RE: Nitro 90" (1/7 scale)P-38J Build with mods
Made some more progress on the wing sections. Here are the fiberglass sleeves that a friend made for me. I chose 3/4" OD carbon fiber tubes and am laying it in just behind the main spar.
I made a fixture, out of a piece of brass I had on hand, to hold a step bit for reaching into the wings to drill out the ribs just behind the spar. I used CA to glue the bit in the end of the tube, then slid another piece of smaller diameter aluminum in the other end to keep the chuck from crushing it. Works great.
I tried a very sharp spade bit on the first hole, but it was too rough on the rib, as you can see. The step bit does a great job without cracking the ribs. A 13/16 hole saw would work also if you had an extension for it. I didn't have that tool on hand.
I am gluing the first sections in the outboard wings with Guerrilla glue and when dry, I will install the wing tubes, slide the inboard sleeves and the tubes into the center section, line it all up and then glue the center sleeves in place. I capped the inside end of the sleeves with balsa and CA to prevent any glue from getting in the end as I glued them in the wings. In the center, I went in as far as the back stop for the factory tube. In the outboard sections, I went three bays.
I have made light ply end plates to cap the exposed ends. I plan to use 1/4 X 20 nylon wing bolts and blind nuts to secure the outer sections. These I will access through the gear doors for the retracts. My intension is for the wing to boom, and turbo cover to top, all to be permanent attachments. Everything will be accessed via the gear bay, including servos.