anyone know the math involved in the effects of changing the flywheel's weight?
torque, inertia, rotating mass, etc.

 

The math could get a tad complicated. This is a brief discussion:

Flywheel Basics

On a rotary, a lightweight flywheel will make launching a bit trickier due to the rotary's lack of torque at low rpms. Once you're rolling, the benefits of less rotating mass will be evident.

 

The flywheel is a method of storing energy. So the engine appears to have more torque, than is actually the case. Of course this sytem only works for a second, and helps the unwashed operator leave a standstill without complaints from the drive line. There is a reason the Mazda seems to have the prize for heavy flywheels.

The downside of that is, there is a recurring need to reaccelerate the flywheel after every shift. This reduces available energy to drive the car as it is expended in the flywheel, and once under way, there is no need for the flywheel effect.

In racing, great effort is expended reducing the recurring expendature of energy of flywheel effect as other parts act in the same way. Thus the need for Carbon or aluminum drive and half shafts, carbon brake rotors, lite aluminum racing wheels, and even the weight of different brands of racing tires. Another benefit of reduced flywheel effect being reduced all around, is that under braking less energy needs to be removed by the braking systems. Also, up and down shifts in dog ring boxes are much improved as RPM matching is instantaneous.

Do not forget the clutch drivin disc. The lighter the better. The racer has a dual disc Tilton 5 1/4" system.
It does not slip at all. More like an electric switch than a clutch. The complete clutch system with discs is under 4 pounds. It could be less with the pricy carbon discs.
My flywheel weighs 3 pounds. It is a steel button.
Once under way the clutch is not used.

So, starting up is a problem that you can practice to eliminate. And the up side is faster acceleration from reduced flywheel effect and the actual mass removed from the system.

Lynn E. Hanover

 

The flywheel is a method of storing energy. So the engine appears to have more torque, than is actually the case. Of course this sytem only works for a second, and helps the unwashed operator leave a standstill without complaints from the drive line. There is a reason the Mazda seems to have the prize for heavy flywheels.

The downside of that is, there is a recuring need to reaccelerate the flywheel after every shift. This reduces available energy to drive the car as it is expended in the flywheel, and once under way, there is no need for the flywheel effect.

In racing, great effort is expended reducing the recuring expendature of energy of flywheel effect as other parts act in the same way. Thus the need for Carbon or aluminum drive and half shafts, carbon brake rotors, lite aluminum racing wheels, and even the weight of different brands of racing tires. Another benefit of reduced flywheel effect being reduced all around, is that under braking less energy needs to be removed by the braking systems. Also, up and down shifts in dog ring boxes are much improved as RPM matching is instantaneous.

Do not forget the clutch drivin disc. The lighter the better. The racer has a dual disc Tilton 5 1/4" system.
It does not slip at all. More like an electric switch than a clutch. The complete clutch system with discs is under 4 pounds. It could be less with the pricy carbon discs.
My flywheel weighs 3 pounds. It is a steel button.
Once under way the clutch is not used.

So, starting up is a problem that you can practice to eliminate. And the up side is faster acceleration from reduced flywheel effect and the actual mass removed from the system.

Lynn E. Hanover

 

I like the idea of flywheel batteries. A smaller flywheel sealed in a vacuum, that can spin much faster, for much longer. I read about it a while ago, but I'm not sure what developments have been made in that area.