Rotor system for electrically powered rotorcraft

A torque activated system for biasing a collective pitch of a set of rotor blades, comprising:

• a rotor hub having a central axis of rotation and coupled to the set of rotor blades;
• an electric drive motor coupled to the rotor hub and configured to provide a torque to the rotor hub to cause rotation of the set of rotor blades;
• a set of pitch adjustment mechanisms configured to adjust the collective pitch of the set of rotor blades;
• an articulation plate (i) rotatably mounted on the central axis and coupled to the set of pitch adjustment mechanisms and (ii) configured so that rotation of the articulation plate about the central axis causes adjustment of the collective pitch of the set of rotor blades;
• and
• a torsion spring, disposed on the central axis between the rotor hub and the electric drive motor, which couples the motor output to the rotor hub, the torsion spring configured to be compressed as a function of the torque, wherein compression of the torque spring causes the articulation plate to adjust its angular orientation about the central axis of rotation, and thus to move the set of pitch adjustment mechanisms so as to adjust the collective pitch of the set of rotor blades in a manner responsive to the torque.