Abstract: A variable inertia flywheel includes a generally circular body coupled to a shaft, and a cavity positioned radially on the body. The flywheel may also include a mass configured to translate radially in the cavity and form an inner chamber proximate a center of the body and an outer chamber distal to the center of the body. The flywheel may further include a conduit fluidly coupling a hydraulic fluid to the outer chamber, and a control valve coupled to the conduit and configured to direct the fluid to the outer chamber.