More Filling and Sanding Rivets

Time 1.25 hrs

Just filled and sanded some rivets on the top of the rear fuselage. Not too many rivets so it didn’t take too long. Next I need to roll the fuselage over to the left so I can fill the right side. After that is the hard part of rolling the fuselage over so I can fill the bottom rivets. I’m not exactly sure how I’m going to do that yet. I’m thinking of maybe hanging it from the garage rafters with some straps with Come-Alongs.

IMG_4658.JPG

Here’s what I’ve been using to sand the rivets. I’m also using the tool I made (posted in a previous post) that protects the skin when you are sanding the rivet. It’s very quick to sand off the resin. I just sand until I see the rivet get a little brighter which means I’ve sanded all the resin off that doesn’t need to be there. Don’t sand too much because you can sand down the actual rivet. The only issue I have with this is my drill weighs a ton so ideally it would be better to use a lighter drill. I originally was thinking that you want a high RPM drill, but I end up running my drill at around half speed anyways so probably around 800-1000 RPM. It makes the process a bit more controllable with slower RPM.

Main Gear

Time: 1.75 hrs

Wow I figured I’d quickly put the axels on the main gear… well it took a bit longer then anticipated. There was one bolt on each side that seemed to have been drilled out a little off in the main gear (at the factory) so that made putting the wheel spat bracket on very difficult. I did manage to get everything together after some gentle hammering. It should be fun taking it apart again. Also it seems that the factory didn’t prime the whole gear so I’m thinking I should prime everything.

Note: I assembled this with the main gear upside down… which makes it even more fun   :-). I flipped the photos over so that it’s a little easier to get the orientation. If you notice things hanging from the ceiling that shouldn’t it’s because of that.

Everything assembled looking from the axel side.

Assembled looking from the wheel spat bracket side (inside). finally got that sucker on. Also you can see the M5 rivnuts installed in the wheel spat bracket. This is the newer bracket which gives you access to remove the brake pads without having to pull the whole wheel apart. The old bracket is wider in the back and covers part of the caliper.

You need to align the axel and brake caliper bracket so that one of the holes for the brake caliper bracket lines up with the cut out in the gear (top right of photo) otherwise the brakes won’t fit back on.

Sanding Rivets

Time: 2.75 hrs

Today I sanded the left side fuselage rivets that I filled yesterday. The process is a bit slower then filling them, but still moves along pretty quick. No real tips here, just don’t sand too much. I made a tool to protect the skins when you sand the rivet. I made the tool with two different size holes (one of 4mm and the other for 3.2mm) but you really only need the larger one since the sanding disc won’t get in between that small gap. The width of the tool (about 1-1.5″) was pretty good. I was able to get in between most rivets and have the tool sit flush on the skin. A few places I just had to be careful with the sander and not use the tool. And the few countersunk rivets needed to be done with care as well… just a few light scratches on the skins.

This is what I’ve been using to fill the rivets and the tool I made to protect the skin when sanding. I’m using a small 3″ sanding disc on my electric drill with 240 grit paper (will need to get a photo of that).

 

Filling Rivets

Time: 1.5hrs

Started to fill the fuselage rivets. Yesterday we had a party at the house so what better way to get some help to move the plane. I rounded up a few friends (before we starting drinking) and we managed to lift it and gently place it on its side on the ground. I bought some flotation noodles which work really well to keep anything from getting dented or scratched. I was able to fill the whole left side today so I don’t think it’s going to take as long as I was expecting. 

The process goes pretty quick. Most of the time is spent mixing small quantities of resin, hardener, and talc. I’m mixing very small quantities because you can’t use that much by the time it starts to dry. I use about a teaspoon or resin, 4 drops of hardener and about a teaspoon of talc. The talc is just to make it a little more pasty. You don’t want it too pasty because you want the resin to flow and fill down into the rivet. I use a plastic (Chinese style) chop stick to dab the mix onto each rivet. Just a few notes that I should mention about the process:

The process requires gravity to be on your side so whatever you want to fill needs to be somewhat flat and horizontal. 

Make sure to put plenty of resin mix onto the rivet head. When I started I was being stingy and not using much. However the resin does seep into the rivet so if you don’t fill enough then it may dimple in the middle and you’ll have to add more. This is mostly on the larger 4mm rivets and for some reason the countersunk rivets. 

Don’t fill your static port 🙂 

The mix. This was the first one I made so I made way too much. Also in the photo is the chopstick for dabbing the mix into the rivets which also doubles as the mixer. 

The plane on its side. One noodle cut in half was used. I just put them under the front fuselage at about 3 and 6 feet from the front. 

Filled rivets. Will try out sanding tomorrow. 

Main Wheel Spats

Time: 2.25hrs

Worked on fitting together the spats for the mains. I followed the same procedure as was done on the nose wheel… clamp and tape into place, drill pilot hole, drill 4mm hole then use the hand reamer to ream the inside hole to fit an M4 rivnut. These didn’t seem to come out as well as the nose wheel spat. I couldn’t get the join to sit flush and having to put in the rivnuts made the seam even more pronounced. I’ll have to look at the ones at TAF to see if the job I did is acceptable. I think they came out pretty good so I’m probably just being a bit too picky. 

Finished. The tops will need to be cut down, but I’ll need to fit them into the main gear to see how much to cut. 


A little closer photo. 

Nose Wheel Spat and Seatbelt Cam

Time: 3.75hrs

  • 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. 

Nose Wheel Redux

Time: 1hr

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.