Threw this together today with an I-beam ruler and the H3H3 podcast, so I guess you could say it was a productive Saturday. The two squares hanging off the edges are for my servos- I plan on just gluing them into place. I think the inner diameter is like 13cm, idfk you download it and check. The motor mount is receded 4cm down, and is a perfect fit for an Emax GT2215/09. Sorry if it's garbage, my only modeling experience is from my 7th grade tech ed class 6 years ago.