I'm building an electric tug to push/pull my Cessna out of the hangar. I got a PowerTow frame (single wheel tug with arms that grasp lugs on the nosegear and push and pull the plane) and have installed a 4 hp 24v DC motor (supposedly its a Ramsey winch motor). Solenoids are used to accomplish forward/reverse. I wanted a 24v application since my aircraft's electrical system is also 24 volts ... that way, I can also use the tug as a battery cart for the airplane to run avionics on the ground when updating databases, etc., and also as a source for a jump start should the master accidentally be left "on" on the airplane!
Gasoline models of this tug are also typically about 4 - 6 hp and easily move a plane as big as my Cessna 206. I've geared the motor down with a belt/chain reduction drive that gives a final reduction of about 12-13:1. I use an idler pulley/clutch for engaging/disengaging power (this is what the gas tugs use). However, the electric motor runs a really high rpm when unloaded and I'm afraid it may still run the wheel a little too "brisk" across the ground, although I think the torque is sufficient. I'm also afraid the high rpm's may lead to fairly short belt life with the belt slipping as it engages/disengages.
It appears to me a speed controller would be desireable. I assume I need a "heavy duty" unit like a golf cart uses, etc. I notice some controllers are for 24-36 volt motors and some are for 36-48 volts. Can I use a 36-48 volt controller on the 24 volt motor? (Seems I can find more of these reasonably priced!). If not, anyone know a good source for an inexpensive 24 volt or 24-36 volt unit? I notice a lot of these units are rated for 225 amps. Supposedly my motor runs at 40 amps, 80 amps peak. Any comments, advice, alternatives, or sources would be appreciated!