ORIGINAL: Red Raider
As far as I can tell, having just built the same plane from scratch, it wouldn't be necessary to put the formers back in. The strength of the fuselage is the sheeting, which is 3/16th to 1/4 inch balsa.
Iwould not be so concerned except that this is a very heavy bird. Those 2 Quadras add a lot of weight.
ORIGINAL: Red Raider
If I were you, I'd check for thin spots (over-sanding) and maybe reinforce them with thin sheet balsa on the inside. If the plane was built from the kit, according to the instructions, the only formers I would be concerned about are F5 forward. It seems to me that the majority of the weight problem comes from the engines. The original plane was designed to fly on Supertigre 60's. In my opinion, that's not enough power.OS 91fx or OS 120fs or similar would be good.
When Ibought the Nosen 310 I did some reading of reviews after the fact and it seemed to be mostly unanamous that .60's were not enough muscle for the bird. That was why I went for the Quadras. If comparable electrics were not so expensive I would just go to those but Ialready have the Quadras.
ORIGINAL: Red Raider
I'm using Saito 100's and expect to have more than sufficient power. Who knows, maybe at 40 pounds you need the Quadras!! I have templates for the formers if you insist, but getting them in around the stringers may prove to be more difficult than than building a new fuselage.
I wondered about that. I was trying to figure out how Iwould get the formers back in there without doing more damage than good but felt that at least some of them are needed due to the weight of the thing. Bill sent me some former templates. Icould have sworn that my plans had called for making the formers from just cross pieces and vertical pieces of balsa but that was 30 years ago so was not positive Iremembered right!