To start the ball rolling, I'm re-posting this from another thread:
Originally Posted by
howardcano
I know of no flywheels that are both specifically made for our motors and affordable. For production, the cheapest solution that I can think of is to use a cast-iron V-pulley of an appropriate size (2.5" or so?). But it would have a little more surface area, and therefore drag, than necessary. If the losses are compensated for, that shouldn't be a big deal.
Originally Posted by
pphaneuf
Do you know of some that, um, would be expensive?...
Someone with access to CNC equipment could get something quite nice...
Yes, I do know of some expensive ones. They would be the ones made by the guy I know who owns an NC lathe!
Originally Posted by
pphaneuf
About the weight of a flywheel being too much to mount directly to the motor without support, a greater diameter flywheel of the same mass would have a similar MOI as a heavier, smaller one, right? Mass near the centre doesn't help increase the MOI as much, so you could mill it out, to make it spoked (would need to balance it after, most likely!).
Yes, larger diameter does give more MOI for the same mass. But it also gives more leverage on the motor shaft for secondary imbalances, more aerodynamic drag, and reduces the maximum operating speed. Spokes may look nice, but for drag and structural integrity, I would prefer to stick with a solid disk.
Since I'm going to be using a gear drive, I can easily select the MOI that the motor "sees" by varying the ratio, which makes it easier to get good results with a large variation in flywheel sizes. That's important when being forced to use what's available, rather than what is optimum.