RE: Sig 1/5 scale piper cub
Thanks, it's the same kit Goldwaterman is building. The greenhouse is pretty straightforward, basically it's just substituting the kit center section and wing tube assembly for a framework of hardwood that creates the windows of the greenhouse. I used basswood and spruce square stock for the crossmembers, doubled the thickness of the airfoil shaped piece where the wings attach. Instead of butt-jointing the crossmembers, the wing root is notched to receive them; it gives more glue surface area, plus I pinned the joints. The round framework is 1/4 and 3/16 dowels, and they do share part of the load. The four cabin uprights that boxbeam mentioned are reinforced with dowels, the angled ones that rise from the cabin floor to the center spar are reinforced with carbon fiber bar stock (1/8x3/16). Indeed, these are what breaks in a ground loop where you catch a wingtip.