Quote:
Originally Posted by squirrel
It's pretty easy to get close numbers....find the no load rpm of the motor, find the wheel diameter, decide if you want a wheel on each side of the ball or just one side, and figure out the gear ratio needed to make the wheel(s) spin that fast, or just a bit faster.
If the motor speed drops too much when shooting the ball, add another motor, or add mass to the wheel and wait longer for it to spin up
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But isn't it different with no load rpm? Is no load rpm affected by the load of the wheel? Even if the wheel is 90 degrees vertical, it should still give fight back to the motor thus lowering the no load RPM. Also, the torque would have to pick up the weight of the ball and at that moment in time, the torque is also having to speed the ball up "through" the launch plane and that reduction also slows down the RPM.
If calculating proximities though, like squirrel is suggesting, I would like to add that taking the max efficiency RPM and torque would leave wiggle room for all the complicated math if you don't want to run a long algorithm for precise numbers even if preciseness is probably the best if you don't have the financial or physical means of prototyping.