Thomas, thanks a ton for that breakdown of what is happening. It makes sense to me. I hadn't looked at the equation that would have dictated the centrifugal force and kept thinking about linear vs nonlinear springs and how that could influence this design. I think it's good to know how this rotor works, so it doesn't come as a surprise if the engine loses all spark for a while if the rev limit is reached. For use as an accidental over-rev safety, it's perfect.