Abstract: A coated article is prepared by furnishing an nickel-base article substrate having a free sulfur content of more than 0 but less than about 1 part per million by weight. A protective layer is formed at a surface of the article substrate. The protective layer includes a platinum aluminide diffusion coating. The protective layer may be substantially yttrium-free, or have a controlled amount of yttrium. A ceramic layer may overlie the protective layer.

Abstract: A process for forming a diffusion aluminide-hafnide coating on an article, such as a component for a gas turbine engine. The process is a vapor phase process that generally entails placing the article in a coating chamber containing a halide activator and at least one donor material. The donor material collectively consists essentially of at least 0.5 weight percent hafnium and at least 20 weight percent aluminum with the balance being chromium and/or cobalt.

Abstract: A starting workpiece of a titanium-base alloy having a temperature-composition phase diagram with a beta region and an alpha-beta region separated by a beta transus temperature is processed by first forging the starting workpiece at a first temperature in the beta region to form a billet, thereafter second forging the billet at a second temperature in the alpha-beta region, thereafter third forging the billet at a third temperature in the beta region, thereafter fourth forging the billet at a fourth temperature in the alpha-beta region so that the step of fourth forging accomplishes a reduction in cross-sectional area of from about 5 to about 40 percent, and thereafter ultrasonic testing the billet. The beta-region third forging step combined with a relatively small reduction during the alpha-beta-region fourth forging step produce a microstructure that is conducive to ultrasonic inspection with minimal interference from noise.

Abstract: An aircraft engine mount for mounting an engine to an aircraft includes a mounting frame fixedly joined to the aircraft, first and second prime links and a waiting failsafe link. The first prime link is joined to the engine at a first joint and to the mounting frame at second and third joints. The second prime link is joined to the engine at a fourth joint and to the mounting frame at fifth and sixth joints. The waiting failsafe link is joined to the engine at a seventh joint and to the mounting frame at an eighth joint. The first, third, fourth, sixth and seventh joints are ball joints, and the second and eighth joints are translating ball joints. The fifth joint is a clearance pin joint. All of the translating ball joints include a spherical bearing disposed in an opening in the respective link and a pin extending through the spherical bearing. An inner bushing is disposed on the pin and an outer bushing disposed over the inner bushing.

Abstract: A turbine rotor for a gas turbine engine includes a rotor disk having a plurality of circumferentially alternating dovetail slots and disk posts and a plurality of blades disposed in the dovetail slots. A cooling air plenum is defined in the portion of each dovetail slot located radially inward of the corresponding blade. Air from the plenums is directed through slots formed in axial surfaces of the blades or disk posts into an adjacent wheel cavity, thereby purging the wheel cavity.

Abstract: A method of placing turbulators in a turbine rotor blade includes placing slant turbulators in a radial flow channel offset circumferentially from the blade leading edge. The slant turbulators are all inclined radially inward toward the blade trailing edge for directing coolant along the turbulators co-directionally with Coriolis flow inside the offset channel. In a specific embodiment, turbulator chevrons are also placed in a radial flow channel axially aligned with the blade leading edge consistent with the Coriolis flow therein.

Abstract: A link for use in an aircraft engine mounting system includes a span section having a first connector formed (at one end thereof and a second connector formed at another end thereof. A lumped mass is disposed on the span section for placing the resonant frequency of the link away from engine excitation frequencies.

Abstract: A compressor airfoil includes pressure and suction sides extending from root to tip and between leading and trailing edges. Transverse sections have respective chords and camber lines. Centers of gravity of the sections are aligned along a double bowed stacking axis for improving performance.

Abstract: A method for removing products of hot corrosion and oxidation from selective portions of surfaces of a gas turbine engine, such as coatings and substrates, following exposure of the surfaces to hot oxidative gases of the turbine exhaust. The method involves a high temperature chemical reaction and has no detrimental effect on adjacent coatings and substrates that have not been attacked by the hot exhaust gases.

Abstract: A method of forming a shaped hole in a substrate, including substrates protected by coatings, as is the case where an air-cooled component has a thermal barrier coating for protection from a hostile thermal environment, such as the turbine, combustor and augmentor sections of a gas turbine engine. In particular, cooling holes are formed in an air-cooled component after a ceramic layer has been deposited on the surface of the component without damaging or spalling the ceramic layer. Processing steps generally include forming a hole through the ceramic layer and a substrate protected by the ceramic layer, thereby defining an opening at the surface of the ceramic layer. The diameter of the hole is less than the final size required for the cooling hole.

Abstract: An airfoil includes a leading edge chord barrel between a root and a tip, and forward aerodynamic sweep at the tip.

Abstract: A flow restrictor includes a body which permits the flow restrictor to be self-retained within a bleed port. Bleed ports are located over various portions of a gas turbine engine and extend through an engine casing. The flow restrictor body includes a bore extends between a flow restrictor body first and second ends. A slot extends between the first and second ends of the flow restrictor body. The slot further extends from an outer surface of the flow restrictor body to the bore. During assembly, the slot permits the flow restrictor to expand and conforms against the bleed port.

Abstract: Apparatus for performing laser weld repair of complex titanium-base material parts for gas turbine engines. The complex arts, typically compressor blisk airfoil assemblies are enclosed in a local dry box and purged in an inert gas atmosphere. Laser weld repairs are accomplished within this dry box by using a coaxial nozzle and a mixture of helium and argon. The welding is accomplished by maintaining a proper standoff between the weld nozzle and the weld. The welding is monitored and controlled from a remote location using in a video camera system. Copper shielding is provided within the dry box to protect areas adjacent to the weld area from overheating and weld spatter.

Abstract: High in-flight vibrations in turbofan gas turbine engines are prevented at windmilling speeds after a blade-out induced structural decoupling of the fan assembly by providing a fan assembly support system with a damper assembly that dissipates vibration energy and retunes the natural frequency of the fan assembly to be above windmilling speeds. The support system includes primary and secondary bearing supports separately secured to the fan frame and a bearing disposed between the primary bearing support and the fan assembly. The damper assembly includes a journal formed on the primary bearing support and a bumper ring attached to the secondary bearing support in surrounding relationship with the journal.

Abstract: A process for forming a diffusion aluminide coating on an article, such as a component for a gas turbine engine. The process is a vapor phase process that generally entails placing the article in a coating chamber containing an aluminum donor material, without any halide carrier or inert filler present. The aluminum donor material consists essentially of about 20 to about 70 weight percent aluminum, with the balance being chromium or cobalt. While the article is held out of contact with the donor material, coating is initiated in an inert or reducing atmosphere by heating the article and the donor material to vaporize the aluminum constituent of the donor material, which then condenses on the surface of the article and diffuses into the surface to form a diffusion aluminide coating on the article.

Abstract: A compressor air bleed assembly for a gas turbine engine includes a compressor casing surrounding a row of circumferentially spaced compressor blades and defining a flowpath for receiving compressor air flow compressed by the blades. The casing includes a bleed port disposed down stream of at least a row of the blades for receiving a portion of compressed air as bleed airflow. A bleed port, preferably in the form of an annular slot, extends away from the bleed port and has a first throat downstream of the port and a second throat downstream of the first throat. A first duct outlet in the duct leads to a first bleed air circuit, receives a first portion of the bleed airflow, and is disposed between the first and second throats. A second duct outlet in the duct leads to a second bleed air circuit, receives a second portion of the bleed circuit.

Abstract: A gas turbine engine hollow turbine airfoil, such as a first stage vane of a high pressure turbine of a gas turbine engine includes an outer wall surrounding a hollow interior. The outer wall extends radially outwardly in a spanwise direction from an airfoil base to an airfoil tip and has chordwise spaced apart leading and trailing edges and widthwise spaced apart pressure and suction side portions extending chordwise between the leading edge and a trailing edge block which terminates at the trailing edge. A plurality of trailing edge cooling air ducts extend chordwise through the trailing edge block aftwardly from the hollow interior and a plurality of trailing edge film cooling holes extend from the ducts through the trailing edge block. The cooling air ducts are preferably centered near a neutral axis of chordwise and spanwise bending of the trailing edge block.

Abstract: An electric discharge machine includes a machine base configured to support a work piece, a y-axis alignment assembly having a first direction of travel and mounted to the machine base, and an electrode alignment assembly mounted to the machine base and configured to hold an electrode during a machining process. The electrode alignment assembly has a second, a third, and a fourth direction of travel, and an attached rotary indexer has a fifth direction of travel. Movements in the first, second, third, fourth, and fifth directions of travel are automatically controlled by a processor.

Abstract: An electrical discharge machining (EDM) apparatus includes at least one work station having an electrode fixedly mounted to a base and a workpiece fixture slidingly mounted to the base above the electrode. A servomotor is mounted to the base and arranged to drive the workpiece fixture toward and away from the workpiece. Preferably, the EDM apparatus will include a number of such work stations, and each work station will be connected to a separate control system for independently controlling and energizing the work station.

Abstract: A dome assembly for a gas turbine engine combustor includes an annular combustor dome with a substantially annular flat dome plate and at least one circular opening in the dome plate. A seal plate flange with a flat aft facing surface has a central ring circumscribed about a centerline axis and extends aftwardly from the seal plate flange. The central ring is disposed through the circular opening in the dome plate and the central ring includes a central bore coaxially aligned with the circular opening. A baffle has a cylindrical tubular mounting portion extending upstream through the central bore and is fixedly joined to the seal plate and a flare portion extending aft from the seal plate flange. A carburetor including an air swirler having an annular exit cone is joined to the baffle with the exit cone disposed within the cylindrical tubular mounting portion of the baffle. An aft end of the central ring is joined to the dome plate by a swage joint.