fuel tanks draining uneven

[Glasairjock]

I just recently purchased a 40 hour kitfox 6 with a 912 uls. the fuel seem to drain the left tank first then the right, this to me seems odd.What is your opinions on this.

[Dave S]

Terry,


There have been a lot of posts on this in the past; and, you can likely dredge them up with the search function.


A couple things to start, assuming a person is already flying wings level:


1) Check the fuel cap pitots - they should both be pointed directly ahead - if not, remove the caps from the tanks and bend them to where they are supposed to be. While you are at it - look for a plugged or partially obstructed pitot.



2) Be sure the fuel cap seals are actually sealing - if one is not, this can bleed off the slight positive pressure from the fuel cap pitot.


3) After that, might be time to look at the fuel lines from both tanks to be sure they are routed and clear as designed.






Cheers,

[PapuaPilot]

A couple things to start, assuming a person is already flying wings level:


Actually it is better to say if the ball is centered . . .

If you do all of the things mentioned and the problem still persists, don't worry about it too much. If fuel is getting to the header tank then the engine will keep running just fine.

[ken nougaret]

An easy check of the fuel caps is swap them from side to side. See if the other tank drains faster.

[HighWing]

Agree with the first two posts. Uneven fuel flow has been with us since the beginning. With the IV, which is my experience, I always attributed it to the challenge flying with wings level. No real point of reference and always looking outside at the view and the guys I am flying with. I did have one experience on a return flight from Idaho which, I believe, validates Papua Pilot's words. With prevailing winds from the tail, I decided to do a non-stop and check some things I had been thinking about - fuel flow, Low Fuel Indicator etc. I crossed the Sierras at about 10,500 ft. and put it in a descent that would put me close to pattern altitude - 1300 ft.- at my home airport about 50 miles away. This prompted a close attention to fuel levels in both tanks as well as the level I could see in the vent line. At the time, both tanks had stabilized at about the same level and I was able to watch the fuel levels descend in the vent tube on the right tank until it triggered the low fuel indicator. I then reduced descent a bit reconnecting the aft fuel pick-ups to the fuel in the then produced wing tanks and the flashing red low fuel light turned back to green and I arrived home with six gallons in each tank.

[Glasairjock]

Thanks for the replies, I'll be looking into this a bit more shortly .there are a few mods I'm thinking about, definitely need new sight glass tube on fuel tanks and would like the bubble doors and also thinks should switch the header tank to the aluminum tank. Also seem to have an issue with right rudder peddle on left seat seems to stick or difficult to push. But it's been a real hoot flying it so far.

[kmach]

I see your in the neighbourhood.
Do you have a strip? Or are you flying out of Gull Lake?

[Esser]

The rudder pedals require lots of attention on assembly to make sure they are smooth. You make have ti did assemble and make sure ALL the powered coat is removed.

[jiott]

On a recent trip, to Oshkosh, I stopped at a place to refuel and their tank was dry, so had to go to another airport. I had already been flying for about 1/2 hour with the left sight gauge showing zero and the right gauge showing fuel. After diverting to another airport I arrived there with only 3 gal of fuel, and nothing had been showing on the left sight gauge for about 45 minutes now. Never during this time did the engine miss a beat. So what I am saying is: I agree with Papua Pilot and don't worry about it. Do the best you can with the cap pitots, the plumbing to the header tank, flying level and ball centered, and then don't worry.

[Glasairjock]

Thanks Guys for the replies, Kevin, my plan is to fly out of a grass strip just east of Gull,Lake, but the grass I seeded last fall never came so I'm still working on a strip. I store plane in swift current right now but plan on getting it how sooner or later. I sure like you panel setup.

[Esser]

So I bought the original posters plane and the finger strainer was plugged almost solid. I have pictures but every time I hit the upload button, nothing happens. It looked like it flowed that way so the resin was soft at one point. I also found a big chunk of resin(looks like part of fillet) banging around in there. This plane only had 60 hours on it. I just wanted to post this because the original owner had commented that the one wing was draining faster than the other and some people assured him that this was a normal Kitfox thing. Looking back, some people did advise to look at the fuel system. The uneven fuel drain IS normal. However, if you have doubts, pull these finger strainers! Make sure you are checking them every annual even if it's a PITA.

Now, interestingly enough, the resin got past the strainer but then piled up in the threads. So I'm not saying the finger strainer will save you but lets be diligent!

[DesertFox4]

Good catch and good advise Josh.

[HighWing]

I saw the pictures posted on the Facebook site and thought I might be able to copy and re-post them here. So Far so Good, I think. My thought, though, is that all the debris seems to be inside the finger strainer - opposite of where my expectation says they would likely be. Was it tank failure or gas can debris seeping through the screen and accumulating in the strainer or possibly a bit too much thread sealer that was then pushed into the strainer. The reports of failure I recall from the olden days were of obstruction of fuel flow due to stuff all over the outside of the strainer.

[Esser]

Thanks for posting Lowell,

Looking at the strainer it had seemed to me that resin had "flowed" through the strainer and started to build up against the threads of the 90' elbow that threads into the strainer. It also seam like it stopped against the 90' so maybe it had trouble making the corner? In the header tank their were also things that look liked resin. Not the density of that big chuck I found rolling around but more like something very thin that delaminated.

I'm on the fence whether to replace these tanks or not while the wings are open. I have ethanol free here....

[efwd]

I'd bore scope the tanks before I was comfortable saying they weren't the problem.

[jrevens]

That's an excellent suggestion, Eddie. I wonder if it's possible to bore scope the finger strainers from the fuel fill opening? There are some very reasonable priced bore scope accessories that can be used with a smart phone. It's a shame that the strainers can't be seen from the fuel fill openings.