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.

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More Cowling Work

Time: 3.5 hrs

Over the past few days I finished up (well it’s never really down, Is it?) work on the cowling. I had purchased a sheet of thermo insulation to put on the lower cowling under the muffler/turbo charger area and a few other places where the exhaust gets close to the cowling. The idea is to reduce the temperature so that no damage occurs to the cowling or paint. The thermo shield it good up to around 550 degrees Fahrenheit and provides a few hundred degree reduction in temperature, also I will be wrapping the exhaust so that should help reduce the temperature under the cowling as well. The thermo sheet is pretty flexible and was fairly easy to install. I will probably go around the edges with some clear RTV to seal up the edges and reduce any fraying of the fiber glass that makes up the thermo sheet. Prior to putting on the sheet I sprayed the whole inside of the cowling with high temperature silver paint. I didn’t spend too much time making it perfect. I just wanted it to look a bit more finished and maybe help reflect a little heat as well.

I also finished installing the doors and top air vent. I used some sika on the top air vent so that it seals up… yeah I know water is going to come through the slats, but no need to have more water than necessary.

Top air vent riveted and sika sealed.

Sprayed the inside of the top and bottom cowling with high temp silver paint. It came out OK. Didn’t want to get too caught up into trying to make it perfect. I think it looks better than the natural fiber glass though and the silver paint may help reflect a little heat as well.

A few photos of the thermo sheet installed. Mainly under the muffler and turbo charger area, but I also put some in areas where the exhaust gets close to the cowling.

The cowling is pretty much finished. Install the doors and camlocs. I’m pretty happy with the way the doors came out.

Cowling Work and ALT2 Relay

Time: 2.0hrs

Today I fit the top vent and doors on the cowling. I need to do some sanding on the doors to get the gap equal all around and to get a little better fit. Tomorrow I’ll spray the inside with high temp silver paint and I have a sheet of heat shield that I want to put on the bottom cowling. I didn’t have the hinges for the cowling doors so I had to make up some out of some extra hinge material I had.

I also finished up the install of the ALT2 (internal alternator) relay. I drilled a few holes in the relay mount and harness so I could safety wire them together and then wrapped the join with some silicone tape. I also sealed the wire entry points with black RTV.

Hopefully that will keep it from falling off. It’s on there pretty good, but you never know.

All sealed up and safety wired and mounted back onto the bracket.

Finished fitting the top vent and doors onto the cowling. I need to drill out the door rivet holes to 1/8″ (3.2mm) and do a little sanding to the doors. I had to heat one of the doors with the heat gun at 600 degrees to get it to bend a little more for a better fit.

The air vent fits well. I’m thinking of using some sika on the join so it seals up.

The doors line up pretty well. I need to do some fine tuning and also install the cam locks.

FT-60 Fuel Flow Transducer Bracket

Time: 1.5hrs

I made up a fairly simple bracket for the FT-60 Fuel Flow Transducer. I originally had just a temporary L shaped bracket and I was going to just replicate that in some thicker aluminum, but after looking at how close the aft mounting hole of the FT-60 sat to the bend I decided to make it a little more complex and extend the flat portion of the bracket by making a cut pretty much up the middle of the bracket so I could bend out a small section on top. I also made the bracket a little wider than the original and made the height adjustable. I noticed also that the bottom mounting screw hole so that it will slip over the screw (that mounts the Rotax 3-way solenoid to the airbox. I did this because it’s almost impossible to put that bottom screw back in with the bracket on. Now only the top screw needs to be removed (and the bottom loosened) to get the FT-60 bracket on. The only thing I have in question is that from a little more reading it seems that you’re not supposed to have a 90 degree bend in the fuel line within 6″ of the FT-60 and I have like 3 of them. The TAF way only really has one (coming off the fuel pressure regulator). I guess I’ll need to do a test to see how actuate the FT-60 is in this arrangement. If it’s not I can always reroute the fuel line to loop around rather then using the two 90 degree fittings.

I’ll be writing up a complete step by step on how to install the fuel lines and what fittings go were when I do the fuel line install.

Here’s the layout of the bracket. I cut out a 2 1/8″ x 4 ¬†3/4″ piece from a sheet of 0.09″ 6061 aluminum.

A few photos of the bracket. I notched the bottom hole so it can slide over the mounting screw. And I also made the mounting holes adjustable to accommodate the short hose run.

Side view of FT-60 on the mounting bracket.

After facing view. The bracket uses the same mounting screws as the 3 way solenoid that mounts to the airbox.

Top view

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.

Fitting the Cowling (Part5)

Time: 3 hrs

Well I think I pretty much finished the fitting of the cowling. There is still a few more things that need to be done like put on the access doors and the cooling fins, but most of the hard stuff is done. Today went fairly well. I had received the longer camloc studs from Skybolt which all worked fine except the -5s for the two in the very front of the cowling (under the cooling holes). I tried -5s and also -6s and even those seemed too short. I need to investigate what’s going on, even -4s “should” be long enough so I’m at a loss as to what’s going on there.

The part that I thought was going to be difficult, drilling the holes for the camlocs along the firewall join, ended up going pretty quick. If I did it over I think would have been best to not drill out the existing 8mm holes to 5/8″. I did this on most of the hole and only had a few left that were 8mm, but it was easier to match drill the 8mm hole and then drill the cowling out to 7/16 and the mount strip to 5/8″. The ones that I previously drilled out to 5/8″ I had to watch closely and adjust with each step of the step drilled to make sure it was staying centered with the hole in the mount strip. I uses a mirror inside the cowling to verify. All the holes came out to be very accurately drilled and the use of the floating camloc receptacles made the mounting of the cowling come out pretty good. I have one spot on the top right of that cowling that I’m not happy with and the very bottoms stick out a bit. I’ll see if I can improve those areas, but they don’t Bother me too much. Most of the gap around the cowling is between 1/32″ – 1/16″ so I’m happy with that.

Got the top 2 camlocs in. A pretty good fit on the top. I had put some reference marks to locate the holes for the camlocs.

This was one I could match drill to 8mm. This was much easier then doing the holes that I had drilled out to 5/8″

All camlocs are in and things line up pretty well.

When the camlocs go in they push in on the cowling. In most areas it’s not that noticeable, but the bottoms stick out a bit because of this. I noticed if I bend the mount that is on the nose wheel with the 2 most bottom camlocs that it helps minimize this, but don’t want to bend it too much more. It doesn’t bother me that much since it on the bottom, but I’ll try to improve it at some point.

The gap behind the spinner is good as well, it’s about 6mm.

The left side is slightly wider (about 8mm) then the right, but it’s not very noticeable. This is because the engine is at a slight offset while the cowling is straight. I had tried to put the cowling on an offset to match, but it proved to be a bit difficult and I didn’t have enough material on the firewall side of the cowling to do it.

This one area bothers me the most. It bulges and  sticks up a bit. Since taking this photo I improved it a little by using the fluting pliers on the mount strip to pull the camloc mount down a little.

The cowling is finally on and held by the camlocs… no tape… YAY!

Another review of the cowling.

Left cooling hole cut back for alternator.