Fuel Filters, Wing Tanks

[DesertFox6]

Hmmm..in this case Marshawk, I'm going to refer you back a few entries on this thread, to read the conversation between 5770phil and cap01 on 12-13 January where cap01 directly addressed this issue for 5770phil's Model III, to include offering an excellent photo and a short explanation of how to vent the header tank to the right wing, as has been the factory setup since at least my Model IV came off the line back in '94.

You really need to get your vapor vent line connected to one of your wing fuel tanks so your fuel stays withing the fuel system instead of de-icing your tailplane! I know there's plenty of folks on this august forum who can offer more specific advise for your Model II, but this internal-vent-loop hookup is the best solution for your situation; the 90 degree "L" bend won't do anything positive for you at all.

"E.T."

[mr bill]

KF4--- Aug 01 wing instructions show a fuel tank vent line protruding out of the bottom of the right wing (presumably for the header tank). May 02 wing tank instructions show the header vent going to the right wing tank vent. What I have seen in the forum says header vent to right tank vent. What is the vent line out the bottom of the right wing for?
Thanks in advance.

[t j]

Bill, the vent coming out the bottom of the wing is used when there is a panel tank ony and no wing tank. It is a 1/4" OD aluminum tube a little over 4 feet long with a couple 90 degree bends on the outboard end.

[Kiriako]

I share most of the experiences you have all mentioned on this thread and some more. Let me give you a quick list of my travails over the last 6 months of owning a KF3 built in 1992:

-In my first few flights I quickly realised that my left-wing tank drained fuel much quicker than the right one. I have put this down to my Rotax 582 torque causing the right wing to want to push up and this resulting in the greater fuel-flow (does anyone agree with this idea?)

-Soon after, I suffered my first serious problem when my engine spluttered about in-flight causing me certain angst only to finally track the problem down to fibres from the fiberglass-tanks obstructing the carburetor jets.

The plane already had two large Rotax plastic filters between the wing tanks and the header tank. I proceeded to add a further BMW membrane filter after the header tank and before the gascolator, thinking that the fine membrane filter would take care of the fibres; well it did just that...unofrtunately it also took care of reducing the fuel flow to the engine to the point where I suffered an engine failure inflight! I dead-sticked it to the nearest ploughed field and felt a better pilot for it!

After the BMW filter fiasco I proceeded to put a very fine glass-filter to replace it while initiating a jets inspecting regime after every ten hours of flying. This seems to have put paid to the fibres-in-the-jets issue for the time being.

I then proceeded to suffer another two engine failures in-flight with equally anxious but perfectly competent dead-stick landings out in the boonies!

It took me a long time to figure it out but to cut a long story short I finally found the problem in the metal tubing between the right wing tank and the header tank, which had accumulated raisin muck from the tank and was obstructing the fuel flow enough to cause an engine failure if I had the left tank shut-off and was working the engine at fairly high RPMs.

I have now run a vent/bleed-line from the vent-valve at the top of my header tank to the boundary air-flow layer below the right wing tank just adjacent to the top of the lexan of the copilot's door. If left open at all times this vent-line overflows and the fuel splashes horribly onto the lexan and even into the cockpit if the tanks are full. So I have put a little fawcet to it so that I can vent it if I suspect that air has entered the header tank or any other part of the system while keeping it shut-off the rest of the time.

The added value of this set-up is that it acts as a primitive but perfectly good fuel flow indicator. If the fuel circuit is full of gas I can see the fuel running up the transparent vent-line all the way to the fawcet; if however the fuel circuit becomes clogged up again with raisin-debris from the ever decomposing tanks (due to the high level of ethanol content in our local fuel) I am immediately alerted to it by seeing the vent-line filled with air bubbles moving up towards the fawcet; if the fuel blockage is major than all fuel is drained from the vent-line and all I see is air! I can thus take immediate emergency action such as to look for the nearest landing field before the remaining fuel in the header tank is gone!

As I am sure you more senior Kitfox flyers have realised by now I am just a dimwitted Kitfox novice with no technical acumen to speak of plodding along from one half-baked solution to another because I cannot drum-up the energy or the money to go for a new wing-tank installation and be done with all this nonsense!

It would be great to continue hearing from others with similar experiences and the solutions they have found.

My kindest regards to all of you...this is one hell of a great community of flyers that I am truly proud to be now a member of!
Kiriako

[rogerh12]

Kiriako
If you are having issues with the high alcohol content of your fuel, perhaps you should remove the orignal fuel tanks and install some alcohol friendly ones. Kitfox sells glass versions, and I ahave heard of other tanks made from blown molded plastic that can take the alcohol too.

Hope this helps

Roger

[Kiriako]

Roger,
Thank you for the advice, this is clearly the definitive solution to my problems but it is a major effort and I am trying to postpone it as much as possible. Although when my tanks are finally perforated by the alcohol and fuel is dripping off my wings I will be left with no choice!
All the best,
Kiriako