Right, naive question time: by 'feathering hinge' I assume you mean the one that allows the change of blade pitch (as opposed to flap or drag).
Quite obviously every ship has a means of changing the pitch of the blades. Does this mean that a true rigid rotor relies on twisting the root of the blade to get the change, and the blade is bolted 'rigidly' to the head? Or have I misinterpreted 'feathering'?