Shooter flywheel ratios

Hey so I am designing my team’s shooter but I don’t know how to do the math for the ratio needed between the motors and the flywheel. I don’t know if it’s a JVN calculator sheet or something else. Anywhere else I have looked just tells me the ratio instead of how to do it. Thanks.

As with most math problems, start with what you know. Are you designing for a certain flywheel RPM? Surface speed?

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So the math is very simple at a basic level and very complicated at an advanced level. We’ll shoot for somewhere in the middle.

At a basic level, the gear ratio is the ratio between the motor’s top speed (more or less a constant) and the flywheel’s top speed. If you know the top speed you want the flywheel to go, you can divide the motor’s free speed by that (and multiply (edit: divide) by ~120% or so for some headroom) to get the gear ratio.

Now here’s the more complicated part. The lower your gear ratio (i.e. higher flywheel speed), the less torque the motor is putting into the flywheel and the it longer it will take for the flywheel to reach its speed. If you need a fast flywheel but it’s taking too long to get to speed you can add more motors to get more torque. In my experience, calculating the time it takes to spin-up or recover after shooting is not very accurate (despite there being a few calculators on here that will do it for you); you’re better off building a prototype and testing it in real life.

If you design your prototype to be able to switch gears/belts/planetary stages easily, you can test a bunch of different ratios and quickly find which tradeoff between top speed and recovery time is the best for your use case. It will depend on all kinds of factors (e.g. wheel size/type, ball size/weight, compression, backing, etc). The closer you can get your prototype to your final design, the better your testing will be

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well uhh, not particularly i guess, we need it to be powerful enough to shoot from the farthest zone and to be able to maintain momentum, which yeah we can use a metal wheel too for that.

ok got it

That’s dependent on so many more variables than just shooter ratio. Like AriMB was saying, you’ll need to prototype.

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