In a hybrid flight vehicle, having four rotors attached to a frame and configured to produce propelling force to propel the frame, a gas turbine engine attached to the frame and configured to rotate when fuel is supplied, a generator connected to an output shaft of the engine and configured to generate electric power when driven by the engine, a battery configured to store the electrical power generated by the generator, and four first electric motors each connected to the rotors to drive associated one of the rotors when the electric power is supplied from the battery, and an electronic control unit configured to control flight by regulating driving of the four rotors by the first electric motors. In the vehicle, the output shaft of the engine is attached parallel to at least one among yaw axis, pitch axis and roll axis of the frame.

A system is described that includes a turbine engine including an engine fan including one or more variable-pitch blades driven by a shaft, which rotates at a rotational speed which depends on a pitch of the one or more variable-pitch blades of the engine fan. The system further includes a generator configured to produce alternating-current (AC) electricity at a particular frequency relative to the rotational speed of the shaft. The system also includes a propulsor, which includes a propulsor motor and a propulsor fan. The propulsor motor is configured to drive, based on the AC electricity produced by the generator, the propulsor fan. The system includes a controller configured to control the particular frequency of the AC electricity by at least controlling the pitch of the one or more variable-pitch blades of the engine fan and thereby the rotational speed of the generator.

A hybrid propulsion system for an aircraft is provided that includes a turbine engine, a first electric machine assembly connected to the turbine engine, a second electric machine assembly driven by the first electric machine assembly, and multiple third electric machine assemblies driven by the first electric machine assembly, wherein the multiple third electric machines provide a thrust output to propel the aircraft.

Energy storage systems for aircraft and methods of operating the same are provided. The energy storage system may include a main battery, a propulsion power bus, a non-critical bus, a critical bus, and an engine starter bus. The propulsion power bus may be configured to convey electricity, which is supplied by the main battery, to an electric propulsion machine configured to provide propulsion for the aircraft. The non-critical bus may be configured to convey electricity to a hotel load on the aircraft. The critical bus may be configured to convey electricity, which is supplied by the main battery, to a critical load on the aircraft. The engine starter bus may be configured to convey electricity, which is supplied by the main battery, to an electric starter for a gas turbine engine, where the gas turbine engine is configured to power the electric propulsion machine.

Control logic for a power sharing system on a hybrid propulsion aircraft, utilizing parallel multiple control loops outputting difference commands which provide bumpless transfer between control loops without integrator wind up or reset logic, allowing for efficient load distribution between electric generators and batteries powering electric motors.

A power plant for an aircraft such as a UAV with a gas turbine engine that drives an electric generator to produce electrical power. The electric generator is rotatably supported by two foil bearings. A centrifugal compressor is secured to a forward side of the generator rotor shaft. The centrifugal compressor draws in cooling air that flows through the two foil bearings and between a space formed between the rotor coil and the stator coil of the electric generator to provide for cooling of both foil bearings and the coils of the generator.

A distributed propulsion system includes a first propulsor and a second propulsor, a first generator configured to generate a first AC current, and a second generator configured to generate a second AC current. The system includes a power regulation circuit. The power regulation circuit includes a first current path that includes a first power electronics circuit, a second current path that includes a second power electronics circuit, a third current path that bypasses the first and second power electronics circuits, and a fourth current path that bypasses the first and second power electronics circuits. The power regulation circuit also includes a plurality of switches configured to selectively couple each respective input to a respective selected output to cause a respective current to flow from the respective input to the respective selected output via one of the first current path, second current path, third current path, or fourth current path.

Neutral Axis Duct with Tandem Telescopic Thrust Vectoring Leading and Trailing Edge Propellers for Multi-Mode Spatial Vehicle [NADTVPMSV] is a single monocoque chassis frame for a multi-mode vehicle that can travel in all land, air, over water and under water as a perfect road vehicle, perfect flying machine, perfect speed boat and perfect submarine. NADTVPMSV comprising of a longitudinal and transverse ducts with tandem thrust vectoring leading and trailing edge propellers integrated with at least one concealed or non-concealed leading and trailing bidirectional edge thrust vectoring propeller propellers connected with shaft and power source like motor or engine for providing vertical, horizontal and angular thrust to monocoque chassis frame; retractable under chassis wings with single to multi directional fluid flow design, opening and closing mechanism to control the flight as well as to adapt according to mode of the vehicle; one or more wheel tires and suspension components for the vehicle with at least one steerable wheel to travel on surface; at least one ballast tank to submerge and manoeuvre the vehicle under water.

An example hybrid propulsion system is described that includes a plurality of propulsors, a first drive shaft, a second drive shaft, a gas turbine engine, a motor-generator, and a clutch. The gas turbine engine includes a first turbine stage operatively coupled to the first drive shaft and a second turbine stage operatively coupled to the second drive shaft. The motor-generator is operatively coupled to the second drive shaft and is configured to generate electrical power to drive at least one propulsor of the plurality of propulsors and selectively drive the second shaft. The clutch is configured to operatively couple the second drive shaft to the first drive shaft.

A method of operating a hybrid electric power plant in cold climates comprises absorbing heat generated by an internal combustion engine, and using at least part of the heat absorbed from the internal combustion engine to warm a battery pack operatively connected to an electric motor.