Here are some tools that I've created to help assist me in designing combat robots
Calculators
Brushless Drivetrain
Calculator for determining speed and pushing power of a brushless combat robot drivetrain
Brushless DT calculatorBrushed Drivetrain
Calculator for determining speed and pushing power of a brushed combat robot drivetrain
Brushed DT calculatorTip Speed
Calculator for determining linear tip speed of a spinning combat robot weapon
Tip speed calculatorCenter Distances
Calculators for determining distance between centers of commonly used belt and chain drives
Chain center distance calculator Belt center distance calculator