Abstract: A woven structure comprising at least a continuous band around an internal axis, suitable for impregnation with resin or for internal deposition of graphite from a reactive vapor, comprises axial threads, circumferential threads, and radial threads. The device employed to produce the structure comprises principally a series of flat rings or disks, aligned and slightly spaced from each other axially, having small apertures located around their circumference or one or more helical worms, with central openings, whose successive turns are similarly provided with apertures. Radial threads are passed through homologous apertures in successive disks, or successive turns of the helical worm, and are then drawn toward the central axis by wrapping of circumferential threads around them in the axial space between adjacent disks. Axial threads are then passed between the radial threads, and are drawn by further wraps of circumferential threads.

Abstract: In a system for converting information in the form of an AC frequency to digital data, a binary number having a magnitude proportional to the frequency is derived by generating a stream of pulses at a known clock rate and counting the number of pulses occurring during a specified period of the AC frequency. A high degree of accuracy is achieved by varying the clock rate as a function of the frequency of the AC signal such that an optimum numeric count is reached. The counter counts the duration of the first half period of the first cycle of the AC signal at a first fixed clock rate. The most significant bits of the generated count are input as a scaling factor to a binary rate multiplier which increases the clock rate in proportion to the magnitude of the scaling factor. The duration of the first half period of the succeeding cycle of the AC signal is then counted at the new rate.

Abstract: A metal vapor generator comprises a slug prepared from: a mixture of titanium powders, boron powders, and certain other metal powders selected from a group consisting of: alkali metals (Na, K, Cs), alkali earths (Ba, Ca), groups (IVA (Sn, Ge, Si), aluminum, copper, and other metals whose boiling point is generally below 3500.degree. C. The slug is reacted to generate heat and temperatures in excess of 2700.degree. C, by which selected metals of the above group and mixture may be vaporized.

Abstract: A design technique, method and apparatus for controlling the bypass gas stream pressure and varying the bypass ratio of a mixed flow gas turbine engine in order to achieve improved performance. The disclosed preferred embodiments each include a unique mixing device for combining the core and bypass gas streams which includes means for varying the area at which the bypass stream is injected into the core stream. The variable area mixing device permits the static pressures of the core and bypass streams to be balanced prior to mixing at widely varying bypass stream dynamic pressure levels.

Abstract: The fan section of a gas turbine engine is divided into a front section and an aft section axially displaced downstream of the front fan section. A duct is provided for bypassing the inlet gas stream around a gas generator. The bypass duct has a first inlet disposed intermediate the front and aft fan sections and a second inlet disposed downstream of the aft fan section. In order to provide increased flexibility in modulating the engine bypass ratio, a diverter valve is provided downstream of the aft fan section to selectively distribute the airflow exhausted from the front fan section between the aft fan section and bypass duct and to selectively distribute the air exhausted from the aft fan section between the bypass duct and gas generator.

Abstract: A design technique, method, and apparatus for varying the bypass ratio and modulating the flow of a gas turbine engine of the bypass type in order to achieve improved mixed mission performance. The disclosed preferred embodiments each include a gas flow control system for management of core and bypass stream pressure comprising diverter valve means downstream of the core engine to selectively mix or separate the core and bypass exhaust streams. The flow control system may also include variable geometry means for maintaining the engine inlet airflow at a matched design level at all flight velocities. Each preferred embodiment thus may be converted from a high specific thrust mixed flow cycle at supersonic velocities to a lower specific thrust separated flow turbofan system at subsonic velocities with a high degree of flow variability in each mode of operation, wherein the engine inlet airflow may be maintained at a matched design level at all engine velocities.

Abstract: A polar weave (i.e., three-dimensional, reinforced, composite material) flywheel, assembly comprises an outer polar weave portion and an integral metal hub. The hub includes a plurality of recessions and projections to provide an interface between the outer portion and the hub. The outer portion has a cylindrical configuration and is composed of woven and bonded unidirectional high-strength elements aligned and positioned in directions parallel to the polar coordinate axes. The elements so aligned are mechanically imbedded and locked into woven engagement with the recessions and projections, through which the woven outer portion becomes an integral part of the hub, and the interface is inherently strong enough to withstand failure caused by internal and external forces associated with operation of the assembly.

Abstract: In a gas turbine engine of the type which includes an inlet particle separator, there is provided apparatus for measuring the temperature of the air entering the engine compressor.A remote temperature probe is disposed in a feed duct having an inlet in flow communication with the engine inlet upstream of the particle separator and an outlet disposed intermediate the particle separator and inlet to the engine compressor. Airflow through the feed duct is generated by the pressure drop across the particle separator without the use of compressor bleed or other air sources which result in performance degradation of the engine. Temperature measurement errors during engine anti-icing are reduced by selectively cross-bleeding a predetermined quantity of anti-icing air into the feed duct during activation of the engine's anti-icing system. The response rate of the probe is significantly improved by enclosing the probe in an impingement heat transfer blanket.

Abstract: A fuel supply and distribution system is provided for a gas turbine engine wherein a plurality of flow dividing valves disposed about a manifold are positively controlled through an actuator which interconnects the flow dividing valves by linkage means extending through the manifold thus preventing sticking or seizing of the pressure regulating valves on account of contaminant particulate matter in the fuel.

Abstract: In a mixed flow gas turbine engine of the type which includes an outer nacelle spaced apart from a core engine to define an annular bypass duct therebetween, a thrust reverse is incorporated into the outer nacelle immediately aft of a fan disposed in the inlet. The thrust reverser reverses the discharge direction of the airflow exhausted from the bypass duct thereby to develop reverse thrust. The unique design and location of the thrust reverser permits the use of an aerodynamically efficient and relatively easy to manufacture cylindrical structure immediately aft of the engine fan frame.

Abstract: A diffuser provides a transition from a centrifugal compressor to the annular combustion chamber of a gas turbine engine. The diffuser comprises a plurality of linear passages which gradually merge radially outward from a circular cross-section to an outlet having a near rectangular cross-section defined by two flat opposing parallel sides and two opposing curved sides. The two opposing curved sides produce a razor sharp trailing edge which maximizes the diffuser efficiency. The linearity of the diffuser passage allows the diffuser to be manufactured to close tolerances by electric discharge milling an annular plate in a manner which assures uniformity and consistency between diffusers. The near rectangular shape of the outlet of the diffuser passages optimizes flow distribution to the annular combustion chamber. A transition region and deswirler section downstream of the near rectangular outlet may be provided to match the diffuser flow path to the combustor geometry.

Abstract: One or more of the aft stages of the fan section of a gas turbine engine are rotated by the high pressure turbine of a gas generator and the remainder of the fan stages are rotated by a low pressure turbine downstream of the gas generator. This arrangement divides the fan work between the low and high pressure turbines to permit more efficient utilization of the total available turbine capacity, reduction in low pressure turbine workload, increased aft fan stage pressure ratio capability and greater flow and pressure ratio modulation potential for a split fan engine. The invention has a wide range of application for various turbofan configurations including separated and/or mixed flow turbofan engines with separated or close coupled fan sections.

Abstract: A fuel supply and distribution system is provided for a gas turbine engine wherein a plurality of flow dividing valves disposed about a manifold are positively controlled through an actuator which interconnects the flow dividing valves by linkage means extending through the manifold thus preventing sticking or seizing of the pressure regulating valves on account of contaminant particulate matter in the fuel.

Abstract: An infrared suppression system is provided for an aircraft gas turbine engine for reducing the level of emitted infrared radiation from the engine exhaust. The hot exhaust stream emitted from the engine is mixed with the cooling airflows received from a plurality of sources in order to more effectively reduce the level of emitted infrared radiation. In addition, the infrared suppression system prohibits a direct line of sight back into the core engine.

Abstract: A two stage bypass augmentation burner is provided for a gas turbine engine wherein the downstream end of the primary burner is convoluted to define alternating cold and hot chutes.

Abstract: A cold metal ring is greatly expanded in radial diameter and simultaneously contoured to a desired cross-sectional shape by successively rolling the ring between selected pairs of roll dies. If necessary, the ring may be annealed between successive cold rolling operations sufficiently to permit movement of ring material without fracturing the ring. Thereafter, the rolled ring may be expanded to a precise radial diameter utilizing a precision expander. Dimensional and contour control of the ring is comparable to that attainable by machining.

Abstract: Undesired leakage from a system of labyrinth seals used to retain turbine cooling air is reduced by providing passageways which direct all parasitic leakage to a point between the teeth of one of the seals in the system.

Abstract: A cowling arrangement is provided for a turbofan engine of the variable pitch fan blade type wherein the aft portion of the fan cowling has the ability both to slide axially with respect to the main forward portion, providing an annular intake to increase reverse airflow during reverse pitch fan operation, and to vary radially so as to adjust exit area during normal operation at forward pitch.

Abstract: Fatigue failure of an engineering article is primarily influenced by a natural inherent defect in the material from which the article is made. By an ability established to allocate a quantitative measure to such defect as a new material property influenced only by environment and material manufacturing procedures as are other basic properties, and using known methods for determining critical stress areas, a wide range of fatigue design data can be generated from a few basic measurements. Thus, from the deduction of a characteristic material defect length, there can be determined both a material's basic fatigue properties and the fatigue capability of the article for which the material is used.

Abstract: A fuel supply and distribution system is provided for a gas turbine engine wherein a plurality of flow dividing valves disposed about a manifold are positively controlled through an actuator which interconnects the flow dividing valves by linkage means extending through the manifold thus preventing sticking or seizing of the pressure regulating valves on account of contaminant particulate matter in the fuel.