Brake fittings installed

Time: .75hrs

I guess I’m getting pretty good at installing these fittings on the brake lines. Installing the two 45 deg. fittings on the brake line ends near the calipers only took 30-40 minutes. The spreader also helps a bit, but you still have to cut back the stainless steel braiding to get the olive to fit all the way onto the Teflon hose. The 45 deg. fitting also seems to work very well. The straight fitting put a hard bend in the hose and tended to pull the hose out of the channel, but now the hose sits into the channel much better. After I get the plane painted I’ll put some RTV in the channel and tap the hose into the channel with a rubber mallet to get it to seat in. I also found some nice plastic coated aluminum zip ties that I think I’ll use at the ends just to keep the hose in place. The zip ties will be hidden under the wing fairing and wheel pants so it will look clean.

The 45 deg. fitting works well to minimize the hard bend in the hose that the straight fitting would have had.

Hose run through the channel in the gear. The hose fits in fairly tight so it’s not completely seated right now.


Parking Brake Lines

Time: 1.0hrs

Installed the 45º fittings on the parking brake and -4AN fittings on the lines. I wanted to finish this up because I will be making a mold of the throttle console piece for the carbon fiber part. BTW I have toe brakes so my parking brake is a little more involved then the simpler leveler brake type.

Left side of the center console. I have 90º fittings in the back and 45º fitting in the front. The lines are run kind of weird so that the bends in the lines aren’t too tight. The left and right lines run from the pedals and attach to the parking break with left on the left and right on the right, but then they leave switched. This is because it was just cleaner to leave the caliber lines on the sides on the channel that they came up on. The bend into the channel is pretty tight so from say the left brake caliper the line runs into the center channel and stays on the right side of the channel up to the parking brake rather then cross them back over.

Here’s the right side of the center console.

The 90º fitting will hit each other so I had to angle them a little oddly. I was thinking of putting an extension on the top one, but I think this angle works fine.

Here’s a side view of the parking brake. This is a little older photo when I had the straight fittings on the front. Those were changed out with 45º fittings to make the angle better on the brake lines.

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.

Fuel Lines

Time 1.25hrs

Today I received most of the parts I ordered from Summit Racing. I did a rough install of the fuel lines that run between the fuel select valve (which I don’t have yet) and the wing tanks. The Fragola 8600 hose is very easy to work with. It doesn’t hold the coiled up shape so you’re not fighting to keep it straight and it seems to bend nicely around corners. I was a bit worried about putting the ends on because in the reviews people had said it was near impossible to get the ends on all the way so I tried putting one end on just to see. I heated the hose end with the heat gun set at 200 degrees and used a little spit on the fitting end (not as gross as it sounds… well maybe a little) and the fitting went on very well. The last 1/8″ was a little tough but still not as bad as I thought it might be.

I also put the 1/8″ NPT to -4AN fittings on the brake caliper and did a check on how the braided brake lines need to fit onto the gear. I don’t want to use tie wraps to hold the brake line in place on the gear so I’m thinking I can use a router to deepen the cut out in the back of the gear and then use some RTV to keep the line in place.

Box of fun arrived

-6AN fitting on the Fragola 8600 hose. I need the buy the tool to crimp the clamp, but I really don’t want to install the hose ends until I have the fuel select valve and I know exactly how long they need to be.

Hose routes down along the front of the main spar and out the hole in the side of the fuselage. The feeder hoses that run from the tank to the fuel select valve are -6AN while the return lines are -4AN (6mm). Also fuel filters get installed on each feeder line so I need to buy those as well.

The brake line and fuel feeder hose outside the fuselage. Hopefully will get the return lines in a few days. The grommet on the brake line isn’t installed. I think I’ll try to find a bit smaller OD grommet. I also need to figure out the wiring that needs to be run out to each wing. Both sides get similar wiring, but the right side (I believe) gets a few extra for pilot heat.

-4AN fitting on the caliper.