An aircraft defines a vertical direction and includes a fuselage and a propulsion system comprising a power source and a plurality of vertical thrust electric fans driven by the power source. A wing extends from the fuselage. The plurality of vertical thrust electric fans are arranged along a length of the wing along a lengthwise direction of the wing. The wing comprises a diffusion assembly along the lengthwise direction of the wing and includes a first diffusion member positioned downstream of at least one of the plurality of vertical thrust electric fans. The first diffusion member defines a curved shape relative to a longitudinal direction of the aircraft. The longitudinal direction is generally perpendicular to the lengthwise direction of the wing.

Certain aspects relate to a blended wing body aircraft with a fuel cell and methods of use. An exemplary aircraft includes a blended wing body, at least a propulsor mechanically affixed to the aircraft and configured to propel the aircraft, at least a first fuel store configured to store a first fuel, and at least a fuel cell configured to combine the first fuel with oxygen to produce electricity.

Certain aspects relate to a blended wing body aircraft with a fuel cell and methods of use. An exemplary aircraft includes a blended wing body, at least a propulsor mechanically affixed to the aircraft and configured to propel the aircraft, at least a first fuel store configured to store a first fuel, and at least a fuel cell configured to combine the first fuel with oxygen to produce electricity.

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.

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.

An electric aircraft includes a forward wing and an aft wing both located on a top side of a fuselage and both having an upward dihedral angle. The forward wing has a straight or slightly forward-swept leading edge. The aft wing has a swept leading edge. A plurality of propeller engines are located on a leading-edge side of the forward wing. A single propeller engine may be located on a top side of an aft end of the fuselage; alternatively, a plurality of propeller engines are located on the aft wing on either its leading or trailing edge. The propeller engines are each powered by an electric motor. An unobstructed cargo door is located on a side of the fuselage, aft of the forward wing.

An aircraft propulsion system having a variable airflow capture area is provided. The propulsion system includes a main propulsion source and an auxiliary propulsion source. In a first mode, the auxiliary propulsion source is stowed within an aerodynamic profile of the aircraft, and the main propulsion source provides all of the propulsion force for powering flight of the aircraft. In a second mode, the auxiliary propulsion source is deployed to augment the airflow capture area of the main propulsion source and increase an overall airflow capture area of the propulsion system. In the second mode, the auxiliary power source is operated by power extracted from the main propulsion source. The main propulsion source may include one or more low bypass ratio engines. The auxiliary power source may include one or more auxiliary thrust fans coupled at a plurality of locations on the aircraft.

A method is provided for operating a propulsion system of a vertical takeoff and landing aircraft, the propulsion system including a turbomachine, an electric machine, a forward thrust propulsor, and a plurality of vertical thrust electric fans. The method includes driving the forward thrust propulsor with the turbomachine; rotating the electric machine with the turbomachine to generate electrical power; determining a failure condition of the turbomachine; and providing electrical power to the electric machine to drive the forward thrust propulsor with the electric machine in response to determining the failure condition of the turbomachine.

An aircraft includes a fuselage; a propulsion system including a power source and a plurality of vertical thrust electric fans driven by the power source; and a wing extending from the fuselage. The plurality of vertical thrust electric fans are arranged along a length of the wing, the wing including a variable geometry assembly extending along the length of the wing and moveable between a forward thrust position and a vertical thrust position, the variable geometry assembly at least partially covering the plurality of vertical thrust electric fans when in the forward thrust position and at least partially exposing the plurality of vertical thrust electric fans when in the vertical thrust position.

An aircraft includes a fuselage; a propulsion system including a power source and a plurality of vertical thrust electric fans driven by the power source; and a wing extending from the fuselage. The plurality of vertical thrust electric fans are arranged along a length of the wing, the wing including a variable geometry assembly moveable generally along a horizontal direction between a forward thrust position and a vertical thrust position, the variable geometry assembly at least partially covering at least one vertical thrust electric fan of the plurality of vertical thrust electric fans when in the forward thrust position and at least partially exposing the at least one vertical thrust electric fan when in the vertical thrust position.