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Footwell - seal it up!

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  • Footwell - seal it up!

    We just passed the 1,000 hour inspection / ten years of annuals. I wanted to really go through the plane with a fine-toothed comb, as by this point a few things are wearing out, or building up... This is the first of many learnings I will be sharing from the process.

    I have observed that a large amount of sticky, dirty / sandy gunk has accumulated in the belly interior, both fabric and metal areas. It has spread right throughout the plane, but it's worse near the front and at the port side. It quickly became obvious how this is happening:
    1. Debris from boots on pedals is dropping down below the floorboards onto the tunnel, and from there it can easily travel all the way down the belly interior, as far as the tail if it wants. It tends to collect on the port side of the port belly stringer especially. Maybe there's some propwash effect pushing it there, at a guess. Or maybe it mostly comes from the pilot who sits on that side.

    2. Oil from the engine area is working its way down the outside of the tunnel and because of the overlap (in my build), being passed onto the inside of the metal belly panel (it cannot pass the little tube where the fabric terminates though, not on the interior of the belly).

    It's collects around stringers and contains small rock fragments, sand, organic matter - all kinds of stuff which you don't want rotting away next to metal / fabric parts. There's a lot of it too. It's not causing any major consequences, but it's highly preventable and hence I thought I would mention it.

    We have ultralight marine carpets on the floorboards, and we vacuum regularly. Without those, the problem would be a lot worse, as dirt could easily bypass floorboards. I have probably vacuumed up 10 lbs of dirt in the last 10 years, which would otherwise have ended up in the belly.

    I suggest consideration of sealing up the tunnel area, or the footwell area, such that debris from pilot's footwear is caught there - and can be easily vacuumed up before it spreads throughout the whole fuselage.
    Last edited by Battson; 11-27-2022, 07:22 PM.

  • #2

    Firstly thanks for the detailed report. I must say from the beginning of fitting and installing floor boards I was suspect of the gap area below the rudder pedals. I had considered removing hiking boots and slipping in clean shoes, and yes this would be inconvenient at worst.

    do you have any ideas for a close out? Now would be the perfect time as my boot cowl is soon to be riveted in place.

    Revo Sunglasses Ambassador


    • Battson
      Battson commented
      Editing a comment
      I haven't many good suggestion, sorry. Some certified designs I've seen use a bit sheet of leather type of stuff, with slots cut for the pedals - but it would need to be EASILY removable for maintenance inspections.

  • #3
    I notice on many builds the tunnel fwd lip overlaps the tunnel firewall flange. I made mine so that the flange overlaps the tunnel so there's no seam being exposed. Might mitigate some oil getting back behind the tunnel.
    Dave B.
    Plane Grips Co.


    • #4
      As someone who very often has very dirty boots on, despite my best efforts, I also have this issue. The oil that seeps back mixes with the sand and makes a cutting fluid of sorts and I have had to patch a spot where it cut through the fabric in line with a stringer.. I hadn't come up with a fix to stop it from re-occurring, but I like the leather idea.


      • #5
        I'm working on a solution and should have it wrapped up soon. Got the mold out of the plug last week and plan on making the first part after Christmas. It will be infused carbon fiber with a layer of kevlar. If it works out I can make more. It will obviously still need cutouts for the pedals which will allow some debris to get by.
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        Last edited by Daniel; 12-14-2022, 09:17 PM.