Abstract: In a twin spool gas turbine engine the electronic engine control modulates the open area of the compressor bleed valves during engine transients as a function of a ratio of the actual rate of change of the compressor speed to a maximum scheduled rate of change such that the bleeds are opened more as the actual rate of change approaches the scheduled maximum rate. This continuous modulation provides smooth thrust transition from one steady state condition to another while maintaining a proper safety margin relative to the engine surge line.

Abstract: A two dimensional exhaust nozzle for a gas turbine engine having reverse thrust capability includes a pair of spaced apart converging flaps which are able to rotate about their respective axes until their downstream edges meet along the engine centerline to block the flow of gases through the engine and to redirect the flow through fixed area reverser outlet ports. The axes about which each convergent flap rotates are spaced inwardly from their respective convergent flap surfaces. The flaps themselves cover the outlet ports when the flaps are in forward thrust operating positions. The flaps move away from and unblock the outlets as they rotate to their reverse thrust position. The distance between the flap axis and its convergent surface is critical to being able to use short flaps while obtaining large reverser outlet areas.

Abstract: A hollow, cooled airfoil has a pair of nested, coolant channels therein which carry separate coolant flows back and forth across the span of the airfoil in adjacent parallel paths. The coolant in both channels flows from a rearward to forward location within the airfoil allowing the coolant to be ejected from the airfoil near the leading edge through film coolant holes.

Abstract: A coolable wall configuration includes a slot formed between two wall portions for carrying coolant fluid in a downstream direction wherein the slot is divided into a plurality of parallel channels by as plurality of parallel barrier walls extending in a direction perpendicular to the downstream direction, the barrier walls having openings therethrough at regular intervals to interconnect the channels, wherein the openings in adjacent barrier walls are staggered so that cooling fluid flowing through each opening impinges upon a wall portion of the next barrier wall and ultimately traverses a square wave-like flow path as it moves downstream from channel to channel. This configuration is particularly suitable for use in the trailing edge region of an airfoil.

Abstract: In a gas turbine engine electronic control system the engine total inlet temperature is synthesized from aircraft Mach number and the nozzle expansion ratio. When the engine is in a transient mode of operation the synthesized value of the total inlet temperature is maintained constant at the value calculated just before entering the transient mode. The synthesized temperature is used when the actual measured temperature is unavailable or unreliable.

Abstract: A film cooling passage through the wall of a hollow airfoil for a gas turbine engine has a metering section communicating with the interior of the airfoil for directing a metered amount of coolant through the passage in a first direction, followed by a mixing section to create turbulence in the flow as it leaves the metering section, followed by a diffusing section leading to the passage outlet at the outer surface of the airfoil. The mixing section comprises a sudden jog or step in the flow path of the fluid to suddenly disrupt its forward momentum in the first direction and to create turbulence therein whereby the fluid is more readily able to spread out within the following diffusing section and thereby stay attached to more widely diverging diffusion section walls. Wider diffusion angles in the coolant passage permits the same amount of coolant to be spread out over a wider area of the surface of the airfoil.

Abstract: The wall of a hollow airfoil for a gas turbine engine includes a film cooling slot therein elongated in the longitudinal direction and having a base within the wall and an outlet at the external surface of the airfoil. A plurality of metering passages extend from inlets at the internal surface of the wall and intersect the slot near its base. The metering passages are angled to direct a metered flow of coolant fluid at a sharp angle against a surface of the slot to cause turbulence and diffusion of the coolant fluid within the slot in order that the coolant fluid fill the entire slot. The coolant fluid thereupon exits the slot as a thin film over the surface of the airfoil downstream of the slot outlet along the full length of the slot.

Abstract: In a gas turbine engine with a bypass duct, a rotating stage of airfoils in the bypass duct is supported through and driven by torque transmitting members extending across the core stream flow path, but which are sufficiently flexible in the radial direction to avoid passing centrifugal loads from the rotating stage across the core stream flow path. The rotating bypass stream stage is also supported through a bearing secured directly to the engine main support structure radially outwardly of the core stream flow path. The majority of aircraft maneuver loads are reacted at this bearing, and a minor portion of the maneuver loads pass across the core stream to a bearing located radially inwardly thereof. The airfoils may be either variable pitch airfols or fixed airfoils. If variable pitch, they may be used to reverse the flow in the bypass duct for thrust reversing.

Abstract: A matrix for holding the electrolyte within a phosphoric acid fuel cell is made from silicon carbide and a binder of polyestersulfone. Preferably the matrix consists of 10-20 weight percent polyethersulfone with a balance of silicon carbide. The matrix has improved strength, wettability and bubble pressure compared to the best known prior art matrix.

Abstract: A convergent/divergent gas turbine engine exhaust nozzle having reverse thrust capability includes a door which blocks a reverse flow outlet port when the nozzle convergent flap is in any forward thrust operating mode. The door is coupled to the convergent nozzle flap such that it opens as the convergent nozzle flap moves to a reverse thrust position and the flap directs the exhaust gases through the reverser outlet.

Abstract: A film cooling passage through the external wall of a hollow airfoil for a gas turbine engine has a metering section in series flow relation with a diffusing section leading to the passage outlet at the external surface of the airfoil over which a hot gas flows during operation. The diffusing section is generally rectangular in cross section perpendicular to the axis of the passage. Upstream and downstream longitudinally extending, spaced apart, facing surfaces of the diffusing section are joined together by a pair of spaced apart side walls which face each other and diverge from each other in the longitudinal direction toward the outlet of the passage. These side walls blend, along their length, with the downstream surface as a smooth curve of large radius. The diameter of the corner curvature of the passage is on the same order of magnitude as the distance between the upstream and downstream surfaces of the diffusing section at the location in question.

Abstract: The external wall of a hollow airfoil for a gas turbine engine has a plurality of longitudinally aligned diffusing coolant passages having their outlets at the outer surface over which a hot gas is intended to flow. The airfoil external wall also includes a longitudinally extending slot formed in the inner surface thereof. Each of the coolant passages intersect such longitudinally extending slot to define metering inlets to each passage for receiving coolant fluid from the slot at a controlled rate. The coolant diffuses as it passes through each passage and exits as a thin film on the external surface of the airfoil. The slot is cast in the inner surface of the wall at the time of forming the airfoil; and the passages are machined into the wall from outside the airfoil. Very small, accurate metering areas for each passage can thereby be formed in single-piece hollow airfoils without access to the interior of the airfoil.

Abstract: In the fabrication of a hollow airfoil having a longitudinally extending slot in the airfoil wall with the slot outlet at the external surface of the airfoil, a metering passage extending from the coolant compartment within the airfoil to the slot for carrying a metered amount of coolant fluid into the slot is formed by machining a passage completely through the wall from the external surface to the internal surface and which intersects the slot. The portion of the passage between the slot and the external surface of the airfoil is blocked, such as with a plug or by welding. With this fabrication method metering passages for directing coolant fluid from inside the airfoil into the slot may be formed without access to the interior of the airfoil. Coolant fluid from the interior flows into the slot through the unblocked portion of the passage and thereupon flows out of the airfoil through the slot as a film of coolant over the surface of the airfoil.

Abstract: The wall of a hollow turbine airfoil has a longitudinally extending coolant outlet slot in its external surface which intersects, along its length, a longitudinally extending cylindrical channel within the wall. Metering passages extend from the inside surface of the airfoil wall to the cylindrical channel and direct a metered amount of coolant into the channel in a manner which results in a swirling motion being imparted to the fluid as the fluid diffuses within the channel. The coolant is thereupon ejected from the channel through the slot in the external surface as a film on the external surface of the airfoil along the length of the slot. The swirling of the fluid within the cylindrical channel helps diffuse the fluid such that the outlet slot becomes completely filled with coolant, whereby a film of coolant is created on the airfoil surface downstream of the slot over the full length of the slot.

Abstract: The wall of a hollow airfoil has a longitudinally extending slot in its external surface which is intersected, at its base, by a plurality of coolant passages in a longitudinally extending row. Each coolant passage has a metering portion at its inner end which communicates with a coolant compartment within the hollow airfoil. Each passage includes a pair of walls downstream of the metering portion which diverge from each other in the longitudinal direction and intersect with the base of the slot to form an outlet for the passage. The diverging walls of adjacent passages substantially meet each other at the base of the slot, wherein coolant fluid from the metering portions of the passages diffuses in the longitudinal direction as it flows toward and into the slot, filling the entire slot and forming a thin, continuous film of coolant downstream of and along the entire length of the slot over the external surface of the airfoil.

Abstract: A first turbine rotor hub 32 and a second turbine rotor hub 42 each have respective internal splines 52, 62 which engage coaxial, non-concentric external splines 54, 64 on a shaft 20 and are in thrust bearing relationship. The assembly requires no bolts between the rotor stages 30 and 40 to hold the two stages together. In another embodiment the turbine stages 30, 40 are part of a turbine module 5 which includes a stator assembly 94.

Abstract: A flap for a jet engine flap-type nozzle is constructed of a plurality of sheet metal louver elements along the length of the flap, each louver element has a forward U-section having a forward flange and a rearward flange with an interconnecting bottom portion, a plate member extends rearwardly from the end of the rearward flange at the open end of the U-section, said plate member extending over the U-section of its adjacent louver element, said plurality of louver elements being connected together by welding the forward flange to the mating rearward flange, a beam plate extending axially along said U-sections and being fixed thereto, said plate members of adjacent louvers being free to move relative to each other.

Abstract: Tubular catalytic reactors within a furnace are each surrounded by a radiator having an inner cylindrical surface spaced from the reactor defining a flow path for the furnace gases. The inner surface of the radiator has a plurality of adjacent helical channels formed therein extending the length of the conduit. Heat from the furnace gases traveling through the flow path is picked up by the radiators by convection and radiated to the reactor. The helical grooves improve heat transfer efficiency and circumferential uniformity of heating with minimum pressure drop; and they prevent the cut off of heat to localized areas of the reactor in case of contact between the reactor and radiator walls.

Abstract: Film coolant passages through the wall of a hollow airfoil for a gas turbine engine are oriented to direct coolant fluid therefrom at a substantial acute angle to the downstream direction and at a shallow angle to the surface of the airfoil. Each passage includes a metering portion at its inlet end and a four sided diffusing portion at its outlet end. The diffusing portion includes a pair of adjoining surfaces which are both parallel to a central axis of the passage, and another pair of adjoining surfaces which diverge from the central axis, the diverging pair of surfaces being located on the downstream side of the passage. With this configuration the coolant completely fills the diffusing section and exits as a wide film of coolant within the boundary layer downstream of the passage outlet.

Abstract: A first turbine rotor hub 32 and a second turbine rotor hub 42 each have respective internal splines 52, 62 which engage coaxial, non-concentric external splines 54, 64 on a shaft 20 and are in thrust bearing relationship cooperating, circumferentially disposed, radially inwardly extending lugs 35, 45 on each hub 32, 42 define radially inwardly extending projections 80. A resilient split metal band 60, having circumferentially disposed apertures 61 overlies the projections 80 which extend through the apertures 61. The uninstalled diameter of the band is greater than the installed diameter such that the band is self-retaining. The assembly requires no bolts between the rotor stages 30 and 40 to hold the two stages together. In another embodiment the turbine stages 30, 40 are part of a turbine module 5 which includes a stator assembly 94.