Brief Description: Fabricated tail tie down and installed wing tie do
With the wings still in the garage, I decided to install the tie down rings. I also decided to fabricate the tail tie down bar which will be installed on the inside of the very aft fuselage bulkhead (F-712). Four bolts that hold the vertical stabilizer aft spar will pass through the tail tie down bar. As usual nothing is as easy as I thought it would be.
The QB wings already contain the tie down bars, but they need to be tapped to 3/8" x 16 threads per inch. The wing skin hole for the tie down is 3/8" but the tie down ring has a 3/4" base that will bend the skin if it is not enlarged. I enlarged the skin holes just enough for a flat washer (5/8" OD x 3/8" ID) and lock washer that took up the small space between the skin and the tie down bar. The lock washer holds the ring tight and keeps it from vibrating loose. I'll seal the ring hole with tank sealant or RTV.
I fabricated the tail tie down bar per Van's drawing 21. I used the band saw to cut the bar per the drawing and then drilled out the hole to 5/16" before tapping to 3/8" x 16 threads per inch. I'll install it on the F-712 bulkhead before installing the verical stabilizer.
Tie down bar drilled to 5/16" before tapping and skin hole enlarged.
