Systems and methods include providing an aircraft with a fuselage and a convertible engine disposed within the fuselage. The convertible engine is operable as a turbofan engine in a thrust mode and a turboshaft engine in a shaft power mode. The convertible engine includes a housing, an engine core having a low pressure turbine shaft, and a bypass fan system. The bypass fan system includes a bypass fan having a fan clutch. The fan clutch selectively couples at least a portion of the bypass fan to the low pressure turbine shaft when the convertible engine is operated in the thrust mode and decouples at least a portion of the bypass fan from the low pressure turbine shaft when the convertible engine is operated in the shaft power mode.

An actuation system for a gas turbine engine oriented about a centerline includes a translating ring, at least one hydraulic actuator, and at least one electric actuator. The translating ring is oriented about the centerline and configured to move axially along the centerline. The at least one hydraulic actuator is configured to provide a first mechanical force to move the translating ring along the centerline. The at least one electric actuator is configured to provide a second mechanical force to move the translating ring in the axial direction. The at least one electric actuator is controlled to provide the second mechanical force upon determination of an operating condition.

A gas turbine engine including a support structure including a conduit coupled to a static support. The conduit defines an end wall between which a fluid is contained within a volume defined by the conduit. An effort variable provided to the support structure modulates a stiffness of the support structure.

A piezo-actuated valve, system, and method of exciting gas turbine turbomachinery are provided. The piezo-actuated valve includes a valve body extending along a first axis between a first and second end, the valve body defining a first opening near the first end, a second opening near the second end, a third opening centrally located on the valve body, and a valve cavity between the first opening and the second opening, a tube connected to the third opening and extending from the valve body along a second axis transverse to the first axis, a shuttle valve assembly slidably disposed within the valve body, wherein the shuttle valve slides between the first end to a first stopper and the second end to a second stopper, a first piezo injector having an injector tip extending through the first opening, and a second piezo injector having an injector tip extending through the second opening.

A system for minimising the formation of ice crystals in the fuel system pipework of a gas turbine engine. The system includes an ultrasonic transmitter located within a wall of a pipe in the fuel system through which fuel passes. The system also includes a controller that causes said ultrasonic transmitter to produce ultrasonic waves when the temperature of the fuel is sufficiently low for any water in the fuel to freeze, the ultrasonic waves being sufficient to break particles of ice contained in the fuel that passes through the pipe. A method of minimising the formation of ice crystals in the fuel system pipework of a gas turbine engine is also disclosed.

The invention concerns an aircraft propulsion system comprising at least one member (1, 3, 4, 8) in contact with a turbulent flow of a stream (F), characterised in that said member is covered, at least partially, by a piezoelectric structure (S) such as a piezoelectric film, said structure (S) comprising a grooved structure (5, 6, 7, 9) comprising a series of grooves, in contact with the flow of the stream, the grooves extending in the direction of flow of the stream, the grooved structure comprising at least one geometric parameter (h, s, w) configured to adapt depending on at least one parameter of the flow of the stream and/or an operating point of the propulsion system and/or an engine speed of the propulsion system.

Methods and apparatus are described for improving fit checking at the bonding interface of a first component, such as a fan blade (1), and a second component, such as an edge guard (2) for the fan blade (1), to be bonded by adhesive. A bondline thickness profile over the area of the bonding interface is determined by interposing a compressible, flexible sensor layer between the components before they are bonded. The sensor layer contains an array of piezoelectric elements which indicate local bondline thickness by signalling pressure due to compression of the layer. The bondline thickness profile can be processed by a programmed control processor to produce an adhesive application schedule prescribing the shapes of pieces of adhesive film which, when applied over the bonding interface, will build up an adhesive layer corresponding in thickness to the bondline thickness. The sensor layer can be prepared as a kit of shaped panels or as a contoured preform (55) matching the form of the bonding interface.

A gearbox monitoring system can include a fan, compressor, combustor, and turbine in axial flow arrangement, with corresponding rotating components mounted to a shaft, and a gearbox assembly operably coupled to the shaft and connecting the turbine and the fan. The gearbox assembly can include a carrier, a sun gear, at least one planet gear, and a ring gear. An oil feed tube is coupled to the gearbox for lubricating at least one of the sun, ring or planet gears. A plurality of bearings rotationally supports at least one of the sun gear, ring gear, or planet gear relative to the carrier. In addition, at least one vibration sensor is carried by one of the carrier or ring gear and is in wireless communication with an engine control unit or health monitoring unit.

Morphable rotor blades for a turbine engine systems include a root portion and an airfoil portion having a morphable portion including a morphable material that changes shape in response to a stimulus.

A power source is configured to apply a first alternating electric excitation signal to an oscillation blade device at a first excitation frequency causing a blade of the oscillation blade device to oscillate at a first oscillation frequency. A current detector is configured to measure amplitude values of the current supplied by the power source to the oscillation blade device. A processor is configured to assess a plurality of successive peak values of the measured amplitudes, determine a second oscillation frequency for the blade if variation in the successive peak values is detected and send a command to the power source to apply a second alternating electric excitation signal to the oscillation blade device at a second excitation frequency which matches the determined second oscillation frequency.