Left Fuel Tank Prep HOBBS 290.0 hrs

Spent all week working on the left fuel tank. First doing the Z-brackets to mount it to the main spar. I used the "Checkoway" method on these. It wasnt too painful and pretty straightforward. I do have a funny feeling that doing it exactly as Van's says to do it would yield perfectly fine results also.

So, the week's activities were...Z-brackets, match drilling skin to ribs/baffle, machine countersinking, capacitive plates, fuel tank mount bracket fabrication and stiffener fabrication and just misc prep work as I get closer to sealing the tanks. After I finish the left tank I will move on to the right tank next. Here are some pics from the week.

Hey look, a 'complete' wing...not quite, but it looks cool

Just before match drilling the end rib z-bracket

Left fuel tank in the cradle

Left fuel tank end ribs and baffle...skin and interior ribs removed. This is what it looks like before match drilling through the main spar.

Here is a step-by-step view of the fabrication of the fuel tank attach bracket. It starts out as a piece of angle aluminum...

Had to find something laying around the shop with a 2" diameter for the layout...this was real close...a smidge big, but it served its purpose.

We never want sharp radii...stress concentrations, especially on something that will be carrying a load like a mounting bracket. So, first step...drill some holes for the inside radii.

And there ya go, a finished part..came out nice

Machine countersinking the fuel tank skins, it really helped to lay the tank on its side like this...better leverage.

Attach bracket cleco-ed in place

Capacitive plates installed...partially. Notice I had to notch one of them to fit around one of the stiffener, they have a recommended clearance from all metal. The plates have to be electrically isolated from the rest of the tank to function properly. There is more to this installation, but I think the rest will wait until the tanks are sealed.