Abstract: A recirculation passageway for a turbine engine provides stall protection in a booster by directing high pressure airflow from a flow path of the booster to the passageway. The high pressure airflow loses energy and decreases in pressure while traveling through the passageway until re-entry into the booster flow path. The airflow recirculates in the passageway until the airflow is discharged through a high pressure compressor.

Abstract: A turbine engine including an oil flow path through the low pressure system shaft which, as compared to at least one known oil flow path, facilitates increasing the rated torque and life of the low pressure system shaft is described. In one embodiment, the lubrication opening in the low pressure shaft is oriented so that with respect to a plane along which an outer surface of the low pressure shaft substantially extends, the center axis of the lubrication opening is substantially normal to the plane. As a result of this configuration, the stress concentration in the low pressure shaft at the location of the lubrication opening is substantially reduced. In addition, such a lubrication opening is relatively easy to form as compared to the known, angularly oriented lubrication shaft.

Abstract: A rotatable turbine frame includes annular outer and inner bands having a plurality of circumferentially spaced apart struts extending therebetween. An annular drive shaft is fixedly joined to the inner band for transmitting output torque therefrom, and the struts are backwardly radially inclined relative to the direction of rotation of the frame so that gas flow between the struts tends to straighten the inclined struts to effect a compressive load component therein.

Abstract: A gas turbine engine rotor support system includes outer and inner rotors having respective outer and inner blades interdigitated in respective blade row stages. A stationary rear frame includes a rear support shaft. A rotatable aft frame is disposed forwardly of the rear frame includes an aft support shaft. And, a rotatable forward frame is disposed forwardly of the aft frame and includes a forward support shaft. The forward and aft frames support the outer and inner rotors, and a first bearing is disposed between the aft shaft and the rear shaft for supporting the aft shaft; a second bearing is disposed between the forward shaft and the aft shaft for supporting the forward shaft; and a third bearing is disposed between a core shaft of a core turbine and the forward shaft for supporting the core shaft thereon.

Abstract: A gas turbine engine combustor includes radially spaced outer and inner liners disposed coaxially about an engine longitudinal centerline axis with each liner having forward and aft ends. An annular dome is fixedly joined to the forward ends of the outer and inner liners. The outer liner has a substantially uniform thickness and is arcuate in a longitudinal plane from the forward to aft ends for providing buckling resistance of the outer liner.

Abstract: A gas turbine engine combustor includes radially spaced outer and inner liners disposed coaxially about an engine longitudinal centerline axis with each liner having forward and aft ends. An annular dome is fixedly joined to the forward ends of the outer and inner liners. The outer liner has a substantially uniform thickness and is arcuate in a longitudinal plane from the forward to aft ends for providing buckling resistance of the outer liner.

Abstract: A counterrotating turbine support assembly includes outer and inner rotors having respective outer and inner blades disposed in an outer casing. A mid-frame is disposed forwardly of the rotors and fixedly joined to the outer casing. A rear frame is disposed axially aft of the rotors and is fixedly joined to the outer casing. A forward support shaft is joined at one end to a forward end of the outer rotor and is rotatably supported at an inner end to the mid-frame by a forward bearing. An aft support shaft is joined at one end to an aft end of the outer rotor and is rotatably supported at an inner end to the rear frame by an aft bearing. An intermediate support shaft is fixedly joined at one end to the inner rotor and is rotatably supported at an inner end to the mid-frame by an intermediate bearing.

Abstract: A lubrication system for a gas turbine engine includes first and second coaxially rotor shafts having at least one differential bearing disposed in outer and inner seats thereof. An annular first scoop extends axially from a first portion of the first shaft, and an annular second scoop extends axially from the inner seat of the second shaft. A plurality of first holes extend axially through the first shaft and radially below the first scoop, and a plurality of second holes extend axially through the inner seat of the second shaft and below the second scoop. An annular first shell extends axially between the second scoop and the first shaft from above the first holes. And, oil is injected under the first scoop for flow by centrifugal force from rotation of the first shaft through the first holes and along the first shell into the second scoop for flow through the second holes to lubricate the bearing.

Abstract: In one type of aircraft propulsion system, propeller blades are mounted on a ring which surrounds a turbine. An annular space exists between the turbine and the ring. If a propeller blade should break free, the unbalanced centrifugal load tends to deform the ring. The invention reduces the deformation, as by locating spacers between the turbine and the ring.

Abstract: A turbine support assembly includes a turbine rotor joined to a fan shaft through a support shaft. The support shaft is joined to the fan shaft in a V-configuration having first and second legs joined together at an apex and inclined axially apart, with at least the first leg forming an integral part of the fan shaft. The second leg is rotatably supportable to a frame. The V-configuration increases the stiffness of the turbine support to reduce blade tip clearances. The present invention also provides an annular integral bolt heat shield and axial retention apparatus to axially retain bolts used for holding together two rotor elements during assembly when the bolts are otherwise subject to sliding into a closed cavity of the assembled engine or one of its modules.

Abstract: A compressor stator includes an axial centerline axis and has a unitary annular outer case and a plurality of circumferentially spaced outer hooks extending radially inwardly therefrom. A circumferentially segmented inner case is disposed radially inwardly within the outer case and includes a plurality of arcuate inner case segments, each including an arcuate shroud and at least one inner hook extending radially outwardly therefrom, with respective ones of the outer and inner hooks being axially slidably joined to each other for radially supporting an inner surface of the shroud at a common radius.

Abstract: A clearance control assembly in a gas turbine engine includes several stages of cylindrical turbine shroud rings and a one-piece continuous cylindrical housing surrounding the shroud rings in radially outward spaced relation. Each shroud ring is composed of at least a pair of semi-cylindrical segments mounted to the housing. The shroud ring segments are radially positioned by thermal expansion and contraction of the housing in response to temperature-controlled air flow between the housing and shroud segments. Coupling elements joins together opposite edge portions of adjacent shroud ring segments to permit axial movement of the shroud segments toward and away from one another. Lands which protrude outwardly from the housing interior and shroud ring segment exteriors are located between the housing and shroud segments for defining several spiral channels for air flow about the interior of the housing and exterior of the shroud segments.

Abstract: An aft entry system in a gas turbine engine is provided for cooling selected one or more of aft high and low pressure turbine stages of the engine. The aft entry system includes an air flow circuit for routing low pressure cooling air radially outward from an interstage region of a multi-stage compressor of a core engine of the gas turbine engine and axially in an aft direction to a plurality of radial passages, such as provided by stationary stator and outlet guide vanes, which provide an aft entry region to the selected high and low pressure turbine stages. The pressure of the cooling air routed by the air flow circuit of the aft entry system can be lower than the pressure of air at a discharge end of the compressor but higher than the pressure of the gas stream discharging from the selected turbine stage.

Abstract: The invention concerns a cowling for aircraft propulsion systems of the counterrotating propeller type. The cowling includes a pair of mounting rings located fore and aft of a propeller array. Removable panels extend between the mounting rings and contain openings through which the propeller blades extend.

Abstract: The invention concerns a connector, in an aircraft engine, for mounting a ring to a turbine rotor which the ring surrounds. The ring carries propeller blades, and the connector transmits both thrust and torque loads between the ring and the rotor, without significant deformation. However, the connector does deform in order to accommodate differential thermal growth between the ring and the rotor.

Abstract: A clearance control apparatus has a positioning mechanism for controlling clearance between rotor blade tips and a shroud segment of a gas turbine engine casing, and a rotatable lever for actuating the mechanism. The positioning mechanism is supported by a casing boss, coupled to the shroud segment, and actuatable for moving the shroud segment toward and away from the rotor blade tips to reach a position at which a desired clearance is established. The mechanism includes a shaft and a pair of cam elements. The shaft is mounted by the boss for radial movement toward and away from the rotor axis and coupled at its inner end to the shroud segment. An outer cam element is attached to the outer end of the shaft and spaced outwardly from the boss. An inner cam element is attached to an end of the lever mounted to the boss for rotational movement about a longitudinal axis of the shaft.

Abstract: A clearnace control apparatus has a plurality of positioning mechanisms and an annular unison ring for controlling the clearance between the rotor blade tips and shroud segments of a gas turbine engine casing. The positioning mechanisms are supported by circumferentially-spaced casing bosses, connected to the shroud, and actuatable by the unison ring for moving radially toward and away from the rotor blade tips. As the positioning mechanisms are moved radially, the shroud segments move therewith toward and away from the rotor axis to positioned between inner and outer positions which define minimum and maximum clearances between the shroud segments and rotor blade tips. The unison ring has circumferentially spaced slots defined therethrough each extending in a transverse inclined relation to the respective directions of movement of the unison ring and positioning mechanisms and having spaced opposite ends defining first and second angularly displaced limit positions of the unison ring.

Abstract: A gear-actuated mechanical clearance control apparatus is operable for controlling the clearance between rotor blade tips and the casing shroud of a gas turbine engine. The apparatus includes a pair of annular rings which extend about the casing shroud, a shroud hanger disposed between the casing and an opening in the casing and between the annular rings, and a shroud segment defining a circumferential portion of the casing shroud and disposed in the casing opening. The apparatus also has an actuating mechanism which includes driven gear sectors on the annular rings which face toward one another and a gear disposed between the annular rings and having a peripheral driving gear sector which intermeshes with the driven gear sectors of the annular rings. Upon rotation of the gear, the annular rings undergo opposite circumferential movement causing radial movement of the shroud hanger and the shroud segment therewith to establish the clearance between the shroud segment and rotor blade outer tips.

Abstract: Blade carrying means for variable pitch propulsor blades of a gas turbine engine are disclosed. The blade carrying means comprise dual, axially positioned rings and a plurality of generally cylindrical bearing journals supported between the rings. Each of the journals has a radially outer and inner edge and is adapted to support a single propulsor blade. The blade carrying means also comprise stiffening means, such as a bulkhead attached to the inner edge, for preventing distortion of the journal inner edge.

Abstract: A rotor stage disposed within an annular fluid flowpath in a turbomachine is disclosed. The rotor stage includes outer and inner rings and a plurality of first and second airfoils. The outer and inner rings define flowpath surfaces for said flowpath. The first and second airfoils extend between the rings for transferring energy between the fluid and the rotor stage. At least one of the first airfoils surrounds means for transmitting energy across the flowpath.