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.

Certain examples disclose and describe apparatus and methods to provide fast response active clearance control system with piezoelectric actuator. In some examples, an apparatus includes a case surrounding at least part of a turbine engine, the at least part of the turbine engine including at least one of a shroud or a hanger to contain airflow in the at least part of the turbine engine. The apparatus further includes an actuator to control clearance between a blade and the at least one of the shroud or the hanger, the actuator including a multilayer stack of material, and wherein the actuator is outside of the case. The apparatus further includes a rod coupled to the actuator and the at least one of the shroud or the hanger through an opening in the case, the rod to move the at least one of the shroud or the hanger based on the actuator.

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. One or more 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 part of the gearbox monitoring system.

A centrifugal pump with adaptive pump stages includes an impeller configured to provide kinetic energy to fluid flow through the pump. The impeller has multiple geometric dimensions. The pump includes a diffuser connected to the impeller that is configured to convert the kinetic energy provided by the impeller into static pressure energy to flow the fluid through the pump. The pump includes an adaptive material attached to the impeller that is configured to modify, during operation of the pump, a geometric dimension to modify fluid flow through the pump.

A centrifugal pump with adaptive pump stages includes an impeller configured to provide kinetic energy to fluid flow through the pump. The impeller has multiple geometric dimensions. The pump includes a diffuser connected to the impeller that is configured to convert the kinetic energy provided by the impeller into static pressure energy to flow the fluid through the pump. The pump includes an adaptive material attached to the impeller that is configured to modify, during operation of the pump, a geometric dimension to modify fluid flow through the pump.

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.

An airfoil for a gas turbine engine according to an example of the present disclosure includes, among other things, an airfoil section that extends from a root section. The airfoil section extends between a leading edge and a trailing edge in a chordwise direction and extends between a tip portion and the root section in a radial direction. The airfoil section defines a pressure side and a suction side separated in a thickness direction, and the airfoil section includes a metallic sheath that defines an internal cavity receiving a composite core. The root section defines at least one bore dimensioned to receive a retention pin. At least one damping element is received in the internal cavity and that selectively causes the airfoil section to stiffen.

A stator vane for a gas turbine engine section includes a stator vane having an airfoil extending between a leading edge and a trailing edge. The airfoil has a suction side and a pressure side. There is at least one piezoelectric actuator for changing a shape of at least one of the leading edge and the trailing edge. A gas turbine engine is also disclosed.

A mobile device case is described. The mobile device case includes a housing configured to retain a mobile device and an active cooling system integrated into the housing. The active cooling system configured to use vibrational motion to cool a surface of the mobile device.

The present disclosure is directed to an engine component for a gas turbine engine, the engine component including a substrate that includes a composite fiber and defines a surface. An energy harvesting fiber is positioned within the substrate.