An aeronautical propulsion system includes a fan having a plurality of fan blades rotatable about a central axis and defining a fan pressure ratio, FPR. The propulsion system also includes an electric motor mechanically coupled to the fan for driving the fan, the electric motor including a number of poles, n.sub.poles, and defining a maximum power, P. The relationship between the fan pressure ratio, FPR, of the fan, the number of poles, n.sub.poles, of the electric motor, and the maximum power, P, of the electric motor is defined by an equation: $\frac{n_{\mathrm{pole}}}{\sqrt{p}}=C_1.Math.e^{-9.062.Math.\mathrm{FPR}}+C_2.Math.e^{-1.2604.Math.\mathrm{FPR}};$
wherein C.sub.1 is a constant having a value between 22,000 and 52,000, wherein C.sub.2 is a constant having a value between 4.0 and 9.8, and wherein e is Euler's number.

A propulsion system for an includes a combustion engine, a propulsor, and an electric machine configured to either be driven by the combustion engine or configured to drive the propulsor. The electric machine defines an axis. The electric machine includes a rotor extending along and rotatable about the axis, and a stator having a plurality of winding assemblies, the plurality of winding assemblies spaced along the axis of the electric machine, each winding assembly operable with the rotor independently of an adjacent winding assembly during operation of the electric machine.

The disclosure herein relates to power leveling mechanisms comprising a high frequency controller. The power leveling mechanism receives a power demand signal indicating a power requirement of a vehicle and determines a high frequency component of the power demand signal. The power leveling mechanism also provides a signal to a primary propulsion system and provides, via the high frequency controller, a high bandwidth signal based on the high frequency component to an auxiliary propulsion system.

The invention relates to an aircraft which can both take off and land vertically and can hover and also fly horizontally at a high cruising speed. The aircraft has a support structure, a wing structure, at least three and preferably at least four lifting rotors and at least one thrust drive. The wing structure is designed to generate a lifting force for the aircraft during horizontal motion. To achieve this the wing structure has at least one mainplane provided with a profile that generates dynamic lift. The wing structure is preferably designed as a tandem wing structure. Each of the lifting rotors is fixed to the support structure, has a propeller and is designed to generate a lifting force for the aircraft by means of a rotation of the propeller, said force acting in a vertical direction. The thrust drive is designed to generate a thrust force on the support structure, said force acting in a horizontal direction. The lifting rotors can have a simple construction, i.e. they can have a simple rigid propeller for example, and a vertical take-off or hovering of the aircraft can be controlled, in a similar manner to quadcopters, by a simple control of the speeds of the lifting rotors. High cruising speeds can be achieved as a result of the additional horizontally acting thrust drive.

An electrical network for an aircraft. The aircraft includes at least one variable pitch propulsor. The electrical network includes a wound field synchronous AC electrical generator having a wound rotor driven by an internal combustion engine. The network further includes a voltage regulator configured to regulate output voltage of the electrical generator by regulating rotor winding magnetic field strength, and a synchronous AC drive motor coupled to a respective variable pitch propulsor and provided with power from the output of the electrical generator.

A system and method of noise mitigation for hybrid and electric aircraft, the aircraft having a controllable pitch propeller or rotor(s) with a plurality of blades. The propeller or rotor(s) are driven by a drive system to provide thrust for the aircraft, and the blades of the propeller or rotor(s) are further movable about pivot axis to vary a pitch thereof. A controller on-board the aircraft is operable to cause rotation or movement of the blades of the propeller or rotor(s) about their pivot axis to alter and/or focus at least one aspect of the propeller generated noise to reduce or mitigate such noise while maintaining a substantially constant thrust, altitude, and/or air speed of the aircraft.

The zero carbon emission vehicle as disclosed herein may include a condenser for extracting fluid water from the atmosphere, an electrolyzer for generating hydrogen from the fluid water, and one or more deformable fluid-retaining chambers that couple thereto for selectively adjusting the buoyancy and altitude of the zero carbon emission vehicle in real-time, to maintain the air vehicle in flight substantially without needing to land and refuel the air vehicle. Solar panels provide the energy for the described systems, and the energy from the solar panels can be stored in the form of hydrogen gas which gives buoyancy to the air vehicle.

A propulsion system for an aircraft includes an electric power source and an electric propulsion assembly having an electric motor and a propulsor, the propulsor powered by the electric motor. The propulsion system also includes an electric power bus electrically connecting the electric power source to the electric propulsion assembly. The electric power source is configured to provide electrical power to the electric power bus, and the electric power bus is configured to transfer the electric power to the electric propulsion assembly at a voltage exceeding 800 volts.

A propulsion system for an aircraft includes an electric power source, an electric propulsor assembly having an electric motor and a propulsor configured to generate thrust for the aircraft, and a power bus electrically connecting the electric power source to the electric propulsor assembly such that the electric power source powers the electric propulsor assembly. The power bus includes an electric line and a fluid cooling system, the fluid cooling system extending along at least a portion of a length of the electric line. The fluid cooling system is in thermal communication with the electric line for cooling the electric line during operation and is further in thermal communication with the electric motor of the electric propulsor assembly for cooling the electric motor of the electric propulsor assembly.

An aerial vehicle includes a hybrid power generation system comprising an engine; a generator mechanically coupled to the engine; and a propulsion system comprising an electric motor electrically coupled to the generator and a rotational mechanism coupled to the electric motor.