Portable AC Window adapter round

This is a remix of the excellent https://www.thingiverse.com/thing:6619437 remodelled from scratch in onshape. Design is [here](https://cad.onshape.com/documents/21a03c0fe104cfe9d3424cca/w/fc2a2751a4d78f3cddf08756/e/1f165849d28a460d12b0b531?renderMode=0&uiState=66bce5cb268c99270617544a) in case you want to modify for your own purposes:

### Changes
* Flange is round
* 6 holes in flange vs 4
* More material at the thinnest part of the flange
* Minor tweak to dimensions to make the angles round numbers

### How to use
* Cut a 7.25 inch (~185mm) hole in the surface you're attaching this to, screw it in. I think I used #8 wood screws. I have a portable Air Conditioner from the local hardware store from a brand I have never heard of and this worked great. The hole size must be quasi standard.