I'd not considered it until now - but it does make sense if you have a lot of air to spare. However, it has "Rotax Starter" stamped into the case.
I've loosely assembled it, but it lacks a vital nut which I shall search for tomorrow.
The German 12V / 300V DC rotary converter scrubbed up very well indeed and took only a couple of hours to tidy up cosmetically. The maker's label tells me the year of manufacture is 1943. It is a nice bit of kit considering what was going on all around it at the time and runs very smoothly without fuss. Much of it is in aluminium and what little paint remained under plates and in odd corners is dark grey. I wonder if it was a bit of flight kit? Aluminium could not have been easy to get hold of in 1943.
I cannot shift two of the case screws and really need to get inside it as the 12V leads are getting rather warm.
Interesting to speculate on the chain of circumstance that brought it to me across fifty one years.