A gas turbine engine has a compressor section with a low pressure compressor and a high pressure compressor having a downstream end. A cooling air system includes a tap from a location upstream of the downstream most location. The tap passes air to a boost compressor, and the boost compressor passes the air back to a location to be cooled. The boost compressor is driven by a shaft in the engine through an epicyclic gear system. A speed control changes the relative speed between an input and an output to the epicyclic gear system.

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 agricultural product distribution system includes a fan configured to provide an air flow that fluidizes and transports particulate material throughout the agricultural product distribution system. The fan includes an impeller, an inlet position on a first axial side of the fan, and an outlet position on a peripheral side of the fan. The agricultural product distribution system includes a power transfer shaft having a first end non-rotatably coupled to the impeller, wherein the power transfer shaft extends through the inlet of the fan.

A fuel system for a gas turbine engine includes a fuel pump to provide fuel flow during engine operation and a transmission system that includes an output shaft coupled to drive the fuel pump, and an input shaft driven through a mechanical link to a shaft of the gas turbine engine. The output shaft drives the fuel pump at a variable speed that is independent of a rotational speed of the input shaft.

A variable vane actuator assembly for a gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a plurality of vanes. A synchronization rings surrounds and is mechanically linked to drive the vanes to pivot for varying an angle of the vanes. A crank shaft is mechanically linked to the synchronization ring for rotating the synchronization ring. A fluid actuated rotary motor is located at an end of the crank shaft for selectively rotating the crank shaft.

Pressurized fluid is stored while a jet engine is running. After engine shutdown, the fluid is used to drive a pneumatic or hydraulic turning motor that rotates the engine's High Pressure (HP) rotor. The rotation encourages even heat distribution across the HP rotor and thus prevents bowing of the HP rotor.

A lock for a cowl of a thrust reverser borne by a nacelle includes a striker fixed on the cowl, a hook that is configured to engage the striker and is elastically returned towards engagement with the striker, and a support fixed on the nacelle and supporting a locking/unlocking component interposed between the hook and the support. The locking/unlocking component is configured to allow, on the one hand, the hook to move in relation to the support between a locking position, in which the hook is engaged with the striker and exerts a pressure thereon, and a unlocking position, in which the hook is disengaged from the striker or is simply in contact therewith, and to allow, on the other hand, the hook to tilt in order to disengage it from the striker or engage it therein.

A gas turbine engine has a compressor section with a low pressure compressor and a high pressure compressor having a downstream end. A cooling air system includes a tap from a location upstream of the downstream most location. The tap passes air to a boost compressor, and the boost compressor passes the air back to a location to be cooled. The boost compressor is driven by a shaft in the engine through an epicyclic gear system. A speed control changes the relative speed between an input and an output to the epicyclic gear system.

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.

A clutch device for a gas turbine engine having a sliding coupling mounted to the engine and slidingly displaceable therein. The sliding coupling is mountable between the gearbox and the output shaft. The sliding coupling is continuously engageable with the gearbox and is selectively engageable with the output shaft to mechanically couple the output shaft to the gearbox. The sliding coupling is slidingly displaceable between a first position in which the sliding coupling is mechanically coupled to the output shaft to transmit a rotational drive of the output shaft to the gearbox, and a second position in which the sliding coupling is disengaged from the output shaft. A piston is disposed within the engine and acts on the sliding coupling to displace the sliding coupling to at least the second position.