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Archive for March, 2014

Installed Purge Line Fitting on Right Tank – 8 hrs

March 30, 2014 Leave a comment

Sunday Mar 30, 2013

Staying with my strategy to get as much done in the garage before moving to the airport as possible I remated the right wing to the fuselage this weekend in order to install fittings for the fuel injection purge line to the right tank. This was necessary because I needed to determine the precise location to install an AN832 fitting on the tank access cover so it will line up with the existing purge line exiting a hole in the fuselage and the tubing had to be cut to the precise length to install a AN818 nut. Moving the wing around is a big deal so I asked my friend Scott to come help me. Here you can see the fuselage and wing set up to mate together.

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After bringing the two together I marked the location for the An832 on the access cover. When I did I realized that the fitting was going to interfere with the anti-hangup bracket on the inside of the cover so I concluded I would have to replace the cover with a new one that has the anti-hangup bracket shifted slightly to make clearance. Taking off the access cover was no easy feat since the ProSeal was doing a good job of bonding it on place. We used a putty knife sharpened on the end to cut through the ProSeal by holding the blade as parallel to the wing rib as possible. After getting it off I installed the fitting at the marked location and put it back in temporarily for a fit check.

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We remated the wing again and I marked the tubing for the proper length then cut it and installed a flared AN818 fitting. Here is the tubing exiting the fuselage.

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While the wings were off the rack we also installed the non-skid wing walk material I bought from FlyboyAccessories.com. We had to trim the corner to clear the wing gap fairing and the aft end to keep if from hanging over the weak section of the skin.

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Categories: Fuel Tanks, Wings

Made Access Panel for Fwd Upper Skin – 12 hrs

March 23, 2014 Leave a comment

Sunday Mar 23, 2014

I find my list of things to do before I move the airplane to the airport is getting shorter although I occasionally find things I overlooked to add to the list. This weekend I took on the mini-project to add an access panel to the upper forward skin of the fuselage. I mean the skin immediately in front of the tip-up canopy. There are quite a few components under this skin, like the VP-X Pro unit, EMS module and the entire array of ground terminals. I have been concerned about access to this area after the skin is riveted on, which will be soon, and I have seen other builders install an access panel or two here so the idea got under my skin (pun intended).

I started by laying out the location for the panel on the skin itself with a sharpie. I also made a scale layout in AutoCad to lock down the dimensions. I cut the new access panel and the doubler I needed from .032 stock sheet. Then I cut the opening in the top skin with the thought that if this does not work out well I can always order a new skin from Vans.

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To ensure a good fit I put the skin on the fuselage to match drill for the rivets that will attach the doubler to the skin since the skin is curved when installed. I started in the middle of the opening and worked my way out to the edges.

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This is how it looked with all the rivet holes drilled and clecoed. There are lots of rivets to help reinforce the skin around the perimeter.

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After deburring and dimpling the skin and doubler and spraying on a coat of primer I put the skin back on the fuselage and riveted the two parts together.

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Then I laid out the hole pattern on the cover plate for the mounting screws, match drilled it, and installed countersunk nutplates for #8 screws.

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This is how it turned out, with only four screws installed for now because it will come off again for a while before the skin is riveted to the fuselage. The access hole is not huge but it provides good access to the VP-X, the ground block and several connectors that would be really tough to get to without the access panel.

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I also finished wiring up the Nav/position lights and landing light on the left wing tip.

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Sanded and Applied Primer to Gear Fairings – 8 hrs

March 16, 2014 Leave a comment

Sunday Mar 16, 2014

Continuing to work on my gear leg fairings, I applied a layer of epoxy/micro to the nose gear upper intersection fairing to smooth out some of the waves and irregularity that came with the layup over the modeling dough. That, of course, was followed by lots of sanding. One coat got me 90% of the way there, so I applied more micro in a few spots to finish it off. Here is the end result, ready for a coat of primer.

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Next I installed the right brake hose and taped it to the gear leg with split tygon tubing spacers at each end and the middle.

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One more check of the fit of the right leg and wheel fairings to confirm that this set is ready for primer.

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An optional step was to mold a little aerodynamic lip onto the front shell of the nose gear fairing where the cutout is for the strut. This directs the airflow up around the strut instead of directly into the slot. I applied a layer of packing tape to the cutout to form a ramp and then two layers of bidirectional cloth to start and let that cure in the basic shape. Then I applied a fillet of epoxy/micro along the front edge and smoothly blended that out on the side. This only took one iteration of sanding to get a decent shape.

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Here is a side view of the front shell where you can see the smoothly blended lip.

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Next came a major primer session. I used UV smooth prime which is thick and a pain to spray but it cover pins holes better than Ekoprime and provides a UV barrier for the fiberglass. It also sands easily and gives a really smooth surface. I had to load my spray gun several times to get all eleven of these part primed including the empennage fairing which has been sitting around a while waiting for primer.

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Here is another close up view of the nose gear fairing front shell where you can see how the lip turned out.

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3/23/14 Update: Here is how the nose gear upper intersection fairing looks after I match drilled it to the cowling. I still need to install nut plates on the cowling and countersink the fairing for flat head screws.

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Categories: Gear Fairings

Making Nose Gear Upper Intersection Fairing – 5 hrs

March 13, 2014 Leave a comment

Thursday Mar 13, 2014

A couple of days ago I started working on the nose gear upper intersection fairing. I could have purchased a pre-made fairing for about $35 but I have an extended slot in my cowling for the gear strut because I have a three-bladed prop and I need the fairing to extend forward far enough to cover the opening. The pre-made ones don’t do that. So I applied a layer of packing tape to the strut and the cowling to start, including over the slot. I also taped a piece of .025 aluminum to the trailing edge to keep the fiberglass on each side from bonding together along that edge. I bought some blue modeling dough at Michael’s and began forming a blended fairing profile around the strut. This is a pain working on my back on the floor with my hands raised while trying to keep from banging my head into the nose gear.

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After getting the profile looking aerodynamic I began laying on fiberglass which I pre-impregnated with epoxy between two layers of plastic sheeting. I put on 3 or 4 layers of 8 oz. bidirectional cloth and let it cure.

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The next day I was able to pop it off the cowling thanks to the packing tape. The modeling dough came off with it. It’s pretty ugly at this point.

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After an initial trim and light sanding it is starting to look better. The general shape seems OK but it will take several layers of micro over the outside and lots of sanding to get it smooth enough to look acceptable to fly.

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On the aft end I saw that it was going to interfere with the lower attachment plate for the cowling so I trimmed the fiberglass away in that area and I plan to apply a few more layers of fiberglass over that area to blend it together. This has not taken as long as I feared to get to this point.

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Categories: Nose Gear

Intersection Fairings – 20 hrs

March 2, 2014 Leave a comment

Sunday Mar 2, 2014

I was out of town last weekend with the wife and for a couple more days this week on business so progress was delayed.

With the gear leg fairings aligned it was time to start installing the lower intersection fairings on the wheel pants. I purchased mine from Cleaveland Aircraft but they are actually made by RVbits. These are supposed to be better quality than the Vans parts. After aligning them to the leg and wheel fairings I match drilled a set of #40 holes to cleco them in place. I then marked a line to cut the intersection fairing into three pieces so it can split with the front and read wheel fairing sections. After wrapping the gear leg fairing with packing tape I mixed up some epoxy with heavy flox and bonded the three pieces back onto the wheel fairing as well as bonded the aft edges of the intersection fairing together. I did this all in place on the gear leg to make sure everything was fitting well. Here is one clecoed together and set up to cure.

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After the epoxy was set I  sanded the surfaces to remove excess epoxy. I applied more packing tape over the aft section of the intersection fairing and laid down three layers of fiberglass overlapping the seam between the front and rear sections to make flaps attached to the front section that overhang the aft section along the gear leg fairing so the air stream cannot get under the aft fairing and lift up the forward facing edge. I took this picture after I removed the fairing sections from the landing gear and clecoed them back together. Here you see the raw fiberglass layup.

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With the two sections separated you can see the fiberglass is bonded to the front section and simply overlaps the aft section. The edges of the layup are still raw.

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After trimming the edges to leave 1/2 inch overlap and sanding the surfaces the parts look like this.

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Here I put it back together again to show the finished overlap on the bottom edge.

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When I was happy with the flaps on the left side fairing set I mixed up more epoxy with micro and smeared it on to smooth out the transitions between the parts including the front and rear wheel fairings which are not very flush along the seam. This photo is before sanding the micro.

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I received two hoses I ordered from TSFlightlines for the brake lines down the landing gear legs. I installed the left hose to verify the length. It looks good so I installed it using three short pieces of plastic tubing and electrical tape to strap it to the leg.

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I sanded the micro on the left wheel pant and intersection fairing using several coats of epoxy to get it well blended and smooth. I also sanded the entire exterior of the both the left wheel and leg fairing. Then I installed K1000-6 nutplates on the aft wheel pant section for the screws that hold the two sections together. After more hours of work than I expected this set is finally complete including the lower intersection fairing and is ready for primer. I just need to get the right set up to the same point.

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Another task on my list was to run a 1/4 inch tube from the firewall to the right fuel tank for the Airflow Performance fuel purge line. I had been dreading this task because there is no easy way to do this. The routing from the firewall to the tank is anything but direct and I knew bending the tubing would be difficult in these tight quarters. I decided to go through the right longeron with a snap bushing and get the line behind the right interior side panel trim as soon as possible, then go downward under the right rudder cable into the area of the right gear weldment which is covered by the carpet. You can see my final routing in this photo before I installed the side panel. I bent the section in front of the longeron first. Then I inserted the free end of the tube through the snap bushing and bent the remainder of the tube run to the tank in situ which was a big pain. I used a coil spring tube mandrel to prevent the tubing from flattening during bending. One of my goals was to keep the tubing away from the copilot’s feet and this accomplishes that goal.

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The tubing comes through the side of the fuselage with a rubber grommet and points straight at the access cover of the right tank. I will have to line up and partially install the right wing to locate the correct spot to install a bulkhead fitting for this line so that will have to wait a while. For now I left the tube a little long so I can cut and flair it to length at that time.

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