Working on my 1/5 Sopwith Pup and i have a small problem.
I have a Saito 91 i wanted to use, but the engine sticks out abit to far outside the cowl

The firewall and Sub firewall is already in place unfortunatly i didnt realize any of this before hand because i wasnt thinking ahead like i should have been

My question is this

Is it ok to extend out blocks for the cowl to mount abit farther out than the plans state.
Or do i HAVE to recess the mount into the firewall?

It will be much more work having to recess and it seems to me it would affect the CG, as far as i have read these WW1 planes are notorious for needing weight in the nose??

So extending the blocks and blending everything in so the cowl sits out farther seems like a better idea

Also i forgot to mention its about 1" at the most i think.

Any experts have any solutions to this problem??
All help and suggestions are appreciated.

Thanks

You can certainly move the cowl out if you don't mind messing up the scale looks. If that doesn't bother you, go for it.

Would it be possible for you to cut a square hole in the firewall and build a box to mount the engine mounts onto, and recess it into the model?

Bill, Waco Brother #1

Cutting the firewall and fabricating a box would be possible. I was more concerned with drastically affecting the CG and needing even more weight in the nose to balance.
In doing so i would need to alter the tank floor and a few braces but nothing that cant be done.

What would be the best way to brace and recess / and attach the box into the firewall??

Im assuming if i do this the box will need to be removable so as to have access to the bolts from the motor to the mount yes>?

I would use a drill bit and drill all 4 corners where the recessed box will fit. I'd use the small pointed Zona saw blade to make the cuts, and then build the new engine box to fit the opening. I'd then tack the box in place and cross drill the firewall and box to accept wooden dowells. I'd then set up the box to accept the engine mount, and once all the blind nuts, holes for fuel lines and pushrods were drilled, I would epoxy the box into position, and epoxy the dowells in place. Once the epoxy has cured, trim off the excess dowell, and sand smooth. Finish with the appropriate colored butyrate dope to fuel proof the new firewall, and you should be good to go. engine setup and balancing the model should be straightforward from that point.

Adding weight to the nose is standard fare with most all WWI birds and others with a short nose moment. Big ol' battery packs are better than a lead lump.

Bill, Waco Brother #1