KF3 minimize unusable fuel level

[NotSoAmish]

My KF3 kit has the wing fuel tank pickups at the trailing edge of the tanks. What is the best place to relocate these for minimizing unusable tank volume? Know that landing approach decents take away usable volume with a rear pickup location.
I also want to go to brass compression fittings made for nylon tubing and clear nylon tubing for tank sight level indicators and fuel pickup. Any thoughts on this?

[kitfoxnick]

Do you have a header tank?

[NotSoAmish]

Yes. A poly header tank will go behind the seats.

[HighWing]

There are several considerations if you decide to move the pick-up fittings. In the rear position, the fuel line is straight out and through the butt rib. This makes periodic inspection of the finger strainer a pretty routine project. If you move the pick up forward, it will be more difficult as the fuel lines will have to be in a tight 90° bend to accommodate the space and the need for the line to actually exit the wing at the aft edge for wing folding. You will need an inpection panel in the fabric below the pick up so you can unscrew the "Ell" for access to the finger strainer. The Ell is just too long to unscrew without impacting the fabric. I worked on this on 5 Outback for a friend. The original builder apparently planned on exiting straight out from the mid tank location and I don't know what his thinking was regarding wing folding. Another issue there was that he took up all the slack between wing tank and the 1st and 3rd ribs by snugging the tank right up to the no.1 rib and it required a modified elbow to fit between tank side and rib web (picture below). It was a real challenge, and not much fun undoing what proved to be some poor planning to restore a maintenance friendly version - sort of like flying out of a box canyon. With all that, I just went to the original plan on my current Model IV project. I flew 900 yours over nine years with the origanal design and only once did I find a porting issue and that was during a flight with a long downhill flight to home when I purposely tried to unport the tank. I still had six or so gallons of fuel, so when the low fuel light came on, it was a few seconds after raising the nose a bit that the light went off and I saw the fuel flowing again in the Purelator filters.
Lowell

[Dave S]

I really like Lowell's modified fitting for the finger strainer/ell. Neat fabricated part.

Here is an attached photo of one solution to an access area between the #1 rib and fuel tank for the 13 gallon wing tank. The cutout is reinforced/polytacked with a "C" shaped piece of aluminum and covered with another aluminum plate held by 2 screws.

I did have an earlier post on the subject of nose down vs unusable fuel and found that the tanks would old 6 gallons unusable on each side with a 10 degree nose down pitch (which is not anywhere near a normal pitch down). Going to 5 degrees basically cut the unusable to 3 gallons on each side. Level pretty much cuts the unusable to a few ounces in the tank depression/sump by the fuel pickup.

Sincerely,

Dave S
KF7 Trigear
912ULS Warp

[kitfoxnick]

You can go straight out with a mid tank hose. The new tanks from kitfox has the output in the middle, at the output location there is a well. The reason I asked about the header is that with a header you have about 15 min worth gas in the header. I would recommend installing a low fuel switch in the top of the header. If you get air in the header you'll know immediately that you have a fuel issue, weather you forgot to turn on your fuel at the tank or you've been on a long decent or whatever at least you have some time to figure out what's going on. You can get just about all of the gas out of the older style tanks by slipping with the nose a little high.