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 configuration and then transitions to a horizontal flight path, with some or all of the rotors rotated to a powered horizontal configuration. The aerial vehicle may have deployment mechanisms which deploy electric motor driven propellers from a forward facing to a vertical orientation. The aerial vehicle may be powered with electric motors.

Abstract: A hydrogen fuel cell powered electric vertical take-off and landing (eVTOL) aircraft with a high efficiency hydrogen fuel system. The eVTOL aircraft may utilized tilt-up rotors for hover flight, which then transition to a forward facing forward flight configuration. The fuel cell system may use one or more compressors to compress air to a sufficiently high pressure for the fuel cell. Liquid hydrogen may be 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 may also be used to cool the fuel cell as it is also depressurized prior to its entry in the fuel cell cycle.

Abstract: A thrust unit for an aircraft with a hydrogen fuel system. The aircraft may utilize 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 thrust unit may be an electrically powered fan unit with a fan within a fan tube. The fan tube may include air inlets for the fuel cell system, as well as outlets for exhaust from the fuel cell system. The fan tube may contain heat exchangers which are part of the fuel cell thermodynamic system.

Abstract: A vertical take-off and landing aircraft which uses fixed rotors for both VTOL and forward flight operations. Some of the rotors are forward canted, while some of the rotors are forward facing. The forward canted rotors are tilted forward slightly from vertical and provide some forward propulsion during horizontal flight. The forward facing rotors may be fixed in a forward facing configuration. Forward swept wings allow for rotor placement which brings efficiency during hover operations.

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.

Abstract: A vertical take-off and landing aircraft and method which uses fixed rotors for both VTOL and forward flight operations. The wing rotors are tilted forward and provide some forward propulsion during horizontal flight. The wing rotors are under power during forward flight and provide some lift during horizontal flight. The fraction of lift provided by the vertical thrusting rotors is greater than 0.2. The rotor assemblies may have rotating propellers with electric motors.

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. By utilizing a larger rotor blade area (and/or larger rotor disc area) and adjusting the blade pitch and RPM, the rotors can augment the lift generated by the aerodynamic profile of the aircraft in the forward flight mode in addition to providing forward thrust. Variants generating lift with the rotors can reduce or eliminate additional control surfaces (e.g., wing flaps, ailerons, ruddervators, elevators, rudder, etc.) on the aircraft since the thrust and motor torque is controllable (thereby indirectly controlling lift) at each rotor, thereby enabling pitch, yaw, and/or roll control during forward flight.

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: 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 may have deployment mechanisms which deploy electric motor driven propellers from a forward facing to a vertical orientation. The aerial vehicle may have rear mounted rotors 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 may be powered with electric motors.

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 may have deployment mechanisms which deploy electric motor driven propellers from a forward facing to a vertical orientation. The deployment mechanisms deploy the rotor forward and up as they deploy from a forward flight configuration to a vertical thrust configuration. A single motor may drive two co-axial propellers, with a first propeller driven when the motor spins in a first direction, and a second propeller driven when the motor spins in a second direction.

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 may have deployment mechanisms which deploy electric motor driven propellers from a forward facing to a vertical orientation. The aerial vehicle may be powered with electric motors.

Abstract: An extension linkage for a wing flap 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 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. The linkage resides entirely within a space defined by the upper skin and the lower skin of the wing rearward of the mounting when in a retracted configuration.

Abstract: An aerial vehicle configured with air intake in an otherwise higher drag location. In some aspects, the aerial vehicle is a vertical take-off and landing aircraft. The aircraft may intake the air to provide air to a hydrogen fuel cell system within the aircraft. The aircraft may have electric motor driven rotor assemblies which provide thrust for both vertical take-off and landing and forward flight operations. The electric motor driven rotor assemblies may be powered by electric power from the fuel cell system. The air intake may be on the forward portion of a nacelle placed in what would be a high drag location, such as at the junction of the wings and the fuselage, or the junction of the vertical stabilizers and the fuselage, for example.

Abstract: An aircraft propulsion system with 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: 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 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 multi-segment oblique flying wing aircraft which has three distinct segments including two outer wing segments and a central wing segment. The central segment may be thicker in the vertical direction and adapted to hold pilots and passengers. The outer wing segments may be substantially thinner and may taper as they progress outboard from the wing center. The multi-segment oblique flying wing aircraft be adapted for rotating into a high speed flight configuration, or may be adapted for take-off and cruise at a constant angle. In an extreme flight case, the central wing segment may rotate to a local sweep of ninety degrees.

Abstract: A vertical takeoff and landing aircraft includes a starboard wing, a port wing, first and second tilt rotors coupled to the port and starboard wings respectively, and first and second batteries. A pair of control surfaces are arranged on a first side of the mid-sagittal plane of the aircraft, the pair comprising a first and a second control surface. A first flight actuator is electrically connected to the first battery and a second flight actuator is electrically connected to the second battery. The first and second flight actuators are mechanically connected to the first and second control surfaces respectively.

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: An oblique flying wing aircraft with internal ducting and airflow. The aircraft may have propulsion units within the wing body. The propulsion units may be off-axis internal to the wing to utilize locations with larger internal space available. In some aspects, the multi-segment oblique flying wing aircraft may have three distinct segments including two outer wing segments and a central wing segment. The central segment may be thicker in the vertical direction and adapted to hold pilots and passengers. The outer wing segments may be substantially thinner and may taper as they progress outboard from the wing center. The multi-segment oblique flying wing aircraft be adapted for rotating into a high-speed flight configuration, or may be adapted for take-off and cruise at a constant angle.