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T3 Tailwheel Suspension Mount

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  • T3 Tailwheel Suspension Mount

    Hey...I bought a T3 tailwheel suspension from Airframes Alaska. The mount pad on the BH for the leaf spring clamp is held in place with two AN4 bolts. The suspension has two AN45 clevises to bolt in that area (5/16ths dia). For those that have installed one of these units, how did you manage the edge distance on the existing 1/4in hole? I'm making the assumption the hole has to be welded up and then re-drilled a bit closer to the tailpost.

  • #2
    I moved the spacing washers around (either side of the eyebolts) to center the eyebolts in the drilled out holes.

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    • alaskabearhawk
      alaskabearhawk commented
      Editing a comment
      Ok, but did you have to enlarge the bolt holes? Mine are 1/4in (AN4), the eye bolts are 5/16ths.

  • #3
    I haven't installed one but if it were me I would simply file the hole out to 5/16, filing on the side towards the tail post.

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    • alaskabearhawk
      alaskabearhawk commented
      Editing a comment
      If I did that I'm pretty sure the edge distance requirement wouldn't be met. I'll have to measure it again to confirm.

  • #4
    See my comments...

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    • #5
      What does airframes say? You're not the first to put a t3 back there. I'd probably inform them it doesnt work as you got it and why as I'm pretty sure they advertise that as bolt on. See if they have suggestions.

      That one on the north side of wolf lake has a t3, maybe stop by and see how they did it.

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      • #6
        Airframes gave me the number of the designer. I’m going to give him a call tomorrow and see what he has to say.

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        • #7
          It shouldn't be a problem? As one bolt pulls towards the edge, the other bolt is pulling into the meat of the tailpost. The bolts are going to break before the edge does.

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          • #8
            Weld the holes up... add a bit of metal if the bolt whole to edge distance is minimal.....drill undersize and ream to fit...don’t want any room for the bolts to walk around...my Pacer tail spring moved quite a bit due to oversize bolt holes at the tail post. It loose no moe!

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            • #9
              My holes were 5/16". Not sure if 1/4" was the original kit size. I may have drilled them out way back when. If edge distance is a concern, move eyebolt washers to the outside and file holes to the inside if you can. I had to relocate the spacer washers to fit hole distance. You may need to move your rudder arm up for clearance also so it doesn't hit the spring station. Mine is just short of touching at 30 deg.

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              • #10
                As Paul Harvey would say...now for the rest of the story. I don’t have enough edge distance even if I favor the hole to the inside with a file and ream to fit. I called Ken at Airframes and explained the situation. Ken referred me to Dan Dufault, the designer of the T3. I called Dan and we talked a bit. Airframes provides a .125 plate of 4130N to go between the suspension unit and the spring pad under the tail post. The two solutions. One is to weld the holes shut and redrill. Option two is to weld the 4130 plate to the bottom of the spring pad and redrill using the existing holes as a guide. Since my tail spring is already aligned to the centerline I’m favoring Option two. When I made my spring pad I already made it wider than the plans so I would have better bolt clearance for the spring clamp. Plans show 2.75in wide, I went with 3in. The pad from Airframes is 1in wide by 3.315 long. Welded onto the bottom I can use the existing holes and it adds plenty of material to meet distance requirements. BTW, both Ken and Dan were extremely helpful and were very kind to this novice builder!!!

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                • #11
                  Something to possibly watch out for; I too made my spring pad wider than what the plans call for. I think it was 3" but I don't recall for sure. It was an unpleasant surprise when I discovered the rudder steering horn hit the the spring pad well before the rudder reached the specified deflection. I had to do a bunch of grinding to make things right.

                  You probly already thought of that but thought I'd share.
                  Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

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                  • #12
                    Thanks for the heads-up whee. I threw the rudder on and checked. It does touch, but just barely. I'm using a Scott rudder horn. A few swipes with a grinder will take care of it. Photo is of the plate for the T3.

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