Category Archives: Wings

Time: 5 Hours

Today I finished up the countersinking of the skin to baffle attach points on the left fuel tank. I also finished up enlarging all the holes for the perimeter screws to the required #19 size. I didn’t take any photos of that stuff since I did a bunch for the right tank and they looked exactly the same. There are two brackets that are attach points for the inboard forward portion of the fuel tanks. These have to me fabricated from 2″x2.5″ aluminum angle. The plans give you dimensions and you have to do the designing.

Once I got the shape pretty close I test fit it to the rib.

After I was satisfied with the fit I transferred the shape to the other blank angle.

I will get that cut and shaped tomorrow as it is getting late and my back was getting a little sore.

Time: 1 Hour

I got home tonight and decided that I need to make some daily progress, even if it’s only 1 hour. So I fired up the heater in the Hangar and went out to do some work. I finished up the right tank countersinks, I just had the top of the skin to do. This is a slow process even though the cage was already setup for the proper depth since I really take my time with them to ensure they come out just right. Once that was done I hit all the spar attachment holes with a #19 drill bit to get them ready for the #8 dimple die. This will make the dimple for the AN509-8R8 screws that will help hold the tank on the spar/wing. I will eventually use stainless steal screws here and not paint them. Once those screws get painted and you have to remove the tank for whatever reason they never look the same so I’m going unpainted with mine. That was enough work for tonight and should get some good time in the Hangar this week as I have a light flight schedule.

Time: 6 Hours

Today started with riveting the K1000-3 nutplates on the z brackets. There are three per bracket and 12 brackets that need them. I set up the squeezer and went at it. It didn’t take too long once I had the setup all done.

You can see one bracket is missing a nutplate! I ran short since I used 4 of them when I was drilling the brackets and used the nutplate as a jig. The drilling process started enlarging the holes of the nutplate after a a couple of brackets so I had to use several. I also used 2 extra when riveting them to the main spars and had to drill out a rivet causing damage to those nutplates. I placed an order with Aircraft Spruce for some more and will finish when they arrive. Next up was to match drill the tank skins to the ribs and baffle. I set up the drill with my #40 reamer and hit every hole, and there are a bunch! On each of the ribs there is on hole that needs to be drilled using the skin as a guide so I did that as well.

After those holes are drilled I opened up the lower half of the tank to get access to where the stiffeners go. I clecko’d those and reamed them as well.

I then removed the stiffeners and closed up the skin and repeated everything on the other tank. The plans call for countersinking all the holes that run spanwise and connect the tank skin to the baffle. This is done rather than dimple so that the installation of the baffle, durning tank sealing, is easier as it would just slide in and not fight with the dimples. The skin is only .032″ thick and the thinnest that you can do countersinking on. You do the countersinking with the skin clecko’d to the baffle so that the holes in the baffle will act as a guide for the pilot on the countersink bit. After removing a strip of the blue film, I set up the bit/cage for the right depth and started on the lower side of the right tank skin.

I was a little nervous about countersinking the skin but it went well and I had no problems on the lower skin. My shoulder was a little tired from all the drilling and decided that this was a good time to call it a day and watch some football. So next time in the Hangar I will finishing the countersinking on the right tank and both sides of the left tank.

Time: 7 Hours

Today started with a couple of hours of deburring and edge finishing on all the fuel tank z brackets. I then hit them all with a scotch-brite pad and cleaned them with some denatured alcohol. I relabeled them with a sharpie and covered the flange that will go up against the fuel tank baffle with blue tape. This is the only surface that I don’t want to prime so that it can be ProSealed. Then they went to the paint table to get primed.

As the brackets were drying I started work on the 3 nutplates that get riveted to the main spar for the inboard most z bracket. The nutplates go on the aft side of the spar and need countersinks on the forward side of the spar so the rivets sit flush. I set up the countersink cage with my #40 bit and drilled them after I reamed the holes.

The only way I could rivet the nutplates was with my gun and bucking bar, and it was tight with the spar doubler plate.

Next up was to fabricate the fuel tank stiffeners that go on the bottom of the inside of the tanks. Van’s sends them in a long piece with notches in them to guide you on their shape.

I rough cut them with the snips and bandsaw.

I then shaped all the corners and debured all the edges and organized them. The brackets were also dry and so I organized them as well.

A pretty good day in the Hangar! Tomorrow I will get to match drilling the stiffeners and skins.

Time: 3 Hours

I had a long day trip to our home base in Omaha, NE today. That meant I would have access to our mechanics great workshop. So I loaded up some tools and all my z brackets for the tanks before I left this morning. First up was to drill each bracket for the 3 nutplates that they needed. I used a K1000-3 nutplate as a templet for drilling by threading an AN3-4 bolt with 5 washers on it so it just grabbed the threads. That centered the nutplate over the bolt hole and allowed me to fine tune the wings of the nutplate so that they were parallel with bracket web. To help hold it while drilling I used a wide mouth vise grip pliers.

I just worked one nutplate at a time and then moved to the next two. Once that was done I loaded up my #40 countersink in the drill and took the brackets over to the bench vise and countersunk the bottoms of the brackets for the AD426 rivets.

Not a bad day of work especially since I was out of town and was at work! Next up will be to treat all the edges if the brackets and clean them up for priming minus the edge that gets riveted to the baffle as that will have ProSeal on then I will rivet the nut plates to them.