Wing Bottom Skins

Time: 7 Hours

I decided today I was going to work on the inboard bottom wing skins as I will hopefully get those riveted in this weekend with the help of my friend. I grabbed the soldering iron and removed the strips over all the rivet holes so I could debur them later. After that I got out all my different grades if sandpaper to finish off the edges. Did I mention before how much I dislike finishing edges? It takes a long time for me to get them to the quality I want, maybe my OCD is a problem here but it’s my airplane! 🙂 It took me 2.5 hours just to finish the edges.

After spending around an hour deburring every hole top and bottom I grabbed the DRDT dimpling tool to dimple the holes. I started with the #8 dimple dies for the center nutplate holes. These holes/nutplates hold the inspection panels in place. There is a slight recess in the skin to allow for these panels to sit flush with the skin. It looked like the edge of my dimple dies would clip the edge of the recess and deform it. So it took dies over to the bench sander and took down a corner of the die to allow for that recess.

I then switched over to the #40 dies and hit all the rest of the holes fairly quick. When I finished those I got out the pneumatic squeezer and attached the nutplates for the inspection panels after I shot some primer on the area where the nutplates attach in the bottom side.

With both sides done I’m now ready to rivet those in this weekend so I just but them on the wings to give them a place to hide until then.

The next task that I wanted to get done today was to bend the aileron skins so I could start the assembly of them. When I got my wood brake that is used for the rudder/elevators I found that I made it around 1.5″ shorter than the aileron skins. I was worried that this might cause a problem when squeezing them and decided to run to Home Depot to grab a longer 2×6″ board. So that took me around an hour to get and replace it in the brake. I then screwed it down to my workbench and added the the left over 2×6″ to the center as 2′ lever/handle. This have me some great leverage to bend the skins and I wish I had done this earlier (sorry I forgot to take a pic of this). I was able to bend the skins really easy and just had to do a little tweaking on both of them.

I had a little bit of energy left so I took the right aileron spar out and matched drilled the reinforcement plates to it, these are made from blank sheet. I also drilled the aileron brackets and opened the holes with my new 3/16″ reamer for the AN3 bolts that will holed them on. I will finish the left side up later this week.

Aileron Skins

Time: 3 Hours

I started today by visiting McMaster-Carr which is local here in Chicago for a couple of new reamers, a .25″ and a .1875″ one.

I got to work on all the prep on the aileron skins. This included deburring all the edges, deburring all the holes and dimpling the holes the attach the stiffeners.

The stiffeners get back riveted so I set all the rivets in their holes and taped them in place.

Once they were all taped in the riveting process is fairly easy and I made quick time of getting both the left and right done.

I decided to call it a night as I was up early this morning for a flight and I’m getting tired. I know that my workmanship decreases as I get tired.

Aileron Work

Time: 5 Hours

Had a fun breakfast with the guys and got several questions answered for upcoming tasks. When I got home I had to take care of some errands, mainly unloading the storage unit of the remaining items that I had stored while the wings were in their stand. When I got back to the Hangar I needed to finish up the aileron stiffeners. I hit them first with the bench disk sander up to the lines I created in them, then to the scotch-brite wheel. I was able to complete a stiffener in 4 minutes, that’s 4 min x 32 stiffeners = 2hr 8min just for these little parts.

I then clecko’d all the stiffeners to the right aileron and matched drilled them.

I deburred all the holes and then grabbed the pneumatic squeezer and dimpled them. I then hit them with primer.

I repeated the ckecko, drill, debur and dimple on left aileron. I will work on the skins next so that these can be back riveted in prep to squeeze the skins shut. The goal this week is to get the bottom wing skins prepped so that I can be ready to rivet those on next weekend as I have the offer of help, thanks Glen! For now I’m gonna call this weekend done and a great time in the Hangar.

Aileron & Flap Gap Fairings/Braces

Time: 9 Hours

Today I needed to complete the prepping of the aileron gap fairings and the flap braces. I started with the left flap brace and hit all the edges on the scotch-brite wheel. These have 17 holes in them that need deburred which took a while.

One corner of the flap brace, the inboard spar side, needed to have the corner trimmed so that it fits around the spar doubler.

I then grabbed the bottom skins so that I could match drill all the holes.

I then removed the bottom skins as well as the fairings and braces. All the holes were deburred on the inside and out. For the aileron gap fairings the flange that rivets to the skin needs to be dimpled so I grabbed the pneumatic squeezer and hit those. Those flanges also needed a coat of primer as they will be riveted to unprimed skin. I could also dimple the corresponding holes on the top skins. I had to wait to do those as I needed to match drill these parts.

While the primer was drying on the aileron fairings I setup the flap braces for countersinking the skin side flange. Normally you could just dimple these however along with the brace and skin I will eventually be riveting the hinge to this spot on top brace flange sandwiching the brace between the skin and hinge. You don’t want to dimple the hinge flange so you need to countersink the brace to accept the skins dimples. I just rolled up the carpet on the workbench and drilled matching holes and clecko’d it in place. These holes will give the countersink bit a guide so it doesn’t wander as the hole in the metal get larger.

I taped off the flange with the countersinks and primed them so I won’t have to prime that area of the bottom skins later. While that primer was drying I got to riveting the aileron gap fairings. I was able to get to all these rivets with my pneumatic squeezer. The spar side flange used AN470’s and the skin side used AN426. All turned out very nice however I had a little pillowing on the spar side flange in just a couple of spots. You won’t ever see it so it’s not a big deal.

The flap brace was then clecko’d on for riveting, I will have to use the gun and bucking bar for these as it is reversed compared to the aileron fairing.

Riveting by myself is a challenge but I’m getting better and better at it. I was able to get bit flap braces done fairly quickly without any problems and they all turned out pretty nice.

I ran the SafeAir pitot and AOA lines in the left wing, just one of many items that I need to accomplish in prep for closing up the bottom of the wings.

To start on the ailerons is the next big task. The ailerons are like the elevators in that they only have end ribs and use small stiffeners in the top and bottom of the skins. They come in a long piece that you have to cut the individual stiffeners out of. Once they are all free you have to cut the angles out so that they fit in the skin as it tapers.

After marking all the angle cuts I fired up the bandsaw and made pretty quick work of them.

I think that will be a good place to call it a day, 9 hours of good Hangar time! Breakfast with the builders and then another good day tomorrow.

Riveted Aileron Brackets

Time: 2 Hours

I had let the primer dry overnight on the mating surfaces of the aileron brackets. I spent some extra time today studying the plans for the rivet call outs for these brackets. There are several places where you need to use AN426-4 flush rivets so that there is clearance for the aileron to move. Once I was sure of all the rivets I grabbed the countersink tool and got to work. I then match drilled all the holes to the spar and cleaned everything up. I was able to squeeze all the rivets holding the different pieces of the brackets together. To rivet the brackets on the rear spar I was only able to squeeze a couple and had to get out the rivet gun and bucking bar. They all turned out real nice, I did make 2 smileys on the brackets but not bad.

I got out the aileron & flap braces which is the next task to debur, dimple and rivet. I will need to put the bottom skins on so the I can match drill them before riveting. I will get started on these tomorrow as it’s hockey time, let’s go Blackhawks!