Those of you with dual wing tanks, lets talk plumbing to the header?

[thebriman 69]

I'm toying with the idea of adding a second fuel tank to give me more range.  I'm curious as to how those of you with dual wing tanks already are plumbing the fuel to the header?  Valves, vents, etc.  I have one wing tank and the round aluminium header behind the seat right now.  I was going to order a second glass tank from Performance Products soon, as one tank just doesnt give me the range I'd like to have. I'd just like to hear what y'all have done.  

[EDMO 1078]

  For one tank in each wing, just run the fuel lines from shut-off valves to the header tank from each - and one of the wing tanks should have a vent line from the header tank - Kitfox says to run the vent line to the right wing tank, but don't think it would matter if you already have a vent line to other tank.

  And there are a couple of guys who fly without the vent lines.

EdMO

Edited 25 Feb 2014 by Ed In Missouri

[Av8r3400 1178]

I am a firm believer that filters between the wing tanks and header tank are not needed and may be hazardous.  Gravity is the only flow motivator here and any restriction in a filter will make that pilot cooling fan in front quit turning...

 

Valves - Yes!

Vent from header to somewhere - Yes!

Filters - NO!!

[EDMO 1078]

I deleted my first post since it was not relevant - I thought he already had tanks in both wings - read it again, deleted, and put in new post.

EDMO

[C5Engineer 1170]

Here's my set up with dual 14 gallon tanks. It's worked flawlessly for 330 hrs and few thousand gallons of fuel. On the left wing I have a line that runs behind my head to the header tank. I have a shut off valve right in the middle of that line. The fuel will transfer wing to wing when it's sitting. The trick with that line is make sure it's tight with no low spots and use a zip tie and piece of fuel line to make stand offs that gradually get longer as you move to the right side to make sure that line is pointing downhill. I've seen guys just zip tie it up tight to the tubing which is too high. You want to make sure that from the outlet of the tank to the header it's going downhill! 

 

My header is NOT vented. Both wing tanks just dump into the top of it. I have the aluminum tubes sticking up approx 3" out of both fuel caps. 

 

From the header exit it runs under the seat and my main shutoff is mounted on a little plate vertically on the truss that the bungees wrap around where the back of the passengers legs would be. From there it goes thru a filter that sits right down by the passenger door and is easy to see. After the filter it goes thru my fuel transducer and then up to the firewall to a brass fitting. After that fitting it goes thru a gascolator which is probably not necessary but Dean Wilson himself put it there so I left it. After that is my primer T and then the pump and onto the carbs. The only filter I have is right after my main shutoff and before the fuel transducer. If your paranoid about junk put them after your fuel pump before the carbs. I didn't because it really gobs up that tight area. I figure I've got the header which has an almost 1" deep sump, my filter, and the gascolator to catch crap before it gets to the carbs. 

 

Don't overthink your fuel system. 90% of two stroke engine outs are due to fuel starvation. Embrace the K.I.S.S. principle with this system. 

[High Country 69]

you will need 3 fittings coming in to the top and one out from bottom side of your header tank (another out of the very bottom for a drain) - in the top fittings 1 hose goes to each tank and the 3rd goes to your vent. the lower goes to the engine. I'm guessing you have two in the top at this time correct? one going to the outlet in the tank the other to the top of the tank for a vent. if this is the case you could remove your header tank drill and tap for one more fitting and just plumb it to your new wing tank. if you don't have enough room to add another fitting you could just put a tee into the line that is already coming from your current tank and hook up the new tank to the side of the tee. keep the tee as close to the header tank as you can, we have another Avid MK IV here in our club that is plumbed this way and he has never had any trouble with it.

 

-Robert-

[High Country 69]

here's a crappy drawing to try and give you a visual, I'm sure others have different opinions and they will share as well

[EDMO 1078]

If you don't have 2 fittings on top of the header, then you can just "T" the lines from both wing tanks together just above the header.

EDMO

[C5Engineer 1170]

Lots of us are not running header vents myself and Leni included.

[akflyer 1427]

Mine is set up just like joeys. He has a pretty good description so I can't add anything further other than I won't add any vent lines, the wings vent through the header to the other wing tank. Which ever tank is fullest it will push the fuel through into the lower tank. Once the air has cleared the header tank, I shut off whichever wing I don't want to burn off of. Both tanks on for take off n landing, other than that I'm running one side or the other.

[Deejayel 1]

Fwiw, here is my system.

2wing tanks feed into my aluminum header tank behind my seat. I have a shutoff valve for each wing feed upstream of my header tank. That allows me to select feed of course. I have a vent line which doubles as my fuel gauge or a "header tank condition indicator". If I cant see any fuel in that line, I know I have header tank fuel only at best and had better be on final.... My fuel lines are black rubber. My vent line is translucent. I suppose if my main fuel lines were translucent, the vent line would not be needed. Ill get some pics...

From the header it flows to my shutoff valve under the instrument panel. Then to the gascolator. Then to the mikuni. Then to the carbs.

Thinking of adding an electric backup fp.

[dynomike 91]

no vent line here ,didn't want to say anything before but now I know there is more like us

[Bandit 286]

I do not use a vent in my header tank either. You shouldn't need one if the tank is vented.

[thebriman 69]

Right now I have no vent either and it performs flawlessly.  Thanks for all the ideas guys.  I'll let you know when its installed

[lostman 198]

When I was talking to John during the time I was picking up the Pursang he said that a lot of the Kitfox problems in their fuel lines could be traced down to having a vent line in the header tank. I can't repeat what he told me about it, but mostly because I don't remember. Pursang has the tank lines coming to a shut off valve that are for each line before the header, then through a clear filter to a pump. It also has a secondary fuel pump incase the first one goes out. From the fuel pumps the lines go straight to the carbs. Fairly simple system that has over 680 hours on it and works well. The bottom of the header tank (under the panel) goes to a fuel sump for the lowest part of the system. My header tank is only about 1.5 quarts though...I haven't measured it but it's not very large. I thought it was 1/2 gallon according to John, but I was up under the panel today working on interior and found it's smaller than I remembered.

 

I echo the K.I.S.S. principle that was already brought up. My motto is, if it's not there it can't break!

[Jon 2]

Which way do you orient the vent tubes (tanks and collector)? I assume the 180 degree bend down but then what ? should it be pointed foreward, sideways or to the rear (the open end )  I have been told if not done correctly it could cause suction.

 

Have I created a  problem that does not exist?  How far into the wing tank does the vent need to go?  I would think just into the cap maybe an inch? 

 

Thanks again for the help,

 

Jon

[Av8r3400 1178]

The vent tubes are a ram air pitot tube to pressurize the top of the fuel tank and help flow.

 

Therefore, they need to point forward into the relative wind.

[EDMO 1078]

The ram-air tubes in the tank caps pressurize the system for better fuel flow, and also let pressure vent out of the tanks when the gas inside is heated by the sun or outside temperature.   They should be pointed forward, and don't need to stick down much into the tanks, as long as they go completely through the bottom of the cap.

The vent lines from the header tank to one wing tank are supposed to prevent an air-lock in the system.  Some want them - Others don't. 

EDMO

[allonsye 85]

Those of you with shutoff valves off each tank -- how often to you really use them? Operationally it seems to make more sense to feed simultanously off of both rather than creating a factor by switching back 'n forth. 

[Av8r3400 1178]

I use the valves for maintenance reasons only.  Operations are always via both tanks.

[EDMO 1078]

Parking mostly - If plane is not level, then upper tank can overflow lower one.

EDMO

[akflyer 1427]

I use them every flight. My plane flys a little left wing heavy so I burn gas outta the left side first. Some flights I may only want 5 gallons in the tank. You need all 5 in one side versus 2.5 per side. When the plane is parked one tank is always shut off so it does not transfer gas from side to side.

[allonsye 85]

I use the valves for maintenance reasons only.  Operations are always via both tanks.

Sorted figured that. I don't have valves on mine but thought it would be nice to add them for this reason.

[EDMO 1078]

What would you do if you got a leak in one of your tank lines while in flight?  A valve would help very quickly!

EDMO

[C5Engineer 1170]

I shut mine off when I park it. I got a flat once in the hangar and all the fuel transferred to one side and overflowed the other tank and made a heck of a mess in the hangar. I also shut mine off if I am fueling from a pump so I know exactly what went into each tank so I can pour the right amount of oil in. I only have a shutoff on the left tank.