An aircraft includes a closed wing, a fuselage at least partially disposed within a perimeter of the closed wing, and one or more spokes coupling the closed wing to the fuselage. A source of electric power is disposed within or attached to the closed wing, fuselage or one or more spokes. A plurality of electric motors are disposed within or attached to the one or more spokes in a distributed configuration. Each electric motor is connected to the source of electric power. A propeller is operably connected to each of the electric motors and proximate to a leading edge of the one or more spokes. One or more processors are communicably coupled to the plurality of electric motors. A longitudinal axis of the fuselage is substantially vertical in vertical takeoff and landing and stationary flight, and substantially in a direction of a forward flight in a forward flight mode.

An aircraft navigational system for a multiengine aircraft can include a flight planning module configured to receive two or more navigational points defining a route and determine if a first degraded operation ceiling is high enough to travel along the route based on obstacle data defining relative location of one or more obstacles and one or more obstacle clearance standards. The module can be configured to receive a status and/or performance limitation of an electric motor system of the aircraft. The module can be configured to determine if the electric motor system is or will be able to provide temporary additional power to produce a second degraded operation ceiling for at least a required time based on the status and/or performance limitation of the electric motor system if the first degraded operation ceiling is not high enough to permit travel along the route. The second degraded operation ceiling can be high enough to travel along the route based on the obstacle data and the one or more obstacle clearance standards.

An aircraft is disclosed having a boundary layer ingestion propulsor. The aircraft comprises an elongated fuselage extending between a nose section and a tail section. The fuselage has an upswept underside in the tail section. The boundary layer ingestion propulsor is positioned in the tail section. The propulsor comprises a fan radially encased by a nacelle circumscribing the fuselage. The nacelle defines a leading edge line extending from a top dead center to a bottom dead center of the nacelle intersecting an axis of rotation of the fan at an angle no greater than seventy degrees.

Embodiments of a propulsion system are provided herein. In some embodiments, a propulsion system for an aircraft may include an electrical power supply; a motor coupled to the electrical power supply, wherein the electrical power supply provides power to the motor; and a fan disposed proximate a rear portion of an aircraft and rotatably coupled to the motor, wherein the fan is driven by the motor.

A power source for an aircraft including a solid oxide fuel cell and a proton exchange membrane fuel cell along with a solid oxide fuel cell multi-power source. At least one battery is electrically coupled to the solid oxide fuel cell, the proton exchange membrane fuel cell, and an aircraft distribution network to supply electricity to the aircraft and also for becoming recharged by the solid oxide fuel cell and the proton exchange membrane fuel cell.

A cargo transportation system includes a cargo platform having an upper surface and a perimeter. A propulsion system is disposed about the perimeter of the cargo platform. The propulsion system includes a plurality of propulsion assemblies, each including a propulsion unit disposed within a housing defining an airflow channel having an air inlet for incoming air and an air outlet for outgoing air such that the outgoing air is operable to generate at least vertical lift. A power system disposed within the cargo platform provides energy to drive the propulsion system. A flight control system operably associated with the propulsion system and the power system controls flight operations of the cargo transportation system.

A method of optimizing the noise generated by a rotorcraft on the ground, said rotorcraft including a hybrid power plant, at least one rotor, and an electrical energy source. Said method makes it possible to monitor whether each engine of said power plant is on or off, and to monitor the state of each electric machine of said hybrid power plant. Said method also makes it possible to monitor whether said rotorcraft is on the ground. Then, each engine that is on is controlled to reach an idling speed, or indeed to be caused to stop by being switched off, and said electric machine is regulated on a setpoint speed of rotation of a rotor so as to drive each rotor while also limiting the noise generated by said hybrid power plant.

A propulsion system for an aircraft having an aft end is provided herein. The propulsion system can include an electric propulsion engine defining a central axis. The electric propulsion engine can include an electric motor, a fan rotatable about the central axis of the electric propulsion engine by the electric motor, a bearing supporting rotation of the fan, and a thermal management system. The thermal management system can include a lubrication oil circulation assembly for providing the bearing with lubrication oil. The lubrication oil circulation assembly can be driven independently of a shaft of the electric propulsion engine.

Technologies are described herein for a drag recovery scheme. In various examples, a recovery engine is placed within a vortex flow of air caused by the impingement of air upon a nacelle of a main engine. The propeller of the recovery engine can use the vortex flow of air to provide additional thrust the aircraft, thus reducing the load on the main engines or providing an increased velocity.

An aircraft having a fuselage with a nose and a flat tail at opposite ends and a pair of wings extending therefrom. A pair of nacelles are detachably connected to the top of respective ones of the wings to be spaced from the fuselage to establish an air flow space therebetween, Each wing-mounted nacelle includes a plurality of fans, a corresponding plurality of electric motors to drive the fans, and dividers that separate the fans from one another. Each wing-mounted nacelle also includes a pair of rotatable air inlet slats at an air intake end and a pair of rotatable air exhaust flaps at an air exhaust end that are rotated relative to one another to control horizontal propulsive thrust, thrust vectoring and thrust reversing of the aircraft. A third nacelle is mounted on top of the flat tail of the fuselage between a pair of horizontal turbo generators.