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Shock Strut Boots

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  • #16
    For anyone who has struggled with a CO issue as I did during the test flying - I remade the shock seals twice, taped all the boot panels from the inside, then systematically plugged holes throughout the fuselage. There's a lot of them in these type of aircraft. None of this worked sufficiently.

    Finally, I lowered the exhaust pipes. This was very easy to do and took 30 minutes, simply pivoting them down around the universal joints a small amount, and also twisting them so that the elbow sat lower. I had originally kept them tucked up close to the tunnel to be streamlined. They're now sitting about 2" lower, and my CO monitor reads zero when the mixture is full rich. Even when I removed the tape from over the hole for my gascolator drain, it still reads zero.

    I plan to get some short curved extensions made up to further direct the exhaust away.
    Last edited by Nev; 02-16-2022, 04:07 AM.
    Nev Bailey
    Christchurch, NZ

    BearhawkBlog.com - Safety & Maintenance Notes
    YouTube - Build and flying channel
    Builders Log - We build planes

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    • robcaldwell
      robcaldwell commented
      Editing a comment
      I've considered lowering my pipes as well. I have the same CO issue. Let us know what you come up with for pipe extensions. Is this something from Vetterman?

    • jaredyates
      jaredyates commented
      Editing a comment
      Clint can sell you a set of bolt-on turndown angles. Let me know if you have any trouble getting in touch with him.

    • Nev
      Nev commented
      Editing a comment
      Rob - at this stage I haven't added any extensions, I've just loosened the support brackets enough to lower the pipes. I was able to get a couple of inches movement. Worth trying this first as it made a large difference.

  • #17
    I referenced an article in post 10.1. Conclusion is Negative pressure in the fuselage can draw exhaust into it. They sealed a hole in the aft bulhkhead to fix there problem.

    I've saw one fix where a NACA vent turned backwards was installed on the belly under the cabin to create suction. It was able to capture the contamination and vent it overboard keeping air above the floor fresh.

    Nev discovered another solution that maybe Piper dealt with in the same way....I mean look at that thing! Its got to be 12" long! Holy Smokes!!


    Screen Shot 2022-02-16 at 10.02.15 PM.png
    Brooks Cone
    Southeast Michigan
    Patrol #303, Kit build

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    • marcusofcotton
      marcusofcotton commented
      Editing a comment
      Actually not Piper exhaust, it's Sutton aftermarket. Might see such on a Bearhawk with a light engine/prop combo someday - you never know...

    • jonmiller0
      jonmiller0 commented
      Editing a comment
      Has anyone done the backwards NACA duct? I saw some nascar video talking about it...https://www.youtube.com/watch?v=rtEsdUzlIEk

      Might work, but I'd hate to cut open the belly of a good airplane, make it colder in winter, all for a fix that might not work. Just desperate to find a solution to the CO

  • #18
    Cessna 180/185s have a tail cone air scoop that was added via a service letter to reduce CO in the cabin. The kit was free and even included the princely sum of $4 to cover installation labor (in 1962).

    Comment


    • svyolo
      svyolo commented
      Editing a comment
      Interesting. Just create a slight positive pressure?

  • #19
    Chuck Dieterich, DIY, firewall, firewall boots, firewall boot, Zenith, CH-701, Zenith CH-701, www.zenithaircraft.com, steering rod, nosewheel, fiberglass, pattern, rubber gasket, CO, carbon monoxide, carbon monoxide monitor, CO monitor, Sonex, boot, fabrication, silicone, putty knife, plywood form, half-inch plywood form, aluminum plate, 0.040-inch aluminum, silicone-impregnated cloth, cone, mounting flange, nylon tie, steering rod, easy.
    Nev Bailey
    Christchurch, NZ

    BearhawkBlog.com - Safety & Maintenance Notes
    YouTube - Build and flying channel
    Builders Log - We build planes

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    • #20
      Creating positive (fresh) air pressure in the cabin would keep the outside out, too.

      Comment


      • #21
        What I finally came up with. Certainly not as elegant as some others have done, but it should work. I need to get this thing done!

        20220627_182731.jpg20220627_182716.jpg20220629_161617.jpg20220630_131913.jpg20220630_142019.jpg20220630_142221.jpg20220630_143319.jpg

        Comment


        • AKKen07
          AKKen07 commented
          Editing a comment
          Looks really good to me!

      • #22
        I used these https://www.lowes.com/pd/Oatey-Maste...er/5001984937? or these

        Figured if they last 15 years on the roof of a house, they'd work.

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        • jonmiller0
          jonmiller0 commented
          Editing a comment
          can you post a photo of these installed?

      • #23
        Great to see all your ideas, here is mine
        You do not have permission to view this gallery.
        This gallery has 7 photos.

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        • #24
          Maule boots fit and look pretty good.

          7B1F9240-091A-4315-9F89-21F40BFCAA12.jpg
          Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.

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          • jonmiller0
            jonmiller0 commented
            Editing a comment
            Where did you find those - they look sweet. I still need to meet up for an Idaho Bearhawk day with ya. In annual right now...great timing.

        • #25
          Originally posted by whee View Post
          Maule boots fit and look pretty good.

          7B1F9240-091A-4315-9F89-21F40BFCAA12.jpg
          Those do look good Jon, do you have any type of reference like a part number or anything?

          Comment


          • #26
            Since I have a Maule M5-235C, I bought the parts catalog :-) Note that this is leather (Naugahyde?) and covers the bottom of the control column in the cockpit. I believe you can buy it as a complete assembly (no sewing or anything required)




            Maule Boot Top.png
            -------------------
            Mark

            Maule M5-235C C-GJFK
            Bearhawk 4A #1078 (Scratch building - C-GPFG reserved)
            RV-8 C-GURV (Sold)

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            • #27
              I made the boot cowl cutouts a couple of weeks ago, and put the gear on (with that part cliché-ed on) to move to another shop. I realized that if I wanted to remove that piece of cowling, I would also need to remove the shock struts. Anybody try making that 1 part into 2 by splitting it transversly through the cutouts to

              That link has shows a thread with the strut cover and rubber seal that Bob Designed. The drawing can be found in Beartracks.

              My origonal was made iaw the drawing with a rubber seal and round hole. Don't cut the sealant hole round like the Beartracks Drawing shows...it way too big. When the gear articulates the hole opens up.

              Stinger (LSA scratch builder) used 1/8" thick silicone sheet (Amazon). I installed his design today and no comparison to my rubber (from an innertube) seals. Silcone can really stretch. Cut the hole rediculously small & oblong...it will fit nice and tight over the strut.

              Dont drill holes in rubber....sharpen a tube end with a file and cut them using a drill.

              IMG_0826.png IMG_0827.png IMG_0828.png
              Screenshot 2023-12-16 at 9.33.56 PM.png IMG_0831.png
              Brooks Cone
              Southeast Michigan
              Patrol #303, Kit build

              Comment


              • DBeaulieu
                DBeaulieu commented
                Editing a comment
                Nice work!

            • #28
              IMG_4626.jpg IMG_4627.jpg IMG_4628.jpg IMG_4633.jpg IMG_4634.jpg
              I used oil resistant neoprene from Granger that met the specification spelled out in Beartracks. I decided to try 1/8 in on one side and 1/16 in on the other. I looks like it is going to work but I am a ways from flying. It sounds like exhaust placement has more effect on CO levels then anything else.

              Roger
              Companion QB
              Roger
              QB Companion C-9
              N51RK

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              • #29
                Brooks, I like the way you cut your hole in the silicone
                Roger
                QB Companion C-9
                N51RK

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                • #30
                  Figured I would share how I did mine they are made out of canvas with a vinyl backing I believe it’s a type of marine fabric. Very lightweight and seem to seal pretty well
                  You do not have permission to view this gallery.
                  This gallery has 4 photos.

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