Abstract: An electrical propulsion system comprises an inverter, an electrical motor assembly, an assembly, and a rotor position sensor. The inverter comprises a printed circuit board assembly (PCBA). The electrical motor assembly comprises a stator and a rotor. The assembly is configured to rotate a propeller and comprises a moving component and a stationary component. The rotor position sensor comprises at least one sensor coupled to the PCBA, and a magnet located on the moving component. The at least one sensor is configured to detect a magnetic field of the magnet through the stationary component.

Abstract: An electric propulsion system for a vertical take-off and landing (VTOL) aircraft having a heat exchanger to cool fluids used in an electrical engine, the electric propulsion system comprising at least one electrical engine mechanically connected directly or indirectly to a fuselage of the VTOL aircraft and electrically connected to an electrical power source. The electrical engine may comprise an electrical motor having a stator and a rotor; a gearbox assembly comprising a sun gear; at least one planetary gear; a ring gear; and a planetary carrier. The electric engine may include an inverter assembly comprising a thermal plate and an inverter assembly housing; an end bell assembly that is connected to the thermal plate of the inverter assembly; and a heat exchanger comprising an array of cooling fins and tubes.

Abstract: The present disclosure relates generally to a method for balancing a rotor of an electrical engine of an electrical propulsion system comprising: identifying an axis of rotation of a rotor, wherein the rotor comprises a sacrificial layer having a mass M formed along a circumference of the rotor; determining an imbalance present in the rotor by rotating the rotor about the axis of rotation, wherein determining an imbalance includes marking the rotor, rotating the rotor, and detecting an amplitude of the imbalance; calculating an amount of mass k to add or remove at a position p along the sacrificial layer such that a center of mass of the rotor coincides with the axis of rotation of the rotor; and removing an amount of mass r from the sacrificial layer such that an amount of remainder mass n is present along the circumference of the rotor.

Abstract: An electric propulsion system comprising an electric motor assembly. The electric motor assembly may include a housing having an internal volume, a stator ring disposed about a perimeter of the internal volume, and a rotor positioned within the stator. The electric motor assembly may include a main shaft connected to the rotor via a gear reduction, wherein the main shaft extends through the rotor. The electric motor assembly may include a collar connected to the main shaft, wherein the collar encircles the main shaft, and at least a portion of the collar is configured to direct a fluid away from the main shaft and toward the stator ring.

Abstract: Fluid formulations, including low traction fluid, low viscosity motor fluid and high pressure viscosity coefficient fluid formulations, that may be used in vehicle drive trains are described herein. The fluid formulations include a base oil and an additive. The fluid formulations may provide efficiency advantages to electric vehicle drive trains.

Abstract: A motor gearbox assembly for an aircraft may comprise a layshaft configured to transmit torque from a rotor to a main power output shaft. The motor gearbox assembly may comprise a gearbox housing, a stator mounted inside the gearbox housing, a rotor rotatably mounted inside the stator on a main power output shaft and a layshaft rotatably mounted in the gearbox housing outside of the stator. The motor gearbox assembly may comprise a first ear reduction between the rotor and the layshaft, and a second gear reduction between the layshaft and the main power output shaft.

Abstract: An electric propulsion system for a vertical take-off and landing (VTOL) aircraft having a heat exchanger to cool fluids used in an electrical engine, the electric propulsion system comprising at least one electrical engine mechanically connected directly or indirectly to a fuselage of the VTOL aircraft and electrically connected to an electrical power source. The electrical engine may comprise an electrical motor having a stator and a rotor; a gearbox assembly comprising a sun gear; at least one planetary gear; a ring gear; and a planetary carrier. The electric engine may include an inverter assembly comprising a thermal plate and an inverter assembly housing; an end bell assembly that is connected to the thermal plate of the inverter assembly; and a heat exchanger comprising an array of cooling fins and tubes.

Abstract: An electric propulsion system for a vertical take-off and landing (VTOL) aircraft having a heat exchanger to cool fluids used in an electrical engine, the electric propulsion system comprising at least one electrical engine mechanically connected directly or indirectly to a fuselage of the VTOL aircraft and electrically connected to an electrical power source. The electrical engine may comprise an electrical motor having a stator and a rotor; a gearbox assembly comprising a sun gear; at least one planetary gear; a ring gear; and a planetary carrier. The electric engine may include an inverter assembly comprising a thermal plate and an inverter assembly housing; an end bell assembly that is connected to the thermal plate of the inverter assembly; and a heat exchanger comprising an array of cooling fins and tubes.

Abstract: An electrical propulsion system for a vertical take-off and landing (VTOL) aircraft comprises an electrical motor assembly and an inverter assembly. The inverter assembly comprises a housing, a capacitor assembly, at least one printed circuit board assembly (PCBA), and a plurality of positioning pins. The capacitor assembly comprises a center hole, at least one capacitor, a capacitor housing having at least one busbar, and a plurality of through holes in the capacitor housing. The capacitor assembly and the at least one PCBA are positioned inside the housing. The plurality of positioning pins pass through the through the plurality of through holes of the capacitor housing and the at least one PCBA and are connected to the housing.

Abstract: An electric propulsion system for a vertical take-off and landing (VTOL) aircraft having a heat exchanger to cool fluids used in an electrical engine, the electric propulsion system comprising at least one electrical engine mechanically connected directly or indirectly to a fuselage of the VTOL aircraft and electrically connected to an electrical power source. The electrical engine may comprise an electrical motor having a stator and a rotor; a gearbox assembly comprising a sun gear; at least one planetary gear; a ring gear; and a planetary carrier. The electric engine may include an inverter assembly comprising a thermal plate and an inverter assembly housing; an end bell assembly that is connected to the thermal plate of the inverter assembly; and a heat exchanger comprising an array of cooling fins and tubes.

Abstract: An electric propulsion system comprising an electric motor assembly. The electric motor assembly may include a housing having an internal volume, a stator ring disposed about a perimeter of the internal volume, and a rotor positioned within the stator. The electric motor assembly may include a main shaft connected to the rotor via a gear reduction, wherein the main shaft extends through the rotor. The electric motor assembly may include a collar connected to the main shaft, wherein the collar encircles the main shaft, and at least a portion of the collar is configured to direct a fluid away from the main shaft and toward the stator ring.

Abstract: An electric propulsion system for a vertical take-off and landing (VTOL) aircraft having a heat exchanger to cool fluids used in an electrical engine, the electric propulsion system comprising at least one electrical engine mechanically connected directly or indirectly to a fuselage of the VTOL aircraft and electrically connected to an electrical power source. The electrical engine may comprise an electrical motor having a stator and a rotor; a gearbox assembly comprising a sun gear; at least one planetary gear; a ring gear; and a planetary carrier. The electric engine may include an inverter assembly comprising a thermal plate and an inverter assembly housing; an end bell assembly that is connected to the thermal plate of the inverter assembly; and a heat exchanger comprising an array of cooling fins and tubes.

Abstract: An electrical propulsion system for a vertical take-off and landing (VTOL) aircraft comprises an electrical motor assembly and an inverter assembly. The inverter assembly comprises a housing, a capacitor assembly, at least one printed circuit board assembly (PCBA), and a plurality of positioning pins. The capacitor assembly comprises a center hole, at least one capacitor, a capacitor housing having at least one busbar, and a plurality of through holes in the capacitor housing. The capacitor assembly and the at least one PCBA are positioned inside the housing. The plurality of positioning pins pass through the through the plurality of through holes of the capacitor housing and the at least one PCBA and are connected to the housing.

Abstract: An electric propulsion system for a vertical take-off and landing (VTOL) aircraft, the electric propulsion system including an electrical motor having a stator and a rotor. The electric propulsion system may include a main shaft possessing at least one shoulder on an outer surface of the main shaft. The electric propulsion system may include a gearbox assembly comprising a sun gear that is concentrically aligned with the main shaft at least one planetary gear that interfaces with the sun gear. The electric propulsion system may include a planetary carrier, wherein a center of the planetary carrier is concentrically aligned with the main shaft. The electric propulsion system may include a propeller flange assembly that travels through the rotor, and an axial buttress positioned in the at least one shoulder located on the main shaft.

Abstract: An electric engine for a vertical takeoff-and-landing aircraft comprising an electric motor assembly including a stator and a rotor. The electric engine may comprise an inverter assembly, a gearbox assembly including a sun gear, and a main shaft including a length of the main shaft that extends from a first end of the main shaft through the gearbox assembly and through the electric motor assembly to a second end of the main shaft. The electric engine may include a hydrodynamic bearing located between the main shaft and sun gear, and a bearing including an inner race mechanically coupled to the main shaft and an outer race mechanically coupled to the rotor. The electric engine may include a bearing including an outer race mechanically coupled to an inner surface of the rotor.

Abstract: A rotor assembly has a sleeve, a rotor hub, a lamination core, and a plurality of tapered magnets disposed circumferentially around an inner diameter of the sleeve. The plurality of tapered magnets are configured to abut on one another. The plurality of tapered magnets includes a first set of tapered magnets and a second set of tapered magnets. Insertion of the first set of tapered magnets axially relative to the second set of tapered magnets is configured to increase a diameter of the sleeve. The rotor hub is configured to retain at least one of the lamination core, the plurality of tapered magnets, or the sleeve.

Abstract: A VTOL aircraft includes a lift propeller configured to provide lift during takeoff, landing and hover operations. The lift propeller is configured to be stowed close to a boom surface when not in use during, e.g., cruise flight, to minimize drag around propeller surfaces. The lift propeller may be displaced vertically with respect to the boom when switching to a lift configuration to provide greater separation from the boom to improve lift efficiency and reduce unwanted vibrations. The lift propeller may have a fail-safe configuration that allows the propeller to move passively between lift and stowed configurations, and to fully rotate even when fully retracted.

Abstract: An electric propulsion system for a vertical take-off and landing (VTOL) aircraft, the electric propulsion system including an electrical motor having a stator and a rotor. The electric propulsion system may include a main shaft possessing at least one shoulder on an outer surface of the main shaft. The electric propulsion system may include a gearbox assembly comprising a sun gear that is concentrically aligned with the main shaft at least one planetary gear that interfaces with the sun gear. The electric propulsion system may include a planetary carrier, wherein a center of the planetary carrier is concentrically aligned with the main shaft. The electric propulsion system may include a propeller flange assembly that travels through the rotor, and an axial buttress positioned in the at least one shoulder located on the main shaft.

Abstract: An electric propulsion system for a vertical takeoff-and-landing aircraft having an inverter assembly, a gearbox assembly, an electric motor assembly. The inverter assembly, the gearbox assembly, and the electric motor assembly may be substantially aligned along an axis. The inverter assembly, a gearbox assembly, and electric motor assembly may each abut at least one of the others. The electric engine may use a liquid, such as oil, for cooling and lubricating components of the inverter assembly, gearbox assembly, and electric motor assembly. Further, the electric engine may use volumes of oil for cooling and lubricating components below a threshold volume so that the electric engines do not require a fire protective barrier.

Abstract: A bus seat for use in a bus comprises a frame and a seat back secured to a portion of the frame. The bus seat further comprises a seat cushion secured to another portion of the frame. The bus seat also comprises a removable two piece cover arranged over the seat back, wherein the cover pieces are secured to one another with a zipper. The zippered two piece seat back cover allows for easy installation, removal or replacement of any damaged or worn portions of the seat back trim cover.