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: 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: 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: 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: 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: 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: 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 self closing valve for use with an engine that prevents the loss of fluid from a transmission connected to the engine when a magnetic chip detector is removed from the transmission housing. The self closing valve and magnetic chip detector being integrated together to form a magnetic chip detection system that provides an indicating signal to the operator of an aircraft when magnetically attractable debris is detected in the transmission. The self closing valve includes a pair of valve doors that rotate about a pivot point so as to be moveable from a central region of a passageway within the transmission housing. Further, the valve does not extend substantially into the interior of the mechanical housing but is closeable to prevent loss of fluid from the interior of the mechanical housing when the magnetic chip detector is withdrawn from the passageway.

Abstract: A pressure signal synthesis method is provided to accommodate failure of a pressure sensor in a gas turbine engine. The pressure signal is synthesized from the torque produced by the engine, and further determined from the corrected speed of a gasifier rotor and power turbine for a free-turbine engine configuration. The synthesized pressure signal may include a correction factor which accounts for the deviation of the engine from a nominal characteristic. This correction factor is determined during engine operation and periodically updated to account for changes in the deviation.

Abstract: A torque signal synthesis method is provided to accommodate torque measurements for a gas turbine engine. The torque signal is synthesized from gas pressure sensed at an engine station. The synthesized torque signal may include a correction factor which accounts for the deviation of the engine from a nominal characteristic. This correction factor is determined during engine operation and periodically updated to account for changes in the deviation. The synthesized torque signal may further be determined from the corrected speed of a gasifier rotor and power turbine of a free turbine engine configuration.

Abstract: A apparatus casting a turbine wheel of a metal alloy, wherein there is generated a columnar grain structure parallel to the leading and trailing edges of the vanes, by directional solidification of the metal from the central aperture in the wheel outward to the vane tips. A form with cavity to receive therein the molten metal has a thin walled core in the center, with the core wall outer surface in place to provide one wall of the cavity. A heat transfer medium in fluid form is circulated through the core, thereby cooling the poured metal by heat transfer from the inner ends of the vanes outward to the tips.

Abstract: The present invention relates to a method and apparatus for producing a cast structure. In one embodiment of the present invention an alloy casting mold has molten alloy injected therein to facilitate completely filling a part cavity within the mold. Further, an alloy charge pressure control device is utilized to reduce the charge pressure of the molten alloy during its injection into the mold cavity to minimize distortion and creep of the ceramic shell. In one form of the present invention the charge pressure control device removes excess alloy so as to reduce the head pressure of the molten alloy thereby eliminating the undesirable creep of the ceramic shell.