The Sd.Kfz. 300 Borgward BI Minenräumwagen was a remote controlled mini tank tracked vehicle creted by Germans engineers in World War II. The Borgward BI carried rollers behind it that were supposed to detonate mines in a field. About 50 of these radio controlled tanks in 1939. Cog like wheels toted behind the mini tank were supposed to reprise a footfall of a soldier and detonate the mines. Unfortunately the tanks were often destroyed by the very mines they were deployed to eliminate.
“Even before this was actually available, the Army Army Office already issued a first series order of more than 50 copies, which were then actually produced. The official designation was “Borgretto B I, (SdKfz. 300)”, which used a 3-jawed reel to clear the mines, which had the weight of the detonators of the mines. After it was clear that this mine cleaner was primarily a so-called “loss device”, which at best only “survived” (if at all) only a few inserts in a usable state, the production should take place as raw material as possible. Therefore, the designers decided to cast the structure of concrete as well as the dividing wall between engine and “equipment” room, in which, among other things, radio remote control, etc., was to be accommodated – but this was not used in any of the SdKfz. 300, since there were considerable problems with their manufacture and they still did not work satisfactorily at this time – to be made of wood. The floor was made of metal as well as the building roof on which the base for the antenna was mounted for remote control and which had a rectangular opening for the ventilation of the engine. The drive had a drive wheel at the front, 3 large casters and a small guide wheel. The casters and guide wheels, however, were not rubberized as usual, but were replaced by wooden supports, since rubber was considered a warmer but scarce raw material. On the left-hand side of the demining car, a lever was installed approximately in the center of the vehicle, with which two speed steps of 2 km / h or 5 km / h could be adjusted by hand or the device could be stopped. The exhaust was also mounted to the rear. At the back of the car was the clearing gear, it had a simple pull axle with two steel disc wheels and three clearing rollers, each of which had 5 gearwheel-like steel discs which were offset with respect to each other by means of a simple tow coupling.”