Abstract: A multirotor aircraft comprises at least three proprotors. Each proprotor has a plurality of rotor blades pivotably attached to a mast assembly. When a rotor blade pitch angle is changed for a proprotor, all rotor blades on the proprotor change to a same pitch angle. The proprotors are configured to spin freely when a power source is disengaged or fails. In various embodiments, one or more engines provides power to each proprotor, or at least one engine provides power to two or more proprotors. A rotor blade control system is configured to control a collective rotor blade pitch angle on each proprotor independently of the rotor blade pitch on the other proprotors. The rotor blade control system is configured to set a negative collective rotor blade pitch angle on an unpowered proprotor, such as in response to manual inputs by a pilot or in response to current engine conditions.

Abstract: A multirotor aircraft comprises at least three proprotors. Each proprotor has a plurality of rotor blades pivotably attached to a mast assembly. When a rotor blade pitch angle is changed for a proprotor, all rotor blades on the proprotor change to a same pitch angle. The proprotors are configured to spin freely when a power source is disengaged or fails. In various embodiments, one or more engines provides power to each proprotor, or at least one engine provides power to two or more proprotors. A rotor blade control system is configured to control a collective rotor blade pitch angle on each proprotor independently of the rotor blade pitch on the other proprotors. The rotor blade control system is configured to set a negative collective rotor blade pitch angle on an unpowered proprotor, such as in response to manual inputs by a pilot or in response to current engine conditions.

Abstract: A rotor blade including a root portion adapted to be connected to a helicopter rotor hub for rotation therewith, the root portion having a first edge surface; a first movable member having a first movable surface adjacent to the first edge surface; a first elastomeric joint disposed between the root portion and the first movable member, the first elastomeric joint having an inner surface facing the first edge surface of the root portion and an outer surface facing the movable surface of the first movable member; and an actuating system mounted within the root portion and the first movable member for moving the first movable member. The first elastomeric joint deforms to adjust for shear from actuation of the first movable member to a first position during helicopter mode; and to a second position during airplane mode.

Abstract: A rotor blade including a root portion adapted to be connected to a helicopter rotor hub for rotation therewith, the root portion having a first edge surface; a first movable member having a first movable surface adjacent to the first edge surface; a first elastomeric joint disposed between the root portion and the first movable member, the first elastomeric joint having an inner surface facing the first edge surface of the root portion and an outer surface facing the movable surface of the first movable member; and an actuating system mounted within the root portion and the first movable member for moving the first movable member. The first elastomeric joint deforms to adjust for shear from actuation of the first movable member to a first position during helicopter mode; and to a second position during airplane mode.