Abstract: An anti-icing system and method for an aircraft engine nacelle. The nacelle has an inlet lip that defines a leading edge of the nacelle and has a cross-sectional shape and oppositely-disposed exterior and interior surfaces. An anti-icing system contacts at least the inlet lip of the nacelle. The anti-icing system includes at least one heating element having a cross-sectional shape that conforms to the cross-sectional shape of the inlet lip and in which carbon nanotubes are oriented and arranged to conduct electrical current through the heating element. Passing an electrical current through the heating element causes Joule heating of the heating element and heating of the inlet lip by thermal conduction.

Abstract: An anti-icing system for a nacelle of an aircraft engine. The nacelle has an inlet lip that defines a leading edge of the nacelle, and further has an annular-shaped cavity adjacent and delimited in part by an interior surface of the inlet lip. An anti-icing system is located within the cavity and includes a manifold with a cross-sectional shape that conforms to the interior surface of the inlet lip. A wall of the manifold faces the interior surface of the inlet lip, and air is conducted to the manifold to cause heating of the inlet lip via the manifold wall.

Abstract: A cowl for an aircraft engine, and processes for producing the cowl to have a layered construction and a high temperature capability. The layered construction of the cowl includes a core member having a cellular construction comprising internal hollow cells, and first and second skins brazed to edges of the cells at opposite surfaces of the core member. The first and second skins and the core member are formed of titanium alloys, the first and second skins are brazed to the core member, and the layered construction of the cowl lacks a thermal insulation capable of thermally protecting the second skin and brazed joints that attach the second skin to cell wall edges at the second surface of the core member.

Abstract: A thermal insulation blanket for an aircraft engine, and processes for producing the thermal insulation blanket to have low thermal conductivity and high temperature capability. The thermal insulation blanket has a layered construction that includes an aerogel insulation material, a composite layer disposed at a first surface of the aerogel insulation material, and a backing layer disposed at an opposite surface of the aerogel insulation material so that the aerogel insulation material is encapsulated between the composite and backing layers. The composite layer contains a resin matrix material reinforced with a fiber reinforcement material.

Abstract: Processes for fabricating polymer composite materials that contain a polymer matrix, reinforcement fabrics, and particles of a filler material. The processes include spraying the particles of the filler material on at least two articles that each comprise at least one of the reinforcement fabrics to form particle-laden articles. The particle-laden articles are stacked to form a stacked structure, and a resin present within the stacked structure is then cured to form a laminate polymer composite material. The process can be employed in the fabrication of at least a portion of an aircraft engine nacelle, for example, the inlet lip of a fan nacelle.

Abstract: A process for producing through-holes in a sheet member to form a perforated article, such as an arcuate (non-planar) acoustic skin suitable for use in an acoustic panel of an aircraft engine nacelle. The process includes deforming a sheet member to have an arcuate shape with an arcuate surface, mounting and rotating the arcuate-shaped sheet member on a mandrel and then, while rotating the sheet member, directing an electron beam at the arcuate surface of the sheet member and deflecting the electron beam toward multiple locations on the arcuate surface to produce the through-holes through the sheet member in a defined hole pattern and thereby yield a perforated arcuate-shaped sheet member with holes having axes substantially normal to the arcuate surface. The holes are not subjected to elongation in a nonuniform manner after they are produced, and have the same transverse cross-sectional shape.

Abstract: A method of assembling a nacelle for a gas turbine engine that includes an inlet end, an exhaust end, and an axis that extends through the engine from the inlet end through the exhaust end is provided. The method includes providing a cowl sized to cover at least a portion of the engine and coupling the cowl to the engine such that the cowl is slideable along the axis toward at least one of the inlet end and the exhaust end.

Abstract: A nacelle assembly and a method for assembling the same is provided. The nacelle assembly includes an inner barrel and an outer structure comprising a highlight and an outer aft section, wherein the highlight is defined by a forward end of the outer structure, wherein the outer aft section includes a point defined by a maximum diameter of the nacelle assembly, wherein the nacelle assembly extends at least between the highlight and the point.

Abstract: A process and apparatus for producing perforated composite structures, such as acoustic skins suitable for aircraft engine nacelle and duct components. The process includes placing a mat member, a non-impregnated fabric member, and a resin film on a tool surface so that pins disposed on the mat member project through the fabric member and resin film to define holes therein. The fabric member is between the mat member and resin film, and the fabric member and resin film define a stack that conforms to the mat member and tool surface. A caul member is then placed on the stack so that apertures in the caul member are penetrated by the pins. The stack is heated to melt the resin film and cause molten resin to infuse the fabric member and yield a resin-infused fabric stack, after which the molten resin within the resin-infused fabric stack is at least partially cured.

Abstract: A process and apparatus for producing perforated composite structures, such as acoustic skins suitable for aircraft engine nacelle and duct components. The process includes placing a mat member, a non-impregnated fabric member, and a resin film on a tool surface so that pins disposed on the mat member project through the fabric member and resin film to define holes therein. The fabric member is between the mat member and resin film, and the fabric member and resin film define a stack that conforms to the mat member and tool surface. A caul member is then placed on the stack so that apertures in the caul member are penetrated by the pins. The stack is heated to melt the resin film and cause molten resin to infuse the fabric member and yield a resin-infused fabric stack, after which the molten resin within the resin-infused fabric stack is at least partially cured.

Abstract: An anti-icing system for a nacelle of an aircraft engine. The nacelle has an inlet lip that defines a leading edge of the nacelle, and further has an annular-shaped cavity adjacent and delimited in part by an interior surface of the inlet lip. An anti-icing system is located within the cavity and includes a manifold with a cross-sectional shape that conforms to the interior surface of the inlet lip. A wall of the manifold faces the interior surface of the inlet lip, and air is conducted to the manifold to cause heating of the inlet lip via the manifold wall.

Abstract: An anti-icing system and method for an aircraft engine nacelle. The nacelle has an inlet lip that defines a leading edge of the nacelle and has a cross-sectional shape and oppositely-disposed exterior and interior surfaces. An anti-icing system contacts at least the inlet lip of the nacelle. The anti-icing system includes at least one heating element having a cross-sectional shape that conforms to the cross-sectional shape of the inlet lip and in which carbon nanotubes are oriented and arranged to conduct electrical current through the heating element. Passing an electrical current through the heating element causes Joule heating of the heating element and heating of the inlet lip by thermal conduction.

Abstract: A process for producing resin-impregnated laminate composite structures that comprise a closed-cell core between resin-impregnated fabric layers, and preliminary and composite structures formed by such a process. The process includes stitching a roving in a preliminary structure that includes the core so as to structurally reinforce the core. The roving passes through through-holes in the core and traverses opposite outer surfaces of the preliminary structure. The outer surfaces of the preliminary structure traversed by the roving may be defined by outer surfaces of the core, or the preliminary structure may further include two or more fabric layers on outer surfaces of the core such that the core is between the fabric layers, the roving passes through one or more fabric layers, and at least one of the outer surfaces of the preliminary structure and traversed by the roving is defined by a fabric layer.

Abstract: A process and apparatus for producing perforated composite structures, such as acoustic skins suitable for aircraft engine nacelle components. The process includes placing at least one mat member, a non-impregnated fabric member, and a pad member on a tool surface so that pins disposed on the mat member project through the fabric member to define holes therein, the fabric member is between the mat and pad members, and the mat, fabric and pad members yield a non-impregnated stack that conforms to the tool surface. The fabric member is then infused with a resin to yield a resin-impregnated fabric and the resin within the resin-impregnated fabric is partially cured, after which the partially-cured resin-impregnated fabric is removed from the tool surface and from between the mat and pad members. A post cure of the partially-cured resin-impregnated fabric can then be performed to yield the composite structure with the holes.

Abstract: A process and apparatus for producing perforated composite structures, such as acoustic skins suitable for aircraft engine nacelle and duct components. The process includes placing a mat member, a non-impregnated fabric member, and a resin film on a tool surface so that pins disposed on the mat member project through the fabric member and resin film to define holes therein. The fabric member is between the mat member and resin film, and the fabric member and resin film define a stack that conforms to the mat member and tool surface. A caul member is then placed on the stack so that apertures in the caul member are penetrated by the pins. The stack is heated to melt the resin film and cause molten resin to infuse the fabric member and yield a resin-infused fabric stack, after which the molten resin within the resin-infused fabric stack is at least partially cured.

Abstract: A process for producing through-holes in a sheet member to form a perforated article, such as an arcuate (non-planar) acoustic skin suitable for use in an acoustic panel of an aircraft engine nacelle. The process includes deforming a sheet member to have an arcuate shape with an arcuate surface, mounting and rotating the arcuate-shaped sheet member on a mandrel and then, while rotating the sheet member, directing an electron beam at the arcuate surface of the sheet member and deflecting the electron beam toward multiple locations on the arcuate surface to produce the through-holes through the sheet member in a defined hole pattern and thereby yield a perforated arcuate-shaped sheet member with holes having axes substantially normal to the arcuate surface. The holes are not subjected to elongation in a nonuniform manner after they are produced, and have the same transverse cross-sectional shape.

Abstract: A process for producing composite structures having a core between resin-impregnated composite layers, and composite structures formed by such a process. The process uses non-impregnated fabric layers and a core layer placed on a mold such that the core layer is between at least two fabric layers, a first of which is disposed between the mold surface and a first surface of the core layer, and a second of which is disposed at a second surface of the core layer. The second fabric layer is then infused with a resin, which flows through holes in the core layer into the first fabric layer, such that the first and second fabric layers are uniformly impregnated with the resin and the core layer is not. The resin is then cured to cause the impregnated first and second fabric layers to bond to the core layer.

Abstract: A sheet of uncured polymer, which is preferably reinforced with multiple layers of fiber, is staged or partially cured to a state in which the sheet is rigid at room temperature. Multiple apertures are drilled into, and preferably through, the sheet. The apertures are for acoustic or laminar flow control, and include holes having diameters in the range of 0.025 to 0.120 inch. In the case in which the fabricated panels must conform to a particular shape, the perforated, partially cured panels are heated to a temperature at which the panel softens, and conformed to the desired surface. The partially cured, perforated sheets are then cured. In order to prevent closure of the drilled holes during the cure, the perforated panel is sandwiched between two layers of glass fabric and cured on an elastomeric tool surface which expands with increases in temperature, forcing the glass fabric to seal the holes during cure. Release coatings are used to aid panel/liner separation.