Empennage Fairing

Time: 5 hrs

Today I fit the empennage fairing along with doing the empennage test fit and some testing of the electrics that run there. The first step in fitting the fairing was to clean up some of the burrs to allow for good fitment. Then fitting it onto the fuselage section and verifying that everything lined up correctly. I ended up with a few small modifications to the fairing. One was I shortened the front most part by around 1/4″ because it landed right on a rivet which pushed it up making it so it didn’t sit flush. I also sanded some parts so that it would miss other rivets and sit more flush. Besides that it was just a matter of drilling 3mm holes through the fairing into the fuselage and then following up with some reaming to fit the M3 rivnuts into the fuselage/VS skins. One thing I learned quickly was to not use the pre marked locations for drilling as they usually landed right on an existing rivet.

I also used this opportunity to test the tail strobe and the trim motor wiring.I had tested these locally at the HS and the rudder before , but not yet through all the cabling and connectors. Fortunately everything tested fine so all the connectors and cabling looks to be good.

Empennage test fit. All looks good I also measured the distance between the tip of the VS and HS and is the same on both side so it’s nice and straight. Of course it was windy today so getting things assembled was a bit fun.

The fairing fit fairly well. After this photo was taken I also installed 3 more screws into the VS to help hold the fairing down in that location.

I ended up drilling out the fairing to match the rivnut already installed for the small cover piece that fits behind the HS. This will help hold the fair and also prevent the fairing from having to cover the screw so that the fair willl sit more flush.

I also spent some time filling the unneeded premarked holes and some minor damage that the fair had on it with some epoxy resin and then sanding.

The testing of the strobe and trim went fine as well. For the trim I put a meter on the position sensor and then connected the power supply to the motor. I ran the motor and watched the meter show the resistance as the position changed. Reversing the polarity on the motor then ran the trim tab backwards.

Bracket for Rear Fuselage Inspection Plate

Time: 2.5 hrs

Today I also management to fabricate a bracket to allow me to screw in the small inspection plate on the rear fuselage. This plate is usually riveted in like some of the fuel tank mounting plates on the wing, but also like the wing I wanted to be able to remove it. The ones for the wing were easy since the holes could be enlarged enough to install M3 rivnuts, but the holes for this inspection plate were too close to the edge to do that. I decided to make an inner ring that I could install the rivnuts into and then the screws could just pass through the holes in the fuselage skin.

The bracket ended up coming out alright. It was a bit difficult to get the inside cut out nice, but that’s just cosmetic. Maybe I’ll see if I can have someone make one up on a CNC someday, but for now it works fine and doesn’t even require being mounted to the fuselage skin.

I also used the edging tool to put a slight tapper on the inspection plate since it was just flat (unlike the ones for the wings which already have a beveled edge.

Bracket is made up and M3 rivnuts installed

The bracket will just sit in like this and will stay removable so that you can get a little more space to work if needed.

This will work well. Because the bracket isn’t riveted in you just need to be a bit gentle getting the first 2 screws in. Seems to hold well though.

Upholstery is Here

Time: 3 hrs

The big news is the custom upholstery that TAF did for the plane arrived and I picked it up from Torrance TAF yesterday. I couldn’t wait to see how it would look in the plane so I put a few pieces in the plane. I’m so happy with the way it came out, they did an amazing job.

I also had to put an O-ring back in the hose inlet for the cooling (it fell out when I had taken it off to turn it and put the hose on). Fortunately I found it when I was cleaning up the garage and kind of put 2 and 2 together. I looked at the IPC for the Rotax and sure enough there’s an O-ring show in there.

The other work was mainly cleaning up, organizing, and labeling wires. Oh yeah and I installed the arm rest.

A few photos of the interior. Nothing is installed yet. I just wanted to make sure things fit and wanted to see how it would look.

This is the O-ring that fell out when I took the inlet off a few weeks ago. I’m just glad I thought about it when I found the O-ring and didn’t just throw it out.

Misc Work

Time: 1.5 hrs

Just did a few miscellaneous things today:

  • Drilled 6mm holes for radiator
  • Added neoprene around edge of radiator mount
  • Fixed hinge on rear seat (I had it backwards)
  • Filled/sanded some rivets
  • Fixed small crack in nose wheel pant

I really need to get the parts from TAF that I order back in December. Once I get those I can finish up a lot of the engine items. I’m also waiting on the oil cooler from California Power Systems.

Added some neoprene to the edge of the radiator mount hole. Also drilled the holes for the M6 bolts.

Cut down some M6 bolts and screwed them into the radiator. The new radiator has rounded ends and the cowling seems to have been updated to fit the new radiator.

I’m wondering how difficult it’s going to be to get the lower cowling off/on with the radiator and oil cooler mounted. There will be a bracket that connects the two and then some camlocs will hold them to the cowling along with the 2 M6 bolt pins (above). It seems like it will be a bit of a challenge to get all the lined up when putting on the cowling.

Avionics Shelf

Time: 2.5hrs

I found got some time to work on the plane. I’ve been so busy with work and then useably tired after that I haven’t had time to do any work on the plane. So today I made two shelves that some of the avionics will sit on. Mainly the GTR20 (Radio), GTX45R (Transponder), and the GMA245R (Remote Audio Panel)… This list might change, but I think this will be the way I’m going for mounting the avionics. Some stuff will mount directly to the rib and then of course a few components mount into the panel itself. The shelves are pretty straight forward. I used some aluminum angle and notched the ends so that it could be riveted to the fuselage stringers. I had to make sure that it didn’t get in the way of the air ducts and anything that will be mounted to the panel. I use .05 6061 aluminum sheets for the shelves themselves and made them removable just incase I have to get in to reach something behind the panel and can’t crawl under for some reason. Now I just need to start buying some avionics, which I will do now that the engine is on and getting close to being done. The nice part about the shelves is it keeps all the avionics out where you can get to them and not buried under the rib section near the firewall which is actually hard to get to when the dash is on.

Shelves are roughed in and mounting holes drilled. Next step is to clean up the parts and install some rivnuts for the M4 screws that will attach the shelves to the angle and rib.

The shelves are mostly installed. I still need to rivet the angle to the stringers and get some shorter M4 screws. I may also make a bracket for the center that attaches the angle to the center console supports or maybe some L brackets to beef up the connection to the stringers on the side. It seems pretty sturdy though so probably not necessary. This will be the basic arrangement of the avionics. I’ll see when I get the actual avionics exactly how everything will fit and how the weight is on the angle piece. I may also be able to cut a little off the end of the shelves to shorten them up for better access behind and less weight. Also I can mount things to the underside of the shelves as well.

Air Vents and EGT wiring

Time: 5 hours

I purchase a pair of 2″ AIrKit anodized aluminum vents from Aircraft Spruce. These things aren’t cheap, they’re around $160 each, but seem to be well made and are a good size for what I need to do. I also have AitKit cabin lights so everything kind of looks similar. I made up some fillers out of anodized aluminum (for the front) ¬†and fiber glass sheet (for the back) with a 3 1/8″ hole saw. I then cut a 2″ hole in the middle using another hole saw. The cuts came out well enough. I had to modify the fiber glass ring a bit to get it to sit a bit flatter. The thread on the vents seemed to be long enough, but it was a pain getting the back to screw on. I epoxied the fiber glass ring to the rear of the dash and the front is just held in place by the pressure of the backing nut. I’m happy with the way these came out. They look a lot nicer then the plastic vents and they will seal off much better as well.

I also finally was able to finish up the wiring of the 2 EGT sensors. I had order some K Type ¬†thermo coupler wire which appeared to be exactly what I needed at a reasonable price, but after running the wire and starting to wire it up I found that they had sent the incorrect wire (knew it was too good to be true). They said they will send the correct wire, but it’s back ordered (of course) and they weren’t sure when it would ship out. I decided to go back to my original place called Omega to purchase the wire. Their wire is really high quality but it’s pretty expensive. I purchase 25ft of armored K-Type thermo coupler wire for around $80. It arrived a few days ago and wow, it’s nice stuff. The wire I used (GG-K-20S-SB-25) is a 20 gauge glass insulated 2 core wire with an other glass insulator and then a stainless steel outer sheath. There are other sheathing you can get, but I wanted to use the braided stainless steel. The connection to the EGTs is made by 2 ring connectors, Unfortunately I could only find spade type connectors that are usable with the K-type wire. The spade connectors are made from Alumel and Chromel which is the same material as the K-type wire so the temperature characteristics will be the same. The yellow wire is Chromel so you use the Chromel spade connector on it and the red wire is Alumel so the Alumel connector is used on that. I used a standard open barrel crimper to crimp them on. Working with the K-type wire is a bit of a pain because the wire insulation is like a cloth material and doesn’t cut well with wire stripers. After the wires are bolted together a final length of heat shrink is put over it.

Lastly I roughed in the CEET tubing for the air vents. Because I’m using 2″ air vents I had to find a 3″ to 2″ reducer to tie into the NACA duct. I found some on Amazon for around $6 each and they look like they will work. The NACA duct is a little smaller than 3″ so hopefully it will seal up OK. I’m waiting on my hose brackets to be able to actually connect everything together. The one issue I ran into is that the bar that I’m going to install to hold the avionics shelf gets in the way of the tubing run.

Finer glass backing rung epoxied in.

Vent mounted in the 3 1/8″ anodized aluminum ring. It’s all just held in place with the pressure of the backing nut. The vent moves fairly easy so I don’t think it will be an issue with it coming loose. The fiberglass ring also creates some tension on the nut so it holds very tight and won’t spin loose at all.

EGT wire connection. I could only find spade connectors in Alumel and Chromel, but this all get wrapped in heat shrink so that will keep everything together and offer some strain relief.

Big piece of heat shrink covers up the join.

This 3″ to 2″ reducer looks like it will work. I may cut down the flange a bit to give more room. I need to use 3″ CEET to join it to the NACA duct and then 2″ out to the air vent.

Test fit of the CEET tubing for the air vents.The tight bend may cut down on air flow, but not much I can do about it. I don’t want to put the bar on the other side of the tubing because it may interfere with the fuel selector.

Dash Stitching

Time: 2.5 hrs

Did some work on dash. I saw that other builders have stitched around the edge of the dash to keep the leather from creeping up after its installed. I figured it would be good to do even though I haven’t seen this happen on any of the Slings at Torrance TAF. The issue as I understand it its that the leather is just glued down to the fiberglass dash and after some time the leather will shrink and the fiberglass will show. By running a band of stitching around the edge of the top of the dash will prevent this from happening. The process was fairly simple. I drilled a whole lot of 5/64″ holes 15mm apparent along the top of the dash and then ran some stitching through the holes. I purchased a leather stitching kit from Amazon which came with a supply of black waxed stitching, some needles and the stitcher.

The stitching process is basically that you push the thread through the hole with the needle and then pull the needle partially back which form a loop on the under side. You then pass some thread (that you had previous pulled through) through the loop that is formed.When the needle is fully pulled back the loop ties down on the thread you pass through and holds. You do this for each hole. After a few times you get the hang of it and the process moves along pretty quickly. I think it only took about an hour to do the whole dash. One thing that I underestimated was the length of the under thread that you pull through. I pulled through enough to reach from the start to the end of the holes and maybe 5 inches more so that it could be tied off at the very end, however almost half way through I noticed I wasn’t going to have enough to reach the end. What I ended up doing was to stop and tie off at the half way point and then I started again at the other end and worked to the middle (half way) point again.

Another change I made from the other builders is that I didn’t run the holes all the way up to the front of the dash. I stopped the holes about 4″ from reaching the front. I did this because I didn’t want to see the holes/stitching and I figured that part of the dash wasn’t going to creep back.

I also made the aluminum blanks for the vents. I order some fiberglass sheet that I’ll use on the inside. When I finally figure out what vents I’ll us then I can drill the correct size hole in these fillers and they will act as a sandwich to hold the smaller vent in the hole of the dash for the vents.

I made up a quick jig to drill the holes. This went very quick since all I had to do was use the middle hole to line up with the previously drill hole and then use the last hole to run the drill through. I just used the drill to line things up. there’s a lot of holes to drill.

I originally just measured out the under thread long enough to run from the start to the end of the holes to be stitched plus about 5″, but it wasn’t long enough so I ended up stopping in the middle and then started again from the other side.

From this photo you can see that I didn’t run the stitching all the way to the very front of the dash. I stopped about 4″ away. I didn’t want to see the stitching so I figured it was safe to stop here and when the wind screen is installed you really won’t see the stitching in this area.

I kept the stitching close to the seam so you can barely see it.

Made a circular blank from some anodized aluminum I have. These will be drilled out larger to accommodate an aluminum vent. I will use some fiberglass behind this to create a sandwich to hold the vent in place.

Faux Panel

Time: 1hr

Today I made up a faux instrument panel out of some blackboard material from Home Depot. I wanted to make sure that the dash had something in it before I finished drilling the holes in the fuselage to mount the dash. I won’t actually be mounting the dash for a while. I will probably use the faux dash to position other things like the choke and heater cables so that I can cut those to size. Now I need to figure out how to somewhat accurately drill the mount holes in the faux panel so I can screw it into the dash.

Once I had the faux panel in the dash I used a laser level to make sure the dash was level. I uses the heater outlets as a reference and measure on both side the same. The outside flanges of the dash aren’t equal between the left and right sides. I noticed this in some factory photos, but it should be OK since the fiber glass band that gets sika sealed to the fuselage after the windscreen is done is quite wide and will cover it.

Top Front Skin and Dash

Time: 3.5 hrs

Today I finally got the top front fuselage skin installed. I think I’ve taken care of most of the items that need to do with the firewall and wiring so I think it’s safe to put on the skin. I’m sure something will come up that would be easier to do with the skin removed, but hopefully that will be at a minimum. I used some sika on the top join to seal it and also ran a bead down each side along the cowling join area. I had a few holes that were a bit tough to get lined up, having the wet sika there made it especially fun.

I also started to line up and drill the mounting holes for the dash. I think I have the dash in the correct spot. I know Craig M had some details on mounting the dash, unfortunately my dash has some funkiness on the tabs that makes measuring a bit difficult. I set the right side to to 20mm that was stated in Craig’s blog and that seemed pretty good, I then used a level to set the left side (the side with the weird cut) and drilled out a few holes for the 4mm rivets,. I’m going to wait on the rest until I make a faux panel out of some 1/8″ plywood. I want to be sure that when a panel is mounted that the center section is in the correct spot and the panel sits flat. The dash is pretty floppy in that area and it could easily be bend back and out of shape and then when I mount the panel it won’t sit correctly.

One finish up task before installing the top skin was to run this safety cable on the turbo server. It is just there to make sure the cable can’t pull all the way out of the server. The Rotax manual doesn’t show how to do this so I improvised something.

All looks pretty good so I should be OK to close it up.

All done. There’s a thin bead of sika along the front and I put some sika in the front join between the top skin and firewall.

Dash is lined up and started to drill a few of the mounting holes. I’ve got a bit of work to do on the dash itself and there’s quite a few things that need to be done with the avionics before the dash can get mounted. NOTE: I noticed that the flange on the dash on the right side is a bit large then the flange on the left so you can’t use that to judge if the dash is on straight.

Fits OK on the center console as well, but I’ll make a faux panel out of some thin plywood just to make sure it will all work OK. Next project is to fit the cowling.

Rear Interior Skins

Time: 2 hrs

Today I labored a bit, even though it’s Labor Day and I’m supposed to be out having fun. I riveted the left and right interior skins. I can’t think of any reason I need to wait on these… famous last words. It all went very smooth, things fit surprisingly well. There were 2 holes at the very bottom of the skin that needed to be drill out and was a bit difficult to get the drill in to drill them out.

So with only a few things left to cover I really need to get the engine ordered. I’m away for 2 weeks in Germany to run the Berlin Marathon so maybe I can get it ordered before then.

Photo of right side rear interior skin done. Left side looks the same so didn’t take a picture of that.Seat belts work great as well.