@rplst8 posted:For anyone is interested and that has a Google account, I've created a spreadsheet to calculate the required motor RPMs for a set of inputs.
It takes wheel diameter in inches, miles per hour, and gear reduction ratio and then calculates the RPMs at the motor shaft required to get that. Wheel diameter and miles per hour are for the prototype size. The gear reduction ratio would be for the model, and is the total reduction from the motor output shaft to the axle gear.
https://docs.google.com/spread...nME/edit?usp=sharing
P.S. the green boxes are what are user editable.
99% of the larger 12V motors are gonna top out in the 6-7K range ….unless you use the wiper motors that early Williams used, then you might find some 9-10K motors ….like in the case of those lousy 42:1 gear boxes, which at any speed above a crawl they sound like a Censa getting ready to toss it’s cookies….it really boils down to cheap motors aren’t good and good motors aren’t cheap …..
Pat
