Tank Baffle Prep

Time: 6 Hours

Today started with the weekend breakfast with the fellow builders and a little hangar talk. I always enjoy these days as I can run my weekly work and questions by the guys to see how my progress is coming. One other thing I wanted to do this morning was to drive to Monee, IL which is south of Chicago to an airpark called MeadowCreek (2IL9) and have a look. This is a beautiful airpark where you can build, or buy, a home with a built in hangar and live with your plane. It’s a gated community and the roads/runway are private. All the roads are also taxiways, so cars give way to any aircraft. You can wake up and open the garage door and just go fly, a complete dream for me! I had the opportunity to meet a resident there and learn that she is a realtor/pilot. It was a great little trip and will be something that I look at for the future. When I got home I was pumped up to get into the Hangar and start working. First up was to finish up all the interior tank items that need taken care if before you can finally seal up the tanks with the rear baffles. I started with finishing the wiring for the fuel capacitor plates. The outboard wire was already in place but I needed to fish the inboard wire through the bushing that has the vent line in it. This was a tight fit and took a little time to get done. Once there I made some measurements and cut them to the correct length. I then crimped the ring terminals on each of them and checked their security.

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20140308-192811.jpgIt’s pretty tight in this bay to attach these wires to the plate since they are cut to the right length. I left a little extra length and will rotate the bushings in turn wrapping the wires around the vent line taking up the slack.

20140308-192953.jpgWith the wires all connected I grabbed the screws and the required hardware to attach the plates. Remember that these plates must be deprecate from the fuel tank structure as far as the metal is concerned. So you must isolate them with plastic pieces. The screw is placed in a tube and the tube is placed in 4 plastic washers. This isolates the screw and plate from touching the rib that it’s attached to.

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20140308-193315.jpgBefore I did the final attaching I tested the continuity of the plates with my Ohms meter. I placed the tips one each plate and got a tone. I then placed one on a plate and the other on the tank structure with no tone. Touch two placed of the structure gets a tone. I also hit the center of the BNC connector and the plates with a tone. This all proves that there is no contact with the plates and the tank structure. Once that test was done I mixed up a little ProSeal and covered the terminals to seal them up followed by attaching them to the ribs.

20140308-193901.jpgThe slack was then removed from the wires and I added a blob of ProSeal about every 2 inches to secure the wire to the vent line.

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20140308-194111.jpgI then attached the corner anti-hangup guides for the flop tubes with a couple of LP4-3 pop rivets.

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20140308-194311.jpgThe last item in the interior was to bend up the tip of the fuel bent so that it is at the highest point of the tank. The vent will replace the fuel with air as it’s used, but it also allows the fuel to escape overboard as the fuel expands in the heat. With out this vent your tank would crush in as fuel is used and pop as the fuel heated up.

20140308-204836.jpgThose were all the remaining items inside the tanks so I grabbed the MEK and cleaned all the parts that would get sealed with the baffles. In prep for the baffles and the z-brackets that go on them I marked the proper orientation of the brackets on the skin. Putting them on in the wrong configuration would really suck. So I drew the correct orientation on the skin for quick reference.

20140308-205636.jpgThose brackets get pop riveted and if you remembered in an earlier post when starting the tanks I moved the rivet holes on the bracket flange to make it easier to pop rivet. Even with that adjustment it is still tight so you have to grind the face off a cheap rivet puller to get to them.

20140308-205917.jpgSo I decided to stop there so that if I forgot any item that needed taken care of I will remember it in the middle of the night! So tomorrow will be the big day and finish the tanks. That will give them a full week to cure and I will grab some 100LL to fill and leak test them.

Deburring

Time: 3 Hours

I first worked on the tank stiffeners by deburring all the holes followed by scuffing the surfaces that will have tank sealant on them.

20140210-174041.jpgI then started the process of deburring all the holes in the tank ribs to get ready for all the dimpling that will be done.

20140210-173056.jpgAll the rib flanges need to be scuffed for the tank sealant before I will dimple all the holes. Before I set out for that task I riveted the the fuel tank trap doors.

20140210-174616.jpgNot a ton of work but any work in the Hangar is good!

Holiday Breaks

Between Thanksgiving, flying and Christmas my work on the -8 has been very very slow! I’m looking forward to spending the Christmas break with my kids and my girl in Chicago. It’s going to be a fun filled week. I’m also looking forward to after the holidays so I can relax and slow down and get back to building. I did receive an early present from Van’s aircraft, my flop tubes!

20131219-131438.jpgThese two tubes will be in the fuel tanks, one in each. They are flexible and will “flop” to the top and bottom of the fuel tank depending on if you are upside down or not. They are what allows fuel to continue to flow to the engine while you fly upside down for an extended amount of time. Next I will need an inverted oil system, doing the same job but for the engine oil. I had a chance to help out my friend Glen, a fellow -8 builder, install his -8 landing gear.

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20131219-131852.jpgI now see why so many builders make a modification to the gear towers so that getting to the gear bolts is easier (that’s easier compared to an unmodified tower) they are a pain either way. Happy Holidays to everyone and enjoy the time with family! I know I will!!

Rib Prep Done & Priming Starts

Time: 5 Hours

Today started with finishing up the clean up after match drilling on the left wing ribs. I hit all the holes with the 3M wheel and die grinder before machine counter sinking them. Once that was done I then dimpled the single tab on the rear if the main spars. This tab gets riveted to the lore flange of the rear spar along with the bottom skin. Based on advice from Glen Vokac I decided to dimple now. The plans call this out later in the plans but that means you would have to dimple the rib and spar at the same time. I have never squeezed two layers of material with the dimple dies. This just seemed to be the right choice based on the fact that Van’s has these items dialed in and match drilling is not really necessary (but still done).

20131103-160202.jpgI then hit all 28 ribs again with the scotch-brite pad to clean up any marks I made. Then the rubber gloves came out and I cleaned all the ribs with M.E.K. and let dry. I then brought out my painting rack out and started the priming process.

20131103-162644.jpgI ended the day with the right wing ribs primed. I will hit the left wing ribs tomorrow after my flight. This will give them the week to sit and I’ll get to rivet next weekend.

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Flanging and Fluting

Time: 4 Hours

After getting all the edge finishing finished this morning and running some errands I got back at it in the Hangar. First up was to straighten the flanges of all the main ribs. So I broke out the tool I made, from Jason Hess’s build, and screwed it to the bench.

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20131101-190403.jpgThe idea is to bring the flange back to a 90° to the webbing. This tool makes that job fairly easy. Here is a before and after photo of the end flange of one of the main ribs.

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20131101-190628.jpgOnce I finished up all the flanging I moved on the the fluting. This straightens the ribs from fore to aft aligning them with the skin holes. Here is a before and after shot looking from the top of the wing down. You can see the bow in the rib one the first one and it removed on the second.

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20131101-191116.jpgI finished both of those tasks in 4 hours and had them back on the shelves.

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20131101-191648.jpgI decided to call it a day and clean up the Hangar. I will get a good day in tomorrow and this time I will get some assembly in!