Bending Leading Edge Skin

The best way to do this is with a press brake where you push the sheet into a die to form a nice bend at the exact location needed. I don't own a 12 ft press brake. I've faked it where the skin is narrow and long by folding it and pressing it between 2 2x4s screwed to the floor. I just didn't think I had the strength to do that with such a wide skin. The plan here is to form it by pulling the skin down over a tool made by screwing a length of 1" schedule 40 PVC pipe to the edge of a straight 12 ft long 2x8. The screws were spaced about every 18", countersunk and any edge of the head sticking out filed smooth with the pipe.

You can see in the first picture with the old skin setting on the tool showing what the desired shape should be.

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To keep the skin from becoming wavy and to protect the edge of the skin, 12 ft long 2x4s were clamped, with backing blocks, to the skin edges.

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With the 2x4s clamped on, the skin was placed over the tool with the nose of the Leading Edge ligned up with the top of the pipe, red marks on skin and pipe.

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Light crank type cargo straps were than wraped around everything about 2 ft on centers. OK, this took about 10 tries because the 2x8 wants to fall over. By holding the 2x8 with my knees while carefully starting to tighten the 2 straps at each end I eventually got it going. I then realized I should have used a 2x8 on the long side and started over with some extra 2x4s so it would all clamp closer to the bend. .

Eventually the bend was tight enough that the clamps and backing blocks were hitting on the 2x8 preventing further bending. We were able to remove the clamps and blocks at this point because the friction of the 2x4s against the skin prevented them from slipping. If I had some pieces of 2x2 to add right at the bend I could have made this bend even tighter.

As it turned out it is not as bent as the old skin but it is identical the the skins I recently installed on some Cub wings with no problem so they should work just fine. Once they're riveted to the spar and top of the nose ribs the straps can be used to pull the bend tight to finish the underside riveting.