I want to design a lure course system for my dogs to chase after. The systems I have seen use a 12v car starter motor, solenoid and car battery. It is a closed loop system with nylon type string around the drive pulley of the motor and then the string stretches out over 700+' along the ground. When you turn it on, the string moves a plastic bag along the ground and the dogs chase it. Could I use something other then a car starter system? A lot of those systems have issues because the solenoid of those starters are not designed for that type of continuous use (on for 10 mins+ at a time) Maybe something like an 18v drill? or an electric drill (but I dont always have access to 120v) How do I calculate how fast I need to power the pulley to make the string travel upwards of 30 mph? Would it be based on the size of the drive pulley only? Any help would be appreciated.