Bearhawk Aircraft Bearhawk Tailwheels LLC Eric Newton's Builder Manuals Bearhawk Plans Bearhawk Store


No announcement yet.

Fuel line connections at fuselage

  • Filter
  • Time
  • Show
Clear All
new posts

  • Fuel line connections at fuselage

    I had decided I did not want to use a hose connection between wing and fuselage fuel lines, mainly because I didn't have a beading tool. I installed bulkhead fittings in the wing root and planned to run the fuselage lines to connect there. A consequence of that is that the fuel lines out of the tank to the bulkhead fittings are only 8" long. With everything plumbed up it is a very rigid setup. My concern now is that if the fuel tank moves much at all it could crack that short piece of line. Would be a terrible place to have a leak. Using hose connections allows those lines to move a little. Would like to hear others thoughts on this.

  • #2
    Some STC'd fuel systems REQUIRE short runs of rubber hose for just that reason. CubCrafter and Dakota Cub both use sections of mil spec hose to mitigate vibration in their upgraded Super Cub fuel systems. They were designed and tested that way. A beading tool is pretty cheap, Earl's plumbing.


    • #3
      I am using hose connections.


      • #4
        The tanks do move around ever so slightly. There's a lot of weight and g-force involved, and the thin flexible tank straps will allow for some slight movement. But it's almost nothing.

        I don't think it's enough to cause a problem, the aluminium line will move slightly. The weak point will be the AN fittings, which can leak if they move around much. But personally I doubt it would cause an issue.

        Several planes are flying with hard-lines at the wing root. I don't think anyone has reported back though.

        The line beading tool is widely available in the USA and very cheap. You can buy online. Flexible hose is what Bob called for in the plans. Provided there's a large enough gap between the line in the wing and the line in the fuse, to allow the hose to be worked into place, the hose is very easy to use.
        Last edited by Battson; 03-14-2018, 08:56 PM.


        • #5
          I had a similar concern with the 6ā€ fuel line between my electric fuel pump and the firewall bulkhead fitting. Iā€™m replacing the aluminum tube with a pre-made AN6 Jose from Summit Racing. You could do the same from the tank to a bulkhead fitting at the wing root.

          Or you could buy the 3/8ā€ Earls bead roller for $40 and sell it to me for $30šŸ˜ I have to buy a 1/2ā€ bead roller too.
          I'm a Tapatalk user so I can't see your "comment"


          • #6
            Like Jon said it probably would be okay. I called around and a builder locally has both an Earls bead roller and a homemade one that he says makes a better bead. I'm going to be using hose attachments, will be one less thing to worry about. Would have taken you up on your suggestion Whee if I hadn't found one to borrow.