The potentialities of the super flywheel are re-examined by two analysis techniques. The first technique utilizes a highly idealized model that permits one to easily see the basic physics of the problem; the second technique employs a more realistic model that provides detailed information about the super flywheel behavior. Both techniques demonstrate that the kinetic energy and the stresses are higher, at a given rotational speed, than classical analyses predict and that an inertio-elastic instability provides a theoretical upper limit to the rotational speed attainable by the super flywheel.