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  • Patrol Brake System

    I have been looking into the details of a Patrol brake system with co-pilot brakes and parking brake valve. This might be helpful for the next person trying to compile an order. I also appreciate any constructive feedback.

    Here is what I know:
    • 3/16" 5051 aluminum tubing with AN -3 fittings are typically used
    • connections to movable parts require flexible lines
      • lines to master cylinders
      • line across gear leg hinge
      • line from gear leg to caliper may be done with 5051
    • flexible lines are typically Aeroquip 303 (black cloth sleeve) or 666 (stainless sleeve)
      • 666 is lighter than 303
      • Teflon/PTFE hose material has no limited shelf-life like rubber
    • ACS has a configurator ($60-100 per line)
    • alternatively, automotive high performance lines can be used ($15 per line)
    Looking at the parts list for both I think using flex lines all the way makes a lot of sense. Everything is very close together and patching all the way through actually does not add much cost. In the following I sketched out both approaches.

    nonflex.jpg​​
    • (for MI-H-5606 hydraulic fluid)
    • 1x grove reservoir
    • 4x gerdes master cylinders
    • 2x grove dual calipers
    • 1x matco parking brake
    • 12x flex line
    • AN fittings size 3, 3/16"
      • 11 x AN816-3D (flare to 1/8" NPT, reservoir, cylinders, valve)
      • 1x AN825-3D (flare to flare, reservoir tee)
      • (use AN834-3D + AN924-3D for mounting into firewall)
      • 4x AN822-3D (flare to 1/8" NPT 90°, valve output, caliper)
      • 2x AN833-3D (flare to flare, 90°, bulkhead, gear leg hinge)
      • 2x AN924-3D (nut for bulkhead AN fitting)
      • 17x AN819-3D (fitting sleeve)
      • 17x AN818-3D (fitting nut)


    For comparison the same setup mostly built from flex lines:

    flex.jpg
    • (for MI-H-5606 hydraulic fluid)
    • 1x grove reservoir
    • 4x gerdes master cylinders
    • 2x grove dual calipers
    • 1x matco parking brake
    • 10x flex line
    • AN fittings size 3, 3/16"
      • 11 x AN816-3D (flare to 1/8" NPT, reservoir, cylinders, valve)
      • 1x AN825-3D (flare to flare, reservoir tee)
      • (use AN834-3D + AN924-3D for mounting into firewall)
      • 4x AN822-3D (flare to 1/8" NPT 90°, valve output, caliper)
      • 2x AN833-3D (flare to flare, 90°, bulkhead, gear leg hinge)
      • 2x AN924-3D (nut for bulkhead AN fitting)
      • 2x AN819-3D (fitting sleeve)
      • 2x AN818-3D (fitting nut)
    Last edited by noema; 02-09-2021, 06:34 AM.
    Bearhawk Patrol, O-360, Trailblazer 80", 26" Goodyear, Stewart Systems

  • #2
    I just looked at the Husky brake system again. I never noticed this but it only has master cylinders on the rear pedals. The brake pedals are simply connected via rods like the rudder pedals. This might be doable on the Patrol as well? Has anybody tried that? Thoughts?

    p1100478_orig.jpg
    Bearhawk Patrol, O-360, Trailblazer 80", 26" Goodyear, Stewart Systems

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    • #3
      I used a solid 4130 tube from the front to rear brake pedals to avoid the flopping cable interconnect. Brake reservoir and parking brake setup are pretty much duplicate of what they do on a Citabria. I have had very good luck with hoses from Summit Racing, they pressure test them as well. I did use solid lines in places. Have you mounted your calipers yet, I have full drawings of everything.

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      • #4
        Installing rear seat brakes can be done either way in a Patrol or LSA. With a 2nd set of master cyls in the back or a tube connecting both sets of brake pedals. Wayne Giles in South Africa built his first Patrol with the tube connecting the front & rear brake pedals. On his subsequent LSA he used the 4 master cyls because he didn't like the connecting tube being in the way getting in and out. After trying both set ups he said he preferred not having that tube in the way.

        Entirely a personal preference kind of decision. The correct production kits are all set up with the mounting tabs for rear master cyls. No welding required. Mark

        Comment


        • noema
          noema commented
          Editing a comment
          That's an interesting data point. Four master cylinders then.

      • #5
        Thanks for the insight into brake planning, Noema. I will be using much of your setup. I put 4 master cylinders in my QB kit because there are going to be four of us learning to fly it with little TD experience, and we want the ability to use an experienced instructor. Our thinking is that he or she will need a set of brakes and a throttle. Not planning to duplicate instruments, mixture prop control or carb heat though.

        The kit is nicely set up for this installation and it was easy to fit the master cylinders to the rear pedals. I haven’t figured out how to route the tubing or hose though. A single reservoir on the firewall is cheaper than individual ones at each master cylinder and should be easier to service but will require extra plumbing.

        If we really dislike having allege items required yo have rear brakes in the way, we will remove it once we are all comfortable flying the plane. Hopefully we can keep the installation clean though.
        Last edited by Pbruce; 02-08-2021, 02:49 PM.

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