[junkcollector]

Bob – great work by your lead design engineer figuring out the relationship between the loss of wheel inertia and the transfer of energy to the ball. It puzzled me though, the idea that we could choose the rpm loss of the wheel to be 250 – that didn’t seem like an appropriate input to the problem. What if I chose 300 – how would the answer be different?

After some thought, I realized that the kinematic relationship between the velocity of the ball (300 ips) and the final rpm of the wheel was not captured. The wheel inertia formula assumes that just the right amount of energy is transferred to the ball to achieve the target velocity, but how that is controlled is not presented.

In our team’s shooter design, and probably like many others, we are accelerating the ball by a drive wheel on one side so that the surface of the wheel and the surface of ball are traveling in unison at the time of release. So that creates a kinematic relationship – the center of the ball is traveling at 1/2 the velocity of the surface of the wheel. For a 6 inch pitching wheel, that would require the rotation to be around 1900 rpm to achieve 300 ips in ball velocity.

I think the input values can be tweaked to accommodate matching the ball speed to a corresponding wheel2 rotation. That would tell us the initial wheel1 rotation speed needed to achieve the target ball velocity for a given wheel inertia. That seems like something we can control.