Abstract: A voltage controlled aircraft electric propulsion system includes an electric propulsion system. The voltage controlled aircraft electric propulsion system may include electric propulsors providing thrust for the aircraft. In hybrid systems, a gas turbine engine may also be included. The electric propulsion system may include at least one electric generator power source, at least one propulsor motor load, and at least one stored energy power source, such as a battery. The propulsor motor load may be supplied power from a power supply bus. The voltage of the power supply bus may be adjusted according to an altitude of the aircraft while maintaining a substantially constant current flow to the propulsor motor load. Due to the adjustment to lower voltages at increased altitude, insulations levels may be lower.

Abstract: A disclosed gas turbine engine includes a first electric motor assembly that provides a first drive input for driving fan blades about an axis. A geared architecture is driven by a turbine section and is coupled to the fan section to provide a second drive input for driving the fan blades. A second electric motor assembly is coupled to rotate the geared architecture relative to a fixed structure for controlling a speed of the fan blades provided by a combination of the first drive input and the second drive input.

Abstract: A method includes using an electric motor to start a thermal engine. The electric motor and thermal engine are connected to one another as the electric motor and the thermal engine of a hybrid-electric power plant in an aircraft. The electric motor can be connected to a combining gear box. The thermal engine can be connected to the combining gear box so that the electric motor and the thermal engine can provide torque to the combining gear box in a parallel hybrid-electric configuration. The combining gearbox can output torque to an air mover for providing thrust to the aircraft.

Abstract: A magnetic pole structure for a Hall thruster is provided. The magnetic pole structure includes: multiple wide-envelope outer magnetic pole components, a magnetic bridge, a pagoda-shaped inner magnetic pole component, a top plate, and a bottom plate, where the multiple wide-envelope outer magnetic pole components are arranged on an outer edge of the Hall thruster, symmetrical about the pagoda-shaped inner magnetic pole component, and enclose a semi-open structure; the magnetic bridge is located between each of the wide-envelope outer magnetic pole components and the pagoda-shaped inner magnetic pole component; the bottom plate is attached to a bottom part of each of the wide-envelope outer magnetic pole components and a bottom part of the pagoda-shaped inner magnetic pole component; and the top plate is attached to an upper part of each of the wide-envelope outer magnetic pole components.

Abstract: A liner support system for an exhaust liner in an aircraft engine. The liner support system includes a plurality of posts that space the exhaust liner from the exhaust duct, the plurality of posts spacing the exhaust liner from the exhaust duct further supporting the exhaust liner. Each post includes an interface region adjacent to the back side of the exhaust liner sealed to the back side of the exhaust liner, a shank extending to a low pressure region, and a hollow passageway internal to the shank, providing fluid communication between the interface region and the low pressure region. The low pressure region results in pressure against the liner, pulling the liner adjacent the post interface region against the post while preventing fluid leakage between the exhaust liner and the interface region. The posts create a pattern of alternating pressures in the liner allowing for elimination of hangers.

Abstract: A gas turbine engine is provided having a combustion section with a liner extending between a forward end and an aft end. A structural member is positioned in or around at least a portion of the combustion section. Additionally, a piston ring holder is provided attached to the structural member at a first end and positioned proximate to the aft end of the liner at a second end. The piston ring holder is a bimetallic member including a first portion formed of a first material and a second portion formed of a second material. A coefficient of thermal expansion of the first material is different than a coefficient of thermal expansion of the second material.

Abstract: The present disclosure is directed to a gas turbine engine defining a radial direction, a longitudinal direction, and a circumferential direction, an upstream end and a downstream end along the longitudinal direction, and an axial centerline extended along the longitudinal direction. The gas turbine engine includes a fan assembly including a plurality of fan blades rotatably coupled to a fan rotor in which the fan blades define a maximum fan diameter and a fan pressure ratio. The gas turbine engine further includes a low pressure (LP) turbine defining a core flowpath therethrough generally along the longitudinal direction. The core flowpath defines a maximum outer flowpath diameter relative to the axial centerline. The gas turbine engine defines a fan to turbine diameter ratio of the maximum fan diameter to the maximum outer flowpath diameter. The fan to turbine diameter ratio over the fan pressure ratio is approximately 0.90 or greater.

Abstract: An aircraft hybrid propulsion system (5) comprises an internal combustion engine (10) comprising a main drive shaft (24), an electric machine (28) comprising an electric machine rotor (78), a propulsor (12) mounted to a propulsor shaft (62), and a clutch arrangement configured to selectively couple each of the gas turbine engine main drive shaft (24) and electric machine rotor (78) to the propulsor drive shaft (62). The electric machine rotor (78) is mounted coaxially with the main drive shaft (24) and the clutch arrangement comprises a first overrunning clutch (52) configured to couple the main drive shaft (24) to the propulsor drive shaft (62), and a second overrunning clutch (54) configured to couple the electric machine rotor (78) to the propulsor drive shaft (62).

Abstract: A hybrid electric propulsion (HEP) system can include a heat engine torque sensor connected between a heat engine and a combining gear box to sense a heat motor input torque input to the combining gear box, an electric motor torque sensor connected between an electric motor and the combining gear box to sense an electric motor input torque input to the combining gear box, and a combining gear box torque sensor connected to an output of the combining gearbox. The system can include a HEP controller operatively connected to each of the heat engine torque sensor, the electric motor torque sensor, and the combining gear box torque sensor to receive one or more torque signals therefrom. The controller can be configured to output one or more output signals as a function of the signals from each of the heat engine torque sensor, the electric motor torque sensor, and the combining gear box torque sensor.

Abstract: A propulsion system for an aircraft, which has a chassis, a propeller able to move in rotation about an axis of rotation, a main gear as one with the propeller, an electric generator, at least one linear electric motor having a fixed element and a slider able to move in translation, for each linear electric motor, a secondary gear meshing with the main gear and mounted to be able to move in rotation about an axis of rotation perpendicular to the axis of rotation, and a rod of which one end is articulated on the corresponding slider and of which the other end is articulated on the corresponding secondary gear at an articulation that is offset with respect to the axis of rotation of the secondary gear.

Abstract: An aircraft propulsion system and computing system are provided. The propulsion system includes a low pressure (LP) spool and a core engine having a high pressure (HP) spool. A frame is positioned in serial flow arrangement between an HP turbine and an LP turbine. The frame includes an inter-turbine burner including a strut forming an outlet opening into a core flowpath of the propulsion system. A first fuel system is configured to flow a liquid fuel to a combustion section for generating first combustion gases. A second fuel system is configured to flow a gaseous fuel to the core flowpath via the inter-turbine burner for generating second combustion gases. The propulsion system forms a rated power output ratio of the core engine and the inter-turbine burner with the LP spool between 1.5 and 5.7.

Abstract: A method of optimizing the noise generated by a hybrid power plant of a rotorcraft in flight, the hybrid power plant driving a main rotor of the rotorcraft in rotation and being provided with at least one engine, with at least one electric machine, and with at least one electrical energy source that electrically powers the electric machine. The method includes a determination step for determining a required power delivered by the hybrid power plant and that is required for the flight phase, and a distribution step for distributing the required power between the at least one engine and the electric machine as a function of a target noise level and of the required power for the flight phase, as well as of a model for the noise generated by the at least one engine as a function of one of its parameters.

Abstract: An electronic controller for an engine and a propeller, a control system and related methods are described herein. The control system comprises the controller having a first channel and a second channel independent from and redundant to the first channel. Each channel comprises a control processor configured to receive first engine and propeller parameters and to output, based on the first engine and propeller parameters, at least one engine control command and at least one propeller control command. Each channel also comprises a protection processor configured to receive second engine and propeller parameters and to output, based on the second engine and propeller parameters, at least one engine protection command and at least one propeller protection command. The control system comprises sensors for measuring the parameters of the engine and/or the propeller and effectors configured to control the engine and the propeller.

Abstract: An after-fan system for an engine may comprise an after-fan turbine an electrical generator operationally coupled to the after-fan turbine, and an electric motor electrically coupled to the electrical generator. The electrical generator may be configured to generate an electrical current in response to rotation of the after-fan turbine. The electric motor may be configured to generate torque.

Abstract: An engine parameter estimation tuning system includes an engine parameter estimator unit and a gas path analysis (GPA) unit. The engine parameter estimator unit includes an onboard model (OBM) configured to output estimated parameters based on operation of a gas turbine engine. The gas path analysis (GPA) unit includes a performance health monitor unit configured to adjust a long-term deterioration parameter independently from adjustment of a short-term tuning parameter to tune one or more targeted estimation parameters included in the estimated engine parameter. In this manner, the engine parameter estimation tuning system can realize the different time scales associated with uncertainties in an engine and accommodate them separately so that the estimated engine parameters become much more accurate.

Abstract: Flow path assemblies for gas turbine engines are provided. For example, a flow path assembly comprises an inner wall; a unitary outer wall; and a plurality of nozzle airfoils having an inner end radially opposite an outer end. The unitary outer wall defines a plurality of outer pockets each configured for receipt of the outer end of one of the nozzle airfoils, and the inner wall includes defines a plurality of inner pockets each configured for receipt of the inner end of one of the plurality of nozzle airfoils. A portion of each inner pocket is defined by a forward inner wall segment and an aft inner wall segment. In another embodiment, a flow path assembly comprises an inner wall defining a plurality of bayonet slots that each receive a bayonet included with each of a plurality of nozzle airfoils that are integral with a unitary outer wall.

Abstract: A controller for a gas turbine arranged to supply a load is described. The gas turbine includes a fuel supply arranged to supply fuel at a fuel flow rate to a combustor. The fuel supply includes a first fuel supply and a second fuel supply. The controller is arranged to control a proportion of the fuel flow rate supplied via the first fuel supply based, at least in part, on the fuel flow rate. A gas turbine includes such a controller and a method controls such a gas turbine.

Abstract: A combustor liner for a gas turbine has a cold side liner segment, and a hot side liner segment, with a baffle cavity between the cold side liner segment and the hot side liner segment. At least one cooling airflow dispersing member is arranged within the baffle cavity. The at least one cooling airflow dispersing member includes a main cavity portion, and at least one peripheral cavity portion surrounding the main cavity portion. The main cavity portion includes a main cavity inlet side having a cooling airflow opening, a main cavity outlet side having plurality of hot side cooling airflow openings, and at least one peripheral cavity outlet flow passage providing fluid communication between the main cavity portion and the at least one peripheral cavity portion. The at least one peripheral cavity portion includes a peripheral cavity outlet side having a plurality of hot side cooling airflow openings.

Abstract: A gas turbine engine includes a fuel cell assembly including a fuel cell stack and defining a fuel cell assembly operating parameter, a fuel source, and a turbomachine. The turbomachine includes a compressor section, a combustor, and a turbine section arranged in serial flow order. The combustor is configured to receive a flow of fuel from the fuel source and further configured to receive output products from the fuel cell stack. A controller is configured to perform operations including receiving data indicative of system operation conditions, determining a set of fuel cell operating conditions to move the system emission output into or maintain the system emission output within an emissions range, and controlling the fuel cell assembly operating parameter according to the determined set of fuel cell operating conditions.

Abstract: An electronic control system (30) for a turbopropeller engine (12) having a gas turbine (20) and a propeller assembly (13) coupled to the gas turbine (20), controls propeller operation based on a pilot input request, via generation of a driving quantity (Ip) for an actuation assembly (29) designed to adjust a pitch angle (?) of propeller blades (2) of the propeller assembly (13).