HAL......
What are you planning to use for the prop shaft?
What kind of bearings?
I would also try to find a thrust bearing to help take the load off the mount and get more usable rpm's on the shaft.
You may also want to consider some kind of bracing (horizontal-from front brace to rear brace) to connect the sides of the upright mounts. The thrust of the prop will want to push the rear upright forward, causing binding on the shaft.
But then I'm sure you already thought of this

Looks very good so far.[8D]