Study this pic, and my suggestion in the pics underneath. I think this would add great detail to your model. The suggestion is what's important, use UHU outside piece, but cut out the hole, Cut out the very center, and slip it into the whole that's left. Making it look like a vain with blades, again, using UHU's piece, but adding real vanes, angled, and I would mount them to a small tubeI for support. Glue that in, and it will make the model "POP", as this piece does not really make sense. This would give the appearance of it being able to spin, and add depth. My Render is for reference, I made that quick and dirty, to try and explain what I was saying with a pic. Just a suggestion, as you are really early on.