Andreas, as always you have done a great paint work, beautiful colors!
In my opinion the dope (in german "Spannlack") should be more glossy ("..glänzt wied' Sau.."), see for example the upper wing in this picture:

Source:1000aircraftphotos.com
... but this is also personal style.
With the next pictures I thought, now comes a rotating rotary engine - be there, done that. But with that little electric motor you made my day!

How cool is that?

And the battery/switch accessable via a existing maintenance lid?
You should not mount the battery fix, even if is a coin cell. I had lately some cells leaking a bad liquid into my digital measuring slide

A great addition, nicely done! You are always good for a surprise!
Cheers,
Frank