Imagine we have two rockets, each with a long cylinder with it spin axis alligned with the long axis of the rocket. On one rocket the cylinder is spun up to a high speed. Both rockets have an equal load of fuel. If both rockets are launched from the same spot simultaneously in the same direction will they accelerate at the same rate and reach the same terminal velocity when the fuel runs out? An external observer that does not accelerate see the the spinning cylinder's rate of rotation slow down. If the rockets have the same terminal velocity, where has the stored angular energy of the spinning cylinder gone?