[dtengineering]

I'm not surprised at the 50% mass increase in the ball... amazing what a little change in radius does!

The shooter video I linked to, however, was driven by only one FP, geared down about 4:1 using a banebots planetary, if I recall. The design was originally set up so that a second gearmotor could be placed on the other end of the axle shaft, but we didn't need it... in fact it would have broken the shooter speed limit that was in place that year so we left it off.

I wish we had known more about programming and PID loops when we built that robot. We could have added the second motor and used a control loop to maintain a constant speed on the shaft. That way the second motor would have brought us (back) up to shooting speed more rapidly, but then would have dialled back the power to control range. The "new" controller (okay, I guess to most students doing FRC, the cRio isn't exactly new...) makes closed loop motor control MUCH easier... most experienced teams will have had some experience with closed-loop feedback, but for newer teams looking for a good excuse to learn more about closed-loop speed control, the shooter would be a great place to start.

So while I fortunately/unfortunately don't have a robot/team to experiment with, I'm reasonably confident that two FP's, properly arranged and geared, should have good range and repeatability when configured as a vertical shooter.

And I do have to say the backspin was incredible... occasionally the balls would land in the goal, and backspin themselves right out. This year I can only see backspin as being a good thing!

Jason