INTRODUCTION Formula One regulations for 2009 (See Reference 1.) have been introduced which allow the use of Kinetic Energy Recovery Systems (KERS). These are limited in terms of maximum power at 60kW@ and in terms of energy storage and recovery per lap at 400kJ. The type of system is not regulated@ so electrical and mechanical solutions may compete side-by-side. This paper considers only mechanical solutions@ which consist of a continuously variable transmission (CVT) and a flywheel. Energy is stored in its kinetic form as speed of the flywheel. The CVT is required to connect flywheel to drive-train@ as during a braking event the car slows down@ whilst the flywheel must speed up. The gear ratio is thus constantly changing.