A gas turbine engine and method of operation are provided. The gas turbine engine may include a variable geometry component operably driven by a component actuator. The component actuator may be in fluid communication with a primary line having a valve associated therewith. The method may include determining a demand pressure associated with actuating the variable geometry component using the component actuator. The method may also include adjusting a position of the valve based on the demand pressure to generate a fuel pressure at the component actuator that is greater than or equal to the demand pressure.

A solenoid for a bleed valve includes a solenoid body with an actuation fluid passage, a bleed valve passage, and a drive fluid chamber. A main armature is disposed within the solenoid body and is movable between open and closed positions, the actuation fluid passage being in fluid communication with the control outlet in the open position, the actuation fluid passage being fluidly isolated from the bleed valve passage in the second position. A pilot armature is disposed within the solenoid body, is movable relative to the main armature, and is operably coupled to the main armature by the drive fluid chamber to move the main armature between the open and closed positions by controlling issue of a drive fluid into and out of the drive fluid chamber.

A gas turbine engine comprises a relatively high pressure compressor coupled to a relatively high pressure turbine by a relatively high pressure shaft; a relatively low pressure compressor coupled to a relatively low pressure turbine by a relatively low pressure shaft rotatable independently of the high pressure shaft; a first combustor located downstream of the high pressure compressor and upstream of the high pressure turbine; and a second combustor located downstream of the high pressure turbine, and upstream of the low pressure turbine. The engine further comprises a coupling arrangement configured to selectively transfer torque between the high pressure shaft and the low pressure shaft.

The subject matter of this specification can be embodied in, among other things, a turbofan engine assembly includes a engine, a nacelle defining a generally forward-to-aft bypass air flow path, a thrust reverser comprising a first movable element, movable to and from a reversing position where at least a portion of the bypass air flow is reversed, a hydraulic actuator coupled to the first movable element to move the first movable element into and out of the reversing position, and a second moveable element, configured to move in synchronicity with the first moveable element, a first hydraulic valve operable to control a flow of hydraulic fluid for actuation of the hydraulic actuator, a second hydraulic valve operably coupled to the second moveable element and moveable between a restricted condition wherein the flow of hydraulic fluid is restricted, and a permit condition wherein the flow of hydraulic fluid is permitted.

An aircraft cabin blower system is described having a hydraulic circuit comprising a first hydraulic device and a second hydraulic device. The first hydraulic device is mechanically coupled to a cabin blower compressor and the second hydraulic device is arranged in use to be mechanically coupled to a spool of a gas turbine engine. The first hydraulic device is capable of performing as a hydraulic motor and the second hydraulic device is capable of performing as a hydraulic pump. When, in use, the system is operating in a cabin blower configuration, a driving force supplied by the spool of the gas turbine causes the second hydraulic device to pump liquid provided in the hydraulic circuit and thereby to drive the first hydraulic device, which in turn rotates the cabin blower compressor.

A combustion staging system has: a splitter; pilot and mains fuel manifolds; mains flow control valves; and fuel servo line. Each mains flow control valve has a chamber containing a piston, the chamber to a piston mains side fed by the mains fuel manifold, and the chamber to a piston servo side fed by the servo line. The piston has an open pilot-and-mains position allowing flow from the chamber mains side to the respective injector mains discharge orifice. The piston prevents flow from the chamber mains side. The piston is movable under a pressure change in the servo line relative to the mains fuel manifold. The system has a servo pump and a hydraulic motor driving it. The servo pump changes fuel pressure. Motive power for the hydraulic motor is fuel diverted from a fuel pump high pressure output, the motor returning the diverted fuel to a low pressure input.

A starter assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a fluid-actuated starter coupled to a spool, and a controller operable to cause a reduction in torque output of the starter in response to determining that a first threshold is met. The first threshold relates to an engine operational condition. A method for starting a gas turbine engine is also disclosed.

A hybrid electric propulsor equipped with a hydraulic coupling is provided. In one aspect, a propulsor includes a gas turbine engine and an electric machine operatively coupled thereto. The gas turbine engine includes a fan spool and a core spool. The electric machine is operatively coupled with the fan spool. A hydraulic coupling defines a sealed volume in which hydraulic transmission fluid is provided. The hydraulic coupling encases at least a portion of the fan spool and at least a portion of the core spool. The hydraulic coupling hydraulically couples the fan spool and the core spool and allows for power transmission between the fan spool and the core spool.

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.

A wash system for a gas turbine engine includes a core turning assembly having a motor configured to be mechanically coupled to the gas turbine engine. The rotor of the core turning assembly is further configured to rotate one or more components of a compressor section or a turbine section of the gas turbine engine at a rotational speed greater than two (2) revolutions per minute and less than five hundred (500) revolutions per minute during washing operations of the gas turbine engine.