Hey UKIE, as an OLDTIMER scratch builder one item needs to be discussed. When using balsa and plywood, the direction of the grain is one that needs to be taught. There are books that go into detail about this, but basically ribs are cut with the grain and wingtips are a composite of differant angles on the grain. Also there are differant weights of balsa; very light for F/F, R/C and a slightly heavier weight for U/C, boats etc. How you position the grain direction gives you the added strenght needed for light weight and durability. I'm sure there is someone near you with skills needed to get you on the path to the art of scratch building. If not check with a woodworker or furniture maker their knowlege would be helpful. Once you get hooked on your own work you'll NEVER buy an ARF again!!!