Said preform (3) defining two parts (21, 23) and comprising: a first group (C1) of layers of warp yarns, which is external in the first part, a second group (C2) of layers of warp yarns immediately beneath said first group, and a first group (T1) of layers of weft yarns which is external in the first part. Furthermore, the first group of layers of warp yarns is absent in the second part and the first group of layers of weft yarns (19) extends into the second part, the first group of layers of weft yarns being external in the second part. The yarns of the first weft group have a lower yarn count than the yarns of the second weft group; and/or the yarns of the first warp group have a lower yarn count than the yarns of the second warp group.

Stringers and aircraft skin structures and related methods are disclosed. An example apparatus includes a skin structure and a support. The support includes a first surface, a second surface opposite the first surface, and a tapered edge extending from the first surface. The example apparatus includes a first material disposed between a first portion of the support and a first portion of the skin structure to couple the second surface of the support to the skin structure and a second material disposed between a second portion of the support and a second portion of the skin structure. The second material is different than the first material. The second portion of the support includes at least a portion of the tapered edge.

Methods of assembling an aircraft wing includes adhering fuel dams to stringers and adhering the fuel dams to ribs. Fuel dams include a fuel-dam body that defines a channel shaped to receive a portion of a stringer of an aircraft wing. The fuel-dam body includes a stringer adherent surface, a rib adherent surface, and a pair of spaced-apart flanges extending from the rib adherent surface and positioned to project from the rib adherent surface on opposing sides of a notch of a rib.

A duct stringer forms at least part of a duct with a closed cross-section which is adapted to transport fluid. The duct stringer has a duct wall and a female bayonet fitting in the duct wall. The female bayonet fitting is configured to engage with a male bayonet fitting on a fluid transporting conduit to connect the fluid transporting conduit with the duct.

A method includes dispensing a first set of lanes, that each comprise a tow of fiber-reinforced material, at a first angle such that the lanes are placed side-by-side with respect to each other, forming a first layer of a multi-lane tow. The method further includes applying a film directly in contact with multi-lane tow that resists shear forces applied to the multi-lane tow, transporting the multi-lane tow to a mandrel, and compacting the multi-lane tow via a Ply-By-Ply (PBP) machine disposed at the mandrel. The method further comprises removing the film from the multi-lane tow.

Described herein are stringer assemblies, such as blade stringers, and methods of forming thereof. A stringer assembly comprises a first fabric composite stiffener, a second fabric composite stiffener, and an intermediate tape composite stiffener, disposed between and connected to each of the first and second stiffeners. Using three separate components allows forming sharp bends, eliminating voids and gap fillers, and adding new features, such as edge reinforcements. Each of the first and second fabric composite stiffeners comprises a web portion, a flange portion, and a curved portion, positioned between the web and flange portions. The web portions surround and are attached to the intermediate tape composite stiffener and, in some examples, include tapered-out edges for additional rigidity. The flange portions are attached to the composite base. The curved portions conform to the flared-out edges of the intermediate tape composite stiffener, which extends and connects to the composite base.

Provided are methods and devices for supporting of variety of different pre-cured composite stringers after forming and prior to curing. A post-forming processing device comprises a base with a channel for receiving hat portions of different stringers. The device also comprises a support structure, at least partially extending within the channel. The support structure is configured to conform to different hat portions and to retain the shape of these hat portions. For example, the support structure is made from a flexible material, which conforms to any shape variations. In some examples, the support structure is made from a jamming material that is reshaped together with each of the pre-cured composite stringers. A post-forming processing device is used for supporting different pre-cured composite stringers while various operations are performed on these stringers, such as stringer trimming, inspection, installation of bladders and noodles, and the like.

Duct stringers for aircraft wing boxes. The duct stringer comprises a base, a pair of sidewalls projecting from the base in a spaced-apart relationship, and a cap wall that extends between and interconnects the pair of sidewalls, with the cap wall being positioned spaced apart from the base by the pair of sidewalls. The duct stringer further comprises an ovaloid vent formed in the cap wall. The ovaloid vent comprises a perimeter that circumscribes an aperture and that defines a closed shape. The perimeter comprises a pair of curved end regions opposed to one another and that each arc at least substantially through 180 degrees. Each curved end region comprises a non-uniform radius of curvature.

An example aircraft wing includes a skin, a composite shear tie, a stringer base charge overlaying the skin, and a stringer overlaying the stringer base charge. The composite shear tie includes a shear-tie web, a first shear-tie flange extending from a first side of the shear-tie web, a second shear-tie flange extending from a second side of the shear-tie web, and a first shear-tie tab extending from an end of the first side of the shear-tie web. The stringer includes a stringer web, a first stringer flange extending from a first side of the stringer web, and a second stringer flange extending from a second side of the stringer web. The first stringer flange is stitched to and integrated with the stringer base charge and the skin. Further, the first shear-tie flange is stitched to and integrated with the first stringer flange.

An airfoil structure for an aircraft includes a spanwise-extending load-carrying member, a leading-edge structure, a trailing-edge structure, an upper cover, and a lower cover. The load-carrying member is configured to react more than half of all flight loads experienced by the airfoil structure during flight and is configured to have selected stiffness properties selected such that the airfoil structure bends and twists in a predefined manner in response to applied flight loads. The leading-edge structure is configured to form a leading-edge part of an aerodynamic surface of the airfoil structure. The trailing-edge structure is configured to form a trailing edge part of the aerodynamic surface. The upper cover is configured to form an upper part of the aerodynamic surface. The lower cover is configured to form a lower part of the aerodynamic surface.