Drilling skins

I have been drilling tailcone skins all day long. I still have one more side skin to do. I forgot how much work goes into drilling all the skins on. Lots of joints to get right and line up. However, when it's done correct, it will look good on the flight line.

Take a look at the pics to see how I drill the skins in place. I will drill one side at a time so I can access the back drilling from the outside. Takes a little longer but I won't have to try and squeeze into the small tailcone either.

Hit a speed bump while trying to drill the tail skins. I was all set to go to backdrill the tail skins when I found out that the skin overlap on the my lower longeron/lower skin/ side skin was not going to be enough. The lower longers create a "V" from the baggage bulkhead down to the F-610 bulkhead. I did find some dimension for the longeron placement near the baggage but nothing down by the F-610. I even had a set of RV-7 drawings and could not glean anything off those prints. So I used the skin and some derived dimensions from other parts located there and came up with about 5" or each longeron was placed 2.5" from the centerline. I had to cut a new .032 bottom skin since the original is .025 and not wide enough at the top. I wanted .032 on the bottom skins to help with old canning, smoother finish and strength. So I cut the skin and placed it on the longeron. That was good. Next comes the side skins and there is where I found out that my overlap on the bottom was only about 3/8". Not quite enough to be legal. SO I had to move the longerons out another 3/8" on each side which meant more cutting and filing on the bulkheads. I don't know why Vans even puts those notches in the bulkheads because they are way off. I then had to make some small tabs to rivet to the bulkhead flanges over to the longerons because there is nothing left to attach them to they are moved over so far. BASH TO FIT, PAINT TO MATCH......I then cut another bottom skin and I thin I will have just enough .032 left over to do the bottom seat skins. 4X12 .032 sheet is about 300 bucks now! I need to get this correct. I will move the other longeron tonight and then start back drilling skins.
Progress is slow sometimes, something I have learned as I get older. Be patient and it will come together......

Working on the tailcone

Now that fall is here and winter is not too far off, I have resumed work on the tailcone. I have to drill all of the holes in the longerons and bulkheads. Then I will put the skins on and strap everything down and backdrill the skins. This the best way to get the skins drilled since you know your holes are all in the center of the longerons and bulkhead flanges. Blind drilling is not easy and you can get off center.

After that, then it's on to the bottom skins. All of the bottom skins will be .032 for some added strength and a better finish.