Abstract: In accordance with at least one aspect of this disclosure, a variable displacement pump system can include, a variable displacement pump disposed in a main line and configured to supply pressure to receive a low pressure fluid and to output a high pressure fluid. The main line can connect a hydraulic fluid source to a plurality of system actuators, where the variable displacement pump is disposed in the main line between the hydraulic fluid source and the plurality of system actuators to pressurize the hydraulic fluid.

Abstract: A method of controlling an actuator includes switching a primary solenoid valve to a first mode to fluidically connect a supply pressure source to a control chamber of a pilot valve. A fluid from the supply pressure source is directed through the primary solenoid valve to fill the control chamber of the pilot valve and put the pilot valve in a first position. The first position fluidically connects a second chamber of the actuator to a return pressure source. The actuator includes a cylinder between the first chamber and the second chamber and a rod attached to the cylinder. The fluid from the supply pressure source is directed into the first chamber of the actuator to move the cylinder and the rod in a first direction while the pilot valve is in the first position.

Abstract: A hydraulic actuator system of an aircraft includes a hydraulic actuator having a housing with a piston having a piston shaft with a piston head attached thereto and arranged within the housing. The piston head divides in internal volume of the housing into an extend cavity and a retract cavity and the extend cavity is configured to be connected to low pressure fluid source. The system also includes a pressure selector unit fluidly connected to the retract cavity and configured to be connected to the low pressure fluid source and to a high pressure fluid source. The unit include three solenoids with the first and second connected in parallel to the fluid sources and the third solenoid having a third solenoid first input connected to the first solenoid output, a third solenoid second input connected to the second solenoid output, and a third solenoid output connected to the retract cavity.

Abstract: A fuel pump system includes a main fuel pump between a system fuel inlet and a system fuel outlet, a fuel flow path at least partially defined between the main fuel pump and the system fuel outlet, and a support fuel pump between the system fuel inlet and the system fuel outlet. The support fuel pump is sized to provide more flow to the system fuel outlet, when in an active state, than the main fuel pump. The system includes a valve assembly in fluid communication with the support fuel pump configured and adapted to connect the support fuel pump to the system fuel outlet, and a pressure regulating valve in fluid communication with the fuel flow path between the main fuel pump and the system fuel outlet. The system includes an EHSV in fluid communication with the fuel flow path between the PRV and the system fuel outlet.

Abstract: A hydraulic actuator system includes a hydraulic actuator having a housing with a piston having a piston shaft arranged within the housing. The housing is formed to have first, second and third regions, wherein the first region is between the second and third regions and has a larger major dimension than the second and third regions. The system also includes first, second, and third piston heads connected to the piston shaft with the first piston head being tween the second and third piston, wherein the first position head is within the first region and divides the first region into two volumes, the second piston head is in the second region and defines a first volume and the third piston head is in the third region and defines a fourth volume. The system also includes a mode selection device operably connected to the first, second, third and fourth volume.

Abstract: A fluid delivery system can include a main pump disposed in a primary fluid line configured to receive a low pressure fluid on a low pressure side and output a high pressure fluid on a high pressure side to provide flow from the fluid source to a fluid destination via the primary fluid line. An interconnected valve system can be disposed in the primary fluid line configured to control flow through the primary fluid line.

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 variable positive displacement pump actuator system for a variable positive displacement pump can include a supply line configured to provide a supply pressure, a main pump line configured to provide a pump pressure greater than the supply pressure from the variable positive displacement pump, and at least one electro-hydraulic servo valve (EHSV) in fluid communication with the supply line and the main pump line to receive the supply pressure and the pump pressure. The at least one electro-hydraulic servo valve can be configured to output a first regulated pressure and a second regulated pressure.

Abstract: A fuel system of an aircraft engine, having: a boost pump having an input and an output; one or more selector valves; a first component pump having an input fluidly coupled to the output of the boost pump and an output of the first component pump is configured to direct fuel to a first component via the one or more selector valves; and a second component pump having an input that is selectively coupled to either the input or the output of the boost pump by the one or more selector valves, and an output of the second component pump is fluidly coupled to a second component and selectively coupled to the first component by the one or more selector valves.

Abstract: A fuel system of an aircraft engine, having: a boost pump having an input and an output; one or more selector valves; a first component pump having an input fluidly coupled to the output of the boost pump and an output of the first component pump is configured to direct fuel to a first component via the one or more selector valves; and a second component pump having an input that is selectively coupled to either the input or the output of the boost pump by the one or more selector valves, and an output of the second component pump is fluidly coupled to a second component and selectively coupled to the first component by the one or more selector valves.

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 fuel system can include a selection and shutoff valve (SSOV) configured to allow a primary flow having a primary flow pressure to pass therethrough in a first state such that the primary flow can travel to an output line. The SSOV can also be configured to shut off the primary flow in a second state to prevent the primary flow from travelling to the output line. In the second state, the SSOV can be configured to allow a secondary flow from a secondary flow source to pass therethrough such that the secondary flow can travel to the output line.

Abstract: A solenoid driven actuator system includes a first solenoid having at least one pressure input and a pressure outlet downstream from the at least one pressure input. The system includes a second solenoid having at least one pressure input and a pressure outlet downstream from the at least one pressure input. The system includes a pressure-switching valve operatively coupled to the first and second solenoids. The system includes an actuator operatively coupled to the pressure outlet of the second solenoid.

Abstract: Hydraulic actuator systems of aircraft are described. The hydraulic actuator systems include a hydraulic actuator having a housing and piston therein. The piston includes a piston head separating the housing into a retract cavity and an extend cavity. An actuator controller is hydraulically coupled to the retract cavity by a first hydraulic line and hydraulically coupled to the extend cavity by a second hydraulic line and configured to control a hydraulic pressure within each of the retract cavity and the extend cavity to control actuation of the hydraulic actuator. A position-lock controller is arranged along at least one of the first hydraulic line and the second hydraulic line, the position-lock controller is configured to hydraulically decouple the actuator controller from at least one of the retract cavity and the extend cavity.

Abstract: A fuel pump system includes a main fuel pump between a system fuel inlet and a system fuel outlet, a fuel flow path at least partially defined between the main fuel pump and the system fuel outlet, and a support fuel pump between the system fuel inlet and the system fuel outlet. The support fuel pump is sized to provide more flow to the system fuel outlet, when in an active state, than the main fuel pump. The system includes a valve assembly in fluid communication with the support fuel pump configured and adapted to connect the support fuel pump to the system fuel outlet, and a pressure regulating valve in fluid communication with the fuel flow path between the main fuel pump and the system fuel outlet. The system includes an EHSV in fluid communication with the fuel flow path between the PRV and the system fuel outlet.

Abstract: A hydraulic actuator system includes a hydraulic actuator having a housing with a piston having a piston shaft arranged within the housing. The housing is formed to have first, second and third regions, wherein the first region is between the second and third regions and has a larger major dimension than the second and third regions. The system also includes first, second, and third piston heads connected to the piston shaft with the first piston head being tween the second and third piston, wherein the first position head is within the first region and divides the first region into two volumes, the second piston head is in the second region and defines a first volume and the third piston head is in the third region and defines a fourth volume. The system also includes a mode selection device operably connected to the first, second, third and fourth volume.

Abstract: Hydraulic actuator systems of aircraft are described. The hydraulic actuator systems include a hydraulic actuator having a housing and piston therein. The piston includes a piston head separating the housing into a retract cavity and an extend cavity. An actuator controller is hydraulically coupled to the retract cavity by a first hydraulic line and hydraulically coupled to the extend cavity by a second hydraulic line and configured to control a hydraulic pressure within each of the retract cavity and the extend cavity to control actuation of the hydraulic actuator. A position-lock controller is arranged along at least one of the first hydraulic line and the second hydraulic line, the position-lock controller is configured to hydraulically decouple the actuator controller from at least one of the retract cavity and the extend cavity.

Abstract: A hydraulic actuator system of an aircraft includes a hydraulic actuator having a housing with a piston having a piston shaft with a piston head attached thereto and arranged within the housing. The piston head divides in internal volume of the housing into an extend cavity and a retract cavity and the extend cavity is configured to be connected to low pressure fluid source. The system also includes a pressure selector unit fluidly connected to the retract cavity and configured to be connected to the low pressure fluid source and to a high pressure fluid source. The unit include three solenoids with the first and second connected in parallel to the fluid sources and the third solenoid having a third solenoid first input connected to the first solenoid output, a third solenoid second input connected to the second solenoid output, and a third solenoid output connected to the retract cavity.

Abstract: A fluid flow system includes a main valve having a spool, a first chamber, and a second chamber. A pressure difference between the first chamber and the second chamber is configured to move the spool to control fluid flow. An electromechanical meter interface device (EMID) is in fluid communication with at least one of the first and second chambers of the main valve. The EMID is configured to meter fluid from a first source and a second source to the at least one of the first chamber and the second chamber. The first source has a different pressure from the second source. A fixed orifice is arranged between the main valve and the EMID. A fuel system for a gas turbine engine is also disclosed.

Abstract: A solenoid driven actuator system includes a first solenoid having at least one pressure input and a pressure outlet downstream from the at least one pressure input. The system includes a second solenoid having at least one pressure input and a pressure outlet downstream from the at least one pressure input. The system includes a pressure-switching valve operatively coupled to the first and second solenoids. The system includes an actuator operatively coupled to the pressure outlet of the second solenoid.