Building a BUSA 1/4 Nieuport 17. Plan on putting a Zenoah G-26. Buddies at the field say I should "re-inforce" firewall with CF rods. Cant seem to find any posts or videos about this topic. Any help would be greatly appreciated.

Use any 1/4 to 3/8 inch birch plywood instead. Dan.

No need to do anything if you use a g-26. Tons of them have flown with that setup with no modifications. Just use a good slow epoxy to install the firewall and make sure it is 1/4" ply and you will be fine.
Larry

Probably no need to do this as your model may already have it installed, but I have epoxied triangle stock into the firewall joints.

+1. I do this on all my planes. Extra ins.

Yayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy ........... somebody that's have finally agreed with me. LOL

I've heard of people inserting wood dowels or CF rods through the side of the fuse into the firewall. These have been perfromance planes and wont be under stress like this one will be.

Thanks for all the good comments!

Using rods through the sides into the firewall is called pinning. It is a very common practice. I commonly use pinning at wing hold down locations. and hi stress points on large heavy models. The most common material I use is bambo skewers I get in the cooking isle. There are two sizes about 1/8 and 1/16. One dollar a bag and very good shear strength (can not be beat for cost vs strength).

Butt joints are not very strong. Even well designed laser cut kits with interlocking tabs can benefit from pinning and using triangle stock.

Don't fixate on the engine and miss the tail strength or landing gear though!

That Nieuport is just a big kite though. The 26 is shy of 3D power for it. You won't have to try hard to fly it scale like haha.
So make it pretty.