There is provided a hybrid electric aircraft propulsion system and method for operating same. The method comprises providing, to a first electric motor and a second electric motor, alternating current (AC) electric power from a generator, the generator receiving rotational power from a thermal engine, providing, to the first electric motor and the second electric motor, AC electric power from at least one motor inverter, the at least one motor inverter configured to convert DC electric power from a DC power source into AC electric power, and selectively driving the first and second electric motors from the generator, the at least one motor inverter, or a combination thereof, wherein the first electric motor drives a first rotating propulsor and the second electric motor drives a second rotating propulsor.

An unmanned vehicle includes at least one navigation sensor configured to measure navigation data indicative of an environment, at least one status sensor configured to measure status data indicative of operating parameters of a hardware system and a computing system. The computing system includes a navigation engine configured to receive the navigation data and status data and plan a path through the environment and a security engine. The security engine is configured to detect that an unauthorized user is attempting to access the navigation data or the status data, send an alert to an authorized user indicating that the unauthorized user is attempting to access navigation data or status data, and send, to the unauthorized user, simulated data including one or both of simulated navigation data and simulated status data.

A turbine engine is provided that includes a propulsor rotor and an engine core. The propulsor rotor is rotatable about a propulsor axis. The engine core is configured to power operation of the propulsor rotor. The engine core includes a core compressor section, a core combustor section, a core turbine section, a first rotating structure and a second rotating structure. The first rotating structure includes a first compressor rotor arranged within the core compressor section. The first rotating structure is rotatable about a first structure axis which is offset from the propulsor rotor axis. The second rotating structure includes a second compressor rotor arranged within the core compressor section. The second rotating structure is rotatable about a second structure axis which is offset from the propulsor rotor axis and the first structure axis.

A craft comprises at least one hull, a main wing coupled to the hull and configured to facilitate airborne operations of the craft, a plurality of propellers that include one or more electric motor propellers and one or more combustion motor propellers arranged along each of a port side and a starboard side of the main wing and configured to generate lift on the craft by blowing air over the main wing, and a control system. The control system comprises data storage having instruction code stored thereon that, when executed by one or more processors of the control system, causes the control system to: after receiving a takeoff indication, increase thrust generated by the electric motor propellers to cause the craft to transition from a hull-borne mode of operation to an airborne mode of operation, and after a thrust adjustment condition occurs, increase thrust generated by the combustion motor propellers.

A first power source includes a high discharge rate battery and a second power source includes a high energy battery. An electronically activated switch switches between the first power source and the second power source in response to a control signal from a power controller. If the electronically activated switch fails, it fails with one of the first power source and the second power source in an open circuit position and with the other one of the first power source and the second power source in a closed circuit position. The power controller generates the control signal, including by: during a vertical landing associated with a vertical takeoff and landing (VTOL) vehicle, generating the control signal to switch from the high energy battery to the high discharge rate battery independent of a measured current.

A hybrid propulsion system for an aircraft includes a gas turbine engine, an energy storage device, at least one propulsor configured to use energy provided by one or both of the gas turbine engine and the energy storage device to provide thrust. The system also includes a controller configured to vary the power provided to the propulsor(s) in response to a signal. The signal may be provided manually by a user of the system or automatically. Automatic signals may be indicative of a threat to the aircraft, geographical location of the aircraft, altitude of the aircraft, or ingestion of particles into the gas turbine engine.

UAV configurations and battery augmentation for UAV internal combustion engines, and associated systems and methods are disclosed. A representative configuration includes a fuselage, first and second wings coupled to and pivotable relative to the fuselage, and a plurality of lift rotors carried by the fuselage. A representative battery augmentation arrangement includes a DC-powered motor, an electronic speed controller, and a genset subsystem coupled to the electronic speed controller. The genset subsystem can include a battery set, an alternator, and a motor-gen controller having a phase control circuit configurable to rectify multiphase AC output from the alternator to produce rectified DC feed to the DC-powered motor. The motor-gen controller is configurable to draw DC power from the battery set to produce the rectified DC feed.

A electrical power system comprises: an electrical machine operable to output AC; a DC electrical network; a power electronics converter connected between the AC output of the electrical machine and the DC electrical network and including a plurality of transistors and associated diodes connected in parallel with the transistors; and a controller configured to control switching of the transistors of the converter so that, during normal operation of the electrical power system, the converter rectifies the AC output of the electrical machine to supply the DC electrical network with DC electrical power. The controller is further configured, responsive to a determination to the effect there is a fault in the DC electrical network, to control a voltage source, to inject a voltage to bias the diodes of the converter, and to control the switching of the transistors to control a level of current supplied to the faulted DC electrical network.

A turbo-compounded engine includes a piston engine connected to drive a propulsor. An outlet of the piston engine is operable to connect products of combustion from the piston engine to pass over a turbine. The turbine is connected to drive a turbine shaft also connected to drive the propulsor. An outlet of the turbine is connected into an exhaust duct configured to exhaust the products of combustion. The exhaust duct is provided with an exhaust duct outer wall defining an exhaust chamber. A further cooling air outer wall is positioned outwardly of the exhaust duct. Flow dividers are received within an exhaust chamber inward of the exhaust duct outer wall. The exhaust duct outer wall has an inner surface and the flow dividers have an outer surface. Acoustic treatment is provided on both the inner surface of the exhaust duct outer wall and the outer surface of the flow dividers.

A propulsion assembly includes a first torque source coupled with a first shaft and a second torque source coupled with a second shaft. A coupler selectively couples the first and second torque sources. When the first and second torque sources are coupled via the coupler, in response to a command to decouple the first torque source, an unloading operation is performed to decrease the torque output provided by the first torque source to a threshold, and when reached, the first shaft is decoupled from the coupler. When the first torque source is coupled with the coupler but the second torque source is not, in response to a command to couple the second torque source, a speed matching operation is performed to increase the speed of the second shaft to match a speed of the first shaft, and when the speeds are matched, the second shaft is coupled to the coupler.