KF-IV fuel lines routing.

[rwaltman]

Dutch asked for pictures of the fuel system in my KF. Here they are.

1 - Header tank to left fuselage.
2 - Forward by the mixer.
3 - Into the fuel valve (plastic in, aluminum out.)
4 - To the firewall.
5 - Across the firewall.
6 - Into the gascolator and electric pump.

Roberto.

[Dutch]

Hi Roberto.

Thanks for the pics. they are very helpful. In pic.# 2 that fixture with the black hose attached to it, mounted on the metal plate.Is that a fuel drain? I have thought about putting a drain there to be able to drain both my header and wing tanks.But wonder if having a valve protruding below my airplane is such a good idea.

Thanks Dutch

[cap01]

That black hose is probably coax for an antenna . That is the location of my atc antenna

[HansLab]

very nice, clear pics, they are a great help in the stadium I'm in right now!
A big hurray for this forum again.

[rwaltman]

That black hose is probably coax for an antenna
Correct. That's an electrons drain ...

Roberto.

[HighWing]

Mine is similar but all on the passenger side. Two exceptions, the Facet pump is immediately after the header tank output, and because the fuel valve is in the center below the instrument panel, the line runs up the forward door post and across behind the cross tube below the panel to the valve. From there it runs straight back to the firewall. I have no gascollator per the theory that the header tank is the low point in the system.
Lowell

[rogerh12]

no gascollator?
I can't figure a way to run fuel line through a kit fox without at least two!!!! I figure, one behind the seat, one on the firewall is minimum (but maybe I am just water paranoid). That's what my model 2 used anyway, and never a drop of water ever made it to the carb.

Anyway, if you are going to use low cost paper fuel filters at the carb, be sure you have a gascollator right before it (and below it), else the water can swell the paper and block fuel flow.
Roger

[HighWing]

Roger,

Well, it is just theory, but all moisture is introduced into the fuel system through the main tanks, either from the air, presumably through the vent tube on the tank caps. Or conceivably, from poorly stored fuel, or buying from a low volumn fuel vendor where water can collect in the storge tanks. In any event it is introduced through the main tanks, not through the rubber or aluminum lines. If there is water in the fuel introduced in the wing tanks, how can it get past the behind the seat header tank with it's drain two inches from the bottom skin and two inches below the outlet port? This idea has been discussed many times and back then, yes, I did have a gascollator - because my Cessna did, but it also didn't have a header tank. I never ever found water in it, but then I am in the West in a much drier climate than many here. But let me quote a guy from the old days talking about Kitfoxes - posted 2006,

"Tom,I have the Classic IV and my kit (Late 95) didn't come with a Gascalatoror or include it in the installation manual. My low point is the header(located low behind passenger seat). Just wondering why you have a gascalator?
Don"

The Guy quoted was an engineer by trade and worked at Newport News, VA - yes humid. He was employed at the Naval Shipyard there and his specific responsibility was in Nuclear Submarines and more specifically in risk management. In other words, A submarine at a mile down is in much greater doo doo than a Kitfox a mile up if something goes wrong. He was in the group that would critically evaluate every single system and scenario in an attempt to keep our submariners out of harms way. I would suggest that he was qualified to evaluate a simple Kitfox fuel system.

Regarding "cheap" paper filters, are you suggesting that in addition to adding a gascollator, I also have to replace all my Ace Hardware bolts and nuts? I can't imagine anyone participating on this forum going price shopping for their fuel system or any other critical system components.

I have no desire to make this sound like my way or the highway and really don't care if you have one, two, three, or none. If I was building around a Volkswagon, I would probably have four - couldn't hurt. This particular airplane was not invented yesterday or last year. It has a rich history and there are many ways builders have designed systems and the vast majority successfully. That's what discussion groups are all about - various approaches and then to each his own. Don, above, was in the discussion group many years and flew many hours in his presumed gascollator free death trap. I'm getting tired.
Lowell

[rogerh12]

Regarding "cheap" paper filters, are you suggesting that in addition to adding a gascollator, I also have to replace all my Ace Hardware bolts and nuts? I can't imagine anyone participating on this forum going price shopping for their fuel system or any other critical system components.

Lowell: Yes actually, if your complete fuel system design will allow cheap paper filters, then yes. Any why not? The best NASA spec’ed components are a liability if used in the wrong application in kitfox, just as a cheap part can be the right part in the right application as well. The key is a fuel system designed to use these cheap filters. Design it right, and it will be all right (I always say...)

He was in the group that would critically evaluate every single system and scenario in an attempt to keep our submariners out of harms way. I would suggest that he was qualified to evaluate a simple Kitfox fuel system.

Lowell: Not sure what expertise a sub commander can add to a kitfox fuel system, as I recall subs travel though water and a kitfox through the air……. But if he can cold start a nuclear reactor, well then, that’s good enough for me….. out with the gascollator !!!!!!!
Roger

[desertfox1]

I'm with Lowell on this one. I trust well thought out simple systems.
I have over 1400 hours in the Vixen and 500 in the SS without a gascolator.
I personally feel comfortable sumping the header tank before flight. But
everyone should feed there comfort level and if that takes multiple gascolators just go for it.

Phil

[rwaltman]

... I trust well thought out simple systems.
This was said about software systems, but it is applicable here as well:
"The unavoidable price of reliability is simplicity" (C. A. R. Hoare)

Roberto.

[HighWing]

After looking at the pictures again it appears that in this particular system, the outlet on the header tank is on the bottom rather in the side with a drain on the bottom. This particular tank is not appropriately designed to act as a water trap in the system and the gascollator is a must.
Lowell

[jiott]

Good catch Lowell. I think you are absolutely right.

Jim

[rogerh12]

Hey my model 4 has already been switch over to Tri-grear.
I don't even know if I have a low spot in the fuel system anymore as the plane sits level on the ramp.....

If you have a Tri-gear, where did you mount your gascollator?
Roger

[rwaltman]

... it appears that in this particular system, the outlet on the header tank is on the bottom rather in the side with a drain on the bottom.

That is correct.

Roberto.