Leading Edge Skin Clamps - Tips and Tricks

[David H]

Some tips on using the leading edge skin clamps:
(I have standard fuel tank wings, there may be differences with extended range tank wings).

Here are excellent tips on installing the skins:
Leading Edge Skin Installation Tips


The set I received had four of the clamps in the well traveled box.


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Make sure you have wing nuts on all the threaded rods.
Set the threaded rods to 2 1/2" on three of the clamps and 4 1/2" on one clamp.



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I made this stack up for three of the clamps. A single screw holds all pieces together. The fourth clamp has just the caul board and will use the bridge. This really helps:


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I build a simple bridge for clamp #4 which helped greatly. This bridge traverses the drag wires and makes things a whole lot more efficient.


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This is how your wing should look when you are ready to clamp:


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Move the wing to the edge of your sawhorse so the lower edge of the skin will clear as you form it around the nose ribs. Start from the middle of the outer skin and apply the first clamp (#1) between two nose ribs. You want to center the clamp between the ribs to allow clearance for drilling and riveting. The first skin may be a bit intimidating. Push in on the skin and get it wrapping around the rib. You can push the skin in with your hands and hips (watch you belt buckle). Slip the first clamp in place being careful that the threaded rods don't scar the aluminum skin. Place the caul and steel tube. Just start the wing nuts to hold everything in place.
Place the second clamp (#2) between the nose ribs adjacent the first clamp and snug it up by turning in on the wing nuts until there is about 1/4" gap between the clamp and the most forward point of the skin. Place and snug clamps three and four one rib over from clamps one and two.


Now adjust all four clamps so they are flush with the skin. A clamp at a slight angle will be noticeable at this point. The clamp on the left needed adjusting.


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Start tightening the center clamps and work outward. Finger tight on the wing nuts is all you need. You can feel and hear the clamps tightening. When the clamps flush the skin to the ribs, the resistance to turning the wing nut will very quickly increase. Check all around the ribs. Look for the “gap” present between the bottom edge of the rib and the skin just past the leading edge. Others have commented on this. As long as it is <1/32” and consistent among the ribs you are OK. Even when pulled with straps instead of the clamps this gap may be present.


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Once you are satisfied with everything, remove the Cleco and rivet, drill for the bottom rivet and install the bottom rivet. Repeat for all nose ribs between the clamps.


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Now remove clamps #1 and #2 and place them outboard of clamps #3 and #4. Tighten, check, remove Cleco, rivet, drill, rivet.
Move to the next inboard skin and repeat.

Use the clamps to help with the landing light install:
Landing Light Install

This setup really helped me getting my second wings done with much less frustration of pesky little wooden blocks dropping to the floor when moving the clamps.


I hope this is helpful.

David