Sunday, April 26, 2020

Tail Time

My original plan, after completing the nose, was to build the lower center wing section. However, I was unable to find the spar tube (1.75 x .035) in stock at Aircraft Spruce, and available, but pricey at TW Metals ($388 for two 96" long tubes, about $13.00 for shipping). That's about $2,500 for the wing spar tubes alone. I was unable to find those dimensions in 6061-T6 aluminum tubing anywhere else on line. (Update: don't tell anyone, but Wick's has this tubing for $6.15/ft. An 11-hour road trip and I can save the shipping cost, too).

So, instead I began on the tail. I started with a few parts seen in the pics below. Since the shipping cost for anything over seven feet skyrocketed about eight months ago (at least for UPS), I bought shorter lengths and will connect them with an internal splice.


Temporary nuts.

Internal splice for trailing edge tube.
I was thinking of using an external sleeve on the trailing edge, but I saw what looked like an internal splice on one of Mike Sandlin's photo gallery pictures:

Splice?

My method was to cut a two inch piece of 3/8" tubing, put it in a vise and cut lengthwise on one side. I then tightened the vise to close the gap and repeated six to eight more times. I filed and rounded the piece to get the result in the picture. I plan to place two rivets about 1/2" apart on each side of the cut - facing inward.

I was able to find a very good price for pultruded (epoxy impregnated) carbon rods, 1.5mm x 1000m at a place called https://www.racedayquads.com. I'm hoping the very slightly smaller diameter is aceptable as the plans call out .063"