Lightweight, energy-dense, high-efficiency, hybrid power systems for electric aircraft including a prime mover internal combustion engine or gas turbine coupled to a self-cooling polyphase axial-flux dual-Halbach-array motor/alternator where the number of phases N.sub.phase is greater than or equal to three. The motor/alternator is connected to a regenerative power converter drive also having N.sub.phase phases, which, in turn, is connected to a DC power bus, a battery, a battery management system, and a system controller. In some embodiments, the motor/alternator and regenerative power converter drive have a neutral connection.

Lightweight, energy-dense, high-efficiency, hybrid power systems for electric aircraft including a prime mover internal combustion engine or gas turbine coupled to a self-cooling polyphase axial-flux dual-Halbach-array motor/alternator where the number of phases N.sub.phase is greater than or equal to three. The motor/alternator is connected to a regenerative power converter drive also having N.sub.phase phases, which, in turn, is connected to a DC power bus, a battery, a battery management system, and a system controller. In some embodiments, the motor/alternator and regenerative power converter drive have a neutral connection.

A system (166) for transferring mechanical power in a turbine engine (150/151) including a low pressure spool (162) and a high pressure spool (156) includes a power transfer unit (168) coupled between an output shaft (172) of the low pressure spool (162) and a drive shaft (174) of the high pressure spool (156) to mechanically link the low pressure spool (162) to the high pressure spool (156), and a clutch (170) coupled to the power transfer unit (168), wherein the clutch (170) is configured to transfer power produced from the low pressure spool (162) to the high pressure spool (156).

A system (166) for transferring mechanical power in a turbine engine (150/151) including a low pressure spool (162) and a high pressure spool (156) includes a power transfer unit (168) coupled between an output shaft (172) of the low pressure spool (162) and a drive shaft (174) of the high pressure spool (156) to mechanically link the low pressure spool (162) to the high pressure spool (156), and a clutch (170) coupled to the power transfer unit (168), wherein the clutch (170) is configured to transfer power produced from the low pressure spool (162) to the high pressure spool (156).

A method of operating an aircraft with multiple actuators, such as propulsion units, preferably electrically powered propulsion units, is provided and includes the steps of: i) monitoring an operational state of said multiple actuators; ii) when detecting a malfunctioning or failure of any one of said actuators, indicating said malfunctioning or failure to a pilot in command (2b) of the aircraft; iii) controlling a human machine interface (2ab) of the aircraft to display and enable a limited choice of possible operating measures in connection with said malfunctioning or failure to the pilot in command (2b); and iv) programming at least one control element (2ae) in association with said one actuator to perform said measures when actuated by the pilot in command (2b).

A method of operating a hybrid-electric propulsion system for an aircraft and a hybrid-electric propulsion system is provided. The method includes: a) providing at least one thermal engine sized to provide sufficient thrust to the aircraft for at least one flight mission independent of a second non-thermal engine source of thrust for the at least one flight mission; b) providing at least one electric motor powered by a non-hydrocarbon fuel burning electrical energy source, the at least one electric motor configured to provide thrust to the aircraft for the at least one flight mission; and c) selectively providing thrust during one or more segments of the at least one flight mission using the electric motor.

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.

An electrical power distribution network of an electric power system of an aircraft is operated in at least one normal operation mode such that it provides for load sharing across electrical power sources (A, B, C, D) with respect to electrical loads (AA, BB, CC, DD), wherein the electrical power distribution network, in case of an electrical fault, is operated in at least one electrical failure mitigating operation mode, which provides for electric fault isolation, such that a network portion of the electrical power distribution network including the electrical fault is isolated from at least one other network portion of the of the electrical power distribution network.

An electrical power distribution network of an electric power system of an aircraft is operated such that it sequentially adopts a plurality of different partial load sharing modes in a time variable manner, which provide for partial load sharing across electrical power sources (A, B, C, D) with respect to associated electrical loads (AA, BB, CC, DD), by sequentially switching between a plurality of different partial load sharing configurations of the electrical power distribution network, each partial load sharing configuration being associated to a particular one of the partial load sharing modes.

Powertrains and related methods for an aerial vehicle may include a torque control system associated with the powertrain and configured to receive torque signals indicative of engine torque supplied by a mechanical power source or generator torque generated by an electric power generation device resisting the engine torque. The torque control system may be configured to generate, based in part on torque signals, a torque control signal configured to change the engine torque or change the generator torque. When torque signals indicate a relative reduction in the engine torque supplied by the mechanical power source, torque control signals may be configured to cause a relative reduction in the generator torque resisting the engine torque. When torque signals indicate a relative increase in the engine torque supplied by the mechanical power source, torque control signals may be configured to cause a relative increase in the generator torque resisting the engine torque.