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One piece wingskin

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Staunch111

Well Known Member
Hi all, looking for guidance. I am replacing the two top wing skins (W702 & W703) with a single skin. Can anyone advise what the gap is (if any) between the two skins? As far as transferring the holes (from W702/703), can anyone recommend an appropriate tool to ensure I am marking dead centre? I really don't want to risk drilling oblong holes in the rib flange when match drilling due to being slightly out. I'm currently looking at 'transfer screws'. Any thoughts on size? Thanks
 
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One way that I use to transfer hole locations:

Once the old skins are clamped in place over the new skin, use a drill bit sized to the existing holes, or one size smaller. Twist drill in each hole by hand or gently with a drill. Unclamp old skins. The indentations left by the twisted drill will give you a nice center for your center punch. Once center punched, drill holes to correct size.
 
I am assuming the holes to be transferred are for 3/32 in rivets. Use a 3/32 in pin punch to accurately locate the hole center. Now drill the center with a small bit (1/16). Next, drill using a bit slightly smaller than 3/32 in. Finish up with a no. 40 reamer. Doing it this way should prevent wallowing out the hole.
 
I remember a Youtube video showing WW2 airplane restoration where they used the original skin as template to drill rivet holes onto a new aluminum sheet.

Get a large particle board, lay the new aluminum sheet between the board with the original skin on top. Start drilling and after every hole, insert a cleco to keep the sheets aligned. The particle board should keep the clecos in place. At the end you should have duplicated all the rivet holes of the original sheet metal. Good luck.
 
Staunch111 said:
Hi all, looking for guidance. I am replacing the two top wing skins (W702 & W703) with a single skin. Can anyone advise what the gap is (if any) between the two skins? As far as transferring the holes (from W702/703), can anyone recommend an appropriate tool to ensure I am marking dead centre? I really don't want to risk drilling oblong holes in the rib flange when match drilling due to being slightly out. I'm currently looking at 'transfer screws'. Any thoughts on size? Thanks
Click to expand...

Answer to your first question - There is no gap between the 2 skins, one overlaps the other.
A good method to maintain perfect skin alignment is to leave the two skins riveted together, drill out only the rivets that attach the skins to the ribs & spars, leave the skin overlap line of rivets so the two skins come off the wing intact as one piece.
As others have described, lay down the new (.032) aluminum sheet on particle board, than clamp & align the old skins on top.
The old dimpled rivet holes are a bit bigger in diameter than the new required #40 drilled holes. Find a drill bit (probably a #38 or #36 drill bit) that will snugly fit thru the old skin dimpled holes, use it in a hand drill or slow turning electric drill motor, only a couple turns are required (do NOT drill thru with the #36 or #38 bit!) to mark a perfectly centered pilot for the #40 drill bit you will use to final drill all the rivet holes. Cleko the skins to the particle board as you go.
Good drilling!
 
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