Matt,
Thank for your reply and ideas.
Where do you get your carbon tubes that will telescope inside each other? How do you glue them to the fuse sides? I assume to the top and bottom of the side. What material do you make your fuse formers from?
I had planned on using plain Dubro tanks since they are cheap and available. I'm using a 100 oz and 80 oz for fuel and an 80 oz for smoke. The same for the aluminum wing tubes, they are much cheaper than carbon and available with pre-made sleeves. I have looked at PET bottles before but never figured out how to close them up and put fittings in.
I also use Radio South heavy duty hinges. I like them since they are easy to slot, use lots of them, 2-4" apart, and allow great gap seals just by ironing covering material in the hinge line.
Gary