I have an idea pertaining to energy storage in flywheels, something like they do in the KERS, and need assistance here... Ok, my idea involves using a flywheel of around 10 kg (steel) with I~1 kg.m^2, to be charged to an RPM of around 7,000 RPM. This allows E = 0.5 x 1 x (7000x2x pi /60)^2 = 268 KJ of energy to be stored. I want to charge it with a small engine (something like a Honda GX50) which, according to the charts will give max torque of 3 Nm at 4000 rpm and max power of 1.6 kW at 7000 rpm (approx). I want to discharge it to run a light vehicle (170 kg including driver) such that the discharge takes place at one wheel only (a three wheeler). I want discharge in pulses. Now, the questions: 1. How do I calculate the time it takes to charge the flywheel to 7000 RPM? Can I do it without using some intermediate device like a CVT or motor/generator? 2. How do I calculate the discharge time (and characteristics)? Thanks in advance.