Abstract: A low-side contactor coil drive circuit can include an input line and a first solid state switch having a first switch base, a first switch collector, and a first switch emitter. The first switch collector can be connected to the input line and the first switch emitter is connected to ground. The circuit can include a second solid state switch having a second switch base, a second switch collector, and a second switch emitter. The second switch emitter can be connected to the input line in parallel with the first switch collector. The second switch collector can be connected to the first switch base. The circuit can include a third solid state switch having a third switch gate, a third switch source, and a third switch drain. The third switch drain can be connected to the second switch base.

Abstract: A replacement compressor outlet housing includes a compressor outlet housing, having a volute and a radially inwardly extending finger extending from a radially inner end of the volute. The radially inwardly extending finger is welded to an insert. The insert has a bearing support defining a bore. The insert has a web connecting a ledge to the bearing support. The radially inwardly extending finger welded to the ledge.

Abstract: An environmental control system of an aircraft includes a ram air input configured to receive ram air from a ram air duct of the aircraft and an electric motor driven compressor system. The system also includes a RAM heat exchanger and an ejector connected to the output of the RAM heat exchanger that is fluidly connected to the output of a compressor in the compressor system and that causes ram air received at the cooling flow input to be drawn through the RAM heat exchanger.

Abstract: A check valve includes a housing defining a pair of valve openings, a pair of flappers pivotably mounted to a pin and such that they are configured to rotate relative to the housing between an open position in which they permit fluid flow through the valve openings and a closed position in which they prevent fluid flow through the valve openings, and an element configured to stop and hold the flappers in the open position. A cavity is formed between the pair of flappers and stop element when the flappers are in the open position. Each of the flappers comprise one or more contact surfaces configured to contact the stop element when in the open position. The stop element has stop surfaces with stationary contact areas configured to oppose and abut the flapper contact surfaces when the flappers are in the open position.

Abstract: A blower including: a forward end; an aft end located opposite the forward end; a shaft located at the aft end; a flange located at the forward end; an internal surface defining an axial passageway within the blower; an external surface radially outward of the internal surface; one or more radial passageway formed within the flange and fluidly connected to the axial passageway, the radial passageway extending from the internal surface to the external surface; and a plurality of blower blades located within the flange and defining the radial passageway.

Abstract: An exhaust moisture removal system for an electric generation system including: a sorbent wheel; an interchanger; a hydrogen evaporator including an exhaust portion; and an exhaust outflow stream passageway configured to convey an exhaust from a hydrogen fuel cell of the electric generation system through a first pass and then through a second pass, the second pass being located downstream of the first pass, wherein the first pass of the exhaust outflow stream passageway passes through the sorbent wheel, then through the interchanger, and then through the hydrogen evaporator, and wherein the second pass of the exhaust outflow stream passageway passes through the hydrogen evaporator, then through the interchanger, and then through the sorbent wheel.

Abstract: A system and method for testing a resolver circuit is provided. Aspects include a resolver circuit including an excitation signal output, a sine signal input, and a cosine signal input, a switching matrix comprising an excitation input connected to the excitation signal output, a first output connected to the sine signal input, and a second output connected to the cosine signal input, wherein the switching matrix further includes a set of switches configured to route an excitation signal from the resolver circuit to mimic a sine and cosine signal output corresponding to a specified angle for a resolver sensor, a controller configured to operate the resolver circuit to output an excitation signal, determine an angle value based on a sine signal received and a cosine signal received from the switching matrix, and compare the angle value to the specified angle to determine a fault condition in the resolver circuit.

Abstract: A two stage fuel delivery system for an aircraft includes a first stage pump including an inlet connected to a source of fuel and an outlet connected to a combustor assembly, and a second stage pump including an inlet portion connected to the source of fuel and an outlet portion connected to the combustor assembly. A bypass valve is connected between the source of fuel, the inlet, and the inlet portion. The bypass valve selectively disconnects the second stage pump from the source of fuel. A metering valve is connected to the inlet and the inlet portion. The metering valve includes a metering valve inlet and a metering valve outlet. A pressure regulating valve is connected to the metering valve. A stage monitoring system is configured to detect a change in operation of the second stage and control the bypass valve.

Abstract: A generator system can include a dual stator generator comprising a first stator and a second stator, a first rectifier operatively connected to the first stator to receive AC from the first stator, a second rectifier operatively connected to the second stator to receive AC from the second stator, and a first DC output line and a second DC output line. The first rectifier and the second rectifier can be connected in parallel to the first DC output line and a second DC output line without an inter phase transformer (IPT) to output DC to the first DC output line and the second DC output line.

Abstract: A system can include a bi-directional converter circuit comprising a plurality of switches and at least one flying capacitor. One or more the plurality of switches can experience overvoltage in a fault state. The system can include a control module operatively connected to the plurality of switches to control a state of the plurality of switches. The control module can be configured to receive a sense signal indicative of flying capacitor voltage and to control the one or more switches of the plurality of switches to turn on or remain on to prevent switch overvoltage of the one or more switches if the flying capacitor voltage is outside of a normal range.

Abstract: In accordance with at least one aspect of this disclosure, an emergency power unit for an aircraft includes, a fuel cell system configured to generate power using a fuel and an oxidant. A thermal management system is in thermal communication with the fuel cell system to divert heat from the fuel cell system to the thermal management system.

Abstract: A system includes a permanent magnet generator (PMG) with a generator shaft. An input spline is included on the generator shaft on a first side of the PMG with respect to a longitudinal axis of the generator shaft. A brake is operatively connected to the generator shaft axially between the input spline and an end of the generator shaft on a second side of the PMG opposite the first side with respect to the longitudinal axis.

Abstract: In accordance with at least one aspect of this disclosure, an emergency power unit system for an aircraft includes, a fuel cell system configured to generate power using a fuel and an oxidizer and to supply electrical power to an aircraft electrical bus in at least a fuel cell operational mode. An electrical storage is operatively connected to the aircraft electrical bus and directly connected to the fuel cell system to provide electrical power to the aircraft electrical bus and to the fuel cell system in a fuel cell start up mode.

Abstract: A circuit mounting assembly can include a circuit board, a chassis, a sheet of thermally conductive dielectric material, and one or more fasteners configured to compress the sheet between the circuit board and the chassis to provide vibration isolation and electrical isolation between the chassis and the circuit board, and to provide thermal conduction between the chassis and the circuit board.

Abstract: A filter assembly for a servo valve. The filter assembly has a filter body defining a chamber; a first end cap having a first fluid outlet at a first end of the filter body and a second end cap having a second fluid outlet at a second end of the filter body. A flow restrictor restricts fluid flow between the filter body and each of the first and second fluid outlets. A spacer in the chamber spaces the first end cap from the second end cap.

Abstract: The present disclosure provides for heat exchanger assemblies, systems and methods. More particularly, the present disclosure provides for radially-flowing cross flow heat exchanger assemblies and systems that increase primary heat transfer surface, and related methods of use. The present disclosure provides for a cross-flow heat exchanger assembly that can be packaged cylindrically or the like (or other self-enclosed shapes), and where the heat exchanger assembly also increases and/or maximizes primary heat transfer surface area by utilizing a weave-style or interwoven heat exchanger core. A first circuit flow path can be axial or circumferential in nature, and a second circuit flow path can be radial.

Abstract: A plug for retaining a filter screen in a fluid port of a servovalve, comprises an annular body, the annular body comprising: opposed first and second axial end surfaces, a radially inner surface extending between the first and second axial end surfaces, a radially outer surface extending between the first and second axial end surfaces and at least one recess formed in the radially inner surface for receiving a tool for removing the plug from the port. A tool for removing the plug comprises a pair of handles pivotally mounted to one another about a pivot, each handle having a plug gripping portion extending therefrom beyond the pivot, each plug gripping portion comprising an outwardly projecting tooth for engaging in the recess of the plug when the plug gripping portions are moved apart by operation of the handles.

Abstract: A ram air module for use in a ram air system, the ram air module includes a diffuser having a diffuser body including an inlet end and an outlet end, a flow diverter assembly connected to the inlet end of the diffuser body, and a valve connected to the outlet end of the diffuser body.

Abstract: A control system in an atmospheric suit includes a broadcast-type controller area network (CAN) bus and a plurality of motor controllers coupled to the CAN bus. Each of the plurality of motor controllers has a same software design and performs a different control operation based on an assigned hardware address. The control system also includes one or more sensors to sense one or more parameter values in the atmospheric suit and to provide the one or more parameter values on the CAN bus. A primary controller communicates with the plurality of motor controllers via the CAN bus and provides communication to a wearer of the atmospheric suit or communication outside the atmospheric suit outside the CAN bus.

Abstract: The present disclosure provides for hyperloop vapor cycle environmental control systems (ECS) and related methods. More particularly, the present disclosure provides for hyperloop vapor cycle environmental control systems and methods, with the hyperloop vapor cycle environmental control systems and methods configured without a compressor needed to pump a refrigerant through the system and configured without a condenser heat exchanger needed to condense gas refrigerant to a liquid to reject the heat of compression of a compressor to the ambient atmosphere. Since there is no need for a compressor, the example hyperloop ECS of the present disclosure requires only a small fraction of the electrical power of a standard vapor cycle air conditioning system. Power is needed substantially only for the ECS controller and some various valves.