An aircraft hybrid propulsion system (5) comprising an inboard gas turbine engine (10a, 10c) and an outboard gas turbine engine (10b, 10d), each comprising a propulsor (12a, 12b) and a respective electric machine (32a, 32b) coupled to one or more engine shaft (24a, 24b). An electrical interconnection (34) is provided between the electric machine (32a) of the inboard gas turbine engine (10a) and the electric machine (32b) of the outboard gas turbine engine (10b). A controller (36) is configured to transfer electrical power between the inboard gas turbine engine electrical machine and the outboard gas turbine engine electrical machine when a thrust setting change is selected.

Systems and methods to pump fracturing fluid into a wellhead may include a gas turbine engine including a compressor turbine shaft connected to a compressor, and a power turbine output shaft connected to a power turbine. The compressor turbine shaft and the power turbine output shaft may be rotatable at different rotational speeds. The systems may also include a transmission including a transmission input shaft connected to the power turbine output shaft and a transmission output shaft connected to a hydraulic fracturing pump. The systems may also include a fracturing unit controller configured to control one or more of the rotational speeds of the compressor turbine shaft, the power turbine output shaft, or the transmission output shaft based at least in part on target signals and fluid flow signals indicative of one or more of pressure or flow rate associated with fracturing fluid pumped into the wellhead.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle defining a duct, and a fan located within the duct. The fan comprises a hub arranged to rotate around a rotational axis and a plurality of blades attached to the hub, each of which has a span from a root at the hub defining a 0 percent span position (r.sub.hub) to a tip defining a 100 percent span position (r.sub.tip) and a plurality of span positions therebetween (r∈[r.sub.hub, r.sub.tip]). A plurality of outlet guide vanes are positioned aft of the fan. An afterbody is located aft of the plurality of outlet guide vanes and which tapers to an apex having an apex angle with respect to the rotational axis of between 35 and 45 degrees.

Embodiments of system and methods for supplying fuel, enabling communications, and conveying electric power associated with operation of a hydraulic fracturing unit of a plurality of hydraulic fracturing units are disclosed and may include a fuel line connection assembly configured to be connected to the first hydraulic fracturing unit and to supply fuel from a fuel source to a gas turbine engine connected to the hydraulic fracturing unit. A system also may include a communications cable assembly configured to be connected to the hydraulic fracturing unit and to enable data communications between the hydraulic fracturing unit and a data center or another hydraulic fracturing unit. A system further may include a power cable assembly configured to be connected to the hydraulic fracturing unit and to convey electric power between the hydraulic fracturing unit and a remote electrical power source or the plurality of hydraulic fracturing units.

A dispatch advisor for operating a power plant having at least one gas turbine with flexibility is described. The dispatch advisor can generate a representation of a flexible base load map for operating the power plant. The representation can include an aggregation of a primary base load operating space and an expanded portion of the base load operating space. The representation offers a range of operating values for operational parameters of the power plant during base load at various base load settings at predetermined ambient conditions and corresponding power output and efficiency values that are attained while operating the power plant at the range of operating values. This offers an operator of the power plant with flexibility in controlling the plant during base load.

A dispatch advisor for operating a power plant having at least one gas turbine with flexibility is described. The dispatch advisor can generate a representation of a flexible base load map for operating the power plant. The representation can include an aggregation of a primary base load operating space and an expanded portion of the base load operating space. The representation offers a range of operating values for operational parameters of the power plant during base load at various base load settings at predetermined ambient conditions and corresponding power output and efficiency values that are attained while operating the power plant at the range of operating values. This offers an operator of the power plant with flexibility in controlling the plant during base load.

A compressor assembly includes a compressor including a central shaft including an external surface, a shroud extending circumferentially around the central shaft. The shroud including a radially inward surface and radially outward surface located opposite the radially inward surface. The external surface of the central shaft and the radially inward surface of the shroud are in a facing spaced relationship forming a core flow path therebetween. The compressor also includes a plurality of blades extending from the central shaft to the shroud. The compressor assembly also includes a compression ring extending circumferentially around the shroud, the compression ring being in an interference fit with the shroud. The compression ring is configured to apply a radially inward compressive force along one or more portions of the radially outward surface of the shroud, the radially inward compressive is configured to compress the shroud and the plurality of blades into the central shaft.

A hybrid propulsion update system includes a controller in signal communication with a replaceable battery. The controller includes a tuning parameters storage unit configured to store at least one tuning parameter corresponding to the replaceable battery. The controller is configured to execute at least one optimization algorithm that utilizes the tuning parameters to control operation of the hybrid electric aircraft according to a first performance. The tuning parameters storage unit is configured to receive at least one updated tuning parameter from a controller updating device. The controller executes the at least one optimization algorithm that utilizes the at least one updated tuning parameter such that the hybrid electric aircraft operates according to a second performance that improves upon the first performance.

A hybrid propulsion update system includes a controller in signal communication with a replaceable battery. The controller includes a tuning parameters storage unit configured to store at least one tuning parameter corresponding to the replaceable battery. The controller is configured to execute at least one optimization algorithm that utilizes the tuning parameters to control operation of the hybrid electric aircraft according to a first performance. The tuning parameters storage unit is configured to receive at least one updated tuning parameter from a controller updating device. The controller executes the at least one optimization algorithm that utilizes the at least one updated tuning parameter such that the hybrid electric aircraft operates according to a second performance that improves upon the first performance.

Systems, assemblies, and methods to enhance the efficiency of operation of a gas turbine engine may include a turbine housing positioned to at least partially enclose the gas turbine engine, and a filtration assembly connected to the turbine housing to supply at least partially filtered intake air to an inlet assembly associated with the gas turbine engine. The filtration assembly may include a pre-cleaner including one or more inertial separators configured to separate a first portion of particles and/or liquid from ambient air supplied to the gas turbine engine, thereby to provide at least partially filtered intake air, and one or more filters positioned downstream of the pre-cleaner to separate a second portion of the particles and/or liquid from the at least partially filtered intake air.