The Long EZ Build: Fuel lines and OD ribs

With the top strake foam panels on, it was time to for Step 6 of Chapter 21 - end ribs and outlet plumbing of the fuel lines.

I focused on the fuel lines first, and OD (outboard diagonal) rib later. First step was to drill the 7/16" hole through the fuselage wall. This is located 13" fwd of the firewall and 3" below the fuel tank's bottom skin.

Before drilling through the fuselage wall, I triple-checked to make sure that I wouldn't drill into the passenger seat by accident.

You can see here how close it comes to the passenger seat... but all was well!

I had already installed the vent lines. Those were 1/4" aluminum tubing and super easy to bend by hand. However, the fuel lines are 3/8" dia and more difficult to bend. So I purchased this tool from Home Depot for $12.. sure glad I did!

Also, glad I purchased extra length of tubing.. since I scrapped a few pieces practicing bends. Getting dimensions for every bend is difficult - so I used scrap tubing to fit, bending everything by hand causing a bunch of kinks in the tube. I then removed it from the fuselage and used it to make professional bends using my tube bending tool. The result was this:

Here is the right fuel tank line...

Here is the left fuel tank line...

The left fuel tank line is a bit more complex. Since both fuel lines run parallel along the lower right corner of the fuselage, the left line has to snake its way down the back of the passenger seat. My plan is to install these two lines for now... and will use connectors to complete the fuel lines (up to the fuel selector valve where the pilot sits) later on.

I cleaned and dulled the tube surfaces for bonding.... and then cut 1.5" x 1.5" BID squares. Using a pencil, I poked a hole and then passed the square through the tube...

The plans say to use a wood plug to avoid getting flox in the tube.. I just shoved a bunch of cling-wrap in the tube...

Before the tubes could be installed, all bonding surfaces had to be prepped...

View from the backside of the passenger seat... notice I had to notch out a small cutout (as if the passenger bulkhead needed more notches?!) next to the existing cutout.. this allowed me extra room to insert the fuel line tube without kinking it...

Ok, time to install the fuel lines! I started by painting plain epoxy on the tube...

And painted plain epoxy on all surfaces that were going to get 1-ply BID. With my helper on the outside pressing her thumb up against the fuselage hole, I filled the hole with flox from the inside. I then passed the fuel line through. She made sure the flox stayed put...

I then added a bit more flox around the tube and covered it with the 1-ply BID square...

And wetted it out...

I repeated this for the right side... but since this tube simply runs along the lower right side of the fuselage, I zip-tied it to the seat belt buckle for now. I then applied flox fillets where it touches the passenger seat, and applied 1-ply BID on top of it. This provides stress relief to protect it from leakage.

I then installed the 1-ply BID square to the outside of the tube..

For the left fuel line... I also applied 1-ply BID to the back of the passenger seat...

I used duct tape to hold the tube in place while the flox/BID cured... notice I left the tube extra long. It was easier to install it this way, and bend it AFTER cure...

After everything cured, I hand-bended the tube. This will later get fittings and continue down the lower right corner of the fuselage...

Outlet fuel lines are installed! Woooop wooooop!

Now for the OD (outboard diagonal) ribs. CP#33, LPC#102... tells us to glass OD with 1-ply BID and install with flox. So I took two panels of 0.35" thick H45 foam... and laid them up with 1-ply BID...

After cure, I pressed them up against the outboard edges of the strakes...

And traced the contours..

Presto! Instant OD template! CP#30 under builder hints warns us that the OD rib might have to be trimmed down in order for it to blend smoothly with the wing (see my post about that here).

After a little trimming... and making the cutout...

I also beveled the aft and fwd edges to match the spar and R45 rib...

I then double-checked to make sure the outboard edges of the strake skins were straight and coincided on top of each other... sanded and prepped all surfaces... mixed flox and applied it all around the OD rib...