Time: 1.5 hrs
I had previously installed the front seatbelts, but now that it’s getting close to putting the inside skins on I wanted to make sure everything was working and correct with them. I noticed that when it was in the clipped position, as if you were wearing it, there was a twist in the lap belt portion. It seemed that there was no way you could possibly mount the end bracket to make it so that there was no twist in the belt. I ended up having to flip the belt clip and the canopy bracket around on the belt, at that point the twist was gone from the shoulder and lap portion, but now was at the portion that would go into the side skin and down to the take up spool. The only solution to fix that was to unwind the spool and re run the strap through the opening in the stringer of the side of the fuselage and back into the spool which was a bit more challenging now that the take up spool is mounted in the plane.
At first I figured that the problem was caused when I had taken the seatbelt apart the first time, but after some thinking I don’t think there was any way for me to mess that up since the clip and bracket were on the correct side of the belt. If I had flipped it when I respelled it then everything would have been backwards. So I can only conclude that the seatbelts were put together backwards at the manufacturer or that it’s how it is intentionally made and it needs to be flipped to work correctly for how it’s installed in the Sling.
With the end of the strap mounted to the fuselage like this (which is the only way that it can be done) I always ended up with a twist in the strap. I flipped the belt clip and canopy bracket around by folding the belt and slowly pulling back and forth to get the belt to flip inside the part. The twist then moved to the portion between the canopy bracket and where the belt goes behind the side skin down to the spool. Respooling the belt removed all the twisting, everything is straight and works nicely.
Since the end bracket (shown in the previous photo) can’t be flipped this is then the correct orientation of the belt clip and canopy bracket in relation to the plastic stopper. The plastic stopper has a filled in side and a side where you can see the plug. The filled in side should be up (or facing the inside of the plane).
Finally got to install the canopy today. I think it came out pretty well. I noticed that I maybe mounted the front about 1/8″-1/4″ higher then I saw in the factory photos. I don’t think it matters much as there seems to be some wiggle room on the mounting. I checked the top rivets on the inside skins at they seem to have enough room on the inside of the canopy to be riveted so I think all is good.
I ended up using 3.2mm X 8mm rivets for the rear part and the very back of the side join. I first checked the 8mm rivets along the side join and they seemed fine at first. I had started riveting from the back and worked my way forward. When I got to just after the bend in the side skin (right by where the cable comes out to mount to the rear spar) I noticed that the 8mm rivets were too short so I switch to using 3.2mm X 10mm rivets. I wasn’t able to get the Gesipa rivets, but I found some that are pretty similar. In fact when I had to drill out two of the Gesipa rivets that were too short I had a hard time remembering by looking at the from which ones they were. So I’m thinking they will look fine especially once they are filled, sanded, and painted.
So here’s a few things I learned when mounting the canopy. The masking tape along the outside was a huge help in keeping the sika mess to a minimum. I had put a small bead of sika around the whole area on the inside of the aluminum when the canopy was to be mounted. The bead was at the very top edge of the skin. Once the canopy was clecoed I pushed down along the edge to get all the sika out that would come out and wiped it with my finger. I cleaned the remaining off the aluminum with a dry paper towel, but it seems like it comes off pretty easy after it’s dry so I probably shouldn’t have spend so much time on that. When the sika was still a bit tacky and I had wiped all the edges down I pulled the tape off and I was left with a very clean seam. I wanted to be able to see a little of the sika in the seam so that I know it had sealed OK. There were a few small spots where I probably should have put a little more sika so I ended up pushing some sika into the seam with my finger. Also make sure to have enough paper towels because the sika (even a little bit) makes a big mess. I also found that using the sika to hold the metal reinforcing strip to the back of the canopy was really helpful. It’s just one less thing you have to deal with when you’re working against the time the sika is drying. I also think not having the rear windows in made things a bit easier, at least if you’re doing the job by yourself.
Canopy installed. It came out OK. I wanted to have a little sika showing in the seam so it looks a little messy, but not too bad. I really didn’t have any issue with the skin bulging at all. I may replace a few more rivets with the longer 10mm ones as well.
A photo of the rear seam. Still need to rivet the rib.
These are the 3.2mm X 10mm rivets I ended up using.
Time: .25 hrs
I had purchased a drilled bolt from The McFarlane to connect the cable to the cabin heater box flap. I just did a quick check to see if it works and if the clearance is good the cable will need to be cut shorter so this was a final install. I’m not using the standard heater cable for TAF I purchase a McFarlane locking push pull cable. Th center core wire is pretty thicker so the tight bend out of the firewall and into the heater box needs to be relaxed so the wire can move freely inside. The cable seems to work OK and it’s not too difficult to pull on the cable… maybe a little more work on it will get it to move really well. I think this arrangement will work though so that’s all I was check for today.
I also cleaned up the workbench a bit today (not included in the time). It was getting way to out of control. Much better now… Ooops forgot to take an after photo.
The stainless steel drilled bolt for holding the heater cabinet cable wire onto the heater flap. I purchased it from the McFarlane site. There are a few different variations with the hole in different places and different threads. This particular version has the hole at .183 inches from the head and an overall shank length on .653 inches. It’s an AN3 bolt and the hole lined up well using a standard and a thin AN washer (stainless steel).
The bend out of the firewall can’t be too tight or the cable is too hard to pull.
This is just a rough install of the bolt. I had to drill out the hole to AN3 size. On the final installation I can probably put in a little bend on the wire after the bolt… the wire is pretty hard to bend though. Not the best that the bolt is pointing upward, but since the wire is on the top side of the flap tab then this is the way it has to be.
Work bench was a mess so did some spring cleaning. Maybe I’ll get an after shot and post it.
Time: 1.0 hrs
I drilled a few extra rivet holes for areas along the canopy join that looked to need it. Peter C. had emailed me and gave me a few photos of what he did and it looked great, but I wondering if I need to do the same. The skins fit pretty tight against the canopy for most of the length of the join. The only area where it bulges a little is at the bend towards the rear of the canopy. I put in 3 extra rivets in this area. I made a simple jig so that I could drill out the holes without having to measure each time. The spacing is the same all along the canopy join. It does change a little as you move past the front of the windshield post up to the firewall. The one main issue I have doing what Peter did is that I have the parachute cables running through the canopy (he doesn’t). There is one place where putting a rivet may cause an issue with the cable and that’s the last rivet on the canopy join up to right under the windshield post. So if I were to put rivets in all along the join and up to the firewall I would have one missing rivet at that point. The other option would be to stop the extra rivets at the windshield post. I also looked at a few of the Slings at Torrance TAF and they only had a few rivets at the bend and the join looked good so I’m thinking I’ll be OK.
My only concern is that the sika will cause the seemingly good fit to bungle out a little. I came up with a plan for that as well. If this happens I can either finish drilling the holes… not fun with wet sika, but still doable. Or I came up with a plan to lightly clamp the areas between each of the rivets until the sika has dried.
Now I’m just waiting for my 3.2mm x 10mm rivets. I noticed that the 8mm rivets are a bit short for the main join along the sides. I think they would work fine, but 10mm look to work a bit better. I found in one of the pack lists that (80) 10mm rivets are called out in the canopy kit. The pack list for my canopy kit doesn’t list them though so I’m assuming that those 80 rivets would be used for the canopy join. I went to Torrance TAF any they don’t have any. If I want to use the Gesipa multi-grip rivets that are used everywhere on the plane then I have to order 5000 of them. I found another rivet that may work. I’m hoping the head size is the same as the Gesipa rivets because I want it to look the same. I already know that the cherry rivets from Aircraft Spruce don’t look the same, the head is a bit larger. So I’m hoping that when the rivets finally arrive in a day or two that they look like the Gesipa rivets.
Added in 3 extra rivets at the bend in the fuselage
The top curve fits really well and there are a ton of rivets here so I shouldn’t;t have any issue with this area… Oh now I just jinxed it.
So here’s plan B if the sika causes the area between the rivets to bulge then I can clamp it down until the sika dries.
Time: 2 hours
Today I just did some cleaning and prepping to do the install of the canopy (hopefully on Friday). I also decided to use some sika to stick the backing plates on the inside of the canopy so that I don’t have to worry about lining things up while I have the sika sealer oozing from the seams and having to rivet and clean that while installing the canopy.
Just when I thought I was ready to install the canopy a few tings came up. One was that another builder (Peter C.) had mentioned that adding in extra 3.2mm rivets along the fuselage/canopy side seam is somewhat of a must. I did look at that and the skin seems to fit pretty tight to the canopy on my plane. However once sika is put into the seam it may cause it to bulge a bit. So now I ponder if I should add in the extra rivets. I don’t want to do it after the sika is involved because drilling them out with wet sika sealer isn’t going to be pretty.
The other issue is that I was looking at the 3.2mm rivets (the most common used are 8mm in length) and was thinking maybe the rivets are a little short. I kind of eyeballed it so it’s questionable, but to me they see a little short especially for the side section where you are going through the thicker side fuselage skin, plus the fiber glass, and then the thick backing plate. I had purchased some 10mm ones that have a little different head for something else and those seems to be a better length to use, but I never remember seeing 3.2mm x 10mm rivets used on the plane anywhere. I checked my pack list for the canopy kit and no mention of any longer rivets. I then looked on an excel spread sheet that I got from TAF that lists most of the kit pack lists and low and behold there they were quality 80 of HW-RIV-143 rivets (not the more common HW-RIV-142 rivets that are used on the kit) listed on the pack list for the canopy kit. The “3” is the length which is 10mm (2 is 8mm). So it looks like you are supposed to use a little longer 3.2mm rivets on the canopy. The larger 4mm rivets are OK because they are 10mm. So now I need to check with Torrance TAF to see if they have any 10mm 3.2mm rivets or if I can order some that will match better then the cherry rivets I have.
Time: 3.5 hrs
Things done today:
- Masked off canopy to protect from sika sealer
- Made reinforcing backing plates for rear rivet lines on canopy
- Cut side reinforcing plates
- Primed all reinforcing backing plates
- Dimpled and counter sunk holes in canopy and skins where parachute cover goes
More work on the canopy. There were a few holes on the top rear part of the fuselage that needed to be dimpled and countersunk so the the parachute cover can fit flat on the skins. I also made the reinforcing backing plates for the rear (rounded) part of the canopy. These were easier to make then I has expected. I just put some masking tape over the outside of the rear skin along the rivet line that I wanted to make the plate for. I divided the rivet line into two… pretty much all the 4mm rivets as one plate and then the remaining 3.2mm rivets as another plate. I did it this way because it would be more difficult to make one long piece that curved around to fit the inside of the canopy. I cut the tape to match the edge of the skin and then pealed off the tape and stuck it down on the scrap aluminum. I then used snips to cut out the part. I left the tape on the part and put it on the inside of the canopy along the rivet line. The first one I made I made the mistake of putting it on the inside of the skin rather than the canopy. This didn’t work because the canopy is a little tighter radius then the skin so once you mark and drill all the holes they won’t line up. Also a thing to note if you leave the tape on the aluminum it helps to keep the punch tool from slipping around on the metal when you punch to mark the drill hole. By preventing the punch from moving you get a more precisely place hole.
Canopy masked off to protect it from sika if it oozes out from the rivet seem.
Making the backing plate. The tape was put on the aluminum scrap and cut out with snips. The line came out pretty straight. I also marked the holes to be drilled.
All the holes drilled out. The larger part fits on the top most part of the rear of the canopy. the small piece fits behind the remaining rivets (3.2mm) in the rivet line.
A few photos of the backing plates in place. They look a bit more crooked then they are. I think its because the edge of the canopy is so uneven. All this will get covered by leather or carpeting so it doesn’t have to look super pretty.
Time: 3.5 hrs
This morning I was able to sand the spots I had filled and sprayed it with some primer. This evening I drilled out all the holes for mounting the canopy. I had thought I would need to cut back some of the material at the top rear of the canopy to get it to fit better, but after some better positioning it didn’t need to be trimmed at all. The most challenging part was trying to figure out how to know if the canopy was positioned evenly on the fuselage. I ended up going with the method of measuring from the rivet holes on the top of the fuselage side and the edge of the door frame. I made both sides the same and it seems pretty even. It’s difficult to tell because I don’t think the canopy itself is perfectly shaped and due to the curved top it’s a bit hard to use a level to check that it’s level.
All the holes in the top of the canopy are drilled. The canopy fit pretty tight against the skin so I didn’t have to pull it too much while drilling. There are a few holes that are a bit close to the edge of the inside tab, maybe 1/8″. I’m going to see about making a backer strip out of aluminum for this row of rivets like what is provided for the side holes. I don’t like pulling the rivets with only the fiber glass in the back.
Side holes drilled as well. This went pretty quick once I worked out the measuring bit (explained above).
Next step is to make the backer strip for the rear top rivets. After that I need to dimple a few of the holes in the top where the parachute cover attaches and counter sink the fiberglass a bit. Also I need to remember to put Sika seal in between the canopy and skins before riveting the canopy in place.