Month: January 2021

Tonight I finished a little backing plate for the rib repair I made a couple of days ago, and I dimpled the right wing bottom long j-channel stiffener.

Tonight the dryer stopped working, so instead of working on the left wing j-channel, I spent time troubleshooting the dryer. Turned out to be a blown thermo fuse, so I ordered a new one and spent an hour cleaning lint out of the dryer and the vents.

I spent 30 minutes or so on the airplane; I drilled out a rivet that was causing an alignment issue, and pop riveted the last two holes on the gap seals.

The rivet was one of the Quick Build rivets, in the second to last rib from the outboard end of the right wing, where it joins the rib and the wing spar flange. It appears that when setting the rivet, the rib moved out of position slightly, and it was never corrected. The vacant hole above the set rivet was not aligned, and not fixed. The spar flange hole appears to have been countersunk sometime afterwards, and due to the alignment problem, the countersink is elongated slightly. I emailed Vans some pictures and concurred with my plan to drill out the rivet, reset it, and use a doubler as an extra precaution.

I will make up a doubler plate for the inside as my next step, then rivet this when I put the bottom skin on.

Then I set the two cherrymax rivets. I used 4-02 rivets, per the specification. This came out looking nice.

Tonight I finished match drilling the right wing bottom long j-channel stiffener. I used my electric drill, but in hindsight my air drill would have been faster. Will do that on the left wing.

The bottom skins have a length of j-channel running down the middle to stiffen the skins. in a slow build, the plans call for these to be match drilled against the spar early in the build. With quick build, there isn’t a great way to do that, so I have to carefully install the channel, then the skin, and then match drill from the skin. I didn’t realize the j-channel wasn’t match drilled, or I would have done this much earlier before I had dimples the skin. Anyway, I installed the channel and spent time carefully aligning everything and then match drilling the right wing outer bottom skin to the j-channel. I didn’t finish the whole thing, but should get it done tomorrow.

Because I have dimpled already, I had to go much slower. The problem is that dimpling stretches the hole diameter, about two drill sizes larger. So match drilling with a #40 drill bit is too sloppy and inaccurate. To account for this, I used a #38 drill bit to start the hole, really just to put a center point on the channel. Then I switched to a #60 drill bit, and made a tiny pilot hole in the center. Then I stepped up the hole to #40. For each hole, I’m drilling 4 different holes, so it’s slow but the results are good.

Tonight I finished riveting the left wing gap seals. I just have one rivet left (same as right side), where clearance is such that I need a pop rivet. After checking with Vans, I ordered some shorter Cherrymax rivets to get these two rivets done.

I could try bucking these rivets, but the rivet is so close to the angle on the bottom, I’m afraid I’ll end up bending the rivet and making a mess.

Tonight I started riveting the gap seals on the left wing. I was about to get all the rivets between the skin and the gap seals done tonight.

Today I riveted the right wing gap seals. This went quite well.

After clarifying with Vans their recommendation to use pop rivets for the flap gap seal, I started by cleaning the rear spar area, which is the “top” of the wing when sitting in the stand. A lot of dust, pollen, and shavings had gathered, so I took the time to blow it off with air then wipe it down with a damp cloth.

The I clecoed up the gap seals and started riveting. I squeezed all the rivets except those behind the already-installed bottom skin. For those I followed Van’s guidance and used Cherrymax and MSP-42 rivets. This was my first experience with Cherrymax, and I was surprised at how nicely they set. The countersunk rivet heads came. Out looking nice, and the squeezed manufactured heads looked good too. The only annoying thing was having the stems not breaking cleanly on a couple of the 42’s. I ended up filing them down which was time consuming.

I took another pass through the plans looking for any jobs I missed on the wings, before I start closing them up. I came across the access panel in the forward skin of the left wing. This is to allow access to the stall warning system, (which I’m not planning to install). I have been thinking that this would be a great location for a camera. I’d like to have a camera that can see in front of the airplane, as there are some blind spots when taxing, and during takeoff and landing. Anyway, that can wait, for now I just need to install the access panel itself.

I deburred and dimpled the doubler plate and the access panel, then primed the doubler plate. Then I deburred and dimpled the rivet holes in the bottom skin. Once the primer is dry I can finish the job by attaching nutplates to the doubler, and then riveting the doubler to the wing.

Tonight I countersunk a fee holes on the rear wing spars, where the gap seals will flush rivet to the rear spar. it’s about 16 holes in total I think, so not a big job. What took more time was sorting through my countersink cages, swapping out the #30 countersink for a single-fluted bit, and then getting it configured to countersink to the correct depth on some scrap. The single flute is so much nicer than the more common three-fluted bits. It makes a very nice cut and just polishes the hole. It seems to be much easier to avoid chatter or deformation that can sometimes occur with the three-fluted bits.

After countersinking, I primed the holes and touched up the primer on a few other spots on the spar.