Interior Rear Side Skins

1.5 hours

Today I got the interior rear skins ready to get riveted. I had to remove a few rivets from the rear seat floor area to get the skins to fit in. I also had to drill out a few holes for rivets. The skins fit pretty well. The only issue is that if I line up the top of the rear skins with the top of the front skins then most of the holes don’t line up so having them not even seems to work best. These will be covered with the more decorative interior panels so these will never be seen.

I noticed that the cut outs or recesses in the canopy for the seat belts don’t line up great. And since the parachute cable is right behind that area I can’t really even dremel it out more. It’s not that far off, maybe 1/4″ and the seat belt does seem to move OK, though it got a little slow retracting once while I was messing with it. I was thinking maybe the canopy isn’t far enough back (not much I can do about that now), but if that were the case then the upper hinge part of the seat belt strap would be farther back as well and so I’d have the same issue I think. It’s not that big of a deal, it would just be nice if it lined up a little better. Maybe I might need to loosen the seat belt spool and put a slight angle on it instead of it being so straight vertically. Will have to look at that.

I always thought the these flanges go in front, but I saw on the Sling at Torrance TAF that they sit behind the floor panel. Much easier to drill out as well. But now I need to remove these rivets.

OK rivets are out and had to drill one hole in the flange on the floor. On the floor I put the flange under the floor skin even though the Sling at TAF had it on top. I just think it looks better and maybe a little stronger this way.

Right skin, cleaned and clecoed. I’ll do the top row after I get all the other rivets in. Just need to rivet it when I get back from my hiking trip. I think I should be safe to install the interior skins now. I can’t think of anything else that needs to be done behind them.

And same for the left side.

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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.

Install Center Console (Cubby Hole)

Time: 1.5 hrs

Today I made the cubby hole/center console assembly a permanent resident of the plane. It’s been a long time waiting to install this piece so I’m happy it’s finally in. I also install the front seat belt buckles. I added 3 thick AN4 washers on the inside since the hole to mount the buckle is so large. The washers filled the gap well, a little bit of play in it, but much better then mounting without them. With the cubby hole mounted I was also able to install the inner seat rails.

Now I can double check that the brake lines are routed correctly and everything reaches. Next I can cut the lines at the clippers and put the -4AN ends on. I purchased some 45º fittings which look like they’ll work great.

Cubby hole and seat rails in. I will need to install the arm rest when I get that some day.

Rear cover for the cubby hole/center console. The stratus is mounted towards the bottom. This will be great for the kids and also can serve a 2 more USB chargers for the front. The Garmin GMA245R has one that I’ll need to bring up the the instrument panel with an extension, but it’s always nice to have a few more around. I’m thinking of also putting the rear LEMO plug here for the rear seat headsets.

Covering Rib 2

Time: 2.5 hrs

Now that I have some leather I wanted to get this out of the way. On some Slings I saw that the carpet material was used for Rib 2 (the rib behind the rear seat) and on others I saw the leather used. I liked the look of the leather so I went with that. I first made a rough template out of thick paper and then cut the leather to that shape. It went along fairly well the hard part is working in the cramped space. Prior to installing the leather I drilled out the holes for the seat stop bracket and added 2 rivets to the join of the rib halves.

I was looking on Peter C’s build log and I noticed he added some extensions to the seat stops. I may want to do this as well. The catch on the back of the rear seat to hold it upright doesn’t even come close to reaching the stop. I could fix it by moving the catch over a bit closer to the stop, but it may be good to have a bit more material behind the back of the seat as well. I guess I’ll have to think about that.

Here’s the rib all covered. I’m happy with how it came out. There is a piece that covers the gap between the canopy and the rib as well, but I’m not sure if that comes with the upholstery kit (which I don’t have). TAF is going to make me a kit using materials that I supply so I’m not sure if that will be supplied. If not I can always make it from some thick plastic or aluminum and cover it with leather.

Added 2 rivets to the join

Drilled out the 2 1/8″ (32.mm) holes for the seat stop bracket rivets. There’s 2 more to drill but I want to wait until the sides are riveted before doing that since things can move a little.

After making a paper template of the rib I just cut the leather with scissors. I cut the outside edge close to the template and the inside edge I left about 2″-3″ of material so that it could be wrapped around the end of the rib and around to the back of the edge flange.

Here’s the front part glued down. I cut slits in the leather to relieve some of the tightness. I made sure to not slit it all the way to the rib, but left about 1/2″-3/4″ of material. This is so that the cut doesn’t show on the side of the rib when it gets wrapped around. Once the edge was glued down I cut off the most of the excess material and left about 1/2″ to wrap around to the inside of the edge flange. You can’t really see it, even from the luggage area, but when I install the carpet in the luggage area I’ll run the carpet over those ends so you can’t see it at all.

Cubbyhole Covering

Time: 3 hrs

Over the course of a few days (had to wait for tools and supplies) I covered the cubbyhole and rear part of the console. I also installed the Stratus Power Thingy.

The main hold up in doing this was getting some time to go to downtown LA to buy the leather for the plane. This past week I finally got a chance to go shopping for the leather. I was able to find some very nice leather close to the color I wanted for a very good price (around $200/hide). So with that done I proceeded to fit the cubby hole top (the part I made out of carbon fiber) to the cubby hole and then covered the rear panel and the side of the cubbyhole.

I found that for one leather is pretty hard to cut, but with a sharp pair of scissors I was able to make the major cuts. Finer tuned cuts required a very sharp exacto/utility type knife. Making large hole was the next challenge. Drills worked OK for small holes but I wanted to make holes large enough for the rivnut flanges to fit in so that the leather would lay flat and not add to the thickness of the rivnut flange. I found some leather punches on Amazon which seemed to work pretty well. They were only around $7 so I found that a few weren’t super sharp and took some hammering to get through the leather. Most of the holes came out pretty good. Some I had to finish off with the knife

So now the 3 hides of leather and some carpet need to be boxed up and shipped to TAF in SA so that they can make my seats and side panels. I’ll keep enough carpet to do the luggage area and a few other spots.

Another thing to note is that the Barge glue works really, really well. It doesn’t seem like it would but it really sticks and holds the leather well. I ended up getting a quart from Amazon for around $30 and that should do most of the interior. I nicknamed it “Snot” because it looks just like it, and is snot-like in many ways :-). Thanks to Craig M for finding this stuff.

Here’s the cubbyhole pretty much done. I will probably put the Lemo connectors for the rear seat headsets in the rear panel next to the Stratus and I still have to mount the arm rest which I don’t have yet.

Lining things up to fit the cubby hole top. I put in M4 rivnuts and then had to drill out the holes in the top

 

Drilled a 1 1/4″ hole with a hole saw and then cut a small notch with the dremel to install the Status.

Covering the rear panel was pretty straight forward. I found that after making the initial hole for the screws with a drill bit a reamer worked great for opening up the hole and cleaning it up.

Back side on the rear panel.

I used a 9mm leather punch for the M4 rivnuts and a 7mm (though probably should have done an 8mm for the M3 rivnuts. The punch makes a pretty clean hole. I found you can push down with your fingers on the leather to transfer the shape of the rivnut onto the leather then position the punch over that with a wood block behind. You have to be fairly quick since the impression only lasts a minute or so. I did the 4 rivnut holes along the top and then glued the piece onto the aluminum. the 4 rear (M3) rivnut and 4 front (M4) rivnuts were done after. I just only applied glue to the part I wanted to glue.

Glue on the aluminum.

And glue on the leather side.

One side done. One thing to note is that there are no rivet head bumps since I used flush rivets and filled with expo filler.

Close up of the rear panel.

The top. I didn’t realize I probably should have put the cubbyhole top the other way so the carbon fiber weave pattern would have matched. Oh well too late now. Most of it will be covered with the arm rest.

And the side. Pretty happy so far with how it’s coming out.

 

Rear Seat Camlocs

Time: 1.0 hr

I originally installed the retaining springs for the DZUS locks that hold in the rear seat, but after a post on the Sling Builders Facebook group about using 4002 Camlocs on the cowling I decided to make everything the same and replace them with the 4002 camlocs. In my internet searching to learn a bit more on how to install the camlocs, I came across Skybolt which has some very nice 4002 compatible camlocs. The cost is a bit more then Aircraft Spruce, but they seems to be a better quality then what you get from Aircraft Spruce. The other issue was I had to order a minimum to get the ones I wanted. Since I only needed enough to do 3 anchor points I had to order a little more then I needed.

Here’s a little on what I learned about the camlocs. First there are 4 piece and 3 piece systems. Typically you use the 4 piece. The 4 pieces are the grommet, the retaining ring, the stud, and the receptacle. The 3 piece have the stud and grommet as one piece. You can get studs in different lengths which is specified by the -(number) in the part so something like 4002-14 or 4002-5. The numbering of the parts are super confusing because there are a multitude of faster types you can get like slotted, phillips, winged, etc and you can also get different materials (cad plated, stainless steel). The grommets come in basically normal width and wide width and only a few different depths. The one confusing thing for me with the grommets was that the “plus flush” are the grommets that aren’t actually flush, they don’t need to be counter sunk, that’s the “flush” grommet. To me is sounded like the “plus flush” was just better version of the “flush” grommet, but that’s not the case. The last thing I need to mention is that you can technically install these without any special tools, but its a pain in the butt and pretty much impossible to get the stud out of the grommet if you don’t have the special pliers (showing below). Same with the retaining clip. You can get the thing on, but its a pain. The tool that they make to put the retaining clip on makes it supper easy and its only around $20 from Aircraft Spruce or Skybolt (the pliers are fairly cheap as well). I haven’t purchase the retaining ring removal pliers, but maybe I will get those at some point.

So with that said I ordered some nice folding wing fasteners from Skybolt. These are the 40S47 style studs, but Skybolt calls them SK4002SFW folding wing. I like these because they sit fairly flush, but you don’t need any tools to remove them. The -9 seemed to be the perfect length. If you like them and want to use them on your Sling please let me know. I had to buy 10 and only needed 3. I will sell you them at cost which was around $8.50 or so. I also used the wider grommet which was just for aesthetics.

Parts that I ordered from Skybolt. I had also order some phillips style studs, retaining clips and flush washers from Aircraft Spruce. The pliers are for compressing the spring on the stud when inserting it into the grommet (after the grommet is installed with the retaining ring). The tool with the rubber end it the tool to install the retaining ring onto the stud.

Installing retaining ring onto grommet

Retaining ring installed

Installing stud into grommet

Stud installed

Above is the process to installing the grommet, retaining ring and stud. I used a step drill to enlarge the hole to 15/32″ (approx. 12mm). The grommet doesn’t fit supper tight, it moves around a little in the hole, which I think is the way it is supposed to be.

I added a little more neoprene tape to the back of the rear seat so it doesn’t scratch up the luggage floor. I’m not going to install carpet on that part so it needs a little something.

The receptacle installs much like the DZUS springs using 2 counter sunk 3.2mm rivets. I did need to use a step drill to widen the original hole to 5/8″ (approx. 16mm) so that the stud and grommet fit down into the receptacle. The receptacle are the 244-16 style receptacles (from Aircraft Spruce). The -16 have the rivets spaced at 1″ as apposed the the -24 which is wider (like 1 3/8″ I think). The -16 style line up perfectly with the mounting holes for the DZUS springs so those holes can be reused.

Everything installed. The wings on the studs fold down so the sit fairly flush. Its super easy to take out the rear seat, just fold the wing up and twist 1/4 turn.

Now the big question is what was TAF’s intention for the hole towards the from of the rear seat and bracket with the 2 holes on the rear spar? The hole in the seat appears to lend it self to installing the stud side of a DZUS connector, but the bracket doesn’t look like it would get the spring installed. The Sling 4’s I saw at TAF didn’t have anything installed here, just the 3 on the rear portion of the seat. So probably not important, just more curious then anything. I was thinking I could maybe make a sliding latch here so that when you install the seat it would slide down into the latch and then you use the 3 camlocs to loc it in place. the purpose of the slide latch would just be to keep the front of teh seat from lifting up.

Miscellaneous Work

Time 1.0 hr

Wow I was looking at the app I use to log my build time and I last worked on the plane mid June. Time sure does fly 🙂 I’m really at the point that I just need to put down the cash and buy the engine. I don’t want to do any avionics until the engine is on and once the engine is mounted I can fit the cowling and get the plane painted (well I have to build the wings too). So I think I really need to make that commitment if I want to keep moving forward on the build.

Today I just did a few random things on the plane:

• Installed the top mounts for the front seat belts
• Fixed the switch/knob plate for the cabinet lights
• Installed neoprene foam on back seat and ribs
• Looked at where to put ELT antenna

I’m thinking it’s OK to go ahead and install the seat belts. It wasn’t as easy as just tightening the bolt of course. I noticed that the provided washer was a bit thin and the top holder would bind against the canopy. I ended up adding 3 AN7 washers which moved it out just enough so the holder was able to move freely. I also made sure to use some loctite on the bolts. I torqued them to 30ft/lbs. which is a little shy of what you would torque an AN7 bolt to, but since the nut is just epoxied into the canopy I didn’t want to over do it and rip the nut out. These are metric and different material, but it seemed about right.

Added 3 AN7 washers to offset the seat belt holder so it could rotate with the seat belt.

Installed the plastic cap. I hope I don’t have to remove these for anything.

I’m thinking this may be a good place for the ELT antenna. TAF mounts it on the front side on that rib in the photo, but I noticed that it’s a little in the way of someone sitting in the rear seat so it would be good to get it out of the way.

NOTE (7/8/2018): After some thought and a few comments from others I decided that this probably isn’t the best location for the ELT antenna because it does move it back into the metal portion of the cabin. For now I’m going to stick with the TAF location unless I think of a better place.

I had previously purchased some thin neoprene foam tape for the luggage door, but it was a bit too thin. I knew I’d find somewhere to use it. I installed it on the inside edge of the rear seat. I’m not going to put carpet on the luggage floor so hopefully this will keep it from getting scratched. I also put some on the ribs where the seat sits on some rivets there. I was going to install the cam locks that hold the seat to the luggage floor, but I only purchased the flush mount collars for the cowling. I ordered a few of the “plus flush” (4002-NS)  ones which are the ones that don’t need dimpling or countersinking.