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Rear spar caps

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  • Rear spar caps

    Has anyone ever built the rear spar caps, spacer bars, splice plate and root filler as one piece? It would eliminate 30 pieces (per spar) and the pain in the *** to fit all the pieces to a contact only condition. Too late for me but if I was doing it again, I'd run it by Bob. The labor savings would be significant. .062 2024 T3 is not that expensive. The part would be a snap to program. I must be missing somthing here.
    Gerry
    Patrol #30

  • #2
    Sounds to me like you are being innovative.
    Brooks Cone
    Southeast Michigan
    Patrol #303, Kit build

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    • #3
      I agree! have been contemplating this since you posted. the obvious downside is that a major error late in the assembly would require substantial disassembly. perhaps the consolidated part could be based on smaller modules.

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      • #4
        I’ve pondered similar. You’d need to make it out of sheet goods, and there’s a fair amount of waste this way. Aluminum sheet is pretty expensive when you get into the thicker stuff. It pained me seeing the pile of chips and other waste when I cut up a $400+ sheet of .125” a while back. Bar stock is virtually waste free, but it does take longer.

        A milled piece will also be a fraction heavier.
        Last edited by Chris In Milwaukee; 06-29-2019, 07:10 AM.
        Christopher Owens
        Bearhawk 4-Place Scratch Built, Plans 991
        Bearhawk Patrol Scratch Built, Plans P313
        Germantown, Wisconsin, USA

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        • #5
          On the rear spar there are 50 joints that must be perfect. Any gaps effect the efficiency of the joint. With a one piece structure all joints by defination will be perfect. If your making the parts every day at the factory the joints are giing to be better then a scratch builder can accomplishment. Seems to me that the one piece part would be stronger, while being heavier. However because its stronger maybe the dimensions of the part could be reduced to make the weight gain insignificant. A through stress analysis would be required. They could be water jet cut complete with pilot holes making assembly a snap. Dozens could be cut at the same time. The waterjet cutter we had at Boeing could cut 5.5 inchs of titanium. I've forgotten how many hours I've put into the spars trying to get the joints to a contact condition. Fun to ponder.
          Gerry
          Patrol #30

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