Abstract: A composite fan casing for a gas turbine engine includes, in an exemplary embodiment, a core having a plurality of core layers of reinforcing fiber bonded together with a thermosetting polymeric resin. Each core layer includes a plurality of braided reinforcing fiber tows. The braids of reinforcing fiber tows are aligned in a circumferential direction with each fiber tow including a plurality of reinforcing fibers. The core also includes at least one additional fiber tow braided into at least one predetermined axial location to form at least one concentrated stiffening ring.

Abstract: A double-wall airfoil for applications such as the blades and vanes of gas turbine engines. The double-wall comprises an outer airfoil skin and an inner support wall that are metallurgically bonded to one another. The double-wall contains integral channels for passage of cooling air adjacent to the airfoil skin. Airfoil skin may be a metal alloy skin or a microlaminate structure, including microlaminate composite structures. Microlaminate composites typically have a lower density than that of the material used for the airfoil support wall, and a simplified internal geometry which promote weight reductions in the airfoils and increases in engine operating efficiency.