Right Tank Drilling Done, Left Tank Started
Right Tank Drilled and Sunk
I had a goal for the day. Get the drilling done on the right tank and get the Z brackets drilled on the left. I had match drilled the right tank skins and ribs earlier so all that remained was the rear baffle. I reamed all the holes in the skin to baffle and then set out to decide if I was going to countersink or dimple these. Vans tells you to countersink them to make installing the baffle easier when sealing the tank. I have read where others have successfully dimpled these, which is a stronger joint. I tossed the idea around and then decided to stick to the manual here. It does not seem right to countersink 0.032″ material, but it truly is the minimum you can. I tested a scrap piece with my countersink cage and once set, countersunk the holes. I had to remove the plastic to the point where my cage would sit flush to the skin.
Once done, I still was not liking the idea of the countersinks, but many a tank have been built this way and are flying fine. With these done, all that remained were the stiffeners to match drill.
Right Tank Stiffeners Drilled
I disassembled the tank and then clecoed on the stiffeners and match reamed them to the skin. Before removing them I marked their location so I could return them to the same place. With the stiffeners done, I then opened up the screw holes around the perimeter with a #19 bit. At this point the drilling is complete on the right tank [except for the fill cap and drain port]. I have a lot of prep to do for the capacitive senders and plumbing, but I will do those at the same time as the left tank parts.
Working on the Z Brackets on Left Tank
Now that I had all the clecos from the right tank, I assembled the left tank so I could drill the baffle Z brackets. Here you see the tank in place and strapped down. I had already drilled the inboard bracket and was about ready to remove the outboard leading edge to get to the inboard. I completed the outboard bracket and then took the skin and ribs off and drilled the rest of the brackets in short order.
Left Tank Brackets Drilled
With the brackets now drilled for both tanks, I will be able to get the tank prep done. The next time the brackets attach to the spars, it will be on a completed tank. Next up is match drilling the left tank, stiffeners, baffle, and then countersinking the skin to baffle holes. Then I will work on all the attachments to the tanks and start sealing away. I may have completed tanks by Christmas.
