A rotorcraft is provided and includes a fuselage. The fuselage includes drag generating portions, a main rotor assembly and an auxiliary propulsor having an expected propulsion efficiency. The auxiliary propulsor is disposed to ingest boundary layer flows and in wake regions associated with the drag generating portions and is provided with a corresponding increase in the expected propulsion efficiency thereof.

A main rotor system for a rotary wing aircraft is provided including a lower rotor hub to which lower rotor blades are attachable. The lower rotor hub rotates about an axis in a first direction. A hollow rotor shaft extends through the lower rotor hub. The first end of the rotor shaft couples to a component of the rotary wing aircraft for rotation about an axis. An upper rotor hub arranged at the second end of the rotor shaft includes a plurality of similar upper rotor members equidistantly spaced about a circumference of the rotor shaft to form an open center aligned with a hollow interior of the rotor shaft. An opening configured to receive an upper rotor blade is formed between adjacent upper rotor members and the upper rotor hub is configured to rotate in a second direction, opposite the first direction.

The present disclosure provides various embodiments of a multicopter-assisted launch and retrieval system generally including: (1) a multi-rotor modular multicopter attachable to (and detachable from) a fixed-wing aircraft to facilitate launch of the fixed-wing aircraft into wing-borne flight; (2) a storage and launch system usable to store the modular multicopter and to facilitate launch of the fixed-wing aircraft into wing-borne flight; and (3) an anchor system usable (along with the multicopter and a flexible capture member) to retrieve the fixed-wing aircraft from wing-borne flight.

This disclosure relates to various multi-rotor aircrafts including at least one passively tiltable rotor group which may be tilted, typically in a direction of their movement. More importantly, the passively tiltable rotor group can tilt on its own, without having to include any additional electric motor or other power generating devices. This disclosure relates to various multi-rotor aircrafts including various load sharing units capable of taking up at least a portion of a weight load of the aircraft to itself, thereby diverting that portion of the weight load from a tilting unit. Therefore, the tilting units may be tilted more easily under the reduced weight load and friction. This disclosure further relates to various methods of fabricating or operating such passively tiltable rotor groups, tilting units, or load sharing units, and various methods of incorporating such into the multi-rotor aircraft.

A spherical bearing which extends from and connects to a deformable component includes an outer member and an inner member. The inner member is pivotable relative to the outer member about an axis. The inner member has an opening formed therein that defines a plurality of coplanar contact surfaces shaped to accommodate and contact the component. The plurality of contact surfaces are movable to accommodate deformation of the component positioned within the opening.

A spherical bearing which extends from and connects to a deformable component includes an outer member and an inner member. The inner member is pivotable relative to the outer member about an axis. The inner member has an opening formed therein that defines a plurality of coplanar contact surfaces shaped to accommodate and contact the component. The plurality of contact surfaces are movable to accommodate deformation of the component positioned within the opening.

Propulsors (e.g., an electric motor mechanically coupled to a rotor) are described that passively cool the electric motors via an airflow path through the electric motor and out of the rotors. One embodiment comprises a method of cooling an electric motor. The method comprises operating the electric motor of a propulsor for an aircraft to rotate a rotor of the propulsor, where the rotor has one or more air outlets, and where the electric motor has a housing that includes one or more air inlets in fluid communication with the one or more air inlets. The method further comprises generating, by rotating the rotor using the electric motor, an airflow through the electric motor from the one or more air inlets to the one or more air outlets to cool the electric motor.

Propulsors (e.g., an electric motor mechanically coupled to a rotor) are described that passively cool the electric motors via an airflow path through the electric motor and out of the rotors. One embodiment comprises a method of cooling an electric motor. The method comprises operating the electric motor of a propulsor for an aircraft to rotate a rotor of the propulsor, where the rotor has one or more air outlets, and where the electric motor has a housing that includes one or more air inlets in fluid communication with the one or more air inlets. The method further comprises generating, by rotating the rotor using the electric motor, an airflow through the electric motor from the one or more air inlets to the one or more air outlets to cool the electric motor.

A vehicle includes a propulsion system using one or more impellers as opposed to propellers. The impellers impart circumferential and radial velocity components to the working fluid, which may be air or water. The air is deflected by counter-vortex chambers in a shroud to convert the circumferential and radial velocity to an axial velocity aligned with the axis of rotation of the impeller.

A vehicle includes a propulsion system using one or more impellers as opposed to propellers. The impellers impart circumferential and radial velocity components to the working fluid, which may be air or water. The air is deflected by counter-vortex chambers in a shroud to convert the circumferential and radial velocity to an axial velocity aligned with the axis of rotation of the impeller.