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  • Tail Wires

    FINISHED TAIL WIRE.JPG
    I found the price on the Steen wires to be a bit staggering so with considerable conversation with Bob and a local aerospace machine shop I produced my tail wires at about a cost of $70/wire, this would drop even further if I had a quantity to produce. As background Bob turns a piece of 1/4" 4130 down to .200" on a lathe by progressively indexing it, a slow process. I took raw 4130 and centerless ground it down to .226" which is the root diameter of a rolled 1/4"-28 thread. I then set the wires out to the aerospace guys who rolled left and right hand class 3A threads on each end. I discussed the .226" diameter with Bob and he was OK with it. The smaller the diameter the higher the natural frequency of vibration so small is beautiful. That said Bob says there are many flying airplanes with 1/4" wires and cut threads. The aerospace vendor says that keeping the diameter of .226" or the root diameter of the thread is their standard practice for a 1/4"-28 threads. They made this one set as a bit of a favor since I knew the owner as they generally only produce several hundred wires at a time. A picture is attached, they are a thing of beauty. Obviously they will need to be painted to prevent corrosion but a coat of silver would look good. A group buy could possibly get prices down in the $50/wire range. For your information American Champion uses 3/16" tailwires even on their full acrobatic airplanes. They use 316lL Stainless. Stainless would have a lower fatigue strength than 4130 but the Citabria line has been made this way for many years. More in depth engineering would be required to move to a 3/16" wire so I will leave that alone for now.

  • #2
    Good work Bruce. I might suggest you send one sample wire to Bob for him to inspect up close and personal. If he gave his blessing it would be very cool to have an alternative to the very expensive Brunton wires. Mark

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    • #3
      I recall about $50/wire being what I paid for swaged cables from ACS. I'd be down for some of these at 50-70 a piece, 4-place of course .
      Dave B.

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      • #4
        The stainless would be cool. Every annual I've ever done seems to include sanding and painting rusting flying wires.

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        • #5
          Those look great Bruce. A funny thing on tail wires,, I opted for the streamlined tail wires and have had some trouble with vibration/harmonics above 140mph on the Patrol. I can't feel it but when I look back at my tail during flight, I can see the tail wires and the 4130 streamlined struts vibrating slightly. I tightened them up but didn't want to overtighten and it only helped a little. I ended up cutting 6 pieces of 1/4" wide strips of velcro 1" long and sticking them to the underside of the 4130 streamlined tubing and it absolutely eliminated the vibration on all tail wires. I realize this should not be the fix, but found it interesting.

          Reason I did this is that when I was at Oshkosh last summer I took a good look at the Rans S21 outbound. I was intrigued by the design as they basically took the concept of the Glasair Sportsman and made there own version. After a really good look at it, it is very evident that its a very light plane and not anything close to what I would feel comfortable in. Anyway, I noticed a velcro strip running all the way down the underside of the wing strut. When I asked the salesman, he stated that it eliminates the vibration of the strut. I believe they ended up installing a jury strut on it now but Its where I got the idea.

          I realize this post doesn't solve anything but thought I would share,,

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          • #6
            Vibration of the streamlined strut may relate to the stud failures on the 4 place. But if some turbulator tape or velcro stops the vibration, that may be a good fix. I used that method on my Rans S-7 on the aft lift strut for 700 hrs to stop a vibration. The difference between the before and after installation of the tape was impressive.

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            • #7
              Ya, it has completely eliminated the vibration of every wire back there. And as mentioned, I only installed the tape under the 4130 struts

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              • #8
                Interesting feedback, the alignment of the airfoil to the relative wind is probably important. The 3/16” stainless wires on my Citabria don’t vibrate that I can see. It would be ideal to go to a smaller wire which would be much less prone to vibration but that would take some research.

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                • #9
                  If the solution to a vibrating streamlined tail wire (not strut) is to attach something to it, I would wonder about the point of using a streamlined wire to begin with.
                  Dave B.

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                  • Archer39J
                    Archer39J commented
                    Editing a comment
                    If that tape, that is specifically designed to create turbulence in flow, covers most of the surface of the "airfoil" of the wire then yeah it basically defeats the purpose.
                    Last edited by Archer39J; 04-09-2019, 03:28 AM.

                  • zkelley2
                    zkelley2 commented
                    Editing a comment
                    It doesn't create turbulence so much as it delays boundary layer separation.

                  • Archer39J
                    Archer39J commented
                    Editing a comment
                    Exactly, which is great on the leading edge of a wings airfoil. Not so much when you completely cover the streamlined tail wire, then it's just drag.

                • #10
                  I think Isilverone is just talking about applying the velcro to the strut, not the wires. If it is needed, I do not think it adds drag. Used a lot on sailplanes.

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                  • Archer39J
                    Archer39J commented
                    Editing a comment
                    Ah, missed that. Still not sure if the extra drag is worth it then.

                • #11
                  Yes, I only installed 6 little pieces on the 4130 strut. By doing this, it also eliminated any and all tail wire vibrations

                  mike

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                  • Mark Goldberg
                    Mark Goldberg commented
                    Editing a comment
                    "All tail wire vibrations" is a little strong for me Mike. I am sure it helps, but some vibrations are bound to remain. But if it reduces the vibration on the wires - that would be good. Mark

                  • svyolo
                    svyolo commented
                    Editing a comment
                    Or maybe the strut was causing excitation in the wires, or vice versa. The "system" is now not at its natural frequency, or the velcro added damping to quiet it down. Sounds like a big improvement.

                • #12
                  Lol, ok. I will reword.

                  when I’m doing 145mph and look back over my shoulders at the tail wires,, I don’t see any vibration.

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                  • #13
                    Has anything progressed with these wires? I'm about to place an order for two sets - $1600 and 4 months lead time - Ouch!!

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                    • #14
                      Originally posted by N942VT View Post
                      Has anything progressed with these wires? I'm about to place an order for two sets - $1600 and 4 months lead time - Ouch!!
                      Did you check with Burles in AK? He made Zach’s wires I think.
                      Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

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                      • zkelley2
                        zkelley2 commented
                        Editing a comment
                        Ya, burl's did them for a few hundred dollars. Week lead time maybe.

                    • #15
                      I made my tail wires as previously discussed and sent a sample to Bob who blessed them. There has
                      not been any follow up interest on the forum for low cost wires. If you know the exact lengths you want I could work up a price. Setup charges for low quantities are the challenge but since you want two sets it may be tolerable. They will be made from 4130 stock so you will need to paint them or I just wipe mine down periodically with WD-40 and haven’t seen any corrosion but they are not flying yet

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