This is what I did with mine:
first I took out in a piece of paper the outer geomoetry of original plate from Oxai and then threw it to the garbage.
Then I took two 1/8" midwest ply (not lite ply) and made five layer: carbon - ply - carbon - ply - carbon which ended with a little bot more than 1/4" thickness. Then passed the outer geometry, and then drew the holes of the engine directly to this plate, so no intermediate cross or any plate in between the firewall and the motor so only one piece from the fuse to the motor. the only downside of this is that it will be hard to put a new motor different than a Q80 in the future. Even using the original geometry as you can see in the picture, i had to trim it a lot.
then I glued the firewall using 30 min epoxy and very little microballoon.
then i drew the rear suport and my firend Federico drew it in autocad for me. We laser cut the support in normal 1/8" ply and had it laminated with 2 oz carbon on both sides. i used a solid carbon rod to put inside the motor and 4 mm metric screws with washer, locknut and loctite. this is not the lightest setup, but i had enough weight to spare and i am not a big fanof super light biplanes. I now have a final weight of 4920 which is fine for me. On the other hand this is the last place on a Citrin IŽd play to save weight.
Here are some pics of the set up if somebody wants the cad or pdf on scale 1:1 drawing, I can share it no problem, just email me
[email protected]
i have now around 150 flights with the citrin from January 20th this year with absolutely no problems.
Marcelo