- Finshed installing front seatbelt shoulder straps and cams
- Prepped new bracket for main wheel spats
- Worked on fitting nose wheel spat parts together
Today I finished up installing the front seatbelt cams and shoulder straps. The manual only mentions the cam installation so I had to double check the shoulder strap install from some factory photos on Graig’s site. I think it’s correct, if not it can easily be unbolted and changed. The AN7 nuts I purchased works fine on the supplied bolts. The supplied bolts are actually metric, but the threads match the AN7-20 nuts exactly. I suppose you could just replace the supplied bolts with AN7 bolts and make things easier. I also had to use the step reamer on the shoulder strap mount since it was slightly too small. I reamed it to 7/16 and the bolt fit perfectly.
Shot of the bolt holding in the cam. Torqued to 40ft pounds.
Underside of the shoulder strap mount. Torqued to 40 ft pounds.
Top side of the shoulder strap mount.
Yesterday I had gone down to Torrance TAF to get a few more 3.2mm countersunk rivets and had also mentioned to Jean that I didn’t receive the wheel spats in the finishing kit thinking he would have to order them. Well to my surprise he was able to find a complete set of wheel spats. So today I starts to work on fitting the nose wheel halfs together. It came out pretty good and wasn’t too difficult to do just a bit time consuming, but then again what isn’t on this airplane?
Before drilling I fit the halves together and held them with tape and some clamps. There are small dimples where the 4mm pilot holes get drilled so once you have things lined up it’s just a matter of drilling and clecoing.
I noticed that one side wasn’t fitting so well. It turns out there was a bit of a bump on the edge. Using some 220 grit paper and a sanding block it was easily leveled out.
A tip from Jeano at Torrance TAF was to use a hand reamer to ream the holes in the under piece for the M4 rivnuts. He said it stays centered much better then a drill. Seemed to works pretty well. After holes were reamed I installed the M4 rivnuts with a little high strength loctite.
And it’s done. The top gets cut after I fit it to the gear. I may do a little more fine tuning, but it didn’t come out as bad as I thought it would. Also I need to make the hole to access the valve stem on the right side.
There was also a bit of damage to the front half that I needed to fill and sand.
I heard back from Jean on the valve stem issue for the nose wheel. I had noticed a U shaped cut out in the hub before and wondered what that was for. It turns out if you use the longer 90 deg. valve stem then you pass it through the hub, so apart comes the tire.
Stem through the U shaped cut out of the hub.
After getting the first half of the hub on the tire now the valve passes through a hole on the second half of the hub. Also don’t forget the O ring between the two halves. Then torque up the bolts. I torqued them to around 11ft pounds, but I need to see if there are exact torquing values on the Matco site for these hubs. Also the red dot on the tire lines up with either the valve stem or a white or yellow mark on the tube. I don’t have a mark on the tube so I lined it up with the stem. You then inflate to 80% pressure, reduce to 50%, then back up to 100%, which is 2.5bar or around 36psi.
I’m not sure what the pink dot is. I couldn’t find any mention of it on the Desser site.
Things done today:
- Assembled nose gear
- Attached nose gear assembly to engine mount
Assembled the nose gear and attached it to the engine mount. I’m thinking it’s OK to attach it to the engine mount now, it was certainly easier to get all the washers in with the gear upside down. I’m hoping that I won’t need a new spring for the 915 because it’s a little heavier then the 914… I might still use the 914 anyways though.
The Nose Gear all assembled. I probably shouldn’t have torqued the bolts on the top plate yet since almost everything above the spring has to come off to mount it on the engine mount.
Fork assembly with the brackets for the wheel spats. The short brackets on the main gear are the front of the gear. Also installed the M5 rivnuts in the spat brackets. The hole in the very front is for a tow bar.
Well went to put the wheel on and saw that the long valve stem hits the spat brackets. Either I have the incorrect tube or there’s another way to install this. I’ll check with Jean from TAF.
There brackets are used to attach the gear to the engine mount. The bottom two fit a bit tight so I had to remove about 1/16 off the inside of them. The gear seems to turn OK now…maybe a slight bit tight.
Close up of the top of the gear.
I found it easier to flip the gear upside down and then stack the washers in and push the bolt up. There are 5 thick and 1 thin AN3 washer used here in between the plates.
Time: 4.5 hrs
Things done today:
- Finished the soundproofing on the center fuselage… Yay!
- Loosely put together the nose gear
Finally finished all the soundproofing on the center fuselage. I’m so glad that’s done. It’s not particularly hard to do, just time consuming. Plus it’s been about 100 degrees here and the garage gets hot so that doesn’t help. It came out pretty good, not as good as Peter’s but I’m happy with it. There were a few tricky places like around the front NACA ducts.
Nose gear loosely assembled. I had a hard time getting the AN4 bolts in on the top plate. I slowly worked them in and back out over and over and that seemed to do the trick. I also used the grease that came with the undercarriage kit on the bearings. It didn’t say to do this in the manual, but it seems like there should be grease there. I’ll double check with TAF to make sure.
Time: 2.5 hrs
Things done today:
- Finished re plumbing the right static port
- Tested static lines to 20inHg
- Wrapped left front NACA duct in aluminum tape
- Installed NACA ducts
- Painted nose wheel gear grey
The rear NACA ducts were by far the most time consuming to install. Besides having to remove quite a bit of material from the top edge to get it to fit under the metal channel, they also needed some material removed around the rivet holes so the aluminum rivet backers would fit nice. I was also missing two holes that I needed to drill through the side skins and into the duct. The good news is that these rear NACA ducts don’t exist on the newer kits so if you get a kit now you won’t have to worry about them.
I was originally going to use countersunk rivets for the NACA ducts, but there are too many issues with doing this on the rear NACA ducts. Probably if I though about before putting on the side skin then it may have been doable. The fronts work be fairly easy to countersink, but I didn’t want to counter sink those and then use dome rivets on the rear. Oh well.
OK a note about the sikaseal. I bought some Sikaflex 295 UV Black sealant from Amazon. This is specified in the build manual for the canopy and other areas that need to be sealed. You use a caulking gun and it pretty much installs just like caulking. The main difference is that is makes a huge mess. Also if you don’t want your fingers to be black for days then wear gloves, though gloves make it difficult to smooth it out so maybe you just have to deal with black fingers 🙂
Used the dremel with a 200 grit drum sander bit and carefully sanded the areas around the rivet holes. The dremel takes off a lot of material quickly so you have to take it easy or you’ll sand right through the duct.
The rear NACA duct is fairly long and extends well passed the end of the opening in the skin. I decided that there should probably be a few rivets holding that end in, though probably not completely necessary. The two flecks on the fair left are the new rivet holes added.
Rear ducts installed with Sikaseal and rivets
Inside of the rear duct
Outside of one of the front ducts.
This is the inside of the left front NACA duct. I wrapped the top with some aluminum tape so that it contact through to the frame. This is because I will most likely install the GTP-59 Garmin temperature sensor here and the body of the sensor needs to go to frame ground. I tested with a meter and it seems to work fine. I don’t have the probe so I’m not sure what size hole or where it should go in the duct yet.
Things done today:
- More soundproofing in Center Fuselage
- Worked on re plumbing the right static port
- Worked on installing front seat belt cams
I saw in Craig’s build log that he had all the static port lines run up after leaving the port to avoid water getting into the lines. This seemed like a good idea the problem is I already closed up the rear fuselage section. I knew the left side was fine because that route out of the port and up the rib, but the right side routed down and into the split. So it was time to see if I could get to the static lines and fittings from the access holes on the bottom of the fuselage. It was a bit tough, but fortunately I had put things were I could still reach them and rerunning the one line from the static port wasn’t too difficult. Putting the tie wraps back was a bit of a challenge and making any new holes would be difficult.
New line runs up from the static port then down into the splitter. I’ll finish it up tomorrow.
I also did some work on installing the front seatbelt cams. This install in a small area under the rear seat. I can see that it’s going to be fun getting a wrench in there to tighten it down. Some photos of the process of far.
First thing that needs to be done is to un roll the belt and remove it from the cam. I used the rubber end of a punch to keep the tension on the cam. The cam is under a spring tension so if you let it go then you have to turn it a bunch of times to get the tension back. The punch seems to hold nicely. You then remove the black plastic pin from the belt and the end of the belt pulls back through the cam and a small plastic guide. It take a little work getting it pulled back through.
Needed to cut away some of the soundproofing so the cam sits on the metal and not foam. The space is very tight and its difficult to get a razor in there.
No nuts came with the seat belt assembly so I took the bolt down to the hardware store to see if I could figure out what size it is. From the marking it shows it’s a Class 8.8 bolt which would suggest that it’s metric. Well 10mm is too small and 12mm fits but it was loose. I tried various thread pitches as well 1.0, 1.25, 1.5, and 1.75mm. I also thought it could be around a 7/16 bolt so I tried 7/16 nuts and found one that fit great… a 7/16-20. Well that’s the same as an AN7 nut. I ordered a few of them plus washers from Aircraft Spruce so we’ll see if they fit when they get here.