Research of Checkoway Method for Fuel Tank Frame and LE Mod Remaining Steps

Spent several hours revisiting Dan Checkoway's method for ensuring a proper fit of the fuel tank skin against the LE skin. I also reviewed  my own blog from about 3 years ago in 2014 when I was on the path of "normalcy" with this project until I decided to do the LE mod. I had to stop at the point where I normally would have been ready to drill and assemble the fuel tank frame, finish constructing the LE, and moved on to the ailerons and flaps and push rods, like everyone else. Instead, everything stopped at the point where I would have completed the LE.

This is next pic is a subtle reminder of that fact.

Had I decided to do the "normal" thing like everyone else, there would have been no custom-built ribs, no subskin, no patch plate, and instead of the subskin all I would have had to do is install the small square mounting bracket for the access panel. That small square bracket is all I would have had to mount to the outer skin of the LE. There would have been no additional holes to measure and drill, and I am pretty sure that I would have both wings done by now and I would be in the middle of my fuselage. Pretty amazing to think that this small number of customized parts would cause such delays in the building progress.

I am now on what was supposed to be the "hard" part of the modification - figuring out exactly how to measure, cut, and secure the detachable leading edge. I need to figure out the exact placement of all the rivets and nut plates, and then finally take the plunge and make the dreaded cuts of the LE skin.

Before I do that, however, I need to finish dimpling the LE outer skin and remaining ribs, and then I need to countersink a lot of holes in the Main wing spar flanges for the top and bottom mounting holes of the LE skin to the spar. When that is done I can reassemble the LE using the cradle and the table with clecoes, mark the cut lines and rivet and screw holes in the outer skin and subskin, attach it to the main wing spar again, drill the rivet and screw holes for the removable LE, fit the Fuel tank to the wing spar, verify the fit of the tank and the LE skins, drill the inboard Z Bracket rivet holes per the Checkoway procedure, drill the Fuel Tank to LE joiner plate screw and nut plate holes, remove the LE, finish drilling the outboard Fuel tank rib to baffle holes, disassemble the fuel tank skin, finish drilling the remaining fuel tank rib to baffle to Z Bracket holes for the interior fuel tank ribs and Z brackets, disassemble the fuel tank frame, cut the LE outer skin to the predetermined cut lines, fabricate a new removeable LE skin to replace the skin that was cut away from the LE, disassemble the LE ribs and subskin for what should be the very last time, debur and smooth all holes and edges in outer skin and subskin, drill, debur,and dimple all subskin holes and edges, rivet all nut plates in the subskin, drill, debur, and dimple the screw holes in the removeable LE skin in a wrapping and forming procedure to ensure that the removeable skin adheres to the LE shape and dimension with the surrounding outer skin, rivet the LE ribs to the outer skin and subskin, reattach the LE to the wing spar, and finally, rivet the LE to the wing spar (both ribs and skins).

WOW! And I thought I was making "progress!" then, once this is all done, I can 3D all the remaining fuel tank ribs, skins, baffle plate, and fabricate the tank stiffeners. Then I can proceed with the 6 million things you need to do to finish the fuel tanks. Somewhere in between all that I can finally dimple the top wing skins and main wing ribs.

Just a few things left to do until I can finally play with proseal!
Now that I have  few more things figured out, progress continues tomorrow.

KPR