Reinstalling the Wing Root Skins on a 701

Although several years ago, I recollect that the wing root skins when clecoed to the uninstalled wings looked pretty smooth and unbuckled,  a tough job but nicely executed.

Now as I try to install the wing root skins w the wings on the plane,  trimming to clear the skylight per the plans and manual. It seems no matter which way I start clecoing them on, I cannot get away from having a stressed, buckled wrinkled mess (and thats just me). I keep coming back to: Am I sure this is the root skin for the wing I am working on, it is of course. And even with the wings installed how do the holes drilled years ago not line up now For and Aft. they must have at one time to give that nice aerodynamic profile I remember. 

I would appreciate any advice on how to get this done. So far the port side wing skin (the one I started with) is still in good shape no permanent damage, and trimming still has it contacting the skylight. I am tempted to move to the starboard side, but fear I am going to find the same thing. I would jump into doing the beanie mod or some other fix, but I really would like to get final inspection before doing any further modifications.

Thanks in advance for your consideration of this issue.

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Comment by Perry Delano on March 2, 2023 at 8:39am

Hi Jim,

I have access to a strap duplicator. I think you are implying using a new piece, while I was referring to using the originals the holes are only off by a diameter,  so too close to redrill. 

Comment by Jim and Amelia Isaacs on March 1, 2023 at 4:34pm

Perry, no need to have to choose which existing holes to use, rather, order or fabricate the two-piece root skins, then using a strap duplicator use all existing holes.

Comment by Perry Delano on March 1, 2023 at 12:33pm

Hi Jim,

Thanks for sharing your experience with this part, at least on this subject I am consoled, I am not losing my mind.

My wing skins are one piece per side, so I'm guessing an older vintage than yours. I followed what I suspect is an out of date process now, where the one piece root skins were fit to the wings before installation. It was a tough job even then. It does seem evident now that this job should be left until after the wings were fitted (too late). I did see one of your posts, confirming the wing root skin is structural, so that is a concern with going off script.

The skin seems to fit ok if I use either the root rib holes or No. 1 rib holes ( I think, I don't have the plans in front of me) but not both. Other than Shawn's suggestion below, one solution might be to choose either the number 1 rib or root rib, and with the skin in place drill new holes between the existing ones, use them and forget the others. Another might be to use the nose skin back to the spar and use a new piece from the spar back, which is how our Cruzer is built, and I suspect newer 701's. The fly in the ointment with this plan is getting lighter aluminum locally  to replace the rear section is a problem. I have some .032 and .042 on hand, but that is extra weight. I have been reading about the beanie mod, and think I will eventually do it, but don't want to get into that right now. Applying experience building skin on frame kayaks ( See Baidarka - By George Dyson) with aluminum tube and ballistic nylon could be useful in that endeavour.

Patience and Persistence were wearing thin yesterday afternoon, and I probably did the right thing to step away (not my usual modus operandi).

As always thanks for your words of wisdom.


Comment by Jim and Amelia Isaacs on March 1, 2023 at 3:11am


Hi Perry.  I have some thoughts and questions. If those root skins were not crafted and fit with the wings installed, they won’t fit nicely, ever. These wing root skins were the very last items I installed on my plane.  Even after installing the fuel system plumbing. Yes they are of two-piece construction, my 2013 kit had two pieces per side, four total. I found some thin flexible cardboard and used it to mock-up and test fit my patterns before cutting. If the cardboard buckled anywhere I tossed it and started over.  Even then when it came time to use the metal, to curve the metal with my seaming pliers was tricky, and I had to scrap two pieces and fabricate replacements. This task requires patience and persistence!

Comment by Perry Delano on February 28, 2023 at 11:31pm

Hi Shawn,

That is a great solution. I will take a look when I am able to get back to the airpark shop and see how much trouble it will be to get the skylight out.  I still have the issue of why Rib 1 holes are lining up aft of root rib holes, but that might go away with no stress on the skin. Thanks for taking the time to get back to me on this issue.


Comment by Shawn Magin on February 28, 2023 at 6:56pm

Take the top skylight off, put your root skins on, use a level across front to back (allowing for thickness of skylight) and mark skins on that level plane. Be patient- a little at a time if neccesary..refit skylight and try root skins again. Patience makes nice looking (and flying) airplanes! Good luck!

Oh, and by the way, this is i think the toughest fabricated sheet metal on the entire aircraft : )

Comment by Perry Delano on February 28, 2023 at 4:38pm

I’m finding references to two piece wing root skins, is this a new development? On my second day scratching my head on this one. I would appreciate any direction to information or advice.



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