to the core. A thermoacoustic speaker including nanomaterials may be coupled to at least one of the core, the backskin, and the perforated top sheet. A voltage may be applied to the thermoacoustic speaker. The thermoacoustic carbon nanotube speaker may create a dynamic excitation within a resonator chamber in the core. The dynamic excitation may change the liner acoustic impedance to achieve optimum noise attenuation over a wide range of frequencies or engine operating conditions.

Abstract: An acoustic liner that may be for a turbofan engine includes a first panel that may be non-permeable and a permeable panel spaced from the first panel. A non-permeable wall located between the first panel and the permeable panel faces in a first direction away from the first panel and a non-permeable wall, also between the panels, faces in a second direction away from the first panel and traversing the first direction. The liner may further include a plurality of sidewalls spaced from one-another, extending between the panels, and through the walls.

Abstract: An acoustic liner has a honeycomb layer disposed between a first panel and a permeable panel and includes a plurality of serpentine walls spaced apart from one-another. Adjacent serpentine walls outline in-part a first region carried by the first panel and an opposing second region carried by the permeable panel. The first and second regions are offset such that a centerline distance extending between the regions and centered between adjacent walls is greater than a distance measured directly between the panels, enabling the design of thinner acoustic liners. The regions and adjacent walls further define a cell having a constricted portion communicating between an end portion and an entry portion such that the constricted portion creates a frequency shift.

Abstract: A linear acoustic liner for an aircraft includes a cellular core having a first surface and an opposed second surface. A substantially imperforate back skin covers the first surface, and a perforate face skin covers the second surface of the core. The perforate face skin includes an outer face skin layer having a first plurality of spaced openings, an inner face skin layer having a second plurality of spaced openings, and a porous layer disposed between the outer face skin layer and the inner face skin layer. Each of the first plurality of spaced openings are substantially aligned with one of the second plurality of spaced openings.

Abstract: A linear acoustic liner for an aircraft includes a cellular core having a first surface and an opposed second surface. A substantially imperforate back skin covers the first surface, and a perforate face skin covers the second surface of the core. The perforate face skin includes an outer face skin layer having a first plurality of spaced openings, an inner face skin layer having a second plurality of spaced openings, and a porous layer disposed between the outer face skin layer and the inner face skin layer. Each of the first plurality of spaced openings are substantially aligned with one of the second plurality of spaced openings.

Abstract: A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

Abstract: A linear acoustic liner for an aircraft includes a cellular core having a first surface and an opposed second surface. A substantially imperforate back skin covers the first surface, and a perforate face skin covers the second surface of the core. The perforate face skin includes an outer face skin layer having a first plurality of spaced openings, an inner face skin layer having a second plurality of spaced openings, and a porous layer disposed between the outer face skin layer and the inner face skin layer. Each of the first plurality of spaced openings are substantially aligned with one of the second plurality of spaced openings.

Abstract: A linear acoustic liner for an aircraft includes a cellular core having a first surface and an opposed second surface. A substantially imperforate back skin covers the first surface, and a perforate face skin covers the second surface of the core. The perforate face skin includes an outer face skin layer having a first plurality of spaced openings, an inner face skin layer having a second plurality of spaced openings, and a porous layer disposed between the outer face skin layer and the inner face skin layer. Each of the first plurality of spaced openings are substantially aligned with one of the second plurality of spaced openings.