A general mounting method for ducted fan propulsors is disclosed. This mounting method uses extremely slender stators that connect the duct ring to the propulsor which is mounted in the middle and drives the rotor, fan or propeller. The slender stators take the form of spokes and as such are so slender that the midspan stresses within the spokes are dominated by axial tension loads rather than the shear loads experienced by conventional stators. The spokes may have an aerodynamic shape and damping methods may be used to retard spoke vibrations and transmission of engine vibrations to the duct and force. The duct itself is also stiffened by the spoke arrangement, thereby reducing low frequency vibration modes.

A structural panel is provided that includes a first core structure and a second core structure. The first core structure is configured with a first endwall and a plurality of first cavities that extend vertically through the first core structure. The second core structure is configured with a second endwall and a plurality of second cavities that extend vertically through the second core structure. The second core structure is laterally bonded to the first core structure at a complex splice joint between the first endwall and the second endwall.

A general mounting method for ducted fan propulsors is disclosed. This mounting method uses extremely slender stators that connect the duct ring to the propulsor which is mounted in the middle and drives the rotor, fan or propeller. The slender stators take the form of spokes and as such are so slender that the midspan stresses within the spokes are dominated by axial tension loads rather than the shear loads experienced by conventional stators. The spokes may have an aerodynamic shape and damping methods may be used to retard spoke vibrations and transmission of engine vibrations to the duct and force. The duct itself is also stiffened by the spoke arrangement, thereby reducing low frequency vibration modes.

A flow path duct system for a propulsion system of an aircraft includes a base defining a flow surface. The base has an internal surface and an external surface. A plurality of perforations are formed through the base between the internal surface and the external surface. A plurality of supports define a plurality of cavities. The plurality of supports extend outwardly from the external surface of the of the base. One or more of the plurality of cavities are in fluid communication with the one or more of the plurality of perforations. A backing surface is secured to the plurality of supports. The plurality of supports are disposed between the base and the backing surface. The one or more of the plurality of cavities are in fluid communication with an internal volume defined by the internal surface of the base through the one or more of the plurality of perforations. The base, the plurality of supports, and the backing surface can be integrally formed together as a monolithic, load-bearing structure.

Plated polymeric gas turbine engine parts and methods for fabricating lightweight plated polymeric gas turbine engine parts are disclosed. The parts include a polymeric substrate plated with one or more metal layers. The polymeric material of the polymeric substrate may be structurally reinforced with materials that may include carbon, metal, or glass. The polymeric substrate may also include a plurality of layers to form a composite layup structure.

An acoustic treatment panel in which each cell includes a plurality of conduits which extend from the porous acoustically resistive structure to the reflective layer of the acoustic treatment panel, each conduit including at least one opening set away from the porous acoustically resistive structure and configured to cause the inside and the outside of the conduit to communicate.

Disclosed is a gas turbine engine including a fan, a nacelle including a flutter damper forward of the fan, the flutter damper including an acoustic liner having a perforated radial inner face sheet and a radial outer back sheet, the acoustic liner configured for peak acoustical energy absorption at a frequency range that is greater than a frequency range associated with fan flutter, a chamber secured to the radial outer back sheet, the chamber in fluid communication with the acoustic liner, and the chamber configured for peak acoustical energy absorption at a frequency range associated with fan flutter modes, and the engine includes (i) the nacelle and a core cowl forming a convergent-divergent fan exit nozzle; (ii) a variable area fan nozzle capable of being in an opened and closed, the opened position having a larger fan exit area than the closed position; and/or (iii) the fan being shrouded.

A sound attenuation device includes an acoustic panel having a first end and a second end spaced from the first end. The first end is configured for attachment to a first mount and the second end is configured for attachment to a second mount. The acoustic panel comprises a permeable skin and a septum, the septum having a length extending between the first end and the second end.

A double-enclosure acoustic element of small size, in particular for an aircraft acoustic panel. The acoustic element has a first enclosure with a mouth and a second enclosure with, at a front longitudinal end, a mouth and arranged inside the first enclosure, these first and second enclosures being joined together at the front. The acoustic element includes a slotting assembly system, the assembly system including at least one protruding element on the first edge of one of the first and second enclosures and at least one recess in the first edge of the other of the first and second enclosures, the protruding element and the recess having complementary shapes such that the protruding element can be slotted into the recess. Thus, the two enclosures can be assembled by quick and easy slotting.

A method for providing a honeycomb core assembly that includes obtaining a honeycomb core having at least first and second cells that each define a cell interior having an open bottom and an open top, contacting the honeycomb core with a liquid foaming adhesive, contacting a hardening agent with the liquid foaming adhesive, and allowing the hardening agent and liquid foaming adhesive to react to harden and form a first barrier member that spans the cell interior of the first cell and a second barrier member that spans the cell interior of the second cell, thereby forming the honeycomb core assembly.