An aircraft including at least one unducted turbine engine for the propulsion of the aircraft. The turbine engine comprising: a rotor and a stator comprising a plurality of stator blades extending radially with respect to the longitudinal axis, each stator blade being defined, in a plane transverse to the longitudinal axis, by an angular position; and at least one aerodynamic obstruction positioned close to the turbine engine. The stator of the turbine engine comprises stator blades having a first chord, referred to as conventional blades, and at least one stator blade having a second chord larger than the first chord, referred to as the elongate blade, said at least one elongate blade being positioned in an interference angular range defined opposite the aerodynamic obstacle, so as to increase the straightening of the airflow from the rotor in the interference angular range.

A propeller attaching device includes a coupler that rotates integrally with an output shaft of a motor, a movable body, and a resilient body. The coupler allows attachment/detachment of an attachment portion of the motor by rotation of the propeller in the circumferential direction and restricts the movement of the propeller in an axial direction. The movable body includes a second receiving portion, and is supported by the coupler so as to be movable in the axial direction. The attachment/detachment position is a position where attachment/detachment of the attachment portion to/from the first receiving portion is allowed. The restriction position is positioned in a first direction relative to the attachment/detachment position, the first direction extending from the other end to one end of the output shaft in the axial direction of the output shaft, and restricts the rotation of the propeller in the circumferential direction relative to the base.

A propeller attaching device includes a coupler that rotates integrally with an output shaft of a motor, a movable body, and a resilient body. The coupler allows attachment/detachment of an attachment portion of the motor by rotation of the propeller in the circumferential direction and restricts the movement of the propeller in an axial direction. The movable body includes a second receiving portion, and is supported by the coupler so as to be movable in the axial direction. The attachment/detachment position is a position where attachment/detachment of the attachment portion to/from the first receiving portion is allowed. The restriction position is positioned in a first direction relative to the attachment/detachment position, the first direction extending from the other end to one end of the output shaft in the axial direction of the output shaft, and restricts the rotation of the propeller in the circumferential direction relative to the base.

In one possible embodiment, a propeller adapter is provided which includes a base having at least one fastener hole therethrough and a propeller alignment boss extending upward from the base. Opposing capture walls extend upward from the base, each of the opposing capture walls have a lip extending inward to capture and retain corresponding opposing outside edges of a root portion of a propeller therein upon seating of the propeller root portion between the opposing blade capture walls.

An electric vertical takeoff and landing aircraft including a teetering propulsor assembly is provided. The teetering propulsor assembly includes a propulsor, the propulsor including a monolithic blade including first and second blade portions extending radially outward from a hub, formed as a single unit. The coupling assembly includes a pair of torsional bearings coupled at the hub of the monolithic blade. The torsional bearings allow the monolithic blade to passively teeter in response to external forces applied to the propulsor, and exert a biasing, or centering, or restoring force on the monolithic blade that returns the monolithic blade to a neutral position. The torsional bearings may include an elastomeric member having relatively high stiffness, such as a high capacity laminate bearing.

An electric vertical takeoff and landing aircraft including a teetering propulsor assembly is provided. The teetering propulsor assembly includes a propulsor, the propulsor including a monolithic blade including first and second blade portions extending radially outward from a hub, formed as a single unit. The coupling assembly includes a pair of torsional bearings coupled at the hub of the monolithic blade. The torsional bearings allow the monolithic blade to passively teeter in response to external forces applied to the propulsor, and exert a biasing, or centering, or restoring force on the monolithic blade that returns the monolithic blade to a neutral position. The torsional bearings may include an elastomeric member having relatively high stiffness, such as a high capacity laminate bearing.

An assembly for an aircraft propulsion system includes an open propulsor rotor having variable geometry propulsor blades and an open guide vane/stator assembly having a plurality of guide vanes (stator blades) in a fixed position relative to the rotor and assembly. The geometry (e.g., pitch, camber, etc.) of the guide vanes can be manually adjusted by ground personnel but are incapable of adjustment during a flight mission (a flight). The open propulsor rotor is configured to rotate about an axis, and the guide vane assembly includes the plurality of guide vanes arranged circumferentially about the axis and is disposed axially next to and downstream of the propulsor rotor.

A rotor system design can reduce blade-wake interaction by staggering the vertical mounting position of the rotor blades on a hub. By staggering the vertical position, as the hub turns, the turbulent air impingement on subsequent rotor blades can be reduced. By reducing the turbulence on subsequent rotor blades the drag and noise is reduced. In rotor systems with an even number of blades, opposing rotor blade pairs can be mounted at the same vertical distance which can be different from other opposing rotor blade pairs. In rotor systems with an odd number of rotor blades, the rotor blades can be mounted at a fixed or variable vertical distances from the preceding blade so each rotor blade travels in a different tip path plane. Other techniques for reducing the wake vortices impingement can include mounting opposing blades at a dihedral/anhedral angle with respect to subsequent rotor blades.

A rotor system design can reduce blade-wake interaction by staggering the vertical mounting position of the rotor blades on a hub. By staggering the vertical position, as the hub turns, the turbulent air impingement on subsequent rotor blades can be reduced. By reducing the turbulence on subsequent rotor blades the drag and noise is reduced. In rotor systems with an even number of blades, opposing rotor blade pairs can be mounted at the same vertical distance which can be different from other opposing rotor blade pairs. In rotor systems with an odd number of rotor blades, the rotor blades can be mounted at a fixed or variable vertical distances from the preceding blade so each rotor blade travels in a different tip path plane. Other techniques for reducing the wake vortices impingement can include mounting opposing blades at a dihedral/anhedral angle with respect to subsequent rotor blades.

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.