Abstract: A drill guide that is capable of guiding the drilling holes, in particular lockwire holes, transversely through one corner of a nut at an oblique angle to a face thereof and a method for using same. The drill guide comprises at least one guide component having a first and a second side transverse to the first side. The first side has a recess with first and second surfaces for receiving the corner of the nut, the first surface being closer to the second side. Also included is a drill bit guide for guiding a drill bit of a drill that is accessible from the second side and extends towards the first surface of the recess along a longitudinal axis in the direction of the second surface of the recess so that the drill bit is capable of drilling a hole transversely through the corner of the nut at an oblique angle to the face of the nut that the drill bit initially engages.

Abstract: A rotary valve for pulse detonation engines includes a rotor rotatively mounted in the forward end of the pulse detonation tube and a plurality of transfer plenums for receiving fuel and air arranged around the rotor and partially disposed over the forward end of the tube. The rotor has a plurality of internal flow passages formed therein which periodically align with a plurality of inlet ports formed near the forward end of the tube as the rotor rotates. Each one of the transfer plenums is aligned with a corresponding one of the inlet ports so that the flow passages will establish fluid communication between the tube and the transfer plenums when aligned with the inlet ports. Additional features include axial injection of the fuel-air mixture into the pulse detonation tube, pre-compression of the inlet flow and a drive system located outside of the primary gas path.

Abstract: A gas turbine engine exhaust nozzle includes an outlet for discharging exhaust, and a plurality of circumferentially spaced apart stub airfoils disposed adjacent the outlet. The airfoils shed vortices for mixing exhaust flow and attenuating noise and reducing infrared signature with minimum performance loss.

Abstract: A combustor dome assembly includes a spectacle plate having an opening formed therein that defines an inner circumferential edge, at least one swirler assembly defining an inner cylindrical surface, and at least one deflector having an outer cylindrical surface. These components are arranged such that the outer cylindrical surface is joined to the inner circumferential edge and to the inner cylindrical surface. One preferred method of manufacturing the combustor dome assembly includes placing a first ring of joining material over the outer cylindrical surface. Then, the outer cylindrical surface is inserted into the spectacle plate opening so that the first ring is sandwiched between a first surface of the spectacle plate and a shoulder formed on the deflector. A second ring of joining material is next placed over the outer cylindrical surface, and a third ring of joining material is inserted into an annular groove formed in the inner cylindrical surface.

Abstract: A combustor for a gas turbine engine operates with high combustion efficiency, and low carbon monoxide and nitrous oxide emissions during low, intermediate, and high engine power operations. The combustor includes a fuel delivery system that includes at least two fuel stages, at least one trapped vortex cavity, and at least one mixer assembly radially inward from the trapped vortex cavity. The two fuel stages include a pilot fuel circuit that supplies fuel to the trapped vortex cavity through a fuel injector assembly and a main fuel circuit that also supplies fuel to the mixer assembly with the fuel injector assembly.

Abstract: A gas turbine engine hollow airfoil has chordally spaced apart leading and trailing edges extending radially from a radially inner base to a radially outer airfoil tip. A cooling circuit within the airfoil has radially extending first, middle, and last channels arranged respectively in series with the first channel in fluid communication with a source of cooling air from outside the airfoil. The last channel is in fluid communication with one of the edges. A refresher passageway extends through a radially inner wall bounding a radially inner portion of the last channel and is in fluid communication with the source of cooling air. The refresher passageway is separate, spaced apart, and independent from the first channel. In one embodiment, a metering plate covers an inlet to the refresher passageway and the metering plate has a metering hole over the inlet and the metering hole is adjustable.

Abstract: A combustor for a gas turbine engine includes outer and inner liners defining a combustion chamber and an igniter mounted to the outer liner. A dome plate is disposed between the outer and inner liners and has a plurality of circumferentially spaced openings formed therein. A fuel-air mixer is disposed in each one of the openings; each fuel-air mixer includes a swirler mounted in the corresponding opening and a fuel nozzle received in the corresponding swirler. Two adjacent ones of the swirlers are low air flow swirlers in general circumferential alignment with the igniter and the rest of the swirlers are higher air flow swirlers. Each one of the fuel nozzles provides a similar amount of fuel so that the two fuel-air mixers having low air flow swirlers produce a local region of increased fuel-to-air ratio in the vicinity of the igniter.

Abstract: A fuel control system for an aircraft gas turbine engine that includes a thrust augmentation system. An augmentor fuel pump is arranged to provide pressurized fuel to an exhaust nozzle throat area actuation system to eliminate the need for a separate hydraulic pump to provide pressurized fluid for exhaust nozzle actuation. An augmentor fuel bypass arrangement is provided to enable the augmentor fuel pump to provide pressurized fuel to the main fuel pressurizing valve and to components operated by the main fuel system in the event of failure of the main fuel pump. The augmentor fuel pump pressure and output flow are controlled as a function of thrust augmentation demand and main fuel system operation. The system provides redundancy by enabling either the main fuel system or the augmentor fuel system to maintain engine operation if one of the fuel systems fails or provides inadequate fuel flow.

Abstract: A combustor for a gas turbine engine operates with high combustion efficiency and low carbon monoxide, nitrous oxide, and smoke emissions during low, intermediate, and high engine power operations is described. The combustor includes a mixer assembly including a pilot mixer and a main mixer. The pilot mixer includes a pilot fuel injector, at least one swirler, and an air splitter. The main mixer extends circumferentially around the pilot mixer and includes a plurality of fuel injection ports and a conical air swirler upstream from the fuel injection ports. During idle engine power operation, the pilot mixer is aerodynamically isolated from the main mixer, and only air is supplied to the main mixer. During increased power operations, fuel is also supplied to the main mixer, and the main mixer conical swirler facilitates radial and circumferential fuel-air mixing to provide a substantially uniform fuel and air distribution for combustion.

Abstract: Flow control in pulse detonation engines is accomplished using magnetohydrodynamic principles. The pulse detonation engine includes a tube having an open forward end and an open aft end and a fuel-air inlet formed in the tube at the forward end. An igniter is disposed in the tube at a location intermediate the forward end and the aft end. A magnetohydrodynamic flow control system is located between the igniter and the fuel-air inlet for controlling detonation in the tube forward of the igniter. The magnetohydrodynamic flow control system utilizes magnetic and electric fields forward of the igniter to dissipate or at least reduce the ignition potential of the forward traveling detonation flame front.

Abstract: A blisk includes a disk having a rim. A row of blades extends outwardly from the rib in a unitary construction. The blades are spaced apart in the disk rim to define fluted inner flowpath channels extending axially between the blades to bound corresponding flow passages therebetween.

Abstract: A gas turbine engine combustor includes outer and inner liners joined together at an annular dome. Outer and inner air swirlers and cooperating fuel injectors are mounted in two rows in the combustor dome. The fuel injectors are joined to a common fuel manifold for simultaneously channeling fuel thereto over an operating range from idle to full power for reducing exhaust emissions.

Abstract: A mixer for use in a combustion chamber of a gas turbine engine. The mixer includes an annular housing having an upstream end, a downstream end, a mount for attaching the housing to an upstream end of the combustion chamber, and an interior surface defining a hollow interior. The mixer also has a first swirler mounted inside the annular housing including a plurality of vanes extending inward from the housing for swirling air traveling through the housing. In addition, the mixer includes an annular fuel injector having a plurality of fuel injection ports arranged in a generally circular pattern mounted inside the first swirler for releasing droplets of fuel into swirling air downstream from the fuel injector. Further, the mixer has a second swirler mounted inside the fuel injector including a plurality of vanes extending inward from the injector for swirling air traveling through the housing downstream from the fuel injector.

Abstract: A rotor assembly for a gas turbine engine operates with reduced circumferential rim stress. The rotor assembly includes a rotor including a plurality of rotor blades extending radially outward from an annular rim. A root fillet extends circumferentially around each blade between the blades and rim. The rim includes an outer surface including a plurality of concave indentations extending between adjacent rotor blades and forming a compound radius. Each indentation extends from a leading edge of the rotor blades towards a trailing edge of the rotor blades.

Abstract: A multi-stage rotor assembly for a gas turbine engine includes a damper system that facilitates damping vibrations induced to the rotor assembly. The rotor assembly includes a blisk rotor including a plurality of rotor blades and a radially outer rim. The rotor blades are integrally formed with the rim and extend radially outward from the rim. The damper system is attached to rotor blades within at least one stage of the rotor assembly, and includes at least one layer of damping material and a cover sheet. The cover sheet is attached to the rotor blade with adhesive.

Abstract: A gas turbine engine variable geometry exhaust nozzle including a seal system that facilitates extending a useful life of the engine variable geometry system is described. The seal system includes a backbone and an attachment assembly. The attachment assembly frictionally engages the backbone to secure the attachment assembly to the backbone. The attachment assembly includes a plurality of clamp sub-assemblies and base sheet fabricated from a ceramic matrix composite material. The clamp sub-assemblies are clamped through openings extending through the base sheet, such that a predetermined amount of preload force is applied to the base sheet.

Abstract: A gas turbine engine arcuate segment has an arcuate band segment, at least one tab and an arcuate rail segment spaced axially apart from the tab and located along an axial end of the band segment. The tab and the arcuate rail segment extend radially away from the band segment and a space is located between the tab and the rail segment. A tab aperture extends entirely through the tab. The rail segment has a rail aperture entirely therethrough. A leaf seal and a spring are disposed within the space to bias the leaf seal against the aft rail. In an exemplary embodiment, a spring aperture extends entirely through the spring, a seal aperture extends entirely through the leaf seal, and a headless pin is disposed in the apertures such that the leaf seal and the spring are radially restrained by the pin.

Abstract: At least one airfoil shaped vane made of a low ductility material, for example a ceramic base material such as a ceramic matrix composite or an intermetallic material such as NiAl material, is releasably carried in a turbine vane assembly including inner and outer vane supports by at least one high temperature resistant compliant seal. The seal isolates the vane from at least one of the vane supports and allows independent thermal expansion and contraction of the vane in respect to the support.

Abstract: A heat shield and support strut for a turbine engine afterburner. The heat shield can be replaced without moving or disconnecting the fuel tube. The heat shield includes a housing that may be telescoped over the fuel injection tube and is attachable to the strut without moving the housing transverse to a longitudinal axis of the fuel injection tube. The support strut includes a body having an outer end for attachment to an outer wall of the afterburner section, an inner end, and a passage extending through the body from its outer end to its inner end for receiving the fuel injection tube. The inner end has a cavity for receiving the head of the heat shield. The cavity is shaped for a close fit on the head in the cavity. The body has a flat mounting surface in the cavity for engagement by the flat mounting surface of the head.

Abstract: Service life is improved in a swirler assembly including a primary swirler and a secondary swirler having a venturi formed thereon and being disposed in engagement with the primary swirler. First and second rails are formed on the secondary swirler and are positioned to engage the primary swirler and thereby prevent relative rotation of the primary and secondary swirlers.