You don't say how big the plane is or how heavy you expect it to come out. That would help people know how large the stuff is you need to stuff in there.
My first suggestion would be to see if you can rearrange things to mount the battery on the face of the firewall, to get the weight as far forward as you can. Then you just need ESC and timer or receiver in the box behind the firewall. As part of that, there's some quadcopter motors that are very high diameter and short for their power output and they turn slower than a "typical" model airplane motor -- I have not tried this, but it seems that'd be the bee's knees for a radial-engined model, getting the CG more forward and letting you run a bigger prop.
Tim,
Thanks for the reply. I mention in the Thread I'm using a Smoothie wing, but you're right, I don't believe I mentioned the span at 52", the fuselage without the cowling and rudder measures 27" the cowling is 7" in diameter, plenty of wood to sheet this fuselage.
I weighed this stuff just now,
Vertical stab and rudder: .7 OZ.
Balsa cowling ring: .9 OZ.
Sheeted fuselage, un-coved open bay wing, stab together, (they are assembled): 28.2 OZ.
Elevator: 1.2 OZ.
As far as the motor, I was thinking about the Badass 3520 because of the extra long prop shaft offered which can be purchased separately. I need the length to help recess the motor to allow for a faux radial.
Thanks again for the reply.
Charles