fuel shutoffs

[lakertreetopflyer 0]

I am working on the mk4 I just got(just checking everything out).It has a fuel shutoff for each tank behind your shoulder.Is it necessary to have one for each?There is one on the dash to shutoff fuel to engine.It seems like shoulders could bump them .Do you need to be able to shut tanks off individually?

Brian

[High Country 69]

Just my opinion no they are not necessary however I would prefer to have them. reason being if you were to find that one of your tanks was contaminated on a XC flight you could just shut it off and fly on the other until you were in a place to clean it out. also gives a point to take apart the fuel line if you wanted to pressure test the flow coming from just one tank or the other. or you could take it apart here if you needed to remove a wing for any reason. I'm sure others here will either agree or disagree and for good reason. But in the end either way will work. If you're main concern is accidentally shutting them off and you don't plan to use them on a regular basis (ie: off when not in use) then just safety wire them in the open position or adjust them so that there is no chance of interference. Good luck

-Robert-

[larr 0]

I use them. If a tank leaks, you can close one and use from the leaking tank. I do not carring a lot of fuel. I only use one tank unless I have to, otherwise you have more fuel that you can't see and therefore don't know if you rally have it, and end up tankering fuel. Essentially more flexibilty at zero costs.

larry

[C5Engineer 1170]

I installed them because I need to know exactly how much fuel I put into each tank for mixing in the oil. Fuel will transfer wing to wing more than you think if one tank has more fuel in it than the other or you are parked on a slope. It comes in handy also if you need to drain your fuel system for some reason.

[EDMO 1078]

I am moving mine forward to just behind the windsheild - takes more line to do it, but keeps them in sight.

ED in MO

[lakertreetopflyer 0]

I am moving mine forward to just behind the windsheild - takes more line to do it, but keeps them in sight.

ED in MO

I like that idea.........

[EDMO 1078]

I like that idea.........

Just make sure you have them below the tank level - Gas does not like to run uphill in a climb.

Kitfox changed their original wing tank fuel line routing from over the door to under, because of fuel starvation in climbs.

ED in MO

Edited 12 Sep 2012 by Ed In Missouri

[SuberAvid 617]

I recommend a shutoff on each tank primarily to keep the gas from transferring from one tank to the other as Joey says.. This can happen pretty fast if you park it on a much of sidehill. Also, I find that if the tanks are pretty full and I run for much time with both tanks on I end up getting a little differential pressure in my gas cap vent tubes and it will blow fuel out the vent on one or the other.

I put both fuel shutoff valves on a plate behind the passenger so they are easy to see and the passenger's shoulder does not hit them. I do not have any other shut off in mine; probably pro's and cons to that but I want mine to be as simple as possible.

[EDMO 1078]

I recommend a shutoff on each tank primarily to keep the gas from transferring from one tank to the other as Joey says.. This can happen pretty fast if you park it on a much of sidehill. Also, I find that if the tanks are pretty full and I run for much time with both tanks on I end up getting a little differential pressure in my gas cap vent tubes and it will blow fuel out the vent on one or the other.

I put both fuel shutoff valves on a plate behind the passenger so they are easy to see and the passenger's shoulder does not hit them. I do not have any other shut off in mine; probably pro's and cons to that but I want mine to be as simple as possible.

Randy, or anyone,

Do you think the vent tubes are really necessary when you are using a fuel pump. I thought vent tubes were only for using ram air to help pressurize a gravity system. Of course, the caps would still need to be vented. Will your Soob still turn the fan if the fuel pump fails and you only have a gravity system? Or, have you tried that?

ED in MO

P.S. I noticed that Joey's photo shows some real tall vent tubes. How tall do they need to be?

A check valve on each tank line would prevent transfer - but also one more spot for fuel stoppage?

I will have a check valve on each vent line between my main wing tanks and the outer wing tanks, to prevent fuel transfer thru the vent tube, and also a shut-off valve on the outlet line between the tanks.

Edited 15 Sep 2012 by Ed In Missouri

[C5Engineer 1170]

There was an AD posted years ago to make the vents that tall so that when the wings were folded fuel wouldn't run out. This was of course if you had perfectly sealed caps. If I fill my plane to the brim I always have a streak down the wing when I land so I assume my caps leak. The Kitfox vents are only like 2" tall. If I pull the line off my mechanical fuel pump with my plane sitting on the ground it'll shoot fuel 3ft out the line. I have the stock wing spar header tank behind the passenger seat.

[EDMO 1078]

There was an AD posted years ago to make the vents that tall so that when the wings were folded fuel wouldn't run out. This was of course if you had perfectly sealed caps. If I fill my plane to the brim I always have a streak down the wing when I land so I assume my caps leak. The Kitfox vents are only like 2" tall. If I pull the line off my mechanical fuel pump with my plane sitting on the ground it'll shoot fuel 3ft out the line. I have the stock wing spar header tank behind the passenger seat.

I think on some caps that have the vent tube, you are supposed to seal the internal vent with epoxy to prevent leaks and build more ram pressure.

The reason I was asking was because I need a fuel pump to give me 2 to 5 lbs of pressure - and must have another auxilliary pump too - some pumps will let fuel flow if they are not on, and others wont - the plumbing and check valves required to insure gravity flow from each type is a lot different. And, wanted to know if gravity flow would be enough to keep fan turning. Will install a pressure guage in mine, so I should know when the time comes. FAA says gravity flow = 150% of fuel consumption at full power, and fuel pumps = 125%.

I know that KF says not to fold the wings with more 1/2 full. Looks like the weight of folding with full tanks might be a problem too. Probably cant afford that much gas anyway!

Thanks,

ED in MO

Edited 15 Sep 2012 by Ed In Missouri

[SuberAvid 617]

Ed, I have always intended to try running it without the fuel pump on (I put 2 electric fuel pumps in mine but only run one at a time) but have not done so yet. I think I will try it on the ground though so would not have the benefit of the ram air. Stratus manual says you need around 4 pounds but only way to know for sure is to test it. It would be good to know. The pumps I used are the small square automotive fuel pumps (cant remember the name or model at the moment) but when I researched them the have a small built in check valve and will flow fuel one way even if they are not on.

My vent tubes are about 3" high; I drilled a small hole in the trailing side of the vent tube just at the bottom of the curve as I have seen done on most cubs to let rain that enters the tube out the back supposedly before it goes into the tank. I have to have less than 5 gal. in my tanks to fold the wings and not have gas come out the vents so I just siphon it out as I fold the wing and get it as empty as I can.

[EDMO 1078]

Ed, I have always intended to try running it without the fuel pump on (I put 2 electric fuel pumps in mine but only run one at a time) but have not done so yet. I think I will try it on the ground though so would not have the benefit of the ram air. Stratus manual says you need around 4 pounds but only way to know for sure is to test it. It would be good to know. The pumps I used are the small square automotive fuel pumps (cant remember the name or model at the moment) but when I researched them the have a small built in check valve and will flow fuel one way even if they are not on.

My vent tubes are about 3" high; I drilled a small hole in the trailing side of the vent tube just at the bottom of the curve as I have seen done on most cubs to let rain that enters the tube out the back supposedly before it goes into the tank. I have to have less than 5 gal. in my tanks to fold the wings and not have gas come out the vents so I just siphon it out as I fold the wing and get it as empty as I can.

I would sure like to know the make and model of your pumps, and if there is any problem with them. That one-way check valve should work great. My auto parts store has a small square pump for about $45 each, but havent done research on it yet.

My Holly carb requires 2 - 6 lbs of pressure.

Believe Dave Goode's Airdale with the Stratus had Ford 6 cyl pickup dual pumps on it from the 70s or 80s. I have heard that the one Facet pump has to be rebuilt if it sets too long. Dave Johnson stated that his would not work after setting idle all winter. Of course, winter is my best flying down here.

I have seen that teeny-tiny hole in the back of Piper cap tubes - Now, really, is a drop of rain going to pass out of that instead of into the tank? I doubt it - but better safe than sorry, IMO.

Thanks,

ED in MO

Edited 15 Sep 2012 by Ed In Missouri

[EDMO 1078]

I think on some caps that have the vent tube, you are supposed to seal the internal vent with epoxy to prevent leaks and build more ram pressure.

The reason I was asking was because I need a fuel pump to give me 2 to 5 lbs of pressure - and must have another auxilliary pump too - some pumps will let fuel flow if they are not on, and others wont - the plumbing and check valves required to insure gravity flow from each type is a lot different. And, wanted to know if gravity flow would be enough to keep fan turning. Will install a pressure guage in mine, so I should know when the time comes. FAA says gravity flow = 150% of fuel consumption at full power, and fuel pumps = 125%.

I know that KF says not to fold the wings with more 1/2 full. Looks like the weight of folding with full tanks might be a problem too. Probably cant afford that much gas anyway!

Thanks,

ED in MO

Maybe a better idea is to use UNVENTED CAPS to add your ram tubes to - that should stop your folded wing fuel leakage, or in-flight leakage.

ED in MO

[SuberAvid 617]

I would sure like to know the make and model of your pumps, and if there is any problem with them. That one-way check valve should work great. My auto parts store has a small square pump for about $45 each, but havent done research on it yet.

My Holly carb requires 2 - 6 lbs of pressure.

Believe Dave Goode's Airdale with the Stratus had Ford 6 cyl pickup dual pumps on it from the 70s or 80s. I have heard that the one Facet pump has to be rebuilt if it sets too long. Dave Johnson stated that his would not work after setting idle all winter. Of course, winter is my best flying down here.

I have seen that teeny-tiny hole in the back of Piper cap tubes - Now, really, is a drop of rain going to pass out of that instead of into the tank? I doubt it - but better safe than sorry, IMO.

Thanks,

ED in MO

Ed, I looked up the fuel pumps I have; I had one from the parts parts box I got with the first engine before I rebuilt it and I bought a second new one from Leading Edge Airfoils. The LEA part number is a Facet electric fuel pump part number H7278. I am not sure if it is the actual Facet number but I think it is. As far as not working if they sit for a period of time; the one in the parts box had been used and sat for about 8 years before I started using it again and it works fine. They both put out a little under 4 PSI and about 5 PSI if I turn them both on at the same time. I plumbed them in parallel since they have the built in check valve but just run them one at a time; it works fine with the Bing carbs I am running.

Do the small holes in the back of the vent tubes work? I just know they haven't hurt and if they keep some of the rain out of the tanks they are a no cost benefit.

Edited 18 Sep 2012 by SuberAvid

[EDMO 1078]

Ed, I looked up the fuel pumps I have; I had one from the parts parts box I got with the first engine before I rebuilt it and I bought a second new one from Leading Edge Airfoils. The LEA part number is a Facet electric fuel pump part number H7278. I am not sure if it is the actual Facet number but I think it is. As far as not working if they sit for a period of time; the one in the parts box had been used and sat for about 8 years before I started using it again and it works fine. They both put out a little under 4 PSI and about 5 PSI if I turn them both on at the same time. I plumbed them in parallel since they have the built in check valve but just run them one at a time; it works fine with the Bing carbs I am running.

Do the small holes in the back of the vent tubes work? I just know they haven't hurt and if they keep some of the rain out of the tanks they are a no cost benefit.

Thanks for the pump info. There are several Facet pumps in Spruce - I have the number of the one Dave complained about, and there is a larger, round one that has several check-valve options too.

Do the tiny holes work - Dont have a clue - just guessing - Maybe Mr. Piper thought so? Probably wont put them on mine, but cant see that they hurt anything.

ED in MO