Abstract: The present invention generally relates to an external cylindrical or conic section shaped fixture which is tightly fit around the same shaped workpiece prior to expansion forming to a final dimension. During expansion forming, the external fixture is also deformed and is therefore designed for one-time use. The external cylindrical or conic section shaped fixture of the present invention is particularly useful for expansion forming of workpieces which contain brazed lap joints. The external fixture restrains, out-of-plane joint rotation and reduces the stress concentrations existing near the lap joints. Additionally, the external fixture provides additional load carrying capability to allow better load distribution during expansion forming. No change is required to the expansion forming machinery or the inner expander dies (jaws) with use of the present invention.

Abstract: Disclosed is a single-cast, thin wall structure capable of withstanding impinging gases at temperatures of 4300° F. and higher, and method of making the same.

Abstract: Disclosed is an integral single-cast multi wall structure including a very thin wall and a second thin wall. There is a passageway interposed between the pair of walls of the structure, and a high thermal conductivity member extends into said passageways and thermally couples the walls. The high thermal conductivity member increases the heat transfer between the walls of the structure. The present invention further includes a method for casting an integral structure having very thin walls that utilizes the high thermally conductive member in the casting process to hold the pattern and cores in alignment.

Abstract: A high performance hybrid member for use in applications where high stiffness, high temperature capacity and being lightweight are important. In one form of the present invention the hybrid member is formed of a titanium alloy outer portion with a gamma titanium aluminide alloy inner portion metallurgically bonded therin. The gamma titanium aluminide alloy material has a room temperature modulus of elasticity greater than the modulus of elasticity of the titanium alloy outer portion. The hybrid member has a modulus of elasticity greater than modulus of elasticity of the titanium alloy outer portion, and a density equivalent to that of the titanium outer portion. The wear resistant capability of the member can be increased at local regions by surface modification treatment such as plasma ion nitriding or by affixing at ends of the member hardened fittings.

Abstract: An improved cobalt-base braze alloy composition and method for diffusion brazing are provided for use in repairing superalloy articles, such as gas turbine engines, power generation turbines, refinery equipment, and heat exchangers. The improved cobalt-base braze alloy composition includes nickel; at least one element selected from the group of rhenium, palladium, platinum, ruthenium, and iridium; at least one element selected from the group of boron and silicon; and the remaining balance consists of cobalt. This composition may also include aluminum and/or one or more rare earth/lanthanide series elements, and the composition may be combined with one or more powdered base metal superalloy compositions to form an improved diffusion braze alloy mixture. In the improved method for repairing superalloy articles, the foregoing mixture is applied to a region of the superalloy article to be repaired.

Abstract: A cast metallic airfoil structure having a high stiffness core positioned therein for increasing the stiffness of the airfoil. In one embodiment, the high stiffness core is preferably formed of gamma titanium aluminde or a titanium metal matrix composite and is metallurgically bonded to the cast metallic airfoil structure. In one form the airfoil structure forms a portion of an integrally bladed rotor, and in a second form the airfoil structure has a dove tail attachment portion.

Abstract: A gear reduction gearbox connected to a gas turbine engine to reduce the shaft speed and increase the output torque. In one form of the present invention an input shaft and an output shaft are rotatable within a mechanical housing. A face gear set connects between the shafts for changing the speed of the output shaft relative to the input shaft. The present invention, in one embodiment includes load sharing wherein a plurality of pinion gear assemblies distribute the load transmitted through the gearbox.

Abstract: A lightweight high temperature multiproperty rotor disk and method of manufacture for use in a gas turbine engine. The rotor disk of a nickel super alloy and having a plurality of lightweight high temperature single crystal blade attachment lugs bonded thereto. The single crystal high temperature rotor blade attachment lugs being cast in a substantially rectangular shape and bonded to the circumference of the disk. A method of manufacturing the rotor includes positioning the plurality of single crystal attachment lugs on a positioning ring that has locating nests formed thereon. Subsequently, the rotor disk is placed within the bonding ring and a restraining ring is placed around the entire subassembly. Upon subjecting the assembly to high temperature the rotor disk, having a coefficient of thermal expansion greater than the coefficient of thermal expansion of the restraining member, forces the components into a mating relationship.

Abstract: The present invention provides a brazing fixture and method of using the fixture which allows the brazing of a joint in an oxide-dispersion-strengthened (ODS) high temperature alloy workpiece where stresses in the workpiece operate to open the joint during the brazing process. The fixture is formed from the same ODS alloy as the workpiece, such that the fixture exhibits the same coefficient of thermal expansion as the workpiece. This allows maximization of surface area contact between the fixture and the workpiece during the brazing operation in order to force the workpiece to maintain its design dimensions and to prevent the joint from opening. The fixture includes a cavity preventing fixture/workpiece contact in the area of the braze to help control thermal lag in the area of the joint.

Abstract: The present invention relates generally to a lean premix module for an industrial gas turbine engine to satisfy increasingly stringent environmental requirements. A combustion system of the present invention employs a lean premix technique to meet the engine operability requirements and high power emission targets without the use of combustor diluent injection or post combustor exhaust treatment. A lean premix combustion mode is utilized to minimize primary zone combustion temperatures and limit the oxides of nitrogen production during high power engine operation. In one form of the present invention, the lean premix combustion is carried out in an off centerline silo combustor having a plurality of lean premix modules positioned parallel within a common liner. The lean premix modules receive the air from the compressor into a radial swirler and the fuel is dispensed along the radial swirler in order to be premixed with the air.

Abstract: A single-cast, thin wall structure capable of withstanding impinging gases at temperatures of 4300.degree. F. and higher, and method of making the same.

Abstract: A method of brazing which includes deposition of brazing material by electrophoresis. Deposition is performed with a low viscosity, low surface tension bath comprising an alcohol, a nitroalkane, and a complex ionic solute. Brazing powder is added to this bath in the quantity of about 0.02 to about 0.04 kilograms per liter. A nonconductive coating is applied to areas where a brazing material should not be deposited, such as small passageways. This method is shown to be useful in applying brazing material adjacent small passageways, such that the brazing material is accurately deposited and does not flow into and interfere with the passageway after the braze joint is formed.

Abstract: The present invention contemplates a combination bearing for supporting a rotating rotor within a gas turbine engine. The combination bearing including a magnetic bearing system and dry solid lubricated rolling element auxiliary bearings units for sharing the shaft load. The rotating central shaft being normally supported by the active electromagnetic bearing system. The auxiliary bearing unit being soft mounted to the shaft and engine housing and rotatable with the shaft. Soft mounting of the bearings between the housing and the shaft allows a substantially stable transition from the all magnetic bearing support to a physically contacting mechanically assisted support of the shaft.

Abstract: An apparatus and method for reducing noise within the fuselage of a propeller driven aircraft. In one embodiment the propeller blades are spaced apart and in front of an offset inlet. The inlet provides air to a gas turbine engine powering the propeller, and also to a scavenge duct. The propeller blades and inlet are spaced apart such that during cruise conditions for the aircraft, the trailing edge of the propeller blades are spaced apart from the inlet by more than one-fourth of the chord length of the propeller blades, and less than about the chord length of the propeller blades. This spacing reduces the aerodynamic interaction between the propeller blades and a bubble of partially stagnated air in front of the inlet. In another embodiment, the scavenge duct is constructed such that it flows an increased amount of air, thus allowing the inlet duct to flow an increased amount of air.

Abstract: Disclosed is an integral single-cast multi wall structure including a very thin wall and a second thin wall. There is a passageway interposed between the pair of walls of the structure, and a high thermal conductivity member extends into said passageways and thermally couples the walls. The high thermal conductivity member increases the heat transfer between the walls of the structure. The present invention further includes a method for casting an integral structure having very thin walls that utilizes the high thermally conductive member in the casting process to hold the pattern and cores in alignment.

Abstract: An improved cobalt-base braze alloy composition and method for diffusion brazing are provided for use in repairing superalloy articles, such as gas turbine engines, power generation turbines, refinery equipment, and heat exchangers. The improved cobalt-base braze alloy composition includes nickel; at least one element selected from the group of rhenium, palladium, and platinum; at least one element selected from the group of boron and silicon; and the remaining balance consists of cobalt. This composition may also include aluminum, and the composition may be combined with one or more powdered base metal superalloy compositions to form an improved diffusion braze alloy mixture. In the improved method for repairing superalloy articles, the foregoing mixture is applied to a region of the superalloy article to be repaired. The mixture is then heated to melt the cobalt-base braze alloy, thereby joining the base metal superalloy powder particles together, and joining the entire mixture to the region being repaired.

Abstract: A wave rotor apparatus and method of using the transient gas dynamic processes within the wave rotor to accomplish an engine topping cycle. In one form of the present invention the wave rotor is a five port device. Working fluid from the highest pressure outlet port is routed to a port adjacent to and preceding an inlet port admitting air from the compressor. In a preferred form of the present invention there are two port sequences disposed along the circumference of the wave rotor apparatus.

Abstract: A lightweight high temperature rotor blade attachment structure for use in a gas turbine engine. The lightweight high temperature rotor blade attachment lug being cast of a single crystal alloy and the lug is then bonded to a conventional nickel based wheel. A circular arc firtree is utilized to connect the insertable turbine blade between a pair of circumferentially spaced lugs that have been bonded to the turbine disk. In an alternate form of the present invention the attachment lug includes an internal cooling passage for receiving cooling fluid from a compressor. More particularly, the present invention discloses a single crystal attachment lug that is bonded to a powdered metal nickel alloy rotor disk and includes internal cooling passages, and in one form is designed for use with turbine blades that do not have a platform.

Abstract: A lightweight high temperature rotor blade attachment structure for use in a gas turbine engine. The lightweight high temperature rotor blade attachment lug being cast of a single crystal alloy and the lug is then bonded to a conventional nickel based wheel. A circular arc firtree is utilized to connect the insertable turbine blade between a pair of circumferentially spaced lugs that have been bonded to the turbine disk. In an alternate form of the present invention the attachment lug includes an internal cooling passage for receiving cooling fluid from a compressor. More particularly, the present invention discloses a single crystal attachment lug that is bonded to a powdered metal nickel alloy rotor disk and includes internal cooling passages, and in one form is designed for use with turbine blades that do not have a platform.

Abstract: The present invention relates generally to a low emission can-annular combustion system for an industrial gas turbine engine to satisfy increasingly stringent environmental requirements. The combustion system of the present invention employs a dual mode combustion technique to meet engine operability requirements and high power emission targets without the use of combustor diluent injection or post combustor exhaust treatment. A lean premix combustion mode is utilized to minimize primary zone combustion temperatures and limit the oxide of nitrogen production during high power engine operation. A pilot-starting auxiliary fueling system is utilized to augment the main premix fueling system. The lean premix combustion mode is enabled by a lean premix dome having a fixed axial swirler with radial fuel pathways connecting to a circumferential main fuel manifold for distributing the fuel more uniformly across the flow path.