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Switching fuel selector valves

This week my dad brother and I bought our first super cub. We are really excited for this new adventure. One thing that I noticed right away that is different than the PA12 we had been flying is that there is no “both” on the fuel selector. Wondering how hard it is to switch out the fuel selector to one that has a “both” option.
I am sure I will have lots more cub questions as we dig into figuring everything out. I have heard only great things about this group and am excited to be part of it now!
 
I honesty don’t mind switching tanks from left to right. On longer trips I will run one tank empty so that I know where all my remaining fuel is.
I would suggest flying it the way it is for awhile to see if that is really something you want to modify
 
Not a difficult job to switch out fuel selectors, I recently replaced a Univair valve with the Dakota valve that Mike linked to above. With the new Dakota valve in my cub and the selector on both with full tanks it draws almost exclusively off the right tank so I still end up selecting the left tank to balance fuel.
 
I switched out my fuel selector valve on my Super Cub with the Dakota Cub valve. It has Left, Right, Both and Off. I did it because I do dumb **** sometimes and forget to switch when I am down in the river playing and it could have serious consequences. It does feed faster out of the left tank because of the way the stock header tanked fuel system is designed and I switch back and forth between tanks on long cross countries. The Dakota valve has detents built in to meet current FAA requirements that only allow going to Off in one direction. I also have the Dakota Cub gascolator and if I ever decide to rebuild and remove my header tanks I can get the STC paperwork from Dakota Cub or the hearderless fuel system at no additional cost.

Cub Crafters has an STC for L R Both fuel system but require additional fuel lines, removal of header tanks, welding a bunge in the front of the right tank. They use the Allen fuel valve like Aircraft Spruce and Univair sells. They also require two bolts and bushings to restrict the fuel selector from going to off in only one direction. I am lazy and my goal ws to have fuel going to my engine at all times if fuel was in my tanks and that is why I chose the Daota Cub valve. Simple to drain the fuel tanks, remove the old valve, mark the fittings and transfer them to the new valve and install. I have had mine for several years now and like it, I just have to remember that the left feeds faster when I am full and on a long cross country. Most of my flying is 6-10 gallons of gas banging around the river so it works for me.
 
I'm with Canadian farmer, run it for a while. Change it out in a year if you don't like it. Its a non issue for me.
 
I would respectfully point out that Super Cubs have flown literally millions of hours with that right/left/off selector, and done so safely.

If it were me, unless the existing fuel selector valve has a problem, I'd leave it alone, fly it for a while, THEN decide if it's worth the $$.

As to Steve's argument, I know of a case where an experienced pilot was flying a SC with the headerless, and Both fuel selector, engine quit right after takeoff. As Steve noted, he'd had the selector on the left tank, which was empty. So, if you're looking to avoid that, you'd better ensure you put "Fuel on Both" into your absolutely, positively pre takeoff checklist.

Or, you can just put "Fuel seletor on Left Tank" in your takeoff check list, and ensure you have fuel in the left tank, which, according to Piper you're supposed to anyway.

Both work about the same way.

It's important to note that takeoff on the Right main tank is NOT recommended with the stock fuel system, according to Piper's owner's manual. The Right tank, according to Piper, is to be used in level flight. So, the question for Steve Pierce is this: Does the addition of the Dakota selector valve then permit use of the right tank for takeoff and landing?

MTV
 
This week my dad brother and I bought our first super cub. We are really excited for this new adventure. One thing that I noticed right away that is different than the PA12 we had been flying is that there is no “both” on the fuel selector. Wondering how hard it is to switch out the fuel selector to one that has a “both” option.
I am sure I will have lots more cub questions as we dig into figuring everything out. I have heard only great things about this group and am excited to be part of it now!


Steve has a wonderful thread on the installation of the Dakota Cub valve... do a search and you'll find it. Saved me a ton of time on install. Mine was leaking so I just decided to replace. I have the Dakota valve on my crashed/project PA-12 as well.

EDIT:
Here is the thread:
https://www.supercub.org/forum/showthread.php?52341-Installing-a-Dakota-Cub-Fuel-Valve
 
I switched out my fuel selector valve on my Super Cub with the Dakota Cub valve. It has Left, Right, Both and Off. I did it because I do dumb **** sometimes and forget to switch when I am down in the river playing and it could have serious consequences. It does feed faster out of the left tank because of the way the stock header tanked fuel system is designed and I switch back and forth between tanks on long cross countries. The Dakota valve has detents built in to meet current FAA requirements that only allow going to Off in one direction. I also have the Dakota Cub gascolator and if I ever decide to rebuild and remove my header tanks I can get the STC paperwork from Dakota Cub or the hearderless fuel system at no additional cost.

Cub Crafters has an STC for L R Both fuel system but require additional fuel lines, removal of header tanks, welding a bunge in the front of the right tank. They use the Allen fuel valve like Aircraft Spruce and Univair sells. They also require two bolts and bushings to restrict the fuel selector from going to off in only one direction. I am lazy and my goal ws to have fuel going to my engine at all times if fuel was in my tanks and that is why I chose the Daota Cub valve. Simple to drain the fuel tanks, remove the old valve, mark the fittings and transfer them to the new valve and install. I have had mine for several years now and like it, I just have to remember that the left feeds faster when I am full and on a long cross country. Most of my flying is 6-10 gallons of gas banging around the river so it works for me.

Interesting that Steve’s feeds faster from the left side while mine feeds faster off the right side. With the exception of the Dakota fuel selector I have a stock fuel system, put in all new lines this past spring.
 
I would respectfully point out that Super Cubs have flown literally millions of hours with that right/left/off selector, and done so safely.

If it were me, unless the existing fuel selector valve has a problem, I'd leave it alone, fly it for a while, THEN decide if it's worth the $$.

As to Steve's argument, I know of a case where an experienced pilot was flying a SC with the headerless, and Both fuel selector, engine quit right after takeoff. As Steve noted, he'd had the selector on the left tank, which was empty. So, if you're looking to avoid that, you'd better ensure you put "Fuel on Both" into your absolutely, positively pre takeoff checklist.

Or, you can just put "Fuel seletor on Left Tank" in your takeoff check list, and ensure you have fuel in the left tank, which, according to Piper you're supposed to anyway.

Both work about the same way.

It's important to note that takeoff on the Right main tank is NOT recommended with the stock fuel system, according to Piper's owner's manual. The Right tank, according to Piper, is to be used in level flight. So, the question for Steve Pierce is this: Does the addition of the Dakota selector valve then permit use of the right tank for takeoff and landing?

MTV
I will show my ignorance, I have never seen that in the owner's manual or if I did I forgot. I use to run off only my right tank down to 2-3 gallons in and out of places on the rive and never an issue. Ignorance is bliss I guess. Like the peace of mind of the Both positio and my FP5L fuel flow instrument. Because I only top off when doing cross countries and adding 5-6 gallons at a time I periodically drain and check my fuel level which always works out that I have a little more than indicated.
 
Interesting that Steve’s feeds faster from the left side while mine feeds faster off the right side. With the exception of the Dakota fuel selector I have a stock fuel system, put in all new lines this past spring.
In a PA12 or an 18? The left tank is above the valve with two fittings feeding the header while the right tank has one line going to the rear hearder tank at the baggage, around the entire fuselage and back to the valve. I always assumed that was why. Thought about putting a positive pressure cap on the right tank and seeing what that did.
 
I will show my ignorance, I have never seen that in the owner's manual or if I did I forgot. I use to run off only my right tank down to 2-3 gallons in and out of places on the rive and never an issue. Ignorance is bliss I guess. Like the peace of mind of the Both positio and my FP5L fuel flow instrument. Because I only top off when doing cross countries and adding 5-6 gallons at a time I periodically drain and check my fuel level which always works out that I have a little more than indicated.
Steve,

I'm not seeing that admonition in a copy I have here either. That verbiage was in the manual for the ~ 69 model I flew for years. I was never sure what the concern was, other than that the right tank has only an aft pickup, and the header tank and lines run aft of the cockpit. Obviously taking off on a nearly empty tank is never a good idea. The situation I understood to be of concern was a long descent on the right tank.

Anyway, using any close to empty tank while landing or taking off could create unwanted excitement.

MTV
 
Steve,

I'm not seeing that admonition in a copy I have here either. That verbiage was in the manual for the ~ 69 model I flew for years. I was never sure what the concern was, other than that the right tank has only an aft pickup, and the header tank and lines run aft of the cockpit. Obviously taking off on a nearly empty tank is never a good idea. The situation I understood to be of concern was a long descent on the right tank.

Anyway, using any close to empty tank while landing or taking off could create unwanted excitement.

MTV
Mike,
Strictly from a recollection perspective, wasn't the right tank an optional order item? If so, from a certification perspective it would have been treated as either an auxiliary, a supplemental tank rather than another main tank. I'm getting the adjectives mixed here. One is only used to supplement the main tank and the other is to feed directly to the engine. The advantage to Piper for placarding TO & Land on left tank only would have been for simplicity in certification and in the manner of running the plumbing. Since the right tank only has a rear outlet, it would have had a very high minimum fuel requirement. By allowing the use of the right tank for landing, there could be no flow in a nose down condition. Thus is was easier and less expensive for Piper to designate the tank for level flight only. I think the PA-22-108 was like this as well?
 
In a PA12 or an 18? The left tank is above the valve with two fittings feeding the header while the right tank has one line going to the rear hearder tank at the baggage, around the entire fuselage and back to the valve. I always assumed that was why. Thought about putting a positive pressure cap on the right tank and seeing what that did.

It’s on an 18.
 
Mike,
Strictly from a recollection perspective, wasn't the right tank an optional order item? If so, from a certification perspective it would have been treated as either an auxiliary, a supplemental tank rather than another main tank. I'm getting the adjectives mixed here. One is only used to supplement the main tank and the other is to feed directly to the engine. The advantage to Piper for placarding TO & Land on left tank only would have been for simplicity in certification and in the manner of running the plumbing. Since the right tank only has a rear outlet, it would have had a very high minimum fuel requirement. By allowing the use of the right tank for landing, there could be no flow in a nose down condition. Thus is was easier and less expensive for Piper to designate the tank for level flight only. I think the PA-22-108 was like this as well?

Yes, the right tank was initially at least, an option in all -18s. And, your logic makes good sense.

And, frankly, certification standards are so stringent these days, you'd probably have to be aerobatic to unport a tank. My current 175 has 9 gallons of unusable fuel. It has only one pickup in each tank. Whoever thought that was a good idea was a dunce.

MTV
 
Pacer, Tri-Pacers and Colts are placarded for right tank for level flight only with 1/3 tank or less. I would bet because of the header tank there is no issue with the Super Cub.
 
Like some of the others I normally just fly Right tank until empty then switch. No problems with takeoff or landing on that tank. However, I seldom do steep climbs or prolonged nose down descent. I did try a prolonged full power climb trying to figure out what my average climb rate was on a low right tank and after about 3 or so min the engine started to cough. I think if you have enough AOA you can fuel stave the engine with a low right tank because both rear header and tank fuel would be below carb level. You would have to run the rear header tank dry in a prolonged nose down descent but it would be possible if you had a lot of altitude to loose. I like Steve have had my dumb moments and ran dry on both takeoff and landing, switch to left tank was a reflex on first cough and engine ran fine. Nothing wrong with running on both (I do it in my Cessna) but I find fuel management is easier with a stock system.
DENNY
 
Huh? What's easier than "Both" for fuel management???

I really like my Andair fuel valve. I'd never go to a L/R system on a new build.
 
Stewart, you have all that fancy stuff telling you how much fuel your are using, have used, have left down to hopefully .1 gal per tank. Without that when you run both and have uneven fuel usage from each tank now you are relying on gauges and stopwatch (unless you have fuel flow). So how much fuel do you have when that stock gauge is bouncing off the bottom or the red ball is on and off the bottom? When I cough my right tank I know I have a no **** 18 gal remaining. That for me is 140 min of flying time left at normal cruse burn. If you do a lot of long distance flying you will always seem to find that headwind that throws the curve into the fuel planning. No right or wrong but it is only having to think hard about that last tank is in general easier.
DENNY
 
I don't pay much attention to how much fuel is in which tank. I don't need to. Total fuel-fuel used. I always run on Both. Always have.
 
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