RE: MR Aerodesign 1/4 Scale Mudry CAP 10b Review / Build
DAY7..
OK, so now to mount the engine:
First, obtain a good drawing of the engine mounting dimensions. The one that comes with the CRRC50 is not complete, however they emailed me this one that is pretty good.
I need to mount the engine 95mm away from the firewall, that's nearly 3 3/4"! Too long for stand offs I think!
So a box is what I need. The engine comes with nice 22mm standoffs so that means the box neadsa to be offset 73mm. I used Sketchup (free form Google) to draw up a quick 3D plan. The idea is that the box will pass through a hole I will cut in the firewall. It will then be glued and reinforced with 1/2" triangle stock both on the front and rear of the firewall. That should be strong enough. The holes in the box allow access to nylok nuts on the back of the front plate.
I do not want to use T-Nuts (blind nuts) as I feel in a 1/4" ply firewall they will weeken the wood too much, plus the engine need to be as high in the box as posible to match the correct thrust line and 10-32 T-nuts are quite large in diameter..
The box is contructed of 1/4" high qlty ply. NOTLITEPLY. The front plate will be pinned with 1/8" dowel after gluing for aditional support.
I am not commited to this design yet...any suggestions to simplify or improve on this are welcome!!!
Bipeman suggested bolting on the whole thing to the firewall to prevent having to cut into it. That would maintain the firewalls strength. Problem is finding a 5" bolt... Maybe 10-32 threaded rod and nuts on both sides!!!!