The second fuel tank is being prepped for install in the first wing. Confusing I know, but happy to get a few hours in the shop this weekend and tonight.
Most of the work on the second tank is done - I've fitted the centre support rib (added to the inside of both tanks) and the fuel outlet and rain outlets are already fitted. This tank install will go much quicker because most if not all of the planning, thinking and decisions are done.
First up, I added the internal rib rivet line support strip to the bottom side of the tank. This time I have the advantage that I can access the inside of the tank without having to reach through the access hole to maneuver the rib into place.
With the access available, I decided to mount, rivet and seal the rib to the bottom of the tank skin now - no point in waiting for the rest of the tank sealing. More sealant will be added as I mix more up later on.
Fuel drain installed and sealed (inside of tank view):
Fuel drain fitting, all sealed (outide of tank):
Repeated the fuel access cover install using the same template as the other wing:
Hole drilled in access cover (under the cardstocl template):
Transfered the mounting holes from the access plate to the wing skin.
Used a hole saw and Dremmel tool to cu the access hole then mount the access cover via Tinnerman clips (just like the other wing):
Drilled out the drain plug hole in the lower wing skin and the fuel outlet pass-through hole in the tank bay rib.
Fairly short update and not a lot of pictures to share. Like I stated above, most all the thinking and planning from the first wing tank has been done, just got to apply the same process. So far, so good :)
More to come.
Finally it is Saturday and time to get into the shop and work on the left wing. Time to get the fuel tank final install complete, plumbed and wired for operation. Thanks to Brenda and Caitlyn for coming to the shop to help flip the wing back upright - it really made today a productive day.
The left wing tank has been tested for leaks and is ready to be permanently put in the wing tank bay.
Placed the tank back in the wing bay for final fit up. All the extra sealing didn't change anything from prior fit-up.
1/4 inch truss head screws fill in the centers of the rivnuts securing the fuel sensor plate to the top of the tank. Ez-Turn threat sealant on the threads of the screws - it has the consistency of vaseline.
16 screws for 16 rivnuts.
The fuel tank is rquired to be grounded to the airframe to prevent any static discharge from igniting the fuel or fuel vapours in or around the tank. Grounding is via the inboard tank rib - I used an A4 rivet to secure 18AWG aircraft wire with a matching ring terminal. This wire got twisted together as a bundle with a pair (orange/green) wires for the fuel sensor.
The twisted bundle is secured near the top of the rib using a wire clip and A5 rivet as the head on an A4 waa too small.
Used a trick I read about online to make nice wire bundles - put the loose ends in a cordless drill and slowly twist them together.
Green ground wire from the rib connected to the tank via a ring terminal under one of the rivnut screws. Confirmed with an ohm-meter that the tank is electrically connected to the rest of the wing structure.
The orange and other green wires are crimped connected to the white and black wires (respectfully) of the fuel sensor. The sensor has no polarity, but I decided to use the black wire as "ground" feed and whire wire as "positive" in case I need to troubleshoot later.
Next up, I installed the finger screen into the fuel tank outlet. Ez-Turn thread sealant is used here too.
Next the AN6/3/8NPT adapter - it only requires sealant on the NPT threads, AN6 fittings are self sealing.
AN6 90 elbow connects the braided fuel line to the tank via the adapater and finger screen at the outlet. The looks like a very clean and professional installation, but more importantly it is the "right stuff" for th job.
This close up show the assembly and also the back side of the Tinnerman clips that hold the inspection cover on the lower side of the wing that I insalled last week.
Next up, I used contact cement to secure cork strips to the underside of the upper fuel bay skin. I figured if the bottom cork strips are attached to the lower wing skin, these might as well be attached to the underside of the top skin. Two layers of cork strips and a square with a hole to support the threaded tank filler neck.
Some heavy containers on top of some wood scraps hold the cork in place while the contact cement sets up:
Once set up enough, I installed the upper skin in place. It quickly became apparent that the strips were enough to support the skin over the tank, but I needed to add another layer of for the fuel filler neck.
Third layer in place, closes the gap nicely (sorry about the out of focus picture!)
Fuel neck threaded in with Buna-N gasket to seal it. It tightened up perfectly and the fuel cap faces in the correct direction that I want - perfect!
Coiled up in the wing root awaiting connection to the fuselage when the wings are mounted now are the blue static line, the yellow pitot line, the braided fuel line, the orange/green fuel sensor twisted pair conductors and run of orange string which i can use to pull wires out to the wingtips when the time comes to add the navigation lights.
The left wing, almost final and ready for storage. Need to finish some minor items on the wingtip fit up, but otherwise it's ready to go.
Once the wing goes into storage, I'll bring down the right wing back to the shop and get the right wing tank installed. It should go much quicker as it will be the same process as the first bolstered by the lessons learned on the first.
It has been forever since I updated the "completed features" picture so here it is. Both left and right wings are now complete (with the exception of the right wing tank as mentioned).
As always, thanks for following along. Soon the fun of the fuselage begins! Can't wait - it will be nice to look at a all new part of the build.
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Husband, father and 911 dispatcher. Long time pilot with a licence that burns a hole in my pocket where my student loan money used to be. First time aircraft builder. Looking to fly my own airplane.