you can offcourse calculate the rpm you need, but generally you want your drive wheels to run somewhere between 400rpm and 500rpm(correct me if i'm wrong).
for the power you need to get it moving try this link http://buggies.builtforfun.co.uk/Calculator/index.html
Floris
Date: Thu, 10 May 2007 22:34:30 -0400 From: ki4gyt-at-gmail.com To: tanks-at-rctankcombat.com Subject: New builder-to-be [TANKS]
Hi guys, I'm still scoping out tanks and deciding what would be fun to build/battle. I live in southeast Georgia, with enough land to have a decent battle on :) I had considered switching from boats to tanks a while back, but up until now, I didn't have a house large enough to accomodate it. The new house has a 20x20 heated and A/C'd shop, so the wife can't give me grief over a 3 foot long tank taking up space :) I've built scratchbuilt a few combat RC warships, so I'm okay with woodwork, CO2 plumbing, and electrical systems. I have a 6-ch radio for a tank, and a 2-ch for a future support vehicle.
My main pondering question tonite is: Would a couple of 18v cordless drill motors get a tank around well enough? Or do I need to spend a bunch more money than that?