Abstract: The subject matter of this specification can be embodied in, among other things, a computer system that includes a first processor system configured to communicate with a network, a second processor system configured to control a process, and a third processor system configured to selectively operate in a first configuration and a second configuration, wherein the third processor system is configured to selectively block predetermined types of communications from the first processor system to the second processor system in the first configuration, and the third processor system is configured to permit the predetermined types of communications from the first processor system to the second processor system in the second configuration.

Abstract: The subject matter of this specification can be embodied in, among other things, a controller apparatus that includes a digital controller configured to provide a digital position signal based on a setpoint and a differential analog feedback signal, and a converter circuit configured to provide a differential analog electrohydraulic servo valve position control signal based on the digital position signal, and provide the differential analog feedback signal based on the differential analog electrohydraulic servo valve position control signal.

Abstract: The subject matter of this specification can be embodied in, among other things, a turbine combustor assembly includes a primary combustion chamber in fluid communication with a primary fuel injector and a primary air inlet, and an igniter carried by the primary combustion chamber and including a first igniter stage having an auxiliary combustion chamber housing comprising a mixing chamber and a tubular throat converging downstream of the mixing chamber, an ignition source projecting into the mixing chamber of the auxiliary combustion chamber, and a second igniter stage that includes an auxiliary fuel outlet manifold proximal to an outlet of the tubular throat.

Abstract: The subject matter of this specification can be embodied in, among other things, an actuator that includes a worm drive assembly having a worm shaft, and a worm wheel configured as a ring having a radially outer perimeter comprising a first collection of gear teeth extending radially outward from the radially outer perimeter and at least partly engaged with the worm shaft, and a coaxial radially inner perimeter comprising a second collection of gear teeth extending radially inward from the inner perimeter, and an epicyclic gear assembly having a sun gear and a planet gear engaged with the sun gear and the second collection of gear teeth.

Abstract: The subject matter of this specification can be embodied in, among other things, a method of igniting an air/fuel mixture in an internal combustion engine includes receiving an air/fuel mixture into a pre-combustion chamber, the pre-combustion chamber enclosing a portion of an igniter, igniting the air/fuel mixture in in the pre-combustion chamber with the igniter to produce a flame, directing the flame to eject the pre-combustion chamber through a collection of passages in a wall of the pre-combustion chamber, toward a peripheral wall of a main combustion chamber of the internal combustion engine, igniting, by the flame, air/fuel mixture in the main combustion chamber adjacent the peripheral wall, and then igniting air/fuel mixture in the main combustion chamber in a central region of the main combustion chamber with a propagating flame front of the ignited air/fuel mixture or a portion of the directed flame adjacent the peripheral wall.

Abstract: An airplane rudder and brake pedal assembly includes a rudder arm assembly having one rudder arm with first upper and lower arm portions, and another rudder arm with second upper and lower arm portions. The rudder arm assembly is assembled to a beam at an intersection of the first upper and lower arm portions, and an intersection of the second upper and lower arm portions. The first and second rudder arms are configured to rotate about the beam at the intersection. The rotation of the first and second rudder arms is configured to adjust control surfaces that control a yaw axis of the airplane. A brake pedal is attached to the first and second lower arm portions. Rotation of the brake pedal brakes the airplane. A rotary sensor is assembled to the brake pedal and the lower arm portion, and configured to determine an extent of the brake pedal rotation.

Abstract: The subject matter of this specification can be embodied in, among other things, a fluid actuator including a housing defining a first chamber having a first cavity and a first open end, a first piston assembly including a tubular first piston defining a second chamber having a second cavity and a second open end, disposed in said first housing for reciprocal movement in the first chamber through the first open end, wherein a first seal, the first cavity, and the first piston define a first pressure chamber, and a second piston assembly having an second piston disposed in said first piston assembly for reciprocal movement in the second chamber through the second open end, wherein a second seal, the second cavity, and the second piston define a second pressure chamber, and a first portion of the second piston contacts a first end effector.

Abstract: The subject matter of this specification can be embodied in, among other things, a method that includes actuating a closure member at a predetermined first velocity a predetermined first number of cycles between a first configuration and a second configuration, actuating the closure member at a predetermined second velocity a predetermined second number of cycles between the first and the second configuration, actuating the closure member at a predetermined third velocity a predetermined third number of cycles and the second configuration, actuating the closure member at a predetermined fourth velocity a predetermined fourth number of cycles and the second configuration, and actuating the closure member to the second configuration at a predetermined fifth velocity for a predetermined flushing period.

Abstract: Methods, systems, and apparatus for predicting electromechanical actuator health and remaining life include a method storing a reliability model coupled to a controlled actuator system comprising a motive force system coupled to a driven mechanical system. The motive force system is associated with motive force parameters. The driven mechanical system is associated with driven mechanical parameters. The reliability model represents a probability of failure of the controlled actuator system over time based on motive force parameters and driven mechanical parameters. Operational parameters of the controlled actuator system, received over time from a sensor system coupled to the controlled actuator system, include one of the motive force parameters or driven mechanical parameters. The operational parameters represent a degradation of the controlled actuator system over time. The reliability model is updated to represent a revised probability of failure.

Abstract: An airplane rudder and brake pedal assembly includes a rudder arm assembly having one rudder arm with first upper and lower arm portions, and another rudder arm with second upper and lower arm portions. The rudder arm assembly is assembled to a beam at an intersection of the first upper and lower arm portions, and an intersection of the second upper and lower arm portions. The first and second rudder arms are configured to rotate about the beam at the intersection. The rotation of the first and second rudder arms is configured to adjust control surfaces that control a yaw axis of the airplane. A brake pedal is attached to the first and second lower arm portions. Rotation of the brake pedal brakes the airplane. A rotary sensor is assembled to the brake pedal and the lower arm portion, and configured to determine an extent of the brake pedal rotation.

Abstract: A passive flow splitting system for use in a turbine engine control system to provide split fuel flow to two fuel manifolds to supply primary and secondary fuel injectors for the particular combustion zones thereof utilizing intentionally different split ratios dependent on ascending or descending combustion fuel flow is provided. The system includes a passive fuel divider valve (FDV) that includes a primary piston and a secondary piston. The primary piston is moveable independently from the secondary piston during a portion of its stroke, and is hydro-locked to the secondary piston during another portion of its stroke. An ecology valve is also provided to purge the fuel from the primary and/or secondary manifolds during different modes of operation. A transfer valve is included to control the position of ecology piston of the ecology valve.

Abstract: Embodiments of a slotted grommet configured to manage a cable in an electrical cavity are provided. The slotted grommet includes a body structure having a first surface, a second surface opposite to the first surface, and a peripheral surface extending between the first and second surfaces. A first slot is formed in the first surface and extends through the body structure towards the second surface. The first slot defines a chamber having sidewalls in the body structure configured to hold a loop of the cable. The first slot has a first width that is less than a cross-sectional dimension of the cable such that the cable is pinched within the chamber between the first sidewalls to prevent vibration-related chafing of the cable.

Abstract: The subject matter of this specification can be embodied in, among other things, a rotary actuator that includes a first rotary actuator assembly having a first housing, a first mounting assembly radially projecting from a first longitudinal end of the first housing and defining a first axial aperture, and a first output shaft extending into the first axial aperture, a second rotary actuator assembly having a second housing, a second mounting assembly radially projecting from a second longitudinal end of the second housing and defining a second axial aperture, and a second output shaft extending into the second axial aperture, and a bearing assembly having an outer surface in contact with at least one of the first mounting assembly and the second mounting assembly, and an inner surface in contact with at least one of the first rotor assembly and the second rotor assembly.

Abstract: The subject matter of this specification can be embodied in, among other things, a thrust reverser synchronization shaft lock system includes a rotatable shaft comprising at least one radial prong extending radially from the shaft, a hydraulic lock assembly that includes a housing, a piston head having a lock recess, a piston rod extending radially away from the shaft and configured to be urged by the piston head to move the first piston rod end out of engagement with the radial prong to selectably permit rotation of the shaft, and a bias member configured to urge the first piston rod end into engagement with the radial prong, and an electric lock assembly that includes a lock pin and an electric actuator configured to controllably extend and retract the lock pin in and out of engagement with the lock recess.

Abstract: The present disclosure describes a propeller control unit for controlling the blade pitch of a propeller. The unit includes an electrohydraulic servo valve (“EHSV”) and is connected to a propeller actuator that adjusts the blade pitch of a propeller. The EHSV operates to allow pressurized fluid to flow from a pressurized fluid source to the actuator to adjust the blade pitch of the propeller in a flight pitch range and a ground pitch range, to allow pressurized fluid to flow from the source to the actuator to adjust the blade pitch of the propeller in a flight pitch range but not a ground pitch range, and to block the flow of pressurized fluid from the source to the actuator and drain pressurized fluid from the actuator to prevent adjustment of the blade pitch of the propeller in the flight pitch range or the ground pitch range.

Abstract: The subject matter of this specification can be embodied in, among other things, a fluid flow measurement apparatus includes an inlet configured to flow a dynamic fluid flow, an outlet configured to flow the dynamic fluid flow, a first fluid conduit fluidically connected between the inlet and the outlet, configured with a first predetermined geometry, and configured to flow a first portion of the dynamic fluid flow, a second fluid conduit fluidically connected between the inlet and the outlet, configured with a second predetermined geometry, and configured to flow a second portion of the dynamic fluid flow, and a first flow meter configured to measure the second portion of the dynamic fluid flow.

Abstract: Multiple convergent nozzles define multiple flow passages in a flow path from an air inlet of the mixer to an outlet of the mixer. The convergent nozzles each converge toward the outlet of the mixer. An exhaust gas housing includes an exhaust gas inlet leading into an interior of the exhaust gas housing. Multiple convergent-divergent nozzles each correspond to one of the plurality of convergent nozzles. The convergent-divergent nozzles each include an air-exhaust gas inlet in fluid communication to receive fluid flow from a corresponding convergent nozzle and the interior of the exhaust gas housing.

Abstract: A passive flow splitting system for use in a turbine engine control system to provide split fuel flow to two fuel manifolds to supply primary and secondary fuel injectors for the particular combustion zones thereof utilizing intentionally different split ratios dependent on ascending or descending combustion fuel flow is provided. The system includes a passive fuel divider valve (FDV) that includes a primary piston and a secondary piston. The primary piston is moveable independently from the secondary piston during a portion of its stroke, and is hydro-locked to the secondary piston during another portion of its stroke. An ecology valve is also provided to purge the fuel from the primary and/or secondary manifolds during different modes of operation. A transfer valve is included to control the position of ecology piston of the ecology valve.

Abstract: The subject matter of this specification can be embodied in, among other things, a rotary actuator that includes a housing defining an arcuate chamber comprising a cavity, a rotor arm configured for rotary movement, an arcuate-shaped first piston disposed in said housing for reciprocal movement in the arcuate chamber, where a seal, the cavity, and the piston define a pressure chamber that includes part or all of the arcuate chamber, and a portion of the piston contacts the rotor arm, and a rotor assembly rotatably surrounding said housing and having a rotary output tube about the axis, wherein the rotor arm extends radially outward to the rotary output tube and the rotor arm is coupled to the rotary output tube.

Abstract: A combined ball valve for compressor bleed air modulation is provided. The combined ball valve includes a housing defining an inlet, and first and second outlets. A metering element is positioned within the housing and within a flow path extending from the inlet to the first and second outlets. The metering element includes first and second flow ports and is rotatable within the housing to modulate compressor bleed air from the inlet to neither, one, or both of the first and second outlets. The combined ball valve utilizes high temperature materials in a relatively lightweight package.