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Wing skins on LSA

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  • Wing skins on LSA

    Would someone please explain why the wing skins wrap from the rear spar around the nose ribs to the front spar. Why not make it one piece from rear spar around nose ribs to the other side of the rear spar? I see no loss of strength in doing that. Thanks.

  • #2
    I think trying to work with a piece of skin close to 14 ft long with a leading edge bend in it would be challenging for fitting, drilling, dimpling, and riveting.

    For example, when fitting the skin, you need to drill through skin and center of rib flange. That would be tough with both sides covered at the same time.

    There also is an option to use varying skin thicknesses top and bottom.(.016 vs .020 though I used .020 or greater where specified).

    Doubt it would save much weight and would definitely be more challenging(and likely more expensive after a couple go in the "lessons learned: pile).


    • #3
      But on the LSA, each piece of skin only covers 4 ribs or approximately 40" wide. I would like to go from rear spar around the nose ribs to the rear spar. Makes more sense to me. I am using the same skin thickness, 0.016".


      • #4
        I can't remember but I thought one side was optional .016 while the other was .020".

        Again, the headache I see is that when fitting the skins to the wing I used ratchet straps to hold them tight while drilling. If the skin covered both the top and the bottom of the wing at the same time, it would be tough to position the rib center line on the hole pattern in the skins(I pre-drilled my skins and then pushed the rib L/R slightly as required to be centered under the hole pattern).

        Getting the nose ribs in place would be tougher yet but perhaps you could find a way to fixture them in perfect position before putting on the skin.

        Same thing when it is time to rivet. With the bottom skin off one can back rivet most of the top rivets. It would be very disappointing to find that you have fully riveted the top skin but accidentally dented/creased the bottom skin while pulling it out of the way for access.

        I expect the manufacturing hurdles could probably be met but to what advantage? Losing the weight of a .5" ribbon of .016" aluminum approximately 3/4 the length of the wing?

        And likely some of that advantage is lost due to the increased number of overlap seams in the bottom skin.