Hypothetical situation: I have a free source of energy, like a rotating drive, piston or moving water. I want to store this in a flywheel. The amount of energy I can store is limited by the max speed of the flywheel. But if I use, say, gears, the max speed is determined by the max gear ratio. Is there any mechanism with no max speed?
I was thinking if the energy source were a jet of air, I could use a turbine, and maybe change the angle of the blades as it sped up, but the speed would be limited when the speed of the air equalled the speed of the surface of the blades, no?