Abstract: A dual fault tolerant control system for controlling power delivered to an actuator from a power source includes decoders which accept commands representing the length of time power is to be applied to the actuator. Controllers process the command and control power inhibits based upon the length of time indicated by the command for supplying power to the actuator. The dual fault tolerant feature allows reassurance that power is applied to the actuator for the length of time dictated by the command.

Abstract: In a microcontroller-based system that controls the operation of equipment such as lights and wipers in an automobile, overcurrent is detected by comparing the total current through the device with a stored level. If the detected current is excessive the devices are independently activated and the current through each device is compared with stored current level for the device. A device having an overcurrent condition is inactivated and the remaining devices are activated.

Abstract: Protective and security coatings are applied to an integrated circuit by periodically passing the integrated circuit through a flame spray containing molten particles of the coating composition. The integrated circuit is attached to a fixture that is cooled with a coolant that is applied to the integrated circuit. The distance between the flame spray gun and the integrated circuit is controlled so that the particles are molten when they strike the circuit but the circuit heating is minimized. A flame resistant mask retains the integrated circuit on the fixture. The mask is constructed of a low thermally conductive material and the fixture is constructed of a high thermally conducive material.

Abstract: The exhaust in a gas turbine engine is lined with stacks of hollow cooling blocks made of a composite material. Air is pumped into each stack and escapes into the exhaust flow from a slot between the blocks in each stack. In addition, the blocks contain passages so that some of the airflow escapes to a space between the stacks. The blocks are attached using special fasteners that does not create mechanical stresses on the composite material.

Abstract: Corrected fan speed (N1C2) and engine pressure ratio (EPR) are controlled, by controlling exhaust nozzle area (EA) according to a schedule or map so that as altitude increases (P2 decreases) the axial forces on the low rotor are sufficient to minimize low rotor vibrations. The altitude band (critical load region) is determined that produces loading levels in which vibrations appear. As this band is approached, conventional control of N1C2 and EPR is automatically over-ridden. N1C2 is decreased with altitude and exhaust area is reduced, thereby increasing the axial force (load) on the low rotor. When the upper limit of the band is reached, conventional control of N1C2 and EPR is automatically resumed, resulting in crossing the critical load region rapidly over a narrow altitude band.

Abstract: Stator vanes located between compressor stages in a gas turbine engine are fabricated with a composite outer shell made of graphite fibers in an epoxy binder that is laid-up over a core of felt-like material selected to have an elongation velocity that is greater than the elongation velocity of the shell.

Abstract: Eddy current testing is performed at known locations on a metal object having recurring features to provide a data string that is applied to a signal processor that determines a template for one feature and conducts a correlation operation with the template and the data string to create a second string with peaks that periodically appear between two locations. The average width between those two locations is determined. The average value for each location in the second data string along the average distance between peaks is computed. The actual value of the second string at each location is combined with the average computed value to produce a deviation value that shows faults without a superimposed average geometry value. The location of the fault is indicated in response to the deviation signal.

Abstract: An exhaust liner assembly for a gas turbine engine contains a unitary liner sheet and an impingement sheet, which contain holes for cooling air to enter chambers that are defined by chemically milled areas in the liner. The chambers are in an isogrid pattern, with the chambers having a polygon shape defined by walls that are left after the liner is milled. The walls intersect at nodes and fasteners are attached to the nodes to attach the impingement sheet to the liner.

Abstract: Two composite parts, such as sheet and a hollow gas turbine liner tile, are fastened together using a fastening system that includes a journal bearing that fits in a bore in the sheet and springs to support a bolt fastener that is tightened to hold the parts together. Resilient spacers are placed between the sheet and the liner. The springs may comprise a stack of rings, each ring being a tightly wound helical spring, giving the ring a hollow cross section and resilient qualities.

Abstract: A nose cone on the fan of a gas turbine engine contains access holes that provide access to cap screws that hold the nose cone on the fan hub. The cap screws extend through an internal flange on the nose cone. A spring clip extends from the flange in a configuration that covers the access hole and holds the cap screw in the flange as the nose cone is installed.

Abstract: A stack of piezoelectric crystals is placed on a shaft that is rotated to test a component on the shaft. An electrical signal is supplied to the stack, causing the crystals to vibrate, sending vibrations to the component as it spins. The component is enclosed in a vacuum chamber in order to provide a reduced pressure and thereby to reduce the power required to spin the component.

Abstract: In a gas turbine liner, air metering passages are placed in dimples in a first liner sheet to provide an air chamber. A second liner sheet contains an air outlet for each dimple. The second sheet masks the metering passage and a portion of the dimple. A coating is applied to the second sheet and extends into the dimple but does not cover the metering passage.

Abstract: The compressor section of an insert gas turbine engine contains a insert installed around the compressor blades that includes cells in a honeycomb configuration. Each cell is inclined at a compound angle to the blade tip to energize the tip air flow as the tip passes over the cell as the blade rotates, improving stall margin with minimum efficiency loss. Each cell is oriented in the direction of the blade chord and faces the advancing blades. As the blade rotates, it sweeps by each cell and high pressure airflow is first captured in the cell from the high pressure side of the blade and released to the low pressure side as the blade passes the cell in the form of a transient energizing jet of high velocity flow in the direction of the airflow across the blade thereby providing effective mixing of the endwall flows and enhancing the tip flow streamwise momentum.

Abstract: Stator vanes located between compressor stages in a gas turbine engine are fabricated with a composite outer shell made of graphite fibers in an epoxy binder that is laid-up over a core of felt-like material selected to have an elongation velocity that is greater than the elongation velocity of the shell.

Abstract: A forging system comprises a furnace with heating elements to heat a billet which is pressed against a die at a controlled rate and pressure. A signal processor controls the temperature, pressure and rate as a function of parameters entered on a keyboard the signal processor displays those parameters along with real time values of temperature pressure and distance for the billet in a graphical interface that includes a model of the billet and furnace with elements that change size during the forging processor. Forging pressure is displayed, in this interface, on an incremented bar.

Abstract: A general purpose or universal motor control is constructed as integrated circuit using a plurality of state machines and memories. The specific characteristics of a motor are programmed into a programmable "features" memory. A lookup table contains parameters for operating the motor that are accessed as a function of the features. The features memory and the lookup table may be programmed and tested through a communications state machine. External and internal pulse width modulation is provided along with dynamic braking as options that are utilized by the state machines depending upon the features. A multiplexer acts a switch between the state machines, the memories and the motor drive.

Abstract: In a gas turbine, a linear stem extends through a diffuser and a combustor cowl into a sleeve that is attached to the swirler in such a way that the sleeve can move relative to the swirler but is supported on the swirler. The stem slides into the sleeve and contains a fuel nozzle that supplies fuel through a sleeve outlet to a swirler inlet.

Abstract: A control system has several proportion-integral channels, each producing a control signal based on an individual error signal and feedback of the control signal. One of the channels is selected to produce the control signal and that value for the control signal is used to recompute the error signal used by the other channel so that each channel produces the selected control signal. The recomputed error signal is then integrated. A different channel may be selected at a subsequent time and the integration in the other channels is recalculated in the same way.

Abstract: Circumferential and radial inlet pressure distortion on an aircraft gas turbine engine are detected by a plurality of static pressure sensors and a signal processor, which computes the total pressure for each sensor to determine a pressure distortion pattern which the processor correlates with stored data for the engine and inlet to determine if the airflow geometry should be altered during flight. Time varying changes in the pressure from one or more of the pressure sensors is used to determine a stall condition, causing a change in engine airflow geometry to increase stall margin.

Abstract: Loads, such as power relays controlling wipers, windows and lights are connected to an automobile battery through individual transistor drives that are controlled by a microcontroller. A switch, connected to the microcontroller, is operated to activate each drive. The microcontroller checks the load characteristic when each drive is activated and inactivated. When the load is inactivated, it is part of a resistance network producing a test voltage that is digitally converted and supplied to the microcontroller, which compares the test voltage to a stored voltage to determine if the load is correct. An analog multiplexer is controlled by the microcontroller to select the voltage produced for each load.