Author Archives: Michael

Time: 6 Hours

Today my goal was to finish up both the left and right rear wing spars so that I could prime them tomorrow. This would allow me to prime them this weekend and have them ready to rivet next weekend. I have to be out of town to Wichita for a Bombardier safety conference. First up was to layout the all the parts for each side.

The plans have you match drill the two doubler plates to the spar.

The outboard doubler is supposed to have a row of flush rivets that tie the doubler, spar and end rib together, the plans call for countersinking here. I have read several builders sites that have dimpled instead of CS’ing. I decided to follow suite as I’m not sure about the thin material. I will just have to remember to dimple the flange if the rib.

Next up was to match drill the inboard doublers.

The center doubler also needed to have the aileron push tube hole cut in it. Once I had the holes all matched and drilled I used a sharpie to mark the area that I would need to remove.

I used my unibit to drill a couple of holes and then cleaned it up with my dremal’s small sanding drums. I then attached it back to the spar and fine tuned it with a Scotch-Brite wheel.

Once I had both the left and right sides done I cleaned up the shop a little to prep for priming. I debured all the drilled holes then hit everything with a Scotch-Brite pad. I bought a mini orbital sander from Harbor Freight and tried it here. The small pad has Velcro on it and holds a small square of Scotch-Brite pad really nice.

After the prep I cleaned everything real well with MEK and let them dry. While drying I cleaned all my tools and returned everything where they belonged. Then I hit the parts with primer. I will flip them over tomorrow and hit the other sides then.

Another great day in the Hangar!!

Time: 1 Hour

When I got home last night I was able to clean and prime the tie-down blocks. After letting them dry overnight I was able to get to riveting tonight. First up was to rivet the spacers and nut plates to the tie-downs. Once that was done I was able to bolt them to the spars.

After those are bolted to the spars I bolted the aileron bell crank brackets to the spars. These bolts go through the spar and into the nut plates that were riveted to the tie-downs.

I decided to go with Dynon avionics for my panel so I ordered the Dynon autopilot servo for the ailerons. I did this so that I can attach it to the right wing spar. This bracket takes the place of the bottom stock one that Van’s sent. Just a little easier now than later.

I torqued all the bolts to 25 in/lbs and applied orange torque seal. This allows you to see if the nut or bolt has moved since being torqued. Next up is the rear spars. While I work on those I needed a place to store the main spars, what better place than in my living room! 😉

Time: 1 Hour

When I got home tonight I decided to get a little time in the hangar, they say you should do at least one thing even if small everyday, and decided to work on the tie-downs. First up was to tap the bottom hole to 3/8 – 16 threads. These holes will accept any tie-down either Van’s or a different brand. So I clamped the block in the vice and got out my tap kit.

I then cleaned out all the filings from the threads. Then I hit all the surfaces with a Scotch-Brite pad and cleaned with MEK. After drying I started the priming.

I will let these dry until tomorrow night and rivet the nut plates to the block and spacers. Van’s does it this way so that you can remove the tie-down bracket with just bolts and not having to drill out rivets.

Time:7 Hours

Today I started to rivet the fuel tank attach nut plates on the main spars. Each spar has 60 nut plates for the fuel tanks, 30 on the top and 30 on the bottom. Each wing has 12 nut plates that help hold the inspection panels on the bottom flange. Before starting to rivet I spot primed all the CS’s by using my Duplicolor primer sprayed on a paper plate and using Q-Tips to dap the primer in the holes. Then I set up my 3″ yoke in the pneumatic squeezer and set the depth for the AN426AD3-4 rivets and started squeezing away.

I then set up for the inspection panel plate nuts using the same rivets.

And the right spar is finished, on to the left.

Left spar done.

Now on to the 2 center section nut plates on each spar.

Working on the aircraft tie-down block is next in the plans. These blocks, 1 in each wing, will have a threaded hole in which you install a tie-down ring. This is what you will tie the airplane down when parking outside at an airport FBO. I first trimmed down the blocks to the correct length and labeled them left and right.

I then created the spacers that required for the tie-downs.

The plans have you drill one hole in the tie-down blocks and use a bolt to hold it in place. Then you can match drill the remaining 7 holes using the spar as the guide. The spacers need 1″ lightening holes in the center to reduce their weight. I used a Irwin Unibit in my drill press for this.

I then taped those spacers to the spar and clamped the tie-down block to the spar through the one hole already drilled. I also used a block of wood and a clamp to hold it securely. I checked that it was square with the spar before tightening it down.

I used the block to match drill the remaining holes, as I went I added a couple of bolts to help hold everything together.

I then took the parts over to the vise and drilled for the 4 nut plates that get riveted to the block.

I think they turned out pretty nice! I just need to tap the bottom hole to accept the tie-down ring. Then I will clean and prime so they can be bolted to the spars. I decided to call it a day, after 7 hours I was beat!

Time: 7 Hours

Today plan was to get all the countersinking done in the left and right spars. There are 72 nut plates in each side, 142 total. Each nut plate requires 3 countersinks, 2 for the flush rivet heads and 1 to accept the dimple of the overlying skin. So doing the math that’s 432 countersinks(CS) to drill! Well I will just eat this elephant one bite at a time and enjoy some college football at the same time.

Those photos show the all of the rivet CS’s done and the #8 screw holes done. Next up is the inspection plate cover screws which are a #6. I will use my #40 CS to do these holes but I will have to reset the depth as I was using it for the flush head rivets. Before I make that change I decided to go ahead one step and CS the the center section attach plate nuts. There are 2 on each wing and since I have the proper depth set this was a easy decision to complete this step now.

Once I finished the center section CS I moved on the the inspection plates. They are #6 screws so I reset the depth on the CS cage and started the process. It took me about 30 minutes to finish the 12 on one wing.

Tomorrow I will rivet the nut plates and work on the tie down brackets.