Abstract: Disclosed herein are systems and methods for propulsor cyclic control. Propulsor cyclic control may be used to reduce asymmetric loads in aircraft flight. A system for propulsor cyclic control may include an electric aircraft comprising a motor, a propulsor, and a cyclic. Cyclic may be controlled passively or actively.

Abstract: A propulsor assembly of an electric aircraft is described. The propulsor assembly includes an electric motor, where the electric motor includes a stator and a rotor. The assembly further includes a propulsor mechanically connected to the rotor of the electric motor. The assembly also includes a cyclic control assembly including an electric actuator and a push rod, wherein the push rod is mechanically connected to the actuator and the propulsor, the push rod is configured to increase a blade angle of the propulsor when the push rod is displaced in a first direction, and the push rod is configured to decrease the blade angle of the propulsor when the push rod is displaced in a second direction.

Abstract: A system and a method for controlling a propulsor assembly of an electric aircraft. The system may include an electric motor, wherein the electric motor may include a rotor and a stator, a propulsor driven by the electric motor configured to propel an electric aircraft. The propulsor may include a propeller. The propeller may include a blade. The system may include a cyclic control assembly configured to deflect the blade. The cyclic control assembly may include an actuator and a push rod mechanically connected to the actuator and the propulsor. The system may include a flight controller. The flight controller may be configured to receive sensor datum from at least a sensor communicatively connected to the electric aircraft, generate a deflection command as a function of the sensor datum and actuate the cyclic control assembly as a function of the deflection command.

Abstract: Disclosed herein are systems and methods for propulsor cyclic control. Propulsor cyclic control may be used to reduce asymmetric loads in aircraft flight. A system for propulsor cyclic control may include an electric aircraft comprising a motor, a propulsor, and a cyclic. Cyclic may be controlled passively or actively.

Abstract: A combined cyclic and teeter system for an electric vertical takeoff and landing (eVTOL) aircraft is disclosed. In some embodiments, the eVTOL aircraft may include a motor and a propulsor driven by the motor, wherein the propulsor may include a propeller with a rigid blade and configured to propel the eVTOL aircraft. In some embodiments, the eVTOL aircraft may include a cyclic attached to the propeller and configured to change a pitch of blades of the propeller. In some embodiments, the eVTOL aircraft may include a passive flap attached to the propeller and configured to passively control flight transients, wherein the passive flap may include a base rotatably affixed to the propulsor and configured to rotate about a rotational axis and a hinge connecting the base and the propeller and configured to allow the propeller to pivot about a pivot point of the hinge.

Abstract: An electric vertical takeoff and landing aircraft including a teetering propulsor assembly is provided. Teetering propulsor assembly may include a propeller that includes a hub and blades. Hub of propeller may be mechanically connected to a teeter mechanism of propulsor assembly that may be configured to allow the propeller to pivot about a teeter axis relative to the electric aircraft. Thus, teeter mechanism allows for a rotational axis of propeller to move during teetering of propeller. Teeter mechanism may include one or more springs that reduce teetering or prevent teetering of the propulsor at certain rotational speeds of propeller.

Abstract: A locking system for a propulsor teeter of an aircraft is disclosed. The system includes a propulsor, driven by a motor, comprising a hub, wherein the hub is configured to rotate about a rotational axis, a teeter mechanism connected to the hub, wherein the teeter mechanism is configured to permit the propulsor to pivot along an axis, wherein the axis is non-parallel with a longitudinal axis of the propulsor and intersecting with the rotational axis of the propulsor and a locking mechanism configured to lock the teeter mechanism, restricting the pivoting of the propulsor, while the aircraft is in wing-borne flight.

Abstract: Aspects of the disclosure provide a flex connection for high altitude balloon applications. During operation flex connection allows a payload of a high-altitude balloon to remain level when an envelope of the balloon is tilted, in order to change the direction of the balloon. As an example, a system may include a balloon envelope, a payload, a cable between the balloon envelope and the payload, and a flex connection on the cable. The flex connection enables the payload to remain level relative to the ground when the balloon is in flight and the balloon envelope is tilted relative to the payload. The flex connection includes a top portion, a plurality of discs, and a bottom portion.

Abstract: A stratospheric balloon may include an upper structure having a pulley, a lower structure, at least one solar panel suspended between the upper structure and the lower structure, and a first orientation control member connected, at a first end thereof, to a first transverse edge of the at least one solar panel and, at a second end thereof, to a second transverse edge of the at least one solar panel. The first orientation control member is wound about the pulley such that rotating the pulley changes the orientation of the at least one solar panel relative to the upper structure and the lower structure. In another example, the pulley may be replaced by first and second support mechanisms and the system may include a second orientation control member. The first and second orientation control members are connected to the first and second support mechanisms, respectively, and to the solar panel.

Abstract: A parking system for a propulsor teeter of an aircraft is disclosed. The system includes a propulsor including a hub. The hub is mechanically connected to a rotor, wherein the hub is configured to rotate about a rotational axis. A teeter mechanism is connected to the hub, wherein the teeter mechanism is configured to permit a propulsor plane of the propulsor to pivot with respect to a point of intersection between the propulsor plane and the rotational axis of the propulsor. A locking mechanism is configured to selectively lock the teeter mechanism while the aircraft is in flight, wherein selectively locking the teeter mechanism restricts the pivoting of the propulsor plane.

Abstract: An electric vertical takeoff and landing aircraft including a teetering propulsor assembly is provided. Teetering propulsor assembly may include a propeller that includes a hub and blades. Hub of propeller may be mechanically connected to a teeter mechanism of propulsor assembly that may be configured to allow the propeller to pivot about a teeter axis relative to the electric aircraft. Thus, teeter mechanism allows for a rotational axis of propeller to move during teetering of propeller. Teeter mechanism may include one or more springs that reduce teetering or prevent teetering of the propulsor at certain rotational speeds of propeller.

Abstract: Aspects of the technology relate to a braking assembly for a lateral propulsion system of a high altitude platform (HAP) configured to operate in the stratosphere. Power is supplied to a propeller assembly as needed during lateral propulsion so that the HAP can move to a desired location or remain on station. When lateral propulsion is not needed, power is no longer supplied to the propeller assembly and it may slowly cease rotating. However, in certain situations, it may be necessary to cause the propeller assembly to stop rotating as soon as possible. This can include an unplanned descent. Rapid braking can avoid the propeller blades from entangling in the envelope, parachute or other parts of the HAP. A reusable brake is employed to prevent uncontrolled rotation of the propeller on descent, or otherwise to prevent the propeller from spinning freely when not being used to propel the HAP laterally.

Abstract: Aspects of the technology relate to an apparatus and method for testing a material for use in a lighter-than-air craft deployable in the stratosphere. The apparatus and method may include and use a base plate and at least one ring component to attach to the base plate to secure a portion of the material. The at least one ring component has an elliptical shape including a minor radius having a first predetermined length and a major radius having a second predetermined length. The base plate receives a gas to inflate and pressurize the portion of the material. The first predetermined length and second predetermined length are selected to impart a stress ratio up to a predetermined maximum ratio onto the portion of the material through a predetermined temperature range when the portion of the material is inflated to a predetermined pressure.

Abstract: A high altitude or stratospheric balloon system may include a balloon envelope including envelope film, at least one tendon, and a suspender. The suspender may have a first end attached to the envelope film. The suspender is arranged to stretch such that the first end moves towards an equator of the balloon envelope as the balloon envelope pressurizes in order to control movement of the envelope film relative to the tendon and towards the equator as the balloon pressurizes.

Abstract: Aspects of the technology relate to a braking assembly for a lateral propulsion system of a high altitude platform (HAP) configured to operate in the stratosphere. Power is supplied to a propeller assembly as needed during lateral propulsion so that the HAP can move to a desired location or remain on station. When lateral propulsion is not needed, power is no longer supplied to the propeller assembly and it may slowly cease rotating. However, in certain situations, it may be necessary to cause the propeller assembly to stop rotating as soon as possible. This can include an unplanned descent. Rapid braking can avoid the propeller blades from entangling in the envelope, parachute or other parts of the HAP. A reusable brake is employed to prevent uncontrolled rotation of the propeller on descent, or otherwise to prevent the propeller from spinning freely when not being used to propel the HAP laterally.

Abstract: Aspects of the disclosure relate to flight termination systems for aerial vehicles having envelopes. For instance, a flight termination system may include one or more heat sources mounted on the top plate and oriented towards envelope material of the envelope. The one or more heat sources may each include a gas generator configured to generate gas of sufficient temperature to melt the envelope material and vent lift gas from the envelope. The flight termination system may also include a drag device arranged at the top plate which may be being configured to provide stability to the envelope during descent.

Abstract: A stratospheric balloon may include an upper structure having a pulley, a lower structure, at least one solar panel suspended between the upper structure and the lower structure, and a first orientation control member connected, at a first end thereof, to a first transverse edge of the at least one solar panel and, at a second end thereof, to a second transverse edge of the at least one solar panel. The first orientation control member is wound about the pulley such that rotating the pulley changes the orientation of the at least one solar panel relative to the upper structure and the lower structure. In another example, the pulley may be replaced by first and second support mechanisms and the system may include a second orientation control member. The first and second orientation control members are connected to the first and second support mechanisms, respectively, and to the solar panel.

Abstract: A stratospheric balloon may include an upper structure having a pulley, a lower structure, at least one solar panel suspended between the upper structure and the lower structure, and a first orientation control member connected, at a first end thereof, to a first transverse edge of the at least one solar panel and, at a second end thereof, to a second transverse edge of the at least one solar panel. The first orientation control member is wound about the pulley such that rotating the pulley changes the orientation of the at least one solar panel relative to the upper structure and the lower structure. In another example, the pulley may be replaced by first and second support mechanisms and the system may include a second orientation control member. The first and second orientation control members are connected to the first and second support mechanisms, respectively, and to the solar panel.

Abstract: Aspects of the disclosure provide a flex connection for high altitude balloon applications. During operation flex connection allows a payload of a high-altitude balloon to remain level when an envelope of the balloon is tilted, in order to change the direction of the balloon. As an example, a system may include a balloon envelope, a payload, a cable between the balloon envelope and the payload, and a flex connection on the cable. The flex connection enables the payload to remain level relative to the ground when the balloon is in flight and the balloon envelope is tilted relative to the payload. The flex connection includes a top portion, a plurality of discs, and a bottom portion.

Abstract: Aspects of the disclosure relate to terminating flight of a balloon that may include separating a connection between a balloon envelope and a payload of the balloon. In one example, a payload separation apparatus includes a first shaft configured to attach to the envelope, a second shaft configured to attach to the payload, a pair of arms, and a bracket arranged to secure the pair of arms to the first shaft. In another example, a system includes a flight termination assembly having a cutting edge configured to cut an opening in the envelope and a payload separation apparatus. The apparatus includes a first shaft configured to attach to the envelope, a second shaft configured to attach to the payload, a pair of arms, and a bracket configured to secure the pair of arms to the first shaft. The system also includes a controller configured to activate the cutting edge.