ORIGINAL: abufletcher
Ah, if only engine manufacturers would start making heavier engines!
[link=http://www.seidel-triebwerke.de/englisch/englisch.html]
Seidel[/link] made a good start again. Fits perfect in a 1/4 scale, installation diameter (Ø) 230 mm

It's not a rotary but it's a start.