RE: Bob Cat Copy Falcon 120 Jet
If you can find a carbon tube, I would go with it. If not, I would not worry about it to much. I would drip a polyurethane or other good glue into the wings. I put it on ribs, blocks, spars, leading edge, webbing, etc... Keep in mind they use crappy glue and this may have been what happend to Tumblers wing. I wonder if his wing started to fail and then this caused the tube to bend.
If you guys that are still building and are worried about it, then open up the bottom of the wing in a few spots and apply some epoxy to the spar, webbings, stuff like that.
I have a carbon tube that fits, it came from a crashed Fliton Inspire. Not sure where you can get one, but hope it helps. It actually is longer then the alum tube.