Abstract: Aircraft cabin blower systems and methods of operating aircraft cabin blower systems are provided. One aircraft cabin blower system comprises: a cabin blower compressor having a contactless bearing arrangement; a transmission having a transmission output arranged to drive the cabin blower compressor, a first transmission input arranged to receive mechanical power from a gas turbine engine, and a second transmission input; a reversible variator arranged to receive power from the gas turbine engine and to output mechanical power to the second transmission input, the reversible variator operable to output in both forward and reverse directions of rotation; and a controller configured to control an output speed and direction of rotation of the reversible variator.

Abstract: Disclosed is a fuel system for a gas turbine engine. The system comprises a fuel pump for fluid communication with a fuel reservoir; a driving turbine for driving the fuel pump; and a source of compressed air flow to drive the driving turbine. The source of compressed air may be the engine core, a dedicated fuel system compressor or the compressor of a cabin blower system.

Abstract: A system for supplying lubricant to a component of a gas turbine engine having a fan shaft is provided. The system includes a pump drivably couplable to the fan shaft for pumping lubricant to the component. The pump includes an inlet for receiving lubricant from a lubricant source, an outlet for outputting lubricant to the component and a swashplate movable between at least a first position and a second position. The system also includes a swashplate actuator for actuating the swashplate between the first position and the second position according to whether the fan shaft is rotating in a forward direction or a reverse direction opposite to the forward direction.

Abstract: Aircraft cabin blower systems and methods of operating aircraft cabin blower systems are provided. One aircraft cabin blower system comprises: a cabin blower compressor having a contactless bearing arrangement; a transmission having a transmission output arranged to drive the cabin blower compressor, a first transmission input arranged to receive mechanical power from a gas turbine engine, and a second transmission input; a reversible variator arranged to receive power from the gas turbine engine and to output mechanical power to the second transmission input, the reversible variator operable to output in both forward and reverse directions of rotation; and a controller configured to control an output speed and direction of rotation of the reversible variator.

Abstract: A gas turbine engine includes an engine core including a compressor, a combustor, and a turbine, the compressor being connected to the turbines through a respective shaft; and a cabin blower system comprising: an electric variator comprising a first electrical machine connected to a first shaft arranged along a first axis, a second electrical machine connected to a second shaft arranged along a second axis, and a power management system; a cabin blower comprising a compressor driven by a third shaft arranged along a third axis, the compressor comprising an air inlet and an air outlet; and a differential gearbox. The gas turbine engine further includes an accessory gearbox arranged within an accessory gearbox casing and adapted to drive the cabin blower system.

Abstract: A system for supplying lubricant to a component of a gas turbine engine having a fan shaft is provided. The system includes a pump drivably couplable to the fan shaft for pumping lubricant to the component. The pump includes an inlet for receiving lubricant from a lubricant source, an outlet for outputting lubricant to the component and a swashplate movable between at least a first position and a second position. The system also includes a swashplate actuator for actuating the swashplate between the first position and the second position according to whether the fan shaft is rotating in a forward direction or a reverse direction opposite to the forward direction.

Abstract: An aircraft cabin blower system includes a transmission configured to receive mechanical power from a gas turbine engine in the form of a first transmission input; and an electrical circuit including a first electrical machine, a second electrical machine, and power management system, wherein, when operating in a blower mode, the first electrical receives mechanical power from the gas turbine engine and act as a generator to provide electrical power to the power management system, and the second electrical machine acts as a motor providing mechanical power to the transmission in the form of a second transmission input, the second electrical machine being driven by electrical power from the power management system. The transmission's output drives a cabin blower compressor when operating in the blower mode, a speed of the output of the transmission being determined by a function of a speed of the first and second transmission inputs.

Abstract: An aircraft cabin blower system includes: a transmission configured to receive mechanical power from a first part of a gas turbine engine in the form of a first transmission input; and an electrical circuit including a first electrical machine, a second electrical machine, and a power management system, wherein an output of the transmission is configured to drive a cabin blower compressor when operating in a blower mode, the first electrical machine being configured to receive mechanical power from a second part of the gas turbine engine and act as a generator to provide electrical power to the power management system, and the second electrical machine being configured to act as a motor providing mechanical power to the transmission in the form of a second transmission input, the second electrical machine being driven by electrical power from the power management system.

Abstract: 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.

Abstract: An aircraft cabin blower system includes: a transmission configured to receive mechanical power from a first part of a gas turbine engine in the form of a first transmission input; and an electrical circuit including a first electrical machine, a second electrical machine, and a power management system, wherein an output of the transmission is configured to drive a cabin blower compressor when operating in a blower mode, the first electrical machine being configured to receive mechanical power from a second part of the gas turbine engine and act as a generator to provide electrical power to the power management system, and the second electrical machine being configured to act as a motor providing mechanical power to the transmission in the form of a second transmission input, the second electrical machine being driven by electrical power from the power management system.

Abstract: A transmission for receiving mechanical power from a gas turbine engine; and a cabin blower compressor, an output of the transmission being configured to drive the cabin blower compressor; wherein the transmission has a variable gear ratio and the cabin blower compressor has a variable geometry, wherein variation of the gear ratio and the geometry provides a variable output of the cabin blower compressor.

Abstract: An aircraft cabin blower system includes a transmission configured to receive mechanical power from a gas turbine engine in the form of a first transmission input; and an electrical circuit including a first electrical machine, a second electrical machine, and power management system, wherein, when operating in a blower mode, the first electrical receives mechanical power from the gas turbine engine and act as a generator to provide electrical power to the power management system, and the second electrical machine acts as a motor providing mechanical power to the transmission in the form of a second transmission input, the second electrical machine being driven by electrical power from the power management system. The transmission's output drives a cabin blower compressor when operating in the blower mode, a speed of the output of the transmission being determined by a function of a speed of the first and second transmission inputs.

Abstract: The disclosed embodiments disclose techniques for managing a global namespace for a distributed filesystem. Two or more cloud controllers collectively manage distributed filesystem data that is stored in a cloud storage system; the cloud controllers ensure data consistency for the stored data, and each cloud controller caches portions of the distributed filesystem. Furthermore, a global namespace for the distributed filesystem is also split across these cloud controllers, with each cloud controller “owning” (e.g., managing write accesses for) a distinct portion of the global namespace and maintaining a set of namespace mappings that indicate which portion of the namespace is assigned to each cloud controller. During operation, an initial cloud controller receives a request from a client system to access a target file in the distributed system. This initial cloud controller uses the namespace mappings for the global namespace to determine a preferred cloud controller that will handle the request.

Abstract: The disclosed embodiments disclose techniques for managing a global namespace for a distributed filesystem. Two or more cloud controllers collectively manage distributed filesystem data that is stored in a cloud storage system; the cloud controllers ensure data consistency for the stored data, and each cloud controller caches portions of the distributed filesystem. Furthermore, a global namespace for the distributed filesystem is also split across these cloud controllers, with each cloud controller “owning” (e.g., managing write accesses for) a distinct portion of the global namespace and maintaining a set of namespace mappings that indicate which portion of the namespace is assigned to each cloud controller. During operation, an initial cloud controller receives a request from a client system to access a target file in the distributed system. This initial cloud controller uses the namespace mappings for the global namespace to determine a preferred cloud controller that will handle the request.

Abstract: The disclosed embodiments disclose techniques that facilitate of avoiding client timeouts in a distributed filesystem. Multiple cloud controllers collectively manage distributed filesystem data that is stored in one or more cloud storage systems; the cloud controllers ensure data consistency for the stored data, and each cloud controller caches portions of the distributed filesystem in a local storage pool. During operation, a cloud controller receives from a client system a request for a data block in a target file that is stored in the distributed filesystem. Although the cloud controller is already caching the requested data block, the cloud controller delays transmission of the cached data block; this additional delay gives the cloud controller more time to access uncached data blocks for the target file from a cloud storage system, thereby ensuring that subsequent requests of such data blocks do not exceed a timeout interval on the client system.

Abstract: The disclosed embodiments disclose techniques that facilitate the process of performing anti-virus checks for a distributed filesystem. Two or more cloud controllers collectively manage distributed filesystem data that is stored in one or more cloud storage systems; the cloud controllers ensure data consistency for the stored data, and each cloud controller caches portions of the distributed filesystem. During operation, a cloud controller receives a write request from a client system that seeks to store a target file in the distributed system. A scan is then performed for this target file. For instance, the scan may be an anti-virus scan that ensures that viruses are not spread to the distributed filesystem or the clients of the distributed filesystem.

Abstract: The disclosed embodiments disclose techniques for managing a global namespace for a distributed filesystem. Two or more cloud controllers collectively manage distributed filesystem data that is stored in a cloud storage system; the cloud controllers ensure data consistency for the stored data, and each cloud controller caches portions of the distributed filesystem. Furthermore, a global namespace for the distributed filesystem is also split across these cloud controllers, with each cloud controller “owning” (e.g., managing write accesses for) a distinct portion of the global namespace and maintaining a set of namespace mappings that indicate which portion of the namespace is assigned to each cloud controller. During operation, an initial cloud controller receives a request from a client system to access a target file in the distributed system. This initial cloud controller uses the namespace mappings for the global namespace to determine a preferred cloud controller that will handle the request.

Abstract: The disclosed embodiments disclose techniques for using byte-range locks to manage multiple concurrent accesses to a file in a distributed filesystem. Two or more cloud controllers collectively manage distributed filesystem data that is stored in the cloud storage systems; the cloud controllers ensure data consistency for the stored data, and each cloud controller caches portions of the distributed filesystem. During operation, a cloud controller receives from a first client a request to access a portion of the file. The cloud controller contacts the owning cloud controller for the portion of the file to request a byte-range lock for that portion of the file. The owning cloud controller returns a byte-range lock to the requesting cloud controller if no other clients of the distributed filesystem are currently locking the requested portion of the file with conflicting accesses.

Abstract: 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.

Abstract: The disclosed embodiments disclose techniques for using byte-range locks to manage multiple concurrent accesses to a file in a distributed filesystem. Two or more cloud controllers collectively manage distributed filesystem data that is stored in the cloud storage systems; the cloud controllers ensure data consistency for the stored data, and each cloud controller caches portions of the distributed filesystem. During operation, a cloud controller receives from a first client a request to access a portion of the file. The cloud controller contacts the owning cloud controller for the portion of the file to request a byte-range lock for that portion of the file. The owning cloud controller returns a byte-range lock to the requesting cloud controller if no other clients of the distributed filesystem are currently locking the requested portion of the file with conflicting accesses.