ORIGINAL: summerwind
sheesh.......i bought three of these birds.(yes, coming back and i'm hooked).........maybe i should buy a fourth??
I see no reason to avoid the 4th. I would suggest that you layer that firewall with some decent 5ply. 3/32 would be about right. That's what I plan to do if I ever need another one.
really though, the firewall has plenty of mass for the recommened size engines, and of course there have been guys putting double that as in one of the topics here,
Mass isn't the only characteristic to look for in a wood component like a firewall. The same mass of balsa wood still won't be as strong as liteply. And the same mass of liteply won't be as strong as 5-ply Aircraft Plywood.
what i'm really suprised at with your plane Rock, is the cowl........it took me many emails and actually 2 purchases to get perfect cowls (uncracked) for each one i own and 2 spares.
the one i have finished right now was clear coated with Varathane, and that was to get a good gloss finish.
The original ARF package I opened had been packaged with the hardware sack placed loose inside the cowling. And that cowling had been beat all to hell. I got a replacement from Tower as soon as they became available. It's been good since then. Of course, since starting to assemble ARFs, I've found that I almost always reinforce the insides of all the recent cowls where they are going to see stress. This one had 2oz glass cloth painted inside where the 4 hold-down screws go through. Basically 1"x1" squares of glass cloth. Of course, the cowl took all it's abuse in this hit from the spinner backplate and if there had been a bit more energy would have crushed forward of those 4 points.