Abstract: A gas turbine engine includes a radial compressor having first and second blades. The first blade has a tuned leading edge that prevents either blade from exciting at a natural frequency at speeds within an expected operating speed range.

Abstract: A gas turbine engine includes a radial compressor with first and second blades. The first and second blades have tuned leading edges that prevent natural frequencies from exciting at speeds within an expected operating speed range.

Abstract: An accessory gearbox system for a gas turbine engine includes an accessory compressor mounted to a gearbox housing. The gearbox housing defines a seal air core, and the gearbox housing communicates a seal airflow through the seal air core.

Abstract: A startup assistance apparatus for a fine pitch Ram Air Turbine (RAT) is provided and includes a generator to provide motive power to the RAT when operating in a first mode and to generate electricity from RAT operation when operating in a second mode and a control unit, including a speed sensing unit configured to sense an operating condition of the generator and a controller operably coupled to the generator and configured to control the generator to operate in the first or the second mode based on the sensed operating condition.

Abstract: A method of making a reinforced resin structure is disclosed. A volume of uncured resin compound is placed on a first outer surface of a carrier structure comprising a plurality of fibers. The uncured resin compound and the carrier structure are pressed between two cooperating plates to disperse the resin compound into and through a plurality of passages between the plurality of fibers. The dispersed resin compound is cured to fix the resin within the plurality of passages and around the plurality of fibers.

Abstract: A valve assembly is provided and includes a pitot tube having an angled tip to extract from a duct formed by a housing a sample of a fluid to be communicated to an actuator configured to operate the duct, the pitot tube being disposed within the housing whereby the pitot tube is fixed longitudinally between the actuator and the housing and laterally within the housing and an anti-rotation mechanism coupled with the pitot tube to rotationally secure the pitot tube such that the angled tip is fixed to face rearwardly.

Abstract: A compressor impeller includes a hub, main blades and splitter blades. The main blades are equally spaced around the circumference of the hub. Each splitter blade is equally spaced between two adjacent main blades. Each main blade and splitter blade has suction and pressure surfaces formed in substantial compliance with normalized Cartesian coordinate values of X, Y, and Z set forth in Tables 1-4. When connected by smooth, continuing arcs, the normalized Cartesian coordinates form complete main blade and splitter blade shapes that are substantially matched by the main blade and splitter blade shapes of the compressor impeller.

Abstract: An electrical system includes a generator; a generator control unit connected to the generator; and a shunt regulator connected to an excitation output of the generator control unit, wherein the shunt regulator is configured to overload the excitation output of the generator control unit in the event of an overvoltage condition in the electrical system, such that an output voltage of the generator does not exceed a predetermined ceiling voltage during the overvoltage condition.

Abstract: An exhaust eductor for a gas turbine engine comprises: an engine exhaust chamber with an exhaust chamber inlet that receives engine exhaust from the gas turbine engine and an exhaust chamber outlet that discharges the engine exhaust to establish an exhaust gas flow through the engine exhaust chamber; an air chamber with an air inlet that receives ambient air external to the gas turbine engine; and a mixing baffle that couples the air chamber to the engine exhaust chamber, comprising a first side adjacent the air chamber, a second side adjacent the exhaust chamber, multiple apertures through the mixing baffle that extend from the first side to the second side of the mixing baffle, each aperture having a corresponding canopy that extends from an upstream end of the aperture along the second side of the mixing baffle into the exhaust gas flow for at least a portion of the length of the aperture, to establish an air flow from the air inlet of the air chamber into the exhaust gas flow.

Abstract: A rotary apparatus comprises a shaft having a rotational axis, a rotation indicator formed on the shaft, a target feature proximate the rotation indicator, and a sensor proximate the target feature. The target feature extends circumferentially about the shaft, with a radial face transverse to the rotational axis and a circumferential face along the rotational axis. The sensor is oriented toward the rotation indicator to sense a rotational speed of the shaft, and oriented toward the target feature to sense transverse vibrations based on a radial distance to the target feature and longitudinal vibrations based on an axial distance to the target feature.

Abstract: A display system comprises first and second LED panels for displaying first and second priority aviation data, a power supply, a modulator, a processor and a logic gate. The modulator generates a modulated voltage for the second LED panel, where the second priority data are displayed at a modulated brightness. The processor controls the modulator, and generates a status signal indicating a failure condition of the modulated voltage. The logic gate switches the first LED panel from the modulated voltage to the unmodulated voltage based on the status signal, where the first priority data default from the modulated brightness level to full brightness based on the failure condition.

Abstract: A Ram Air Turbine (RAT) is provided and includes a turbine hub having an end plate and a nose cone attached thereto at trailing and leading ends, respectively, a governor shaft, to which turbine blades are connected, which is coupled to the end plate and supported within the nose cone to be rotatable with the turbine blades about a central axis thereof and axially movable from a first position relative to the turbine hub to a second position relative to the turbine hub and a hub assembly operably coupled to the turbine hub, the governor shaft and the turbine blades whereby the hub assembly biases the governor shaft toward the first position at low rotational speeds such that the turbine blades assume a partial coarse pitch angle, and the second position at high rotational speeds such that the turbine blades assume a fine pitch angle.

Abstract: An electrical system includes an alternating current (AC) source; a transformer rectifier unit (TRU) connected to the AC source, the TRU configured to receive AC power from the AC source, convert the AC power to direct current (DC) power, and output DC power; a DC bus configured to receive the DC power output by the TRU; at least one DC load powered by the DC bus; and a shunt regulator connected to the output of the TRU, the shunt regulator configured to overload the output of the TRU in the event of an overvoltage condition at the output of the TRU, such that a voltage available to the DC bus during the overvoltage condition does not exceed a reference voltage.

Abstract: A bearing assembly includes first and second races, a plurality of ball bearings positioned between the first and second races, and a spacer positioned between each of the ball bearings. The spacers each include a body defining opposite first and second sides, a first substantially concave pocket located at the first side of the body, and a second substantially concave pocket located at the second side of the body. The first and second substantially concave pockets each define a central region having a first radius of curvature about a first center point and an outer region adjacent to the central region that has a second radius of curvature about a second center point. The first and second center points are spaced from one another, and the body includes a portion extending in between at least the respective central regions of the first and second substantially concave pockets.

Abstract: A system for reducing compressor noise includes a rotor having a plurality of blades. The blades have a nominal geometry characterized by a blade parameter. At least some of the blades are mistuned, such that they differ from the nominal geometry by greater than a manufacturing tolerance in the blade parameter. The blades produce shock waves at a blade passing frequency, and the mistuned blades shift acoustic energy away from the blade passing frequency to multiple lower amplitude tones at other frequencies. The system is configurable to be deployed with an inlet silencer that preferentially absorbs acoustic energy at some of the shifted frequencies.

Abstract: A variable speed drive for an electric motor has an inverter for receiving pulse width modulation controls. The inverter communicates power signals to a poly-phase electrical motor. A resolver communicates signals from the poly-phase motor back to a motor control. The motor control includes a speed control, a field-oriented control, and a pulse width modulation drive for driving the inverter. The resolver is connected to the speed control and to the field-oriented control, and further communicates with a synchronous compensator. The synchronous compensator is configured to drive the harmonic content at a target frequency or frequencies in a selected signal towards zero over time.

Abstract: A multi-layer seal arrangement includes a dissolution barrier between a braze alloy and a ceramic component. The inventive seal is useful for joining a ceramic component to another ceramic component or a metal component, for example. In one example, the braze comprises a gold alloy and the dissolution barrier comprises a layer of alumina on the order of 2-3 microns thick. A titanium wetting layer is provided between the alumina layer and the alloy. A metallization layer provided between the dissolution barrier and the ceramic component in one example comprises a layer of gold between two thin layers of titanium. In one particular example, a platinum mesh is included with the gold of the braze alloy to control braze flow during the brazing operation.

Abstract: A system adjusts the pitch of a variable pitch propeller having a non-rotating side and a rotating side. The rotating side of the propeller has a hub, a propeller blade mounted to the hub, a propeller shaft that rotates the hub and propeller blade, and an actuation system. The actuation system has a screw and a piston. A motor has a non-rotating component in communication with the non-rotating side of the propeller and a rotating component in communication with the actuation system. When the motor increases speed, the screw rotates and the piston moves laterally in a first axial direction to decrease the pitch of the propeller and, when the motor decreases speed, the screw rotates and the piston moves laterally in a second axial direction to increase the pitch of the propeller.

Abstract: A door system for an inlet comprises: a first door hinged to face a first direction that covers a portion of the inlet; a second door, adjacent to the first door, hinged to face a second direction opposite the first direction that covers the remainder of the inlet; and an actuator system that operates the doors in selectable door system states comprising: first door closed and second door closed; first door opened and second door closed; first door opened and second door opened; and first door closed and second door opened.

Abstract: A mechanism is provided for generator excitation during a fault condition. A low spool generator is coupled to a low spool shaft. A high spool generator is coupled to a high spool shaft. When a fault occurs, the low spool generator provides excitation current to coils of the high spool generator such that a magnetic field is produced in the coils.