Summary

Luft '46 plane.
2 engines, each one driving a prop inside the annular ring.... a counter-rotating ducted fan AND a circular wing.

Just to be different, I guess.

What's next? a Caproni Stipa?

model in full dimensions in blender 2.79b and scaled to 1/100 for the .stl file
scale down to 35% in the slicer.

as usual, the dice are 15mm for reference
if I can't print it, I don't post it.
.