Fuel Lines and Fuel Filters

Time: 2.5 hrs

Things done today:

  • Mounted one of two fuel filters
  • Ran left side fuel return line
  • Installed -6AN bulkhead fitting in firewall for fuel feed line
  • Cut out soundproofing hole for the flap and aileron control tubes

I spent some time today contemplating the placement of the coarse fuel filters. The manual calls for two filters one on each tank feed line before the fuel selector. I’ve seen at TAF Torrance that the Sling 2’s have one filter in the engine compartment right after the fuel line comes through the firewall. While this is a bit simpler and probably easier for maintenance I’m thinking maybe two filters is better just in case one gets clogged. You could always run off the other tank then. I purchased two 40 micron filters and some Adel Clamps from Summit Racing. These fuel filters are nice because they have -6AN fitting on them so they will connect right up to the fittings on the fuel lines without any adapters. I guess one thing to note is that I’m probably note buying the full firewall forward kit (just the parts I need) since I’d really like to make all the fittings AN type which is more prevelant in the US. A lot of the TAF parts and fittings are metric.

Pieced together the console and instrument panel to get an idea of exactly where the fuel selector is located. That’s not the throttle console I’m using since I have toe brakes, but it’s the same size as the toe brakes one so that will work. It was way too tempting not to sit in the plane. I actually haven’t sat in it yet so well… I did… didn’t get a photo though, maybe I’ll take a selfie tomorrow in it. Does anyone know how the throttle console mounts to the instrument panel? I saw on another builders blog that they had an angled metal plate (not sure if they made it or not) behind the fuel selector mounting area. So I’m wondering do you drill a hole into the leather and fiberglass and install rivnuts? Just curious.

So I’m thinking that I’ll mount the fuel filters vertical on the console support though the manual shows them on the floor. It should make it easier for maintenance and I don’t want them banging around so I want them secured to something. I’m going to use 30º AN fittings on the bottom so that I can angle the hose in and away from the rudder cables. Unfortunately I could only mount one because I only had one M5 rivnut (will need to order more). I also ran the -4AN (6mm) return line. I couldn’t run the return line for the right side because well I kind of melted the little yellow plastic part. Note to self don’t heat hose with heat gun when the fitting is on it. The best part is you have to buy a whole new fitting to get the .02 yellow plastic part :-(.

Right now I’ll just use the one hole for both lines and also the electrical wiring seems to be big enough. I ordered the wiring for the left and right wing connections so I should be able to work on that next week.

I installed a -6AN bulkhead fitting to the firewall. I will do the same for the return line, I just need to order more seal washers for that side. This the the engine side of the firewall with the -6AN fitting.

And the cockpit side of the firewall with the other end of the bulkhead fitting. I’m thinking maybe I should do the same for the brake line rather then using the grommet…Hmmm. The thing is the more fittings you have the more potential for leaks… though probably not much of a concern. The main reason I want to put in the bulkhead fittings is because I’m going to switch to SS braided hose for the engine compartment fuel lines with fire sleeve. The rubber hose I’m using is only rated to around 300ºF. Also by using the teflon SS braided hoses rather than the Rotax rubber hoses you don’t have to do the 5 year hose replacements since the teflon hoses will last a lot longer under the higher heat conditions… so maybe 10-15 year replacement.

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