Abstract: A compressor casing is configured to surround blade tips in a compressor stage. The casing includes stall grooves with adjoining lands defining respective local gaps with the blade tips. At least one of the lands is offset to locally increase a corresponding one of the gaps larger than the nominal gap for the casing to reduce tip rubbing thereat.

Abstract: A method for repairing the shroud surfaces of a gas turbine engine to provide corrosion and oxidation resistance of the shroud segments while also restoring the dimensional integrity of the shroud segments. The method entails removing the oxidation and corrosion products from the shroud segment, removing preexisting coating materials, applying a material compatible with the shroud segment substrate material, machining the surface, applying a corrosion-resistant, oxidation-resistant and rub-compliant material to the shroud segment using a HVOF process, machining the shroud segment to preselected dimensions and applying an aluminide coating for improved oxidation and corrosion resistance of the repaired surfaces.

Abstract: A compressor stator includes a casing having a circumferentially extending slot therein in which are mounted a plurality of vane sectors. Each sector includes a plurality of vanes extending between outer and inner bands, with each outer band being mounted in the slot. A plurality of tabs are ranged in interlocked pairs between the outer bands and casing for unloading adjacent sectors from each other.

Abstract: A free flow abrasive hole polishing system and method improves air flow and resultant component cooling efficiency for an apertured article. The free flow abrasive hole polishing system mixes an abrasive particle component with a carrier media to create a free flowing abrasive particle carrier media mixture. This mixture is pumped through apertures defined by aperture walls in the article to improve air flow and resultant cooling efficiency of the article. Since the abrasive particles have mass and velocity and the free flowing media does not have resistance to flow, the abrasive particles impinge on peaks of the aperture walls, predominantly removing high spots in the aperture walls.

Abstract: A composite shaft whose construction and fabrication enable precise placement and orientation of reinforcement fiber bundles, enable close control of runout, and eliminate a separate joining operation for attaching mechanical drive couplings. The composite shaft generally includes an inner shell, a spacing member circumscribing and contacting the inner shell, and a bundle of fibers disposed in each of a number of longitudinally-extending cavities in the spacing member. The shaft also has an outer portion that encases the fiber bundles in the spacing member. The shaft preferably includes end pieces attached to the end of the shaft and adapted as mechanical coupling features. At least the end pieces, spacing member and fiber bundles are joined in a manner that defines a metal matrix surrounding and encasing the fiber bundles.

Abstract: A plain blank is sized to produce an airfoil. The blank is plastically formed to include a pocket blending smoothly in one side thereof. Leading and trailing edges of the airfoil are benched. And, filler is placed into the pocket to effect an aerodynamic profile for the airfoil.

Abstract: The flow of cooling fluid through core tie holes formed between the internal cooling passageways of turbine airfoils is reduced by disposing flow deflectors on the wall adjacent to the holes. The deflectors alter the local static pressure near the holes, thereby minimizing the pressure differential across the holes so as to reduce the flow of cooling fluid.

Abstract: A turbine airfoil includes pressure and suction sidewalls joined together at leading and trailing edges, and extending from root to tip. The tip includes a tip rib extending from a tip cap enclosing an internal flow channel between the sidewalls. An aligned pair of first and second holes extend through the tip cap and rib, respectively, for discharging coolant from the flow channel.

Abstract: An igniter for a combustor of a gas turbine comprises a ground shell electrical conductor which provides the electrical ground path back to the spark source. The spark source connects to the conductor and a ground return path connects to the ground shell. Multiple ignition spark source electrical conductors are used in the single igniter. At least one insulator isolates the spark sources from each other and from the ground shell conductor. An electrical connection, typically a connector that would mate with an ignition source electrical lead having a source conductor, a ground conductor, and insulation to separate these conductors, mates with a spark source to operate the igniter.

Abstract: A fixture for holding a workpiece in a predetermined position during a manufacturing operation. The fixture includes a support having a surface for receiving the workpiece. The surface has a reference point for locating and orienting the workpiece in the predetermined position. The fixture also includes a clamp for clamping the workpiece in a fixed position with respect to the reference point to hold the workpiece in the predetermined position and a brace mounted on the support for bracing the workpiece to prevent the workpiece from deforming during the manufacturing operation. The brace has at least two jaws adapted for clamping the workpiece when received by the support to prevent movement of the workpiece toward or away from the support.

Abstract: A gamma titanium aluminide alloy article, is prepared using a piece of a gamma titanium aluminide alloy having a composition capable of forming alpha, alpha-2, and gamma phases. The alpha transus temperature of the gamma titanium aluminide alloy piece is determined. The gamma titanium aluminide alloy piece is consolidated by hot isostatic pressing at a temperature of from about 50 F. to about 250 F. below the alpha transus temperature and at a pressure of from about 10,000 to about 30,000 pounds per square inch, for a duration of from about 1 to about 20 hours. The piece is heat treated at a temperature of from about 5 F. to about 300 F. below the alpha transus temperature for a time sufficient to refine the microstructure and generate a microstructure comprising from about 10 to about 90 volume percent gamma phase. The step of heat treating is conducted at a temperature of from about 45 F. to about 200 F. above the temperature of the step of hot isostatic pressing.

Abstract: A gas turbine engine nozzle segment includes at least two circumferentially adjacent vanes joined together along an interface between the vanes. Each of the vanes includes a hollow airfoil disposed between radially inner and outer band panels and a cooling air intake duct leading to a hollow interior of the airfoil for directing cooling air into the hollow interior. The intake duct has a duct wall protruding radially outward from the outer band panel and at least one impingement cooling hole disposed through the intake duct wall and circumferentially and radially inwardly angled. A flange portion extends circumferentially along the outer band panel and an opening in the flange portion is in fluid communication with the intake duct. The hollow airfoil, radially inner and outer band panels, intake duct wall, and flange portion are integrally formed and, preferably, integrally cast such that the vane is a single piece integrally cast vane.

Abstract: An improved coating and method for applying the coating to minimize the consumption of substrate material during high temperature service by formation of an intermediate metal aluminide layer. A layer of Ni or Co or combinations of Ni and Co are added to the substrate material as an overlay by a process such as electroplating or electroless plating. A diffusion aluminide is then formed at the surface by exposing the plated substrate to a source of aluminum at an elevated temperature.

Abstract: A turbine casing supports a row of nozzle vanes through which are flowable hot combustion gases. A baffle surrounds the casing to define a cooling duct. A nacelle surrounds the turbine casing to define a bay having an inlet for receiving bay air, and an outlet for discharging the air. The cooling duct includes an inlet which receives the bay air for flow along the turbine casing for selective cooling thereof.

Abstract: Probe chord error compensation is provided in a machine tool including a rotary member for supporting a work piece and a probe having a path of travel. The compensation is accomplished by using the probe to measure an observed diameter of the work piece and then determining the crossover error of the machine tool. The observed diameter and the crossover error are then used to compute the work piece's actual diameter, thereby compensating for any probe chord error.

Abstract: A turbine airfoil includes pressure and suction sidewalls extending between leading and trailing edges and from root to tip. The tip includes a floor bounding an internal cooling channel within the airfoil which channels cooling air. The airfoil tip includes a first rib adjacent the pressure sidewall, a second rib spaced therefrom to define a first slot, and a third rib adjacent the suction sidewall to define a second slot with the second rib. The tip floor includes feed holes extending between the cooling channel and the first slot for supplying cooling air therein for discharge over the second rib towards the third rib.

Abstract: Apparatus and method to improve vapor phase diffusion coating of articles. The apparatus provides a barrier to segregate the portion of the article requiring coating from the portion of the article not requiring coating. The fixture is reusable, being unaffected by the coating gases. The fixture reduces the exposure of the coating gases with the portion of the article not requiring coating. By use of an optional seal, the portion of the article not requiring coating can be isolated from the coating gases.

Abstract: Methods and apparatus for operating a press, such as a forge or trim press, are directed at activating a ram in a press having a lower die and an upper die connected to a ram by heating a workpiece to a first temperature above an impact temperature. The workpiece then is placed on the lower die, monitored during chill down of the workpiece from the first temperature, and the ram actuated based upon the monitoring in a controlled manner to effect an impact of the upper die against the workpiece. The monitoring includes measuring a characteristic parameter of the workpiece and the actuating includes actuating the ram after a predetermined fixed value of the measured parameter is measured. The placing of the workpiece on the lower die is done manually in the preferred embodiment.

Abstract: A turbine blade squealer tip includes an airfoil shaped tip cap having a squealer tip wall extending radially outwardly from and around the perimeter of the airfoil shaped tip cap to define a radially outwardly open tip cavity. The tip wall has an inboard side facing the interior of the cavity and an outboard side facing away from the cavity and the tip cap has an outer tip side on a bottom of the cavity. Thermal barrier coatings are disposed on the inboard and outboard sides of the squealer tip wall and on the outer tip side of the tip cap. One embodiment provides the tip cap with cooling holes disposed therethrough to flow cooling air into the cavity.

Abstract: An improved process for applying aluminide coatings to superalloy components used in gas turbine applications resulting in a more uniform coating with less hazardous waste by-products. The process involves the steps of placing the superalloy components into a retort with an aluminum-containing source, evacuating air from the retort and introducing an inert gas, heating the retort to a preselected temperature, while maintaining the preselected temperature purging the inert gas from the retort by introducing hydrogen gas, while maintaining the preselected temperature, pulsing, by reducing the retort pressure to a preselected pressure below atmospheric pressure, followed by introducing a halide-containing gas to react with the aluminum-containing source to create an aluminum-rich vapor that deposits aluminum on the components, then reintroducing hydrogen gas into the retort to purge the gases within the retort; and cooling the retort.