Abstract: An aircraft rotor system including a hub having a hub axis about which the hub is configured to rotate; a plurality of rotor blades configured to extend from the hub and rotate about the hub axis, at least one of the rotor blades rotatable about a respective pitch change axis; wherein the hub is configured to be rotated about the hub axis only by the plurality of rotor blades. Another aspect includes a method of operating the rotor system.

Abstract: An aircraft rotor system including a hub having a hub axis about which the hub is configured to rotate; a plurality of rotor blades configured to extend from the hub and rotate about the hub axis, at least one of the rotor blades rotatable about a respective pitch change axis; wherein the hub is configured to be rotated about the hub axis only by the plurality of rotor blades. Another aspect includes a method of operating the rotor system.

Abstract: A rotor system for an aircraft including a driving member; an externally driven rim configured to be rotated by the driving member; a hub having a hub axis, the hub including a rotatable housing and a non-rotatable housing; a plurality of rotor blade assemblies rotatably coupled to the rotatable housing of the hub and the externally driven rim such that rotation of the externally driven rim rotates the plurality of rotor blade assemblies about the hub axis, each rotor blade assembly having a rotor blade rotatable about a respective pitch change axis; and a pitch control mechanism operably associated with the hub and the plurality of rotor blade assemblies, wherein, actuation of the pitch control mechanism rotates each rotor blade assembly about the respective pitch change axis to collectively control the pitch of the rotor blade, thereby generating a variable thrust output. Also, a method of operating the rotor system.

Abstract: A rotor system for an aircraft including a driving member; an externally driven rim configured to be rotated by the driving member; a hub having a hub axis, the hub including a rotatable housing and a non-rotatable housing; a plurality of rotor blade assemblies rotatably coupled to the rotatable housing of the hub and the externally driven rim such that rotation of the externally driven rim rotates the plurality of rotor blade assemblies about the hub axis, each rotor blade assembly having a rotor blade rotatable about a respective pitch change axis; and a pitch control mechanism operably associated with the hub and the plurality of rotor blade assemblies, wherein, actuation of the pitch control mechanism rotates each rotor blade assembly about the respective pitch change axis to collectively control the pitch of the rotor blade, thereby generating a variable thrust output. Also, a method of operating the rotor system.

Abstract: A rotor system including a hub; a rim configured to rotate about the hub, the rim including an interior surface and an engagement surface; a plurality of rotor blades extending from the hub and coupled to the interior surface of the rim; and one or more outer drive gears disposed adjacent to the engagement surface of the rim; each of the one or more outer drive gears including a plurality of teeth for engaging the engagement surface of the rim; wherein the one or more outer drive gears are configured to rotate the rim such that the plurality of rotor blades rotates about the hub. Other aspects provide an aircraft rotor system and methods of operating an aircraft rotor system.