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

Announcement

Collapse
No announcement yet.

Aluminum Tubing

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Aluminum Tubing

    I am researching materials for fuel lines. The Bearhawk Assembly Manual calls out either 3003 soft aluminum tubing or 5052 rigid aluminum tubing. Is 5052 aluminum tubing something that can gernerally be sourced locally from an auto parts type of business, or is 5052 tubing something that is generally specific to aircraft?
    Brooks Cone
    Southeast Michigan
    Patrol #303, Kit build

  • #2
    Hi Brooks. 5052 is not an aircraft specific material. It is stocked sometimes in aluminum/metals suppliers that you might have locally. Not automotive suppliers. For me it would be very lucky if a local supplier stocked the 5052 tubing in 3/8" x .035 that you would need. But possible. 5052 is called the "marine" grade aluminum since it is more resistant to corrosion than most other aluminums. The RV kits come with 3003. But most aviation professionals recommend and use 5052 as it is much harder than 3003 and generally tougher. Mark

    Comment


    • #3
      Hi Brooks,

      First, let me make clear that Mark is absolutely correct in his description of the two alloys. The 5052 is significantly harder to work with.

      This is what I used:



      Very easy to work with. Except for LARGE radius bends, always use a tube bender. Easy to make nice flares too. I was able to run a single piece of tubing from the wing root to the selector valve. No hidden connections to leak. I don't think I would have been able to manuver the 5052 like I did the 3003. At "Lowes Aircraft Supply", I bought some 1/2"x1/16" wall nylon tubing. I slipped the nylon over the fuel lines anywhere they encountered structure and firmly tied the tube to structure with rib lacing cord. I saw that done somewhere, but don't remember who to give credit. No matter what tube you use, be sure there's no possibility of it resting/rubbing on any structure or wire or cable or anything.

      Bill

      Comment


      • #4
        I think I am going with the 3003 tubing. I will describe my decision making in order to encourage feedback.

        The alignment of the tubing is vital to obtain alignment of the AN fittings and to eliminate stress on the tubing at the fittings. So, mis-alignment issues introduce safety issues. I have absolutely no experience with tube. I have just a little bit of experience trying to get the coupling nut to thread onto a fitting without harming the aluminum threads. With my skill level, I think the 3003 might be a safer option due to the easier install, and forgiving nature of the softer product.

        I will use Gromets and Nylon tubing, good judgement with a critical eye to avoid damage due to vibration, and apply AC43.13 recommendation of securing the tubing at recommended intervals.

        Brooks
        Brooks Cone
        Southeast Michigan
        Patrol #303, Kit build

        Comment


        • #5
          On the long tubing runs, what is the advisability of having a U shaped section in the tube to allow for expansion and contraction? Or some other route that allows for expansion and contraction? I am thinking of the tube run from the aux tanks in particular.

          Comment


          • #6
            AC 43.13 does not mention the need for a U or a Loop yet addresses the expansion/contraction issue.

            "Never install a straight length of tubing between two rigidly­ mounted fittings. Always incorporate at least one bend between such fittings to absorb strain caused by vibration and temperature changes."

            There is plenty of caution about creating low spots for water to collect. Installing a U that is horizontal and does not allow for collection of water between the two tanks would be prudent I think.
            Brooks Cone
            Southeast Michigan
            Patrol #303, Kit build

            Comment


            • #7
              We used both 3003 and 5052. While the 5052 is much more rigid I didn't notice a significant difference between the two when forming the lines. You should be using a bender for every bend and the use of that bender is the same for the two materials. I must admit, my dad formed the majority of our tubes. He is much better at it than me and I didn't want any fuel line snobs mocking our fuel lines... Zzz
              Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.

              Comment


              • #8
                I assume that everyone sourcing the 5052 from their favorite aircraft parts supplier, then. I think a prudent method is to fabricate a pattern of each tube out of wire before trying to bend that actual fuel line. (welding rod, coat hanger, or will look to source something longer.) Is that how everyone is doing it?
                Brooks Cone
                Southeast Michigan
                Patrol #303, Kit build

                Comment


                • #9
                  That's pretty much how I did it Brooks. There was one line that I made 5 times! But most were good after the first try or two. I used 5052, and you can't unbend it very easily.

                  Comment


                  • #10
                    We are bending it just like you would bend electrical conduit. Measure to the back of the bend, figure takeup and then bend the tube. My dad spent a lot of years as a sparky and I did a short stint as an apprentice so that method made since to us.
                    Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.

                    Comment


                    • #11
                      Jon, you use some nomenclature that's unfamiliar to my small vocabulary.

                      I think "the back of the bend" means the point where the tube will be after the bend is completed.
                      i think "take up" is the amount of tubing that will be used to get to that point.

                      Maybe the tube bending tool that I haven't used yet comes with instructions.
                      Brooks Cone
                      Southeast Michigan
                      Patrol #303, Kit build

                      Comment


                      • #12
                        You got it Brooks. The bender we bought came with some information but no instructions really.
                        Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.

                        Comment


                        • #13
                          Brooks,
                          Buying aluminum tubing for your project is not one of those areas where you want to be too precise, unless you're really good at bending tubing to fit. Buy extra! With a bender, it's not hard to make the bends. It's almost an art form to bend it well. There are YouTube videos showing darned near everything, so I'm sure there are a couple that explain the intricacies of tube forming. If you're anything like me, you'll get it all to fit. And you'll end up with a bunch of 'recyclablle' aluminum tubing!
                          Have fun!

                          Bill

                          Comment


                          • Bcone1381
                            Bcone1381 commented
                            Editing a comment
                            Thanks Bill. I have endorsed and fully participate in he educational experience with other areas off the build will plan to make a few parts more than once to get the benefit bending tube as well.
                        Working...
                        X