What invisible vehicle is driven by an engine on the roof? A hovercraft, with propellers on the roof, maybe? Nope, we’re talking about a vehicle driven by wheels on its roof. And it’s invisible! Give up? It’s a brand-new conundrum of a machine called the ‘subrugmarine’.
You’ll need a fairly low-geared motor-gearbox unit for the driven wheels. A good speed to aim for to start with is 2-5cm/sec. Now we made the first subrugmarine with driven wheels underneath, like a normal car or truck. But it probably won’t work quite as well as putting the driven wheels on the roof. You’ll need a set of small floor wheels glued onto the chassis with the battery box, of course. The subrugmarine needs to be small, but in particular, the wheels should be small enough so that the rug above won’t droop onto the front or back – although you could add little rollers there to stop that.
...