Cutting Out Wing Skins

The wings structures are all together and ribs up drilled to the front and rear spars.

Next step is the wing skins.  We thought we had been pretty clever in our 4′ x 12′ aluminum sheet planning but we discovered once we laid out the wing skins on what is left we will need to buy another sheet for a fuselage skin.  With hindsight we should have cut out the wing and fuselage skins and put them aside.  No biggie.

Dan had cut out the top and bottom skins.  Note that the aluminum sheets are not perfectly square from the mill.  A good framing square will show it.

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2 Replies to “Cutting Out Wing Skins”

  1. Hello , great info on here and quality looks great also ! I am scratch building plans # 1356 and not understanding how to measure , cut and lay out hole pattern in wing skins and turtle deck skins. Can you explain how you got your measurements. I would really appreciate any info you can share.

    1. Hi Dennis,

      Really big question. I started replying and typed for about a half hour before my web page editor went South on me. I don’t have the time right now to re-enter my response so maybe I could ask, what specifically are you wondering about? The wing skins are pretty square, with the exception of the outer edge. We rough cut this edge (measure accurately and cut about 1″ long). None of the holes were ever drilled until very late in the process, until the structures (wing box or fuselage) could be assembled with clecoes to compare the layout before drilling.
      One thing to consider is bending the leading edge. Do a search on U-tube for “Vacuum forming Sonex leading edge skin.” One link is as follows but you should find a few:
      https://www.youtube.com/watch?v=2_QWPoFEhWc

      I would definitely use the vacuum forming and even though you will rough cut the wing skin before vacuum forming, I would not drill any holes until you have the wing box to compare it to. The same is true of the fuselage. The fuselage is a lot more of a pain to layout as it is almost completely a collection of coordinates for each hole on the darn thing. Very time consuming but the drawings seem to be accurate. Follow the dimensions and it will work out. Despite the fact that some (many) of their dimensions are maddeningly awkward to identify. I can’t tell you how many times I’ve mixed up 27/64″ for 26/32″ (or something similar to that). Most of the time I catch it before I follow through with the mistake but every now and then it gets me.

      As far as the leading edge skins, the center line and the Wing Station (W.S.) 22-3/4″ were my datum lines. ONce these were drawn I would reference everything else from these lines. Note the advice on the U-tube of leaving bottom side 3/4″ longer than shown on the drawings to allow for the vacuum forming process.

      I’ll try to write a little detail on the turtle deck and anything else I can recall on the wing skins tomorrow.

      Best regards,

      Dan Theis.

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