Abstract: An aerial vehicle adapted for vertical takeoff and landing using a set of wing mounted thrust producing elements and a set of tail mounted rotors for takeoff and landing. An aerial vehicle which is adapted to vertical takeoff with the rotors in a rotated, take-off attitude then transitions to a horizontal flight path, with the rotors rotated to a typical horizontal configuration. The aerial vehicle uses different configurations of its wing mounted rotors and propellers to reduce drag in all flight modes.

Abstract: The 3D extension linkage 100 can include at least one arm that includes two elements connected by a joint. The linkage can include an actuation mechanism, additional arms and/or each arm can include more than two elements, tie rods and/or cross pieces connecting two or more arms, and any other suitable components. The linkage 100 functions to translate and rotate a body attached to one end of the arm relative to a primary structure attached to a second end of the arm.

Abstract: A vertical take-off and landing aircraft which uses fixed rotors for both VTOL and forward flight operations. The rotors form a synthetic wing and are positioned to achieve a high span efficiency. The rotors are positioned to even out the lift across the span of the synthetic wing. The synthetic wing may also have narrow front and rear airfoils which may provide structural support as well as providing lift during forward flight. The wing rotors are tilted forward and provide some forward propulsion during horizontal flight.

Abstract: An aerial vehicle adapted for vertical takeoff and landing using a set of wing mounted thrust producing elements and a set of tail mounted rotors for takeoff and landing. An aerial vehicle which is adapted to vertical takeoff with the rotors in a rotated, take-off attitude then transitions to a horizontal flight path, with the rotors rotated to a typical horizontal configuration. The aerial vehicle uses different configurations of its wing mounted rotors and propellers to reduce drag in all flight modes.

Abstract: An aerial vehicle adapted for vertical takeoff and landing using a set of wing mounted thrust producing elements for takeoff and landing. An aerial vehicle which is adapted to vertical takeoff with the rotors in a rotated, take-off attitude then transitions to a horizontal flight path, with the rotors rotated to a typical horizontal configuration. The aerial vehicle uses different configurations of its wing mounted rotors and propellers to reduce drag in all flight modes. The aerial vehicle uses deployment mechanisms to deploy rotor assemblies up and away from their stowed configuration locations.

Abstract: A method for the flying of a vertical take-off and landing aircraft which uses fixed rotors for both VTOL and forward flight operations. The rotors form a synthetic wing and are positioned to achieve a high span efficiency. The rotors are positioned to even out the lift across the span of the synthetic wing. The synthetic wing may also have narrow front and rear airfoils which may provide structural support as well as providing lift during forward flight, or may have a single center wing. The wing rotors are tilted forward and provide some forward propulsion during horizontal flight.

Abstract: The system can include an on-board thermal management subsystem. The system 100 can optionally include an off-board (extravehicular) infrastructure subsystem. The on-board thermal management subsystem can include: a battery pack, one or more fluid loops, and an air manifold. The system 100 can additionally or alternatively include any other suitable components.

Abstract: A system and method for use with a VTOL aircraft with batteries in a state of deep discharge which prepares the aircraft for a safe vertical landing despite the deep discharge initial condition. The method may include preparing the batteries for an intense burst of power as may be needed during the vertical landing. The method may include idling the battery, thermally conditioning the battery, and may further include charging the batteries by regenerative use of the rotors. The preparation of the batteries may then allow for a burst of power used for landing the aircraft.

Abstract: A high efficiency hydrogen fuel system for an aircraft at high altitude which utilizes compressors to compress air to a sufficiently high pressure for the fuel cell. Liquid hydrogen is compressed and then utilized in heat exchangers to cool the compressed air, maintaining the air at a temperature low enough for the fuel cell. The hydrogen is also used to cool the fuel cell as it is also depressurized prior to its entry in the fuel cell cycle. A water condensation system allows for water removal from the airstream to reduce impacts to the atmosphere. The hydrogen fuel system may be used with VTOL aircraft, which may allow them to fly at higher elevations. The hydrogen fuel system may be used with other subsonic and supersonic aircraft, such as with asymmetric wing aircraft.

Abstract: The power system can include: a plurality of batteries, a plurality of electric propulsion units, flight computers, and power connections. The propulsion assemblies can include a motor, a propeller, and one or more inverters. The power system can optionally include a plurality of flight actuators. However, the power system can include any other suitable set of components. The power system functions to provide aircraft propulsion and/or aircraft control authority during flight.

Abstract: An aircraft propulsion system with a drag reduction portion adapted to reduce skin friction on at least a portion of the external surface of an aircraft. The drag reduction portion may include an inlet to ingest airflow. The aircraft may also have an internally cooled electric motor adapted for use in an aerial vehicle. The motor may have its stator towards the center and have an external rotor. The rotor structure may be air cooled and may be a complex structure with an internal lattice adapted for airflow. The stator structure may be liquid cooled and may be a complex structure with an internal lattice adapted for liquid to flow through. A fluid pump may pump a liquid coolant through non-rotating portions of the motor stator and then through heat exchangers cooled in part by air which has flowed through the rotating portions of the motor rotor. The drag reduction portion and the cooled electric motor portion may share the same inlet.

Abstract: A vertical take-off and landing aircraft which uses fixed rotors for both VTOL and forward flight operations. The rotors form a synthetic wing and are positioned to achieve a high span efficiency. The rotors are positioned to even out the lift across the span of the synthetic wing. The synthetic wing may also have narrow front and rear airfoils which may provide structural support as well as providing lift during forward flight. The wing rotors are tilted forward and provide some forward propulsion during horizontal flight.

Abstract: The unified command system and/or method includes an input mechanism, a flight processor that receives input from the input mechanism and translates the input into control output, and effectors that are actuated according to the control output. The system can optionally include: one or more sensors, a vehicle navigation system which determines a vehicle state and/or flight regime based on data from the one or more sensors, and a vehicle guidance system which determines a flightpath for the aircraft.

Abstract: An aircraft including an airframe and a plurality of propulsion assemblies coupled to the airframe, wherein each propulsion assembly includes an electric motor, a propeller coupled to the electric motor, and a tilt mechanism that connects the propulsion assembly to the airframe and transforms the propulsion assembly between a forward configuration and a hover configuration; wherein the plurality of propulsion assemblies is transformable between a forward arrangement and a hover arrangement, wherein each of the plurality of propulsion assemblies is in the forward configuration in the forward arrangement, wherein each of the plurality of propulsion assemblies is in the hover configuration in the hover arrangement, wherein the spacing between at least two of the propellers of the plurality of propulsion assemblies changes between the forward arrangement and the hover arrangement.

Abstract: The rotary airfoil 100 defines a cross section and a span, wherein the cross section is a function of the point along the span (e.g., spanwise point) and defines an upper surface and a lower surface at each spanwise point. The rotary airfoil 100 also defines, at a cross section, a lift coefficient (CL) that is a function of the angle of attack at which the airfoil is rotated through the air. The system can optionally include: a rotor hub to mount the rotary airfoil, a tilt mechanism to pivot the rotary airfoil between a forward configuration and a hover configuration, and a pitching mechanism to change the angle of attack of the rotary airfoil 100.

Abstract: A method for determining airspeed of an aircraft that includes determining a rotor model relating a power coefficient of a propeller of the aircraft to an axial inflow velocity through the propeller as a function of a set of rotor operating parameters; determining the set of rotor operating parameters by sampling an electronic control signal associated with an electric motor actuating the propeller; computing the axial inflow velocity through the propeller based on the set of rotor operating parameters using the rotor model; and determining the airspeed based on the axial inflow velocity.

Abstract: The 3D extension linkage 100 can include at least one arm that includes two elements connected by a joint. The linkage can include an actuation mechanism, additional arms and/or each arm can include more than two elements, tie rods and/or cross pieces connecting two or more arms, and any other suitable components. The linkage 100 functions to translate and rotate a body attached to one end of the arm relative to a primary structure attached to a second end of the arm.

Abstract: An aerial vehicle adapted for vertical takeoff and landing using pivoting thrust producing elements for takeoff and landing. An aerial vehicle which is adapted to takeoff with thrust units providing vertical thrust and then transitioning to a horizontal flight path. An aerial vehicle with pivoting thrust units with propellers, wherein some or all of the propellers are able to be stowed and fully nested during forward flight.

Abstract: The aircraft can include: an airframe, a tilt mechanism, a payload housing, and can optionally include an impact attenuator, a set of ground support members (e.g., struts), a set of power sources, and a set of control elements. The airframe can include: a set of rotors and a set of support members.

Abstract: The battery thermal management system includes a battery pack, a circulation subsystem, and a heat exchanger. The system can optionally include a cooling system, a reservoir, a de-ionization filter, a battery charger, and a controller.