RE: PICA Spitfire 1/5 Please Help
I'd also agree with the above posts. I did all the "new" lightening procedures, cutting holes in the balsa empennage center sheets, but I did not use lighter balsa. If I did it again, I'd definitely make rearward formers out of balsa and be very careful with wood selection. Even then suppose you save 3 oz of weight? I saved all the wood I cut out in a bag, and it didn't seem to weigh that much. I think if you plan for as much radio gear, batteries, etc. up front, and then use a heavy gas engine, you'll still have to add some lead. I don't think I've heard of one of these (that has flaps and retracts) that has come in under 24 lbs. I recall the box indicating that a .90 to 1.2 two stroke was recommended. I first installed a ST 3000, and after reading a few reviews, switched out to a G62. Now I'm putting in a 3w-50, and although there will be some cylinder and spark plug sticking out, it won't be much, and I still plan on 3-4 lbs of lead when I balance.
These planes have long fuselages and short noses, and the real ones had large heavy engines to make them balance.
Hope this helps.
Sam