Category Archives: Aft Fuselage

Time: 8 Hours

Today was the start of priming and painting process of the fuselage parts. I started with the bottom skin as well as the two side skins of the aft fuselage. I cleaned the skins and then massed off the areas with tape and painters paper so that I could prime. On the bottom skin I primed the area in the rear baggage compartment as well as a 3/4″ strip at the aft end where it overlaps the other skin.

In between primer coats I started working on the battery mount. As with any other fabrication I do it takes a lot of mental calculations and paperwork to get it right. The battery mount was no different. My plan is to use 3/4″ angle between the firewall lower angle in the gear tower forward angle. This will give me two good attach points besides attaching to the bottom forward skin. I made some measurements and calculations so that the two angles would not hit already installed rivets on either of the two support angles. Once I had those measurements I cut my ankles and set them in place, from there I took the base plate of the battery mount to see how the layout would work. From there I clamped some smaller pieces of angle upside down in the opposite direction of the other angles.

Once I thought I had a good layout I traced the outer edge of the base on the angles. I then removed everything to make the cuts and layout the rivets with my new layout tool.

I used the band saw to trim the ends and the 3M wheel to shape them. The drill press made pretty quick work of drilling and then match drilling the matching angle.

I placed the two brackets back in the battery compartment and laid the base on top. I took some measurements and centered the base so that it all lined up with the underlying angles. I then clamped it in place with four spring clamps. With the brackets and bass back on my workbench I center the battery on top of them and added the two sides with clamps so that I had a tight fit and it was centered. In this position I now had two holes for the base and two holes for the sides that went through the base giving me for total holes per side. I’ve been marked and you to center punch for each of the four holes on both sides and used the drillpress to drill these holes to a #19. I then used my 3/16″ reamer to final size each hole. I cleaned up each hole and put it all back together using AN3-5 bolts and nyloc nuts.

I have not drilled the 4 holes that will attach the angles to the firewall and gear tower as my friend Glenn is going to stop by tomorrow morning after breakfast to look at it for me and make sure my idea is sound. My plan is to have the 2 end bolts, AN3’s, and 2 middle bolts, AN3’s, that will go through the bottom skin giving me 8 total bolts for the battery mount. My concern was while flying inverted and any negative G’s would put a large load in this area as the battery weighs 15lbs. Hopefully he will give me a thumbs up in this setup. In between the fabrication I fished up the aft side skin priming, hitting the area that’s visible in the baggage area and the bottom 3/4″ where it overlaps the bottom skin.

I also got the 2 forward bottom longerons primed. One other item I worked on was to add a 2″ pass thru duct to the seat ribs. If you remember the wing build you install a NACA vent to the bottom of the wing. This scoops up air and delivers it to the passenger vent that sits along side the control stick so the passenger has airflow on hot days. To connect the scoop to the vent you use 2″ tubing and run it from the wing thru a hole in the side skin/seat ribs to the vent. Apparently there is a problem with air seeping around the hole which the tubing goes thru during cold flying allowing cold air to enter the cockpit when you don’t want it. So some have added this 2″ duct to so this area is all sealed up and prevents this. Unfortunately I drilled this hole per the plans which makes it too big for the new flange I bought. So I cut some sheet and drilled a new 2 1/16″ hole in it. I then match drilled the flange to the rib and then to the new sheet I cut. This covered the larger hole and gave me a more appropriate hole. I will ProSeal this fill and flange to the inside of the rib giving a tight seal.

While I was finishing up that work I started the painting of the lower longerons. I gave each of them 3 coats and will let them cure for a few days before installing them. Tomorrow I will get to priming the other 4 skins and start the painting as well. I have a lot of parts that need priming and painting and will keep me busy for some time.

Time: 8 Hours

Today’s task was to finish up the few items that still needed deburring. I then moved on to the big task of dimpling all those holes on the skins. First up I laid out the skins with the plans next to them so that I could mark out the holes that don’t need dimpling with a red marker. That took a little while as there are a bunch of different symbols that tell you what style rivet as well as the length. After I laid out all the holes and their marks I needed to do 2 tasks first. The first was to edge roll on all of the skins. The forward side skins needed the aft edge rolled. The mid side skins needed the aft edge rolled. The aft edge of the bottom skins also needed rolled. This process puts a slight bend in the skin so that when the two skins are riveted the top skin will pull tight and make a tight seal.

The second task was to scuff the insides of the skins that would be visible in the cockpit and rear baggage area. So I masked off the areas and used my small orbital sander with 3M scotch-brite pads which made quick work of it. I also scuffed up the bottom 3/4″ edge of the aft side skin where it will over lap the aft bottom skin. The forward and mid skins got the entire surface scuffed since they will be seen.

I then grabbed the pneumatic squeezer and the DRDT dimpling machine and several dies. I had #8 screw holes, #6 screw holes, 1/8″ and 3/32″ holes to dimple. There was one spot in the mid fuselage bottom skins at the aft end that needed dimpling but they overlap each other and needed to be countersunk instead.

From there I hit every hole with one of the required dies and dimpling tool. It took a while and I used the workbench for some and but the DRDT on the floor for the long aft side skins.

So that was a great 8 hours in the Hangar and got a lot of work done although you may not see it. The skins are now ready for primer and paint. I will start that this weekend and will prep all the other parts for the same. I’m getting so close to assembling the fuselage for the last and final time!

Time: 6 Hours

Now that all the substructure has been final drilled to match the skins all the hikes need to be deburred. The plans have you start with all 6 skin panels, 2 forward, 2 mid and 2 aft skins. That’s a lot of holes to debur since you have to do both the inside and the outside parts of each hole. So with a fully charged electric debur tool I went to work. Not to much to show with this process so I didn’t take any photos. I ran the battery dead before I got halfway done so I had to move on a little while it charged up. The forward skins have 2 reference tabs at the bottom for fitting and they need to be trimmed off at this point.

I also received a few goodies in the mail this week. First up is my Andair fuel valve. These are precision made valves that really make the stock valve that Van’s sends look pretty bad. A lot of builders go this route and there is a lot of documentation showing great installs of this valve.

I also got a gift certificate from the best girl friend ever to Cleveland tools which I used to but a rivet spacer that allows me to evenly space rivet holes when I freestyle build.

The other thing I got was a tail light adapter that will get riveted to the lower part of the rudder and make maintenance easier down the road.

Another item that was delivered was my battery hold down. I want to install the battery in the forward baggage lower area based in my buddy Glenn’s experience with it in the same place. I wanted a sleek yet strong mount that would allow easy battery replacement. Here is what I came up with and will make an attachment plan later this week.

I finished up the deburring of the skins and all other items called out in the plans. I then moved on to the dimpling process. There are a lot of areas that get dimples and some that don’t. I used tape to mask the holes that I don’t want to dimple, these are mainly ones that line up with the longerons as they were countersunk.

I made sure to scuff the items before dimpling them to make it easier later for priming. Not a lot of pictures today but a lot of work done. Another good day in the Hangar.

Time: 6 Hours

There are 201 holes on the upper longeron sides that need countersinking. That’s a lot of holes! Pushing down on the drill to get a countersunk on that many holes has my right shoulder on fire but it has to be done so I power thru it.

I did the right one first and when I was done I deburred all the holes on both sides. On each longeron there are two cut outs needed. One on the very end and one a little forward of that which allows the vertical horizontal stabilizer attach bars to stick up thru. I used a combo of my dremel, files and sandpaper to get the fit right in the first cut.

After cleaning up the right side I moved on to the left. It took me about three hours to finish up both sides. From there I moved on to all of the loose parts and deburring everyone of their holes. I got all except a few arm rest parts deburred and will get them tomorrow. I did 6 hours of actual work throughout the day, as I took lots of breaks to give my shoulder a rest. I’m just glad to have the countersinking done on all of those longeron holes!