A propulsion system includes an electric propulsor and a gas turbine engine. The propulsion system also includes an electric machine coupled to a rotary component of the gas turbine engine generating a voltage at a baseline voltage magnitude during operation of the gas turbine engine. An electric communication bus is provided electrically connecting the electric machine to the electric propulsor. The propulsion system additionally includes a means for providing a differential voltage to the electric propulsor equal to about twice the baseline voltage magnitude.

An aspect provides an aircraft including a fuselage and a cross-flow fan system attached to the fuselage. The cross-flow fan system including a cross-flow fan assembly associated with a rotatable wing member having an exterior aerodynamic surface. In one aspect, there is provided an aircraft with a fuselage having a forward portion and an aft portion; a first cross-flow fan system rotatably attached to the left side of the forward portion of the fuselage; a second cross-flow fan system rotatably attached to the right side of the forward portion of the fuselage; a third cross-flow fan system rotatably attached to the left side of the aft portion of the fuselage; and a fourth cross-flow fan system rotatably attached to the right side of the aft portion of the fuselage.

An aircraft where an engine creates mechanical energy. That energy is then converted into another transmittable form, e.g., electrical using a generator, or hydraulic using a pump, and is delivered to remotely-located motors and thrusters, e.g., propellers at one or more locations on the aircraft. The general concept makes the engine as well as the motors used scalable to accomplish overall efficiency objectives.

A propulsion system for an aircraft includes an engine (e.g., piston engine, or turbine) having an axis made to be nonparallel with the longitudinal axis of the aircraft. This is enabled using an electrical, hydraulic, or other system to transfer energy generated by the engine (e.g., via electrical wiring, fluid conduits, etc.) to remotely power a motor used to drive a thrust-creating device (e.g., propeller or ducted fan). That the engine is able to be freely oriented allows for it being positioned without regard to any mechanical restraints existing in conventional arrangements.

The disclosure generally pertains to a vertical take-off and landing (VTOL) aircraft comprising a fuselage and at least one fixed wing. The aircraft may include at least two powered rotors located generally along a longitudinal axis of the fuselage. The rotor units may be coupled to the fuselage via a rotating chassis, which allows the rotors to provide directed thrust by movement of the rotor units about at least one axis. By moving the rotor units, the aircraft can transition from a hover mode to a transition mode and then to a forward flight mode and back.

An electrical system (1A-1C) for an electric machine (2) comprises: at least three connections (A1-A3) for electrical connection to in each case one phase of an at least three-phase AC voltage; a first star circuit (10A-10C) with three strands (100A-100C) via each of which one of the at least three connections (A1-A3) is electrically connected to a common star point (101) of the first star circuit (10A-10C) and which each have at least (11A-11C) with three strands (110A-110C) via each of which one of the at least three connections (A1-A3) is electrically connected to a common star point (111) of the second star circuit (11A-11C) and which each have at least two tooth windings (Z) which are connected in series; and a measuring device (12), which is electrically connected between the first star circuit (10A-10C) and the second star circuit (11A-11C), for measuring an electrical variable.

An electrical system (1A-1C) for an electric machine (2) comprises: at least three connections (A1-A3) for electrical connection to in each case one phase of an at least three-phase AC voltage; a first star circuit (10A-10C) with three strands (100A-100C) via each of which one of the at least three connections (A1-A3) is electrically connected to a common star point (101) of the first star circuit (10A-10C) and which each have at least (11A-11C) with three strands (110A-110C) via each of which one of the at least three connections (A1-A3) is electrically connected to a common star point (111) of the second star circuit (11A-11C) and which each have at least two tooth windings (Z) which are connected in series; and a measuring device (12), which is electrically connected between the first star circuit (10A-10C) and the second star circuit (11A-11C), for measuring an electrical variable.

One embodiment is an aircraft including a fuselage; a wing connected to the fuselage; first and second booms connected to the wing on opposite sides of the fuselage; first and second forward propulsion systems attached to forward ends of the first and second booms; first and second aft propulsion systems fixedly attached proximate aft ends of the first and second booms; first and second wing-mounted propulsion systems connected to outboard ends of wings; and first and second wing tips fixedly connected to outboard sides of the first and second wing-mounted propulsion systems; wherein the first and second wing-mounted propulsion systems and the first and second wing tips are collectively tiltable between a first position when the aircraft is in a hover mode and a second position when the aircraft is in a cruise mode.

An electric aircraft engine includes an electric motor driving a propulsor. A power source powers the electric motor. An electric compressor supplies compressed air. A nacelle surrounds the electric motor, the power source and the electric compressor. An aircraft and a method are also disclosed.

Aspects described herein may relate to aerial structures such as aircraft. An aerial structure may include a fuselage, a wing attached to the fuselage, and a plurality of propulsion systems configured to generate thrust. A propulsion system may include a plurality of propulsors, such as propulsor fans. A propulsor fan may be configured to be actuated between a conventional take-off and landing (CTOL) flight mode, a short take-off and landing (STOL) flight mode, and a vertical take-off and landing (VTOL) flight mode.