Embodiments are directed to selecting, by a computing device comprising a processor, the size of at least one prime mover associated with an aircraft to satisfy a baseline power requirement for operation of the aircraft during a steady state load condition, selecting at least one power source configuration to supplement power provided by the at least one prime mover during a transient load condition associated with the operation of the aircraft, and selecting, by the computing device, a parameter of the at least one power source configuration to provide a total power in an amount that is greater than a threshold during the transient condition.

An engine assembly includes an intermittent internal combustion engine having an engine shaft, a turbine having a turbine shaft, an output shaft for driving a load, and a gearbox having a first portion and a second portion. The engine shaft is in engagement with an accessory via the first portion. The turbine shaft is in driving engagement with the output shaft via the second portion. The gearbox is configurable between an engaged and a disengaged configurations. In the disengaged configuration, the first and second portions are decoupled, and the engine shaft and the turbine shaft are rotatable independently from each other. In the engaged configuration, the first and second portions are coupled, and the engine shaft and the turbine shaft are drivingly engaged with each other via the coupled first and second portions.

This document describes an unmanned aerial vehicle (UAV) configured to navigate an unmanned aerial vehicle highway. The UAV includes a navigation system that includes a sensor, configured to gather environmental data, and a computing system configured to navigate the UAV. The computing system compares the environmental data to a specified data signature in the one or more spectra and determines a position of the unmanned aerial vehicle in the unmanned aerial vehicle highway. The UAV includes a hybrid generator system including an engine configured to generate mechanical energy and a generator motor coupled to the engine and configured to generate electrical energy from the mechanical energy generated by the engine. The UAV includes a rotor motor configured to drive a propeller to rotate. The navigation system is powered by the electrical energy generated by the generator motor.

A hybrid-electric propulsion system includes a turbomachine, a propulsor coupled to the turbomachine, and an electrical system, the electrical system including an electric machine coupled to the turbomachine. A method for operating a hybrid-electric propulsion system includes operating, by one or more computing devices, the turbomachine in an idle operating condition; receiving, by the one or more computing devices, a command to accelerate the turbomachine while operating the turbomachine in the idle operating condition; and providing, by the one or more computing devices, electrical power to the electric machine to add power to the turbomachine and increase an acceleration of the turbomachine in response to the received command to accelerate the turbomachine.

A method of operating an aircraft hybrid gas turbofan during an idle mode of operation includes reducing a fuel flow to a primary gas turbine engine and boosting a high spool of the primary gas turbine engine using a secondary gas turbine engine via a first power linkage connecting the primary and secondary gas turbine engines, such that a net fuel reduction is achieved. The net fuel reduction accounts for fuel flow to the primary gas turbine engine and fuel flow to the secondary gas turbine engine.

An aspect includes a battery charging system for a hybrid electric aircraft. The battery charging system includes a generator, a battery system, and a controller. The controller is operable to charge the battery system up to a first charge level based on receiving a first charging current at a power input. An operational status of a gas turbine engine of the hybrid electric aircraft is monitored. The battery system is charged at a second charging current received from the generator driven by the gas turbine engine responsive to determining that the gas turbine engine is in a taxi state, where the second charging current is less than the first charging current. Charging of the battery system is halted based on detecting a transition of the gas turbine engine from the taxi state to an off-idle throttle state.

An aspect includes a hybrid gas turbine engine system of a hybrid electric aircraft. The hybrid gas turbine engine system includes a gas turbine engine, an electric motor operable to perform an electric taxiing of the hybrid electric aircraft, and a controller. The controller is operable to prevent fuel flow to the gas turbine engine during at least a portion of the electric taxiing and monitor for a powered warm-up request during the electric taxiing. A powered warm-up state of the gas turbine engine is initiated based on detecting the powered warm-up request. The powered warm-up state adds heat to one or more components of the gas turbine engine prior to transitioning to a takeoff power state. The gas turbine engine transitions from the powered warm-up state to the takeoff power state after reaching a target temperature of the one or more components in the powered warm-up state.

An embodiment of an engine assembly includes a combustion turbine engine having at least a first compressor spool, a first turbine spool, a first shaft connecting the first compressor spool and the first turbine spool, and a combustor disposed in a working gas flow path between the first compressor spool and the first turbine spool. A first controller is programmed with a surge map, and configured to operate the combustion turbine engine in a range extending between a first suppressed idle mode, a second base idle mode, and a maximum takeoff power rating mode. An idle speed suppressor includes at least one idle assist motor connected to the first shaft of the combustion turbine engine. A second controller is configured to manage operation of the idle speed suppressor relative to the combustion turbine engine during times of minimum power demand, such that operating the idle speed suppressor increases a compressor speed in the first suppressed idle mode relative to a compressor speed in the second base idle mode.

An aircraft has an internal combustion engine and a wing including a hollow structural member. The aircraft has an electrical network including: an electrical motor configured to drive an aircraft propulsor; at least one conductor configured to electrically couple the electrical motor and an electrical storage device; wherein the electrical conductor is formed of the hollow structural member of the aircraft wing.

Various embodiments include a drive system for a vehicle, the system comprising: an internal combustion engine for converting chemical energy stored in a liquid fuel into mechanical energy; a fuel tank for storing fuel for use by the internal combustion engine; and an electric machine having a rotor, a stator, and a cooling system for cooling at least one component of the electric machine using a cooling liquid. The cooling liquid comprises the fuel.