Abstract: Cast and forged titanium alloys suited for use at temperatures over 600.degree. C. are based on TiAl gamma phase structure. Useful alloys have about 1.5% or greater tensile ductility at temperatures of 260.degree. C. and below, thereby making them fabricable and suited for engineering applications. Disclosed are alloys having weight percent compositions of 31-36 aluminum, 0-4 vanadium, balance titanium (in atomic percent, about: 45-50Al, 0-3V, bal Ti). The inclusion of about 0.1 weight percent carbon improves creep rupture strength. To obtain high tensile strength, the alloys are forged at about 1025.degree. C. and aged at about 900.degree. C.; to obtain higher creep rupture strength and tensile ductility, a solution anneal at about 1150.degree. C. is interposed before aging.

Abstract: This control serves to optimize thrust during steady state and transient operation modes of a turbofan engine of the mixed flow type by adjusting or trimming the exhaust nozzle area as a function of fan pressure ratio and fan rotor speed and by adjusting or trimming the core engine fuel flow as a function of fan rotor speed and/or turbine inlet temperature. The control serves to enhance stability by assuring airflow in the engine and its inlet is within a given value avoiding inlet buzz and high distortion to the engine and avoiding even transient operation in conditions that might cause compressor flow instability or stall. Fuel flow is adjusted or trimmed as a function of fan rotor speed or turbine inlet temperature limits depending on which is calling for the least amount of fuel.

Abstract: In a system which provides feel-force to the control stick of an aircraft by means of hydraulic pressure, a fault indicating system which responds to excessive differences between desired and actual force in the actuator, only of a polarity in the same direction as concurrent stick motion, to separate pilot induced pressure excesses from force-system faults, is provided with directional sensitivity in the fault-indicating output logic. Excessive pressure errors in either direction of stick travel institute the monitoring of changes in stick position. Changes in stick position of an excessive magnitude are recognized as fault only if they occur in the same direction as the direction of excessive pressure error. A simple analog embodiment utilizes threshold detectors and a track store device; a dedicated-digital embodiment utilizes comparators, registers and a subtractor; and a computer embodiment utilizes a software routine.

Abstract: A turbosupercharging system for internal combustion engines, both otto cycle and diesel cycle, simultaneously varies the geometry of both the compressor discharge diffuser housing and the turbine inlet nozzle housing in a fixed relationship. The geometry variation is preferably accomplished by a single actuator which is positioned for optimum turbomachine geometry by a control responsive to selected engine parameters such as engine output torque demand and/or internal combustion engine volume flow. The variable geometry turbosupercharger effectively changes the size of the machine for varying engine operating conditions resulting in increased efficiency over the entire engine operating range.

Abstract: A catalytic reaction vessel makes hydrogen from a hydrocarbon feedstock and steam using heat stored in the vessel, and the vessel is then regenerated to restore the heat. Regeneration is done by preheating, separately and within the vessel, an oxygen containing gas and a hydrogen purge gas, and mixing these preheated gases so that they combust within the vessel and heat material disposed in the vessel. This is the heat which is used in converting the hydrocarbon feedstock to hydrogen.

Abstract: A sound absorbing structure for use in gas turbine engines is disclosed. Various construction details which enhance the acoustic performance of the structure and prevent the formation of ice in the structure are developed. A sound absorbing panel in the structure is spaced from an engine case to form one or more cavities which extend circumferentially about the engine.

Abstract: To more uniformly distribute heat to the plurality of catalyst tubes in a catalytic reaction furnace, the burner disposed in the furnace above the tops of the tubes includes concentric primary and secondary annular fuel and air outlets. The fuel-air mixture from the primary outlet is directed towards the tubes adjacent the furnace wall, and the burning secondary fuel-air mixture is directed horizontally from the secondary outlet and a portion thereof is deflected downwardly by a slotted baffle toward the tubes in the center of the furnace while the remaining portion passes through the slotted baffle to another baffle disposed radially outwardly therefrom which deflects it downwardly in the vicinity of the tubes between those in the center and those near the wall of the furnace.

Abstract: Titanium-aluminum-niobium alloys having narrow and critical composition ranges are disclosed. The alloys have room temperature tensile elongations of 1.5% or greater and creep strength to density ratios better than certain nickel superalloys. Thus, they may replace other heavier base alloys in many applications up to 750.degree. C. Aluminum content must be closely controlled as excess amount decreases ductility while insufficient amount decreases creep strength. Niobium content is also critical as excess amount adversely affects creep strength-to-density ratio while insufficient amount decreases ductility. And there is an important interrelationship between niobium and aluminum.Disclosed are alloys having atomic percent compositions of 24-27 Al, 11-16 Nb, balance Ti; more preferred are alloys of 24.5-26 Al, 12-15 Nb, balance Ti. (Nominally, these alloys in weight percent are Ti-13/15Al-19.5/30Nb and Ti-13.5/15Al-25/28Nb.

Abstract: The instantaneous values of intake manifold vacuum in an internal combustion (IC) engine running under load are measured to provide an indication of the relative performance and relative suction ability of each cylinder in the engine. The instantaneous values of manifold vacuum are sensed at selected, sub-cyclic crankshaft angle intervals within a full engine cycle, each angle interval being substantial less than that associated with a cylinder sub-cycle, each sensed value of manifold vacuum being identified by the sensed angle position to provide an indication of the sub-cyclic fluctuations in manifold vacuum as they occur at known cylinder intake strokes within the engine cycle, thereby providing identification of each sub-cyclic fluctuation in manifold vacuum as being associated with a particular cylinder, the relative magnitudes of the manifold vacuum fluctuations providing a relative indication of each cylinder's performance and suction ability within a common engine cycle.

Abstract: A fixture capable of accurately manipulating a workpiece through a circular arc is provided. Various concepts useful in the formation of a cylindrical surface on the workpiece are developed. One fixture described includes a pair of opposing spherical surfaces which are restricted in degree of movement by a key extending from one surface into a slot in the opposing surface.

Abstract: The ducting extending a substantial axial length of a gas turbine engine is faired to transition the annular flows of the core engine and fan to a rectangular separate flow in a pair of two-dimensional exhaust nozzles so as to control each flow individually. Each flow is judiciously located to achieve noise control and infrared suppression.

Abstract: An annulus formed in the nut of a fuel nozzle to collect, distribute and atomize water droplets fed into the fuel nozzle for increased thrust produced by a turbine type power plant powering aircraft is discretely formed adjacent the discharge juncture point and discharged angularly into and with respect to the fuel spray emitted into the combustion zone for smoke reduction purposes.

Abstract: The spark voltage waveform at the secondary of the ignition coil of an internal combustion (IC) engine is sensed over a plurality of successive engine cycles. The instantaneous sub-cyclic position of the engine crankshaft is measured at successive crankshaft angle increments within each engine cycle and each sensed spark voltage signal is identified by the instantaneous value of crankshaft position at which it appears, thereby providing identification of each spark voltage signal with an associated cylinder of the engine. The number of samples for each cylinder together with the peak KV voltage magnitude and time duration of each are measured and the maximum, minimum and mean values of peak KV and spark duration for the spark signals associated with each cylinder together with the number of samples obtained are compared with the values obtained for each other cylinder to provide an indication of the relative sub-cyclic ignition efficiency of the ignition secondary circuit and the individual cylinders.

Abstract: Novel fine grained pyrolytic silicon nitride is produced by adding a substantial amount of methane to the normal reactant gases. Silicon tetrafluoride and ammonia in ratios of 60:40 to 10:90 may be employed with additions of methane in amounts equal to from 50 to 500% of the sum of silicon tetrafluoride and ammonia. When these reactant gases are passed over a heated substrate at a low pressure pyrolytic silicon nitride with a grain size of less than about 10 microns results.

Abstract: A turbofan configuration for a gas turbine engine is disclosed. Various construction details which improve engine performance by supercharging working medium gases to the engine core are discussed. Engines configured in accordance with the present invention include an island splitter which is disposed across the fan flow path. The island splitter is spaced apart from the core engine case. A supercharging, compression stage is driven commonly with the fan stage and extends outwardly into proximity with the core case.

Abstract: Disclosed is a method and apparatus for fabricating thermoplastic patterns for investment casting. The patterns define hollow objects and have contained within a very precisely located ceramic core. Thermoplastic is injected into the pattern die on either side of the core, thereby avoiding distortion, movement or breakage of the core. Multiple sprues are used; the sprues are individually fed from a nozzle having a single central bore. The configuration of the nozzle tip and the cavity from which the sprues emanate is such that a gate or bridge is not formed at the entrance to the die assembly. Accordingly, removal of the pattern from the die may be effected by pulling the part coaxially with the sprues, thereby avoiding the necessity of splitting the die where the sprues are located.

Abstract: A gas dynamic laser is formed having a combustor with a cylindrical combustion chamber, said combustion chamber is formed having a discharge opening at one end and primary injection means at the other end with a plurality of injector tubes for injecting a combustible mixture into said combustion chamber; an igniter is included for igniting said mixture; a secondary injection means is located adjacent the discharge opening and has a plurality of nozzle tubes for injecting an oxidizer, one nozzle tube being included for each injector tube; each cooperating nozzle tube and injector tube being axially aligned, with said nozzle tubes directing the oxidizer towards the injector tubes, a mixing chamber being located downstream of the secondary injection means for directing the gases to a nozzle array. The secondary injection means is constructed to have easy accessibility to the nozzle tubes.

Abstract: A durable, outer air seal structure capable of long term, reliable service in a gas turbine engine environment is disclosed. Various construction details which enable the incorporation of high temperature tolerant ceramic materials into the outer air seal structure are developed. The structure is built around a porous, low modulus pad of metallic material which is disposed between the ceramic material and a substrate of solid metallic material. The ceramic material is applied to a preferred density at which the physical properties of modulus of elasticity (E), mean tensile strength (T), coefficient of thermal expansion (.alpha.) and thermal conductivity (K) impart good thermal shock resistance, erosion resistance and abradability characteristics to the seal structure.

Abstract: A seed and method for epitaxial solidification of materials, a preferred seed having at least a portion with a melting point 20.degree.-45.degree. C. depressed from that of the alloy being solidified into an article. Boron and silicon are preferably added to nickel superalloys seeds when directionally solidified columnar grain and single crystal articles are formed. Improved seeds also have surface compositions which promote the dissolution of surface contamination films that interfere with epitaxy.

Abstract: A gas dynamic laser device is formed having an elongated linear combustor having a trapezoidal cross-section. The combustion chamber is formed having a short front plate with two side plates extending rearwardly at an angle to an open end. A short flange extends outwardly from the free end of each side plate and an elongated plate extends forwardly from each short flange to a point located in front of each short plate. A plurality of ribs are placed along the length of said elongated linear combustor normal to the side plates. A primary injection device is placed in said short front plate between each adjacent pair of ribs and a secondary injection device is placed between each adjacent pair of ribs, alternating between side plates extending for the length of said combustor. The oxidizer is passed through the nozzle plates of the nozzle assembly for cooling it and passed through passages in the side plates of the combustion chamber for cooling them.