Abstract: A method for assembling a gas turbine engine that includes providing a first fan assembly configured to rotate in a first rotational direction, rotatably coupling a second fan assembly to the first fan assembly, wherein the second fan assembly is configured to rotate in a second rotational direction that is opposite the first rotational direction, coupling a first shaft to the first fan assembly and to a first turbine rotor that is configured to rotate in a first rotational direction, coupling a second shaft coupled to the second fan assembly and to a second turbine rotor that is configured to rotate in a second rotational direction that is opposite the first rotational direction, and coupling a lubrication system to the gas turbine engine such that a lubrication fluid is channeled through the first shaft to lubricate at least one of the first and second fan assemblies.

Abstract: An actuation system which includes apparatus for transferring control signals for varying the blade pitch from a non-rotating member to a rotating member of a gas turbine engine is described. In one embodiment, the engine includes a main disk containing a row of blades, and the disk is coupled to a main shaft which rotates about the engine axis. An actuating disk, or cone, rotates with the main disk, and the torque required to rotate the actuating cone is transmitted through ball splines attached to the main shaft. The ball splines allow transmission of torque between the disk and the cone and at the same time enable the disk and the cone to move axially relative to each other without binding. The actuating cone is supported at one end by the ball splines and at its other end by ball thrust bearings. The ball thrust bearings are pre-loaded to enable the bearings to withstand axial loads in opposite directions.

Abstract: A non-symmetrical circular row of oil inlets are located in a circular manifold surrounding a squeeze film space in a squeeze film damper. The oil inlets are directed radially inwardly from said manifold to open into the squeeze film space. Certain cluster of inlets provide higher oil pressure to the squeeze film space than other inlets. All inlets are equipped with automatically closing synthetic rubber check valves.

Abstract: An improved shaft damper bearing utilizing spaced apart piston ring seals to seal off an annular squeeze film space between the rings, includes diagonal surface cross-section ring grooves in the bearing housing with diagonal cross-section rings in the housing grooves adapted to engage a bearing support undergoing radial motion in the housing.

Abstract: A non-symmetrical circular row of oil inlets are located in a circular manifold surrounding a squeeze film space in a squeeze film damper. The oil inlets are directed radially inwardly from said manifold to open into the squeeze film space. Certain cluster of inlets provide higher oil pressure to the squeeze film space than other inlets. All inlets are equipped with automatically closing synthetic rubber check valves.

Abstract: Shaft damper bearing utilizing spaced apart piston ring seals to seal off an annular squeeze film space between the rings, includes diagonal surface cross-section ring grooves in the bearing housing with diagonal cross-section rings in the housing grooves adapted to engage a bearing support undergoing radial motion in the housing.

Abstract: A squeeze film damper employs spaced apart diagonal cross-section piston ring seals in diagonal cross-section grooves in cross-section to cross-section matching and registry relationship with diagonal surfaces directly exposed to the squeeze film space between the rings.

Abstract: A shaft damper bearing utilizing spaced apart piston ring seals to seal off an annular squeeze film space between the rings, includes diagonal cross-section ring grooves in the bearing housing with diagonal cross-section rings in the housing grooves adapted to engage a bearing support undergoing radial motion in the housing.

Abstract: An improved thrust bearing shoe and method for making same is provided. The bearing shoe includes a surface having an optimum one-dimensional curved profile maximized as to load carrying capacity in accordance with predetermined relationships for the dimensions of the shoe. The curved profile may be cycloidal, truncated cycloidal, cubic or quadratic in shape depending on the dimensions of the shoe.