Hi fellow scientists and engineers, I have a question regarding the design of a flywheel. I know that the actual engineering of a flywheel is very complex and in no way I should expect actual practical answers from this simple question. I'm just trying to get some estimates for a renewable energy project that I'm working on. I'm trying to find out the best way to calculate the dimensions, mass and torque of a flywheel so that it produces 1500 HP during 50 seconds while reducing its kinetic energy to no less than 33%. It's maximum angular velocity should be no more than 4,000 RPMs. I'm a bit confused with power and the time delta. As you all know Power = (Work) / (delta t). In my calculations I converted 1500 HP into Watts, which is 1.12 MW. I then calculate the Work done by substituting the 1.12 MW for power and assuming that my delta t is 50 seconds. Is this approach correct? What I want to do in essence is be able to store 1 MW of power in a flywheel which feeds a generator during a t(assumed as 50 seconds) second cycle and not loose more than 33% of its speed during this period. Hope that the problem is clear for you guys. Any help is appreciated. Thanks.