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Thread: Size of forming block; how big?

  1. #11

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    Quote Originally Posted by martymayes View Post
    Question:
    Edit: Nevermind - I see what you have planned with the nutplates.

  2. #12
    Yeah, lots of nut plates. I removed the cross brace from the tank bay and replaced with a shear plate under the tank. The tank cover now becomes a structural part of the wing so nut plates every three inches. The cover will have stiffeners to form the top curve of the tank cover. i still have not decided how high above the tank the fuel cap should be. My mock up is set up so the bottom of the cap will be 1/16"-1/8" above cover. On another thread it was mentioned that having a vented cap above the surface of the tank will siphon off fuel. Any comments on that?
    Thanks,
    Marty

  3. #13
    Aaron Novak's Avatar
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    Quote Originally Posted by Martyfeehan View Post
    Yeah, lots of nut plates. I removed the cross brace from the tank bay and replaced with a shear plate under the tank. The tank cover now becomes a structural part of the wing so nut plates every three inches. The cover will have stiffeners to form the top curve of the tank cover. i still have not decided how high above the tank the fuel cap should be. My mock up is set up so the bottom of the cap will be 1/16"-1/8" above cover. On another thread it was mentioned that having a vented cap above the surface of the tank will siphon off fuel. Any comments on that?
    Thanks,
    Marty
    Marty,
    Yep that is a low pressure area by design. Either a forward facing vent on the cap, or an internal vent that exits under the wing would be in order.

  4. #14

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    Quote Originally Posted by Martyfeehan View Post
    My mock up is set up so the bottom of the cap will be 1/16"-1/8" above cover. On another thread it was mentioned that having a vented cap above the surface of the tank will siphon off fuel. Any comments on that?
    Sounds excellent. If you plan to use vented caps, just use the type like a high wing cessna. They have a built in check valve so air can go in and fuel can't come out.

  5. #15
    I took everything to the fabricator to have the tanks built. Turns out, this "fabricator" is one of the top builders in the NHRA and has been building everything related to racing since I was a kid. He has done tanks for everything imaginable, including lots of aircraft. His tanks have to withstand the crash issues associated with NHRA rules. Yes, the tank is being overbuilt with .063 and will weigh about 2 lbs more than if I built them out of .050 but they will be much stronger should anything ever happen. I saw some of the tanks he has buit, including one on a currently competing funny car and they are truly amazing in quality. The cost is about half the cost of production tanks. Production tanks would not work for me as I redesigned the shape of the tank so the control cables can run inside the wing and through the tank well. I feel very fortunate to have found this craftsman so close to my home. I should have the tanks in a month or so. My decision to have them built was simply one of time. The learning curve for me to weld up tanks would have been very high with no progress on my plane. I decided that the month I figured I would need to build tanks and learn the gas welding process of aluminum would be better spent starting the assembly of my fuselage now that all the painting is finished. Some times I feel for me it's best to move forward and let a pro build up something for me. I decided the same thing last year and bought a set of PA-12 struts rather than converting a set I have on hand; a better use of my time. Pictures to follow when my tanks are finished.

    Marty

  6. #16
    I got the first tank back today to test fit before second tank in finished. The fit is perfect! Exactly the same as my mock-up. I'm very pleased with the work and my decision not to build these my self. No worries with these tanks.
    Check it out.
    Marty

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  7. #17
    Nische

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