In accordance with at least one aspect of this disclosure, there is provided a drive shaft system. In embodiments, the drive shaft system includes a generator shaft extending along a longitudinal axis with a longitudinal bore defined through the generator shaft. A thru shaft extends through the longitudinal bore of the generator shaft. In embodiments, the thru shaft includes, a front coupler mount at a first end operative to receive torque input, and a rear coupler mount at a second end opposite the first end.

In accordance with at least one aspect of this disclosure, there is provided a system for aircraft power. The system includes a DC/DC converter having a DC input and a DC output and a switching circuit connecting the DC input to the DC output operable to vary voltage at the DC output. A control module is operatively connected to the switching circuit for variable control of the DC output. The control module includes machine readable instructions to cause the control module to receive input indicative of altitude and control the switching circuit to vary voltage of the DC output as a function of environmental conditions such as altitude and humidity. In embodiments the altitude sensor is operatively connected to the controller.

In accordance with at least one aspect of this disclosure, there is provided a system for aircraft power. The system includes a DC/DC converter having a DC input and a DC output and a switching circuit connecting the DC input to the DC output operable to vary voltage at the DC output. A control module is operatively connected to the switching circuit for variable control of the DC output. The control module includes machine readable instructions to cause the control module to receive input indicative of altitude and control the switching circuit to vary voltage of the DC output as a function of environmental conditions such as altitude and humidity. In embodiments the altitude sensor is operatively connected to the controller.

The disclosure relates to an unmanned aerial vehicle, wherein a fuel cell system component provides a structural component of the vehicle. In some instances propulsion modules affixed to wings are oriented so as to provide airflow to plates of a fuel cell via air inlets for each fuel cell provided at the forward surface of each wing, a fuel cell system component forming a portion of the body and wherein the air inlets are unblocked during flight, each propulsion module is configured to provide air as an oxidant to a fuel cell via the air inlets.

A method for managing the offtake of power produced by an auxiliary power unit of an aircraft. The method comprises a step of calculating a maximum capacity for offtake of mechanical power that the auxiliary power unit can provide to the aircraft, a step of determining an actual offtake of mechanical power taken off by a first mechanical power offtake system of the auxiliary power unit, a step of comparing the maximum capacity for offtake of mechanical power and the actual offtake of mechanical power, a step of optimizing the offtake of mechanical power which step, based on the comparison of the maximum capacity for offtake of mechanical power and the actual offtake of mechanical power, determines at least one corrective action. A device for managing the offtake of power produced by an auxiliary power unit of an aircraft and an aircraft including such a device are provided.

A method for managing the offtake of power produced by an auxiliary power unit of an aircraft. The method comprises a step of calculating a maximum capacity for offtake of mechanical power that the auxiliary power unit can provide to the aircraft, a step of determining an actual offtake of mechanical power taken off by a first mechanical power offtake system of the auxiliary power unit, a step of comparing the maximum capacity for offtake of mechanical power and the actual offtake of mechanical power, a step of optimizing the offtake of mechanical power which step, based on the comparison of the maximum capacity for offtake of mechanical power and the actual offtake of mechanical power, determines at least one corrective action. A device for managing the offtake of power produced by an auxiliary power unit of an aircraft and an aircraft including such a device are provided.

An electrical architecture of an aircraft includes a plurality of primary generators each associated with a propulsion engine of the aircraft, a plurality of primary electrical networks each associated with a primary generator in nominal operating mode, a single-part secondary electrical network, an electrical energy accumulation device connected directly to the secondary network, a first electrical energy converter arranged between the secondary electrical network and a first of the primary electrical networks, allowing energy to be transferred from the first of the primary electrical networks to the secondary electrical network, the first electrical energy converter being intended to supply electrical energy to the electrical energy accumulation device in nominal operating mode, a second electrical energy converter arranged between the secondary electrical network and a second of the primary electrical networks, allowing energy to be transferred from the secondary electrical network to the second of the primary electrical networks.

A ducted propulsion assembly for an aircraft includes a duct and a plurality of stators. The distal ends of the stators are coupled to the duct. The ducted propulsion assembly includes a line replaceable centerbody assembly isostatically coupled to the proximal ends of the stators. The line replaceable centerbody assembly includes one or more electric motors driving an output driveshaft. The ducted propulsion assembly also includes a proprotor assembly interchangeably coupled to and rotatable with the output driveshaft of the line replaceable centerbody assembly. The proprotor assembly is rotatable in a rotational plane to generate thrust.

A ducted propulsion assembly for an aircraft includes a duct and a plurality of stators. The distal ends of the stators are coupled to the duct. The ducted propulsion assembly includes a line replaceable centerbody assembly isostatically coupled to the proximal ends of the stators. The line replaceable centerbody assembly includes one or more electric motors driving an output driveshaft. The ducted propulsion assembly also includes a proprotor assembly interchangeably coupled to and rotatable with the output driveshaft of the line replaceable centerbody assembly. The proprotor assembly is rotatable in a rotational plane to generate thrust.

A drive system comprises a DC-DC converter that is arranged to receive an input voltage from a battery having a nominal battery voltage. The DC-DC converter has a first mode of operation in which the DC-DC converter generates a regulated output voltage from the input voltage and supplies the regulated output voltage to a load, and a second mode of operation in which the DC-DC converter is by-passed such that the input voltage from the battery is supplied to the load. A controller is arranged to compare the input voltage to a threshold voltage that is less than the nominal battery voltage. The controller operates the DC-DC converter in the first mode when the input voltage is less than the threshold voltage, and operates the DC-DC converter otherwise.