A gas turbine engine is provided. The gas turbine engine includes a turbomachine comprising a low speed spool; a rotor assembly coupled to the low speed spool; an electric machine mechanically coupled to the low speed spool at a connection point of the low speed spool; and a clutch positioned in the torque path of the low speed spool between the connection point and the rotor assembly

A gas turbine engine is provided. The gas turbine engine defines a radial direction. The engine includes: an airfoil positioned within an airflow and extending between a root end and a tip along the radial direction; and a mount coupled to or formed integrally with the root end of the airfoil for mounting the airfoil to the engine, the mount including an outer surface along the radial direction exposed to the airflow and defining an air-cooling channel extending between an inlet and an outlet, the inlet positioned on the outer surface of the mount.

A propulsion system according to aspects of the present disclosure is provided, the propulsion system including a rotor assembly with a plurality of blades extended radially relative to the engine centerline axis, and a vane assembly positioned in aerodynamic relationship with the rotor assembly. The vane assembly includes a plurality of vanes extended radially relative to the engine centerline axis, and the propulsion system includes a ratio of a quantity of blades to a quantity of vanes between 2:5 and 2:1.

A computing system for an unducted rotor engine with a variable pitch vane assembly in aerodynamic relationship with an unducted rotor assembly, including a sensor-based controller configured to execute a first set of operations and a model-based controller configured to execute a second set of operations. The first set of operations includes obtaining a first signal corresponding to a commanded low spool speed; obtaining a second signal indicative of a pitch angle corresponding to thrust output from the unducted rotor assembly and variable pitch vane assembly; generating a pitch feedback signal corresponding to a commanded adjustment to the pitch angle based at least on one or both of a variable blade pitch angle or a variable vane pitch angle. The second set of operations include obtaining a desired thrust output via a throttle input; determining, at least via a power management block, a commanded thrust output signal; receiving the commanded thrust output signal; and generating an output signal.

A propulsion system is provided, the propulsion system including a variable pitch rotor assembly including a plurality of blades coupled to a disk. The plurality of blades includes a first blade configured to articulate a first blade pitch separately from a second blade configured to articulate a second blade pitch. A vane assembly is positioned in aerodynamic relationship with the variable pitch rotor assembly. A core engine including a high speed spool and a low speed spool, wherein the low speed spool is operably coupled to the rotor assembly. One or more controllers is configured to execute operations. The operations include articulating the first blade of the rotor assembly, wherein articulating the first blade alters the first blade pitch, and articulating the second blade of the rotor assembly, wherein articulating the second blade alters the second blade pitch.

A method is provided of operating a single unducted rotor engine, the single unducted rotor engine comprising a single stage of unducted rotor blades. The method includes operating the single unducted rotor engine to define a flight speed, V.sub.0, in a length unit per second and an angular speed, n, in revolutions per second, the single stage of unducted rotor blades defining a diameter, D, in the length unit; wherein operating the single unducted rotor engine comprises operating the single unducted rotor engine to define an advance ratio greater than 3.8 while operating the single unducted rotor engine at a net efficiency of at least 0.8, the advance ratio defined by the equation V.sub.0/(nD).

A propulsion system is provided, the propulsion system including a rotor assembly configured to rotate relative to the engine centerline axis, and wherein one or more blades of the rotor assembly are configured to rotate along a blade pitch angle axis. A vane assembly is positioned in aerodynamic relationship with the rotor assembly. The vane assembly includes one or more vanes, wherein each vane includes a vane pitch angle. A controller is configured to execute operations, the operations including moving each blade to a reverse thrust position about its respective blade pitch axis, and adjusting each vane about its respective vane pitch axis when the plurality of blades is in the reverse thrust position to modify an amount of reverse thrust generated by the propulsion system.

A method is provided of operating a single unducted rotor engine, the single unducted rotor engine comprising a single stage of unducted rotor blades. The method includes operating the single unducted rotor engine to define a flight speed, V.sub.0, in a length unit per second and an angular speed, n, in revolutions per second, the single stage of unducted rotor blades defining a diameter, D, in the length unit; wherein operating the single unducted rotor engine comprises operating the single unducted rotor engine to define an advance ratio greater than 3.8 while operating the single unducted rotor engine at a net efficiency of at least 0.8, the advance ratio defined by the equation V.sub.0/(nD).

Embodiments of the present disclosure include a method for controlling a power generation system, the method including: detecting a heat distribution across a component of a power generation system from a thermal output of the component, during operation of the power generation system; calculating a projected heat distribution across the component based on a library of modeling data for the power generation system; calculating whether a difference between the heat distribution and the projected heat distribution exceeds a thermal threshold; adjusting the power generation system in response to the difference exceeding the predetermined threshold, wherein the adjusting includes modifying an operating setting of the power generation system.

A health monitoring system including an array of microphones, a data collection system, and analytic software used to detect health status, pending malfunctions, or faults of several disparate, engine subsystems. The system can be used to monitor health of the main engines, the engine nacelles, and auxiliary power units (APU) on the aircraft.