Priming & Fabricating

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.

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IMG_5081.JPGIn 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.

IMG_5082.JPGOnce 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.

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IMG_5084.JPGI 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.

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IMG_5086.JPGI 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.

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IMG_5088.JPGI 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.

IMG_5091.JPGI 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.

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IMG_5090.JPGWhile 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.

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