Abstract: A method of welding a workpiece assembly includes positioning a flange adjacent to a web to form a workpiece assembly having an interface between a flange edge surface and a web side surface, and in which a web edge portion protrudes beyond a flange front surface on a front side of the workpiece assembly. The method additionally includes constraining the flange and the web against movement, and moving a plasma arc welding (PAW) torch, located on the front side of the workpiece assembly, along a lengthwise direction of the interface, while causing a plasma arc to pass through a flange edge portion and the web side surface, and generate molten material that joins the flange to the web.

Abstract: A method of forming a monolithic aircraft structure having multiple aerodynamic surfaces includes forming a body component to have a body skin defining a body skin outer surface, and a body side wall integrally formed with the body skin and defining a body mating surface, the body skin outer surface providing a first aerodynamic surface. A cover component is formed to have a cover mating surface and a cover outer surface opposite the cover mating surface, the cover outer surface defining a second aerodynamic surface. The body component is positioned relative to the cover component so that the body mating surface engages the cover mating surface. At least portions of the cover mating surface are friction stir welded to the body mating surface to form friction stir welded joints between the body component and the cover component.

Abstract: A method of forming a monolithic aircraft structure having multiple aerodynamic surfaces includes forming a body component to have a body skin defining a body skin outer surface, and a body side wall integrally formed with the body skin and defining a body mating surface, the body skin outer surface providing a first aerodynamic surface. A cover component is formed to have a cover mating surface and a cover outer surface opposite the cover mating surface, the cover outer surface defining a second aerodynamic surface. The body component is positioned relative to the cover component so that the body mating surface engages the cover mating surface. At least portions of the cover mating surface are friction stir welded to the body mating surface to form friction stir welded joints between the body component and the cover component.

Abstract: Provided are wingtip torque boxes and methods of fabricating such boxes using friction stir welding. Specifically, a wingtip torque box may be formed by friction stir welding two monolithic clamshells along their respective spars thereby forming a new monolithic structure. Use of the friction stir welding and monolithic clamshells simplifies the overall fabrication process and yields a robust wingtip torque box that can be bolted on or otherwise attached to an aircraft wing. The wingtip torque box may include internal grid stiffeners and/or external stiffeners that may be also monolithic with other components of the box. For example, the stiffeners may be machined in spars or skin portions of the clamshells during fabrication of clamshells. The wingtip torque box may have a continuous cavity extending between the ends and, in some embodiments, between spars of the box and providing access for performing various operations inside the box.

Abstract: Provided are wingtip torque boxes and methods of fabricating such boxes using friction stir welding. Specifically, a wingtip torque box may be formed by friction stir welding two monolithic clamshells along their respective spars thereby forming a new monolithic structure. Use of the friction stir welding and monolithic clamshells simplifies the overall fabrication process and yields a robust wingtip torque box that can be bolted on or otherwise attached to an aircraft wing. The wingtip torque box may include internal grid stiffeners and/or external stiffeners that may be also monolithic with other components of the box. For example, the stiffeners may be machined in spars or skin portions of the clamshells during fabrication of clamshells. The wingtip torque box may have a continuous cavity extending between the ends and, in some embodiments, between spars of the box and providing access for performing various operations inside the box.