Fuel/Brake Lines

Time: 12 Hours

After I ran my errands yesterday morning I grabbed the left forward skin that has the NACA vent in it to prime and paint it. If you remember I had already primed the skin then riveted and Pro-Sealed the bent into position. I left the seal cure for two weeks which was today.

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(null)I also scuffed up and cleaned the seat back roll bar for priming and painting.

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(null)My buddy Glen was able to come over late morning to give me a hand at running the brake/fuel lines and a lesson on flaring the tubes properly. First up we started with part of the brake line system. These parts will be from a fitting under the dash and thru the gear towers down to another fitting exiting the bottom of the aircraft at the gear legs. This is a long task of trial and fit with a million tweaks as you fit the parts. Here is the finished product.

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(null)Next we ran the fuel vent lines. These will run from the fuel tank (I already put the line inside the tanks when I built them) into the gear towers at the bottom and run up to the top of the tower and back down to finally exit out the bottom of the aircraft. This will allow for the fuel to drain out slightly as the fuel heats up during the day and not damage the tanks. For these lines I started with the right and made an exact copy in reverse for the left side. I strayed from the plans a little with the terminating end of these lines. Van’s has you run the vent line thru a snap bushing out the floor skin and eventually the gear cover plate for an inch or so with a 45° cut on the end. I was worried that I would end up bending or damaging this end durning the rest of the build as I moved the fuselage around. So I followed other builders and terminated the vent line to a AN832-4D bulkhead pass thru. This allows me to be finished in the gear tower area and add the last bit later down the road. Here you can see the straight fitting for the vent as well as the 90° that will continue the brake line down the gear legs to the brakes.

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(null)That took me the rest of Saturday and I waited to finish the work until today, Sunday. Next up was to work on the fuel lines that run from the firewall back to the fuel pump to the fuel filter then to the fuel selector valve. From the valve I needed to run a line to each tank. Each fuel tank line terminated at a 90° just outside the aircraft sides. Normally they would just go straight out but since I put inverted fuel pick-ups for aerobatics they need to run to the forward edge of the tanks. The run from the firewall to the pump was a tight space so I copied my buddy Glen’s solution of a 360° tube bend.

(null)The stretch that runs from the pump to the filter travels thru the left gear tower via two 5/8″ holes. This proves to be a problem as the nut and flare will but fit thru the holes so you need to do one end and place it into position and flare the other end in place which is the tough part. I started with the fuel filter end already flared and worked on the S turn bend it needed. The other end would be a straight shot to the pump. This was all easier said than done! You have to work these tubes in a 3D view and each bend affects the others. I strayed from the plans that have you use plastic snap bushings for these two holes and added rubber grommets based on my buddy’s recommendations.

(null)From there I worked on the filter to valve run, the valve to the left tank and right tank. Again this was a trial and error task as I worked all the angles and bends.

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(null)I received my cabin heat cable and red anodized pull knob from McFarlane Aviation and worked on its lay out so I could have access to it will the skins were off.

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(null)Where the cable ends on the firewall will eventually be a box valve that will be open or closed by pulling/pushing that cable. The valve will be connect via a tube to a shroud that will encompass part of the exhaust pipe which will transfer engine heat to the airflow. Again this layout was stolen from my buddy since its a proven design and I like how it looks. One last task to do today was to add a copper strip from the starter contactor to the ANL fuse, this will transfer energy produced by the alternator thru the ANL fuse, down the copper strip and the hot side of the starter contactor back to the battery. I made the required bends and drilled for the two bolt holes. A few passes on the scotch-brite wheel to clean up all the edges and I put it into position. I also had to trim part of the ANL cover to accommodate the copper strip.

(null)Another great weekend in the Hangar! A few more little items and I’m ready to start riveting the fuselage back together. I’m so thankful that I have access and the friendship of my buddy Glen Vokac! He is a proven builder and always willing to lend a hand or advice. I feel privileged to be in his company and able to learn from his award winning building skills (he is one of the most modest guys I know and will not acknowledge his incredible skills). On another fun note my girl just sold her home in Omaha after being on the market for only 5 days! What this really means is she will soon be living with me in the same ZIP code and I can not wait! Congrats T!!!

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