Interior Skins (Part II)

Time 2.5 hrs

Done today:

  • Installed the left front inside skin
  • Installed outer seat rails on left and right side
  • Test fit rear inside skins

I finished installing the other front interior skin. This one was a little more difficult because it didn’t line up as well as the right side did. I eventually got it installed after some pushing and pulling and had to widen a few holes.

The seat rails went in fairly easily. The hardest part is getting the rivets it at the front of the rail where the flange is. The flange makes it impossible to get a rivet gun straight in so I used a thick piece of metal with a small hole drilled out for the rivet mandrel to pass through. The metal was then clamped in place. It helps hold the rivet flat and firm against the rail which is especially important because they are countersunk rivets so the seat can slide.

A few overhead shots of the interior. Front skins have all been riveted. The rear skins won’t be riveted until the canopy is on and the parachute cables have been bolted to the rear spar.


Interior Skin

Time: 1.5 hrs

It’s been a while since I worked on the plane mainly because I’m out of things to work on. I have been working on the logistics for a few things, but no real physical work on it. I did go down to Torrance TAF a few days ago and purchased the canopy kit. I was hoping I could take the canopy over to the paint place to have them spray the inside a little different color grey, but the kit was up on the top shelf and a fork lift was needed to get the kit down. Hopefully they’ll be able to pull the kit this week and I can get the canopy over to paint next week. I’ve also work on getting details on having some custom upholstery done by TAF. I need to purchase the leather and carpet and ship it over to TAF in South Africa. It will still come out cheaper then having someone here do the work and I’d rather support TAF anyways.

Today though I riveted the front inside skin on the right side. I have a whole row of holes that don’t line up so I had to drill those and debur them. After that was finished the riveting went along pretty well. I’ll have to do the same on the left side and it seems that I may have a few more alignment issues then the right side.

Right side skin riveted

GMU Mount… Finally

Time: 1.5 hrs

I finally got the new mount for the GMU11. I also picked up a Rotax overflow bottle while I was at TAF Torrance so that I could work on finishing up the firewall.

Installing the GMU mount wasn’t as bad as I thought it was going to be. I made some guides out of aluminum that I purchased for the ELT and overflow bottle brackets that I didn’t end up using. Since my fuselage top skins are on and my luggage floor is installed the only way to get to this was through the maintenance panel on the bottom of the fuselage. While there’s a bit of room to work, you can only really work with one hand and you can’t see anything while you’re working, You just need to feel where things are. I don’t think it would have been possible to get the holes drill correctly without the guides I made. The angle guide helped to make sure that bracket was in straight and aligned with the rib. I could also set the drill into the 1/16″ hole in the guide and then slide up to the handle of the drill and drill the hole. Once the 1/16″ holes were drilled enlarging them to 3.2mm (1/8″) was pretty easy. The hard part is done now, I’ll rivet the bracket once the primer has dried and then I just need to finish up the wiring at the pitch servo.

Here’s what came with the GMU bracket. In typically TAF style they give you everything you need to install it and the GMU. In typical my style I’m not using any of it, just the bracket. I had previously purchase some M4 304 stainless steel rivnuts and will use some stainless steel screws and washers as well.

After installing the stainless steel rivnuts I made up some guides with 1/16″ holes in the center of the rivet holes. This allowed me to align the bracket and drill the holes with out seeing what I was doing. I just used some double sticky tape to temporarily attach it to the bracket.

Once the 2 holes on the rib were done I made sure the top of the bracket (where the GMU will mount) was level. I guess one of the good thing about installing the bracket now with the plane on it’s wheels is I know exactly what is level (though that may change a bit when the engine goes on). I’m so glad this is done… well almost done. I still need to finish up the wiring and rivet the bracket in. I prewired the connector on the GMU side so I just need to finish up the splitting of the CAN wiring at the pitch servo and tie up the wires.


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.

Pitot and AOA Lines

Time: 0.5hrs

Almost forgot I had to run the pneumatic lines for the AOA and pitot. That should finish up any fuselage wiring/other lines that need to be run.

I used some colored 1/4 lines. One for the AOA and one for the pitot, both run to the pitot in the wing. I’ll have to install a connector here so it can join the lines from the wing. The hole is kind of packed. Might need a second hole on this side.

Cleaned up some of the wiring. I tried to route it where I think it will be going. The VPX will be in the middle so most of the wires go there. The ELT will mount on the right side on tabs and the COM2 and audio panel will mount on the left side on tabs.

Wiring Runs Done, More Fuel Lines, and Brake Lines

Time: 2.5 hrs

Things accomplished today:

  • Installed -4AN fittings on brake lines and ran brakes lines between parking brake area and wheel calibers
  • Ran wiring for wing strobe lights, taxi/landing lights and fuel sender
  • Ran fuel feed lines to fuel filters and installed fittings
  • Secured wiring and reviewed clearance from rudder cables

Today was a small milestone for the Sling project. As far as I can tell all of the wire runs through the fuselage are now done. I secured down most of the wire ties and also made sure that there is adequate clearance to the rudder pedal cables.

Not too messy and clearance to the rudder cables looks to be good. The rudder cable is a bit slack in the photo so there’s a bout 1.5-2″ of clearance to the wiring

The wring runs up the front of the last console support in the center. There’s a tie wrap mount in the center of the support to keep the the bundle in the center. I’m thinking to maybe adding a cross brace and another tie wrap mount towards the bottom just to keep the bundle from moving into the rudder cable path.

And there’s the mess. Actually everything has temporary labels on it so I know where everything goes… it really looks worse then it is.

I also ran the bundle of wires out to the wing roots. This bundle includes wiring for the fuel sender, Strobe/Nav Lights and Tax/Landing lights. I used different color striped wiring to tell the difference between the landing and taxi lights. I suppose you can also use a multicore-core cable and get some shielding as well. The LED lights don’t draw too much current so EMF should be relatively low.

Brakes lines are run out to the brake calipers from the parking brake area. I need to look at making the groove on the rear of the landing gear a bit deeper and see if I can get the brake line to secure into that groove. I don’t want to use zip ties to hold the brake lines on.

I received the 30º fittings a few days ago so I was able to get the fuel feed lines connected to the fuel filters. The fittings worked well to turn the lines in towards the middle away from the rudder pedal cables. I’m going to leave the ends that attache to the fuel selector unfinished right now until I get the fuel sender and know the exact length they need to be. I’ll also secure the hoses a bit better once I know they don’t need to be moved at all.

I purchased some “cobra” tie wraps also called low profile tie wraps to secure the fuel lines. These tie wraps have a more even grip on the hose so they won’t tend to pinch in on the hose like a regular tie wrap. I also will wrap the area with silicone tape prior to zip tying. I secured the return fuels to the console support behind the fuel filters using a single tie wrap and mount.