A fuel metering system includes a metering valve having a first inlet fluidly coupled to a source of fluid at a first pressure, a second inlet, a first outlet and a second outlet. The metering valve includes a slot, and a valve body movable to control an amount of fluid supplied to the first and second outlet. The fuel metering system includes a servo valve fluidly coupled to the second inlet and to a second source of fluid at a second pressure. The servo valve is in fluid communication with the second inlet and a body of the servo valve is movable to supply a fluid to move the valve body. The slot is configured to variably restrict the flow of the fluid through the second outlet to balance a force applied by a biasing member. The fuel metering system includes a fixed flow restriction downstream of the second outlet.

An air turbine start system includes an air supply duct, an air turbine starter, a starter air valve, a stepper motor, and a controller. The air turbine starter is coupled to the air supply duct to selectively receive a flow of pressurized air therefrom. The starter air valve is mounted on the air supply duct and is movable between a closed position and a plurality of open positions. The stepper motor is coupled to the starter air valve and is configured, in response to valve position commands, to move the starter air valve between the closed position and one or more of the plurality of open positions. The controller is coupled to the stepper motor and is configured to supply the valve position commands to the stepper motor and determine a position of the starter air valve based on the valve position commands supplied to the stepper motor.

A turbine engine including: a rotor having at least one variable-pitch blade which is guided to rotate on bearings relative to a fixed structure; a system for controlling the pitch of the at least one blade, the control system being rigidly secured to the rotor and including a first actuator driven by energy, and the control system further being disposed axially upstream of the bearings; a device for transferring the energy, which is disposed axially between the bearings, the transfer device including a stationary element and a mobile element; wherein the rotor is annular and delimits an inner space which is open towards the upstream side and inside of which the control system is disposed.

First and second towers may discharge air. An airflow guide or converter may change a direction of the air discharged from the first tower and the second tower by moving a gate inside and outside of at least one of the first or second towers so as to block discharged air flowing forward and selectively facilitate an upward air flow. The airflow converter may include a guide motor to provide a driving force, the gate, which may reciprocate between the inside and the outside of the first and/or second towers; and a board guider connected to the gate to transmit a driving force of the guide motor to the gate as a linear motion force.

A multi-redundancy electromechanical servo system for regulating a liquid rocket engine, comprising a triple-redundancy servo controller (1), a double-redundancy servo driver (2), double-winding electromechanical actuators (4, 5), a triple-redundancy position sensor (6), a thrust regulator (8) and a mixed ratio regulator (9). Engine thrust, a mixed ratio regulation instruction and a feedback signal of the triple-redundancy position sensor are inputted to the triple-redundancy servo controller, and the triple-redundancy servo controller outputs thrust and mixed ratio regulation PWM wave control signals to the double-redundancy servo driver. The double-redundancy servo driver outputs a three-phase variable-frequency variable-amplitude sine wave current to drive the double-winding electromechanical actuators to drive the thrust regulator and the mixed ratio regulator to move, thus achieving engine thrust and mixed ratio regulation. The present servo system has a simple system and excellent control characteristics, has the ability to “control a two-degree fault operation and drive a one-degree fault operation”, and significantly improves the reliability and usage maintainability of the thrust and mixed ratio regulation of the liquid rocket engine. Also disclosed is a method for implementing the foregoing multi-redundancy electromechanical servo system.

In an aircraft gas turbine engine equipped with a bleed-off valve that bleeds intake air compressed by a compressor exterior and an electric actuator that drives the valve when current is supplied, a required valve opening θr and a current value Ia corresponding thereto are calculated and Ia is supplied to the actuator to bring valve opening θ to the required opening θr. Then Ia is compared with a current value Ib and if Ia exceeds 1b, the valve is estimated to have failed and another current value Ic is calculated and Ic is supplied to enlarge valve opening toward wide-opening θw. Then a current value Id is calculated and supplied to decrease valve opening toward θr. Next, Id is compared with Ib and the valve is determined normal when Id is equal to or smaller than 1b. If not, it is determined to be faulty.

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.

A gas turbine engine actuation system includes a gas turbine engine, an actuation device, an actuator, and a power source. The gas turbine engine includes a compressor section, a combustion section, a turbine section, and a rotating shaft. The actuation device is operable with the compressor section, combustion section, turbine section, or a combination thereof. The actuator is operationally coupled to the actuation device and includes an electric actuator configured to convert electrical current into mechanical power. The power source is configured to supply electrical current to the actuator, alone or in tandem with a hydraulic actuator.

Provided is an electrohydrostatic actuation system including an emergency shut-off circuit to be actuated stably with a simple configuration. The electrohydrostatic actuation system includes: a hydraulic cylinder (24) including a piston (25) to which a valve element is connected, a first chamber (24A), and a second chamber (24B); a hydraulic pump (21) configured to supply hydraulic fluid to the first chamber (24A) or the second chamber (24B); a servo motor (M) configured to drive the hydraulic pump (21); a shuttle valve (11) configured to establish communication to a downstream side under a state in which a hydraulic pressure generated by the hydraulic pump (21) is maintained; a solenoid valve (12) configured to receive the hydraulic pressure via the shuttle valve (11) as a pilot pressure; and a logic valve (13) including a first port configured to receive the pilot pressure from the solenoid valve (12), and a second port to be communicated to the first chamber (24A) of the hydraulic cylinder (24). When the solenoid valve (12) is brought to a de-energized state, the pilot pressure of the logic valve (13) is released, and the logic valve (13) causes the hydraulic fluid in the first chamber (24A) communicated to the second port to flow into the second chamber (24B) so that emergency shut-off of the valve element is achieved by a return spring (26).

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.