This is a wedge spacer I made to smooth the transition between the overlap of the two aft bottom skins where the stringers attach. It tapers from .040 to .016 and matches the width of the stringer on its rivet face and will transition over 3 rivet holes. Without, it would leave an ugly wrinkle on the outer side skin near the rudder cables exit.
Here, I've put the two upper aft fuselage skins on to make sure the lower aft fuselage is straight with absolutely no twist before drilling. It will be safe in the garage tonight as it looks like a porcupine with all the clecos.
I much preferred fitting the two aft bulkheads to the side skins prior to fitting the bottom skin. They took quite a bit of flange bending to get them to match the taper of the skin.
I also had to hand bend the bottom skin to add more curve. Mainly on the most aft bend and mostly on the left side. After about an hour of tweaking flanges of the two aft bulkheads and bending the bottom skin and repeating, I got the bottom skin to easily slide up into position. This picture shows the perfect alignment of the tie down guide hole in skin through the tie down bracket.
