Abstract: A turboprop engine has in flow series arrangement a crescent shaped inlet, an annular plenum, a compressor, a combustor, and a turbine. The plenum is defined by inner and outer annular walls. A support member referred to as a "boat tail" extends between the walls and is circumferentially positioned 180 degrees from the inlet. A strake extends downstream from the support member and is angled in a direction opposite the rotational direction of the compressor. Thus air entering the engine with either positive or negative swirl is forced to enter the impeller with negative swirl.

Abstract: A gerotor pump having reduced drag torque at low temperatures is disclosed. The pump includes a shaft journalled in the housing. Mounted on the shaft are a pair of axially space metallic port plates and disposed therebetween are metallic interior and exterior gears. A ceramic eccentric ring circumscribes the exterior gear to define a diametral clearance.

Abstract: A turbine blade such as a rotor blade or stator vane in a gas turbine engine is provided of the type having an internal flow path for flow-through passage of a cooling gas stream, wherein the turbine blade includes a heat transfer surface designed for improved heat transfer with the cooling gas. The heat transfer surface comprises a regular pattern of turbulator vanes which extend generally transversely to the flow direction of the cooling gas stream, in combination with comparatively shorter heat transfer ribs which extend generally parallel to the gas stream flow direction. The pattern of turbulator vanes and heat transfer ribs provides significantly improved heat transfer between the turbine blade and the cooling gas stream, such that the cooling flow requirement is reduced to result in increased engine efficiency.

Abstract: A two-piece check valve employing an elastomeric diaphragm retained between two lands of an integral member. The integral member forms a boss on which the diaphragm is seated, and cooperates with the diaphragm to form a chamber surrounding the boss.

Abstract: A method is disclosed for producing a hollow airfoil, specifically, a blade or vane for a gas turbine engine, which is formed with a complex interior for cooling purposes. Broadly, the method comprises the steps of molding a green ceramic core having outer surfaces generally contoured to produce the intended interior surfaces of the completed airfoil, heating the green ceramic core to a sufficient extent to produce a fired core, and operating on the fired core with a laser to modify the characteristics of the fired core. Use of the laser enables the formation of detailed features having a transverse dimension less than approximately 0.020 inches. Specific operations may include labeling, trimming, cutting, drilling either by punching or trepanning, etching or milling, and glazing or strengthening. In another embodiment of the invention, a layer is produced on the core surface having a very high surface energy to promote the flow of the casting alloy around the core within the mold.

Abstract: A butterfly valve plate is provided for use in a pneumatic surge valve or the like, wherein the valve plate is designed for reduced noise with increased mass flow capacity. The valve plate is of the type having an offset stem hub for supporting the valve plate on a pivot stem or shaft for movement between closed and open positions within a flow conduit. A pair of part-circular and generally axially extending acoustic fences are carried respectively at opposite sides of the valve plate in peripheral positions for flow-through passage of air when the valve plate is opened. An enlarged and smoothly contoured noise reduction collar is formed on the stem hub at the downstream side of the valve plate, generally at the periphery thereof to substantially fill and occupy the space between the stem hub and the adjacent end of the downstream-side acoustic fence.

Abstract: An exhaust housing having an eductor is provided. The eductor includes an outer annular casing circumscribing an inner annular casing to define a flow path therebetween for receiving the exhaust gas from the turbine section of an engine. A plurality of struts are integral with both casings. The struts have passages that extend from the exterior of the outer casing to the interior of the inner casing. A non-oil lubricated bearing is mounted within the interior of the inner casing for journaling a rotating shaft. During operation, the kinetic energy of the high velocity exhaust gas flowing between the casings and into a tailpipe induces cooling airflow from the exterior of the exhaust section, through the passages, across the bearing, and then out to the tailpipe.

Abstract: This invention relates to an alkaline scrubber for condensate stripper off-gases. In particular, this invention relates a process for selectively removing hydrogen sulfide and methyl mercaptan from a gas stream containing these compounds and methanol. Such gas streams are commonly generated during pulp and paper production.

Abstract: An air blast fuel nozzle includes a unitary structure which introduces not only axially swirling primary airflow into the primary zone of the combustor chamber, but also introduces radial inflow, coswirling, primary airflow into the premixing chamber immediately upstream of the primary zone of the combustor.

Abstract: A method for preparing a machined surface of a composite article for diffusion bonding is provided. The method includes removing most of the exposed fibers by shot peening followed by acid etching. The acid etch may be followed by grit blasting and then another acid etch. After the method is applied to the surface, the article can be diffusion bonded to other composite article to form complex shapes.

Abstract: A seal compression tool is disposed at a readily accessible location externally of the cylindrical casing of a gas turbine engine, and has a camming surface thereon effective to interengage and axially shift the turbine nozzle of the gas turbine engine. Such axial shifting uniformly and controllably compresses a static seal carried between the turbine nozzle and the casing at a remote, relatively inaccessible location inside the gas turbine engine.

Abstract: A stator vane assembly for a gas turbine engine that includes a plurality of circumferentially spaced ceramic vanes, each of which has an inner and outer ceramic shroud, and a ceramic post extending from one of the shrouds, and a metallic platform having a plurality of circumferentially spaced recesses. The posts are inserted into a metallic sleeve and then brazed. The brazed sleeves are then mounted in the recesses. A method for assembling these components to form the stator assembly is also described.

Abstract: An electro optic sensor for sensing unwanted axial motion of the turbine of a gas turbine engine away from its normal position, includes a pair of fiber optic wave guides interconnected through a frangible member disposed axially adjacent the turbine rotor. Upon axial movement of the rotor away from its normal position, the frangible element is broken to open the optical circuit associated with the guides. Associated electronic circuitry generates an output signal indicative of failure of the gas turbine rotor.

Abstract: A multifunction secondary power system (10) for use aboard an aircraft or other vehicle provides the functions both of an auxiliary power unit and of an emergency power unit. The power system (10) includes two turbine engines (12, 22) operable under differing conditions, a gearbox (34) receiving power from the two engines (12, 22) selectively through overrunning clutches (74,84), and a plurality of accessory devices (36, 38, 40) receiving shaft power from either of the two engines (12, 22) through the gearbox (34). The gear box (34) includes a third clutch (64) operably interposed between the clutches (74, 84) which selectively delivers shaft power from the engine (22) to the engine (12) to affect the start thereof.

Abstract: Output voltage of a switching regulator is rectified and adjusted by the internal body diode of an FET. When the output voltage exceeds a reference voltage, the FET is gated off, causing the internal body diode to reduce the output voltage by a diode drop. When the FET is turned on, the diode is shorted and, as a result, the output voltage is increased by a finite amount of additional energy. This adjustment range, a diode drop, is significant for low voltage, wide bandwidth power supplies.

Abstract: A multifunction integrated power unit (MIPU) for use aboard aircraft provides the functions both of an auxiliary power unit and of an emergency power unit while being smaller, lighter, and less expensive than the two units it replaces. Additionally, the integration of both functions in a single unit allows elimination of duplicated service devices and a further reduction in size, cost, and weight in the aircraft itself. The MIPU includes two turbine engines operable under differing conditions, an integrating gear box receiving power from the two engines selectively, and a plurality of accessory devices receiving shaft power from either of the two engines via the gear box.

Abstract: A critical parameter for a device is generated as follows. The critical parameter is modeled. When the device is operated under steady-state conditions, the modeled parameter is corrected by a measured parameter known to be accurate under steady state operating conditions. The correction accounts for errors which may be present in the synthesis of the critical parameter and normal anticipated performance variation of the device. When the device is operated under transient conditions, however, the correction of the modeled parameter is based upon previous steady-state conditions. Thus, the apparatus generates a theoretical parameter during transient operating conditions.

Abstract: A composite article is manufactured by preparing a machined surface of the composite article for diffusion bonding. The method includes removing most of the exposed fibers by shot peening followed by acid etching. The acid etch may be followed by grit blasting and then another acid etch. After the method is applied to the surface, the article can be diffusion bonded to other composite article to form complex shapes.

Abstract: A method and apparatus for eliminating vortex whistle noise in a radial-to-axial compressor intake uses a plurality of vortex-disturbing tabs mounted to the trailing edges of inlet guide vanes and extending into the flow path between adjacent vanes. The tabs are mounted to the guide vane so that the tab is always perpendicular to the guide vane, regardless of the vanes angular position.

Abstract: A fuel flow delivery system for a gas turbine engine of simple, economical structure including a non-positive displacement centrifugal fuel pump delivering constant pressure, variable flow rate fuel flow through a venturi passage. A conical needle valve is variably positioned within the throat section of the venturi to variably meter fuel flow rate.