Abstract: A propeller assembly including a shaft having a rotational axis; a plurality of propellers connected to the shaft; means for deploying the plurality of propellers using a centrifugal force generated from a rotation of the shaft, so as to provide vertical thrust during a vertical take-off and landing of the aircraft; and means for restoring the propellers into a stowed configuration.

Abstract: A driver can be configured to provide sensed phase currents as feedback to a controller to indicate the output currents from each phase of a switch mode power supply (SMPS). The driver can be configured to temperature compensate the sensed currents in one of two ways. If a temperature sensor is directly coupled to the driver, then the driver may be configured to temperature compensate the sensed currents from each phase based on a temperature measurement made by the temperature sensor. If a temperature sensor is not directly coupled to the driver, then the driver may be configured to temperature compensate the sensed current from each phase based on a temperature signal received from a bus coupled to the driver. The bus can communicate the temperature signal so that multiple drivers can utilize one temperature sensor.

Abstract: A method is provided for operating a vehicle that includes rotors driven by actuators to cause the vehicle to move. The method includes determining rotational speeds at which to drive the rotors to achieve a controlled movement of the vehicle. The rotational speeds include a rotational speed for a rotor of a pair of the rotors driven by a pair of the actuators. The method includes monitoring the rotational speed to detect that the rotational speed has approached or reached a defined avoid band of rotational speeds, and biasing the rotational speed to produce at least one biased rotational speed for respective rotors of the pair that is outside the defined avoid band. The method includes generating commands for the actuators based on the rotational speeds, and modifying the commands including those of the commands for the pair of the actuators based on the at least one biased rotational speed.

Abstract: A method is provided for operating a vehicle that includes rotors driven by actuators to cause the vehicle to move. The method includes determining rotational speeds at which to drive the rotors to achieve a controlled movement of the vehicle. The rotational speeds include a rotational speed for a rotor of a pair of the rotors driven by a pair of the actuators. The method includes monitoring the rotational speed to detect that the rotational speed has approached or reached a defined avoid band of rotational speeds, and biasing the rotational speed to produce at least one biased rotational speed for respective rotors of the pair that is outside the defined avoid band. The method includes generating commands for the actuators based on the rotational speeds, and modifying the commands including those of the commands for the pair of the actuators based on the at least one biased rotational speed.

Abstract: Multi-rotor rotorcraft comprise a fuselage, and at least four rotor assemblies operatively supported by and spaced-around the fuselage. Each of the at least four rotor assemblies defines a spin volume and a spin diameter. Some multi-rotor rotorcraft further comprise at least one rotor guard that is fixed relative to the fuselage, that borders the spin volume of at least one of the at least four rotor assemblies, and that is configured to provide a visual indication of the spin volume of the at least one of the at least four rotor assemblies. Various configurations of rotor guards are disclosed.

Abstract: A rotor assembly for a fixed-wing VTOL aircraft. The rotor assembly is configured to provide vertical flight for the fixed-wing VTOL aircraft. In one embodiment, the rotor assembly includes a hub assembly, a first rotor blade affixed to the hub assembly, and a second rotor blade affixed to the hub assembly. The hub assembly orients the second rotor blade in relation to the first rotor blade about an axis of rotation of the hub assembly with the first rotor blade and the second rotor blade vertically stacked when the hub assembly is stopped for wing-borne flight.

Abstract: The present disclosure provides systems, apparatuses, and methods relating to a fan apparatus including a lift fan mounted in a duct and a cover for the lift fan. In some examples, a fan apparatus has a louvered cover including louvers having different chord lengths and/or different projection distances relative to one another when the louvers are in an intermediate (transitional) position. In some examples, a fan apparatus includes a louver actuation assembly configured to move louvers of the fan apparatus rotationally and translationally between open and closed positions. In some examples, a fan apparatus includes a fluid-actuated sealing assembly configured to form a seal between a sealing member and a cover, such as a louvered cover.

Abstract: A propeller assembly including a shaft having a rotational axis; a plurality of propellers connected to the shaft; means for deploying the plurality of propellers using a centrifugal force generated from a rotation of the shaft, so as to provide vertical thrust during a vertical take-off and landing of the aircraft; and means for restoring the propellers into a stowed configuration.

Abstract: Active fluid control systems and related methods are disclosed. A disclosed example active fluid control system includes a plurality of plenums coupled together to define a fluid flow passageway, and a plurality of fluidic actuators coupled to outer surfaces of respective ones of the plenums. The fluidic actuators define actuator inlets and actuator outlets. The fluid flow passageway defined by the plenums to fluidly couple the fluidic actuators and a pressurized fluid supply source. The plenums are configured to couple to an aircraft structure supporting an aerodynamic surface to enable the actuator outlets to be mounted to the aerodynamic surface. The fluidic actuators are configured to provide the pressurized fluid to the aerodynamic surface to modify an aerodynamic characteristic of the aerodynamic surface.

Abstract: A rotor assembly for a fixed-wing VTOL aircraft. The rotor assembly is configured to provide vertical flight for the fixed-wing VTOL aircraft. In one embodiment, the rotor assembly includes a hub assembly, a first rotor blade affixed to the hub assembly, and a second rotor blade affixed to the hub assembly. The hub assembly orients the second rotor blade in relation to the first rotor blade about an axis of rotation of the hub assembly with the first rotor blade and the second rotor blade vertically stacked when the hub assembly is stopped for wing-borne flight.

Abstract: A rotorcraft has a frame and a plurality of rotors connected to the frame. The frame has a roll axis and a pitch axis. Each of the rotors includes a rotor shaft. The rotor shaft of each of the rotors is canted with respect to at least one of the roll axis and the pitch axis. The rotor shaft of each of the rotors may be canted between 3 and 15 degrees. Each of the rotors may be a co-axial co-rotating rotor. The rotors may be oriented in opposing pairs across the frame. Both rotors in each opposing pair rotate in the same direction. The rotorcraft may include at least two additional rotors, each having a forward cant. Each of the additional rotors may be a co-axial contra-rotating rotor.

Abstract: A rotor assembly for a fixed-wing VTOL aircraft. The rotor assembly is configured to provide vertical flight for the fixed-wing VTOL aircraft. In one embodiment, the rotor assembly includes a hub assembly, a first rotor blade affixed to the hub assembly, and a second rotor blade affixed to the hub assembly. The hub assembly orients the second rotor blade in relation to the first rotor blade about an axis of rotation of the hub assembly with the first rotor blade and the second rotor blade vertically stacked when the hub assembly is stopped for wing-borne flight.

Abstract: Multi-rotor rotorcraft (10) comprise a fuselage (12), and at least four rotor assemblies (14) operatively supported by and spaced-around the fuselage (12). Each of the at least four rotor assemblies (14) defines a spin volume (24) and a spin diameter (26). Some multi-rotor rotorcraft (10) further comprise at least one rotor guard (50) that is fixed relative to the fuselage (12), that borders the spin volume (24) of at least one of the at least four rotor assemblies (14), and that is configured to provide a visual indication of the spin volume (24) of the at least one of the at least four rotor assemblies (14). Various configurations of rotor guards (50) are disclosed.

Abstract: A method and apparatus for controlling an airflow. The method draws air through a group of inlets. The group of inlets is located in a group of locations on the vehicle such that the group of inlets actively controls the airflow relative to an aircraft when drawing the air. The method compresses the air drawn by the group of inlets in a group of air compressor units located in an aircraft structure to form pressurized air. Further, the method sends the pressurized air through a group of exit ports in the aircraft structure. The pressurized air flowing out of the group of exit ports actively controls the airflow for an aircraft, enabling an improved performance of the aircraft.

Abstract: Apparatus for controlling multi-rotor vehicle vibrations and related methods are disclosed herein. An example apparatus includes a vibration level detector to determine a vibration level of a frame of a vehicle based on data received from a sensor of the vehicle, the vehicle including a rotor. The apparatus includes a rotor operation analyzer to determine an operational parameter of the rotor based on the vibration level. The apparatus includes a communicator to transmit an instruction including the operational parameter to a controller of the rotor.

Abstract: A rotorcraft has a frame and a plurality of rotors connected to the frame. The frame has a roll axis and a pitch axis. Each of the rotors includes a rotor shaft. The rotor shaft of each of the rotors is canted with respect to at least one of the roll axis and the pitch axis. The rotor shaft of each of the rotors may be canted between 3 and 15 degrees. Each of the rotors may be a co-axial co-rotating rotor. The rotors may be oriented in opposing pairs across the frame. Both rotors in each opposing pair rotate in the same direction. The rotorcraft may include at least two additional rotors, each having a forward cant. Each of the additional rotors may be a co-axial contra-rotating rotor.

Abstract: Active fluid control systems and related methods are disclosed. A disclosed example active fluid control system includes a plurality of plenums coupled together to define a fluid flow passageway, and a plurality of fluidic actuators coupled to outer surfaces of respective ones of the plenums. The fluidic actuators define actuator inlets and actuator outlets. The fluid flow passageway defined by the plenums to fluidly couple the fluidic actuators and a pressurized fluid supply source. The plenums are configured to couple to an aircraft structure supporting an aerodynamic surface to enable the actuator outlets to be mounted to the aerodynamic surface. The fluidic actuators are configured to provide the pressurized fluid to the aerodynamic surface to modify an aerodynamic characteristic of the aerodynamic surface.

Abstract: A rotor assembly for a fixed-wing VTOL aircraft. The rotor assembly is configured to provide vertical flight for the fixed-wing VTOL aircraft. In one embodiment, the rotor assembly includes a hub assembly, a first rotor blade affixed to the hub assembly, and a second rotor blade affixed to the hub assembly. The hub assembly orients the second rotor blade in relation to the first rotor blade about an axis of rotation of the hub assembly with the first rotor blade and the second rotor blade vertically stacked when the hub assembly is stopped for wing-borne flight.

Abstract: Disclosed herein is one embodiment of a thrust system that includes at least one modular thrust unit and at least one control module. The at least one modular thrust unit includes a base that is made from structural members that are inter-connectable in a plurality of different structural configurations. The at least one modular thrust unit further includes at least one thrust generator coupleable to the base in a thrust configuration and at least one power source operable to deliver power to the at least one thrust generator. The at least one control module is coupleable to the at least one modular thrust unit and operable to control at least one of the at least one thrust generator and the at least one power source.