AlexPeterson

AlexPeterson

Well Known Member
I thought I'd post something many might not know regarding an Andair fuel selector valve set up for 90 degrees between L and R tanks. There is no position in between those positions where there is no fuel flow. The recent thread regarding the second flight of Paul and Louise's -3 reminded me that I had tested this when I replaced my Van's valve with an Andair valve.
 
AlexPeterson said:
I thought I'd post something many might not know regarding an Andair fuel selector valve set up for 90 degrees between L and R tanks. There is no position in between those positions where there is no fuel flow. The recent thread regarding the second flight of Paul and Louise's -3 reminded me that I had tested this when I replaced my Van's valve with an Andair valve.
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The question is...is there a reduction in fuel flow? You don't need a complete cut-off of fuel to stop the fan.
 
Jamie said:
The question is...is there a reduction in fuel flow? You don't need a complete cut-off of fuel to stop the fan.
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Not sure - I remember doing a ground run up with the valve in between L and R, which would run around 5 or 6 gph through it. More than enough for flight. I'll test in the air next flight.
 
Not sure - I remember doing a ground run up with the valve in between L and R, which would run around 5 or 6 gph through it. More than enough for flight. I'll test in the air next flight.
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Alex, please post the results of your testing. Yes, I have read of Paul's adventures and was thinking about the Andair valve in my project, as well as other things. I am glad I have the Andair, and am anxious to hear of your testing results.

What a great place to share information!
 
Same as "Both"

If you look on Andairs website under FAQs you will see this

"What is the difference between a FS20-3 and a FS20-4?
There is no difference to the valves except that the FS20x4 has a detent in the middle position for BOTH, whereas the FS20-3 has no detent.
It is not recommended that the FS20x3 is used in the centre position as vibration could cause the valve to move round to the position in between LEFT and BOTH and here there is a restriction in the fuel supply. "

This would infer that when in the middle it is actually acting the same as "both" its just that there in detent there.
 
The 90 degree between Left and Right selector is the FS20-7, not the FS20-3 (180 degrees between Left and Right). Therefore I suspect that whilst between Left and Right there will be a restriction in flow.
 
Paul's incident was the result of an improperly installed after market valve handle. I have never heard of an incident or accident caused by the standard valve and handle being left in a mid position cutting off fuel flow. I suppose it could happen.
The standard valve is clunky, a bit rough to turn, of ancient design, and not set up well having to cross over the lines, but never proven dangerous or inadequate. You can argue the Andair valve is superior, I like it, but there are a lot of things RV that you can upgrade. Some of those things, like the after market handle, can cause more problems than they fix.
 
JonJay said:
Paul's incident was the result of an improperly installed after market valve handle. I have never heard of an incident or accident caused by the standard valve and handle being left in a mid position cutting off fuel flow. I suppose it could happen.
The standard valve is clunky, a bit rough to turn, of ancient design, and not set up well having to cross over the lines, but never proven dangerous or inadequate. You can argue the Andair valve is superior, I like it, but there are a lot of things RV that you can upgrade. Some of those things, like the after market handle, can cause more problems than they fix.
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There are a lot of average quality items in the RV that could be upgraded, but how many can/will stop the motor when they fail? That's my justification for using Andair gascolator and selector. Fail that part and you're landing, or worst case, leaking fuel onboard. Andair is a superior quality and functioning critical component. Mine have worked flawlessly for 1350 hours and 11.5 yrs.
 
Low Pass said:
There are a lot of average quality items in the RV that could be upgraded, but how many can/will stop the motor when they fail? That's my justification for using Andair gascolator and selector. Fail that part and you're landing, or worst case, leaking fuel onboard. Andair is a superior quality and functioning critical component. Mine have worked flawlessly for 1350 hours and 11.5 yrs.
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Fuel line between valve and filter
Filter
Fuel line from filter to Boost pump
Any number of valves in the fuel pump (ask Andair!)
Fuel line from pump to firewall
Fuel line from firewall to mechanical pump

etc, etc, etc.

From the selector on down the line, it's all single string. The brand name isn't important - the design and field history is far more important. Most every brand has had critical issues. Look at their design, and how they are addressed.
 
Low Pass said:
There are a lot of average quality items in the RV that could be upgraded, but how many can/will stop the motor when they fail? That's my justification for using Andair gascolator and selector. Fail that part and you're landing, or worst case, leaking fuel onboard. Andair is a superior quality and functioning critical component. Mine have worked flawlessly for 1350 hours and 11.5 yrs.
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The valve didn't fail. They have an excellent history.
If you want to argue service hours, there are hundreds if not thousands more RV's flying with the standard valve than the Andair and I would bet many thousands upon thousands of hours more service on them. I have nothing against the Andair, have one myself, but not because the standard valve is unsafe or is even remotely likely to fail. I like the operation of the Andair.
People can justify their upgrades to themselves but lets keep the facts straight about Paul's incident so others are not misled.

(sorry Paul, wrote and sent while yours was in the que)
 
JonJay said:
The valve didn't fail. They have an excellent history.
If you want to argue service hours, there are hundreds if not thousands more RV's flying with the standard valve than the Andair and I would bet many thousands upon thousands of hours more service on them. I have nothing against the Andair, have one myself, but not because the standard valve is unsafe or is even remotely likely to fail. I like the operation of the Andair.
People can justify their upgrades to themselves but lets keep the facts straight about Paul's incident so others are not misled.

(sorry Paul, wrote and sent while yours was in the que)
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Actually, the valve in question did fail. It didn't deliver fuel from the selected tank to the engine when called upon.

Paul -

Very glad you didn't bend your new plane. And your point about all the components in the fuel delivery system is correct. That's exactly why I chose to go with what I perceived to be the better products and installation methodology all the way from the tank to the engine. Brand is irrelevant, but in this case the Andair brand represents to me the more reliable product.
 
test procedure

When I built the plane I verified by blowing through the valve with the handle in different positions that the Andair in-between Left and Right positions on my valve was "Both".

It never occured to me that there might be a reduction and I never tested it. I want to tomorrow and was thinking about how I would determine if there is a reduction. What do you think about setting up in cruise, in gliding distance of an airport, but with a richer than normal mixture. Note fuel flow. Then move it to directly in between Left and Right and note the fuel flow, and then move to either side of directly in between, noting if there are changes in fuel flow and where they occur. Would this work? I'll also ask over in the flight test section where Paul's thread started this discussion.

Jeremy Constant
 
It would work if

That would work if the restriction provided less fuel flow than the engine demanded. If the engine demands less than the restriction, you are unlikely to see any changes in pressure or fuel flow.

You would almost have to do this test on wide open lines on the ground.

More interesting, do you get cross flow in between?

Rick 90432
 
Don't forget vapor lock

Restricting fuel flow in warmer climate may prove more troublesome as it increases the chance of vapor lock between the engine-driven fuel pump and the restriction. So it's entirely possible that the restricted fuel line could provide sufficient fuel flow on the ground but in the air (where it matters) restricting the flow could still stop the engine.

Has anyone actually tested Van's valve to see if it cuts off fuel flow entirely between L and R positions? I seem to remember testing this way back when I was building and it didn't cut flow completely. Maybe my memory fails me on this issue. This thread seems to treat the topic as a foregone conclusion.
 
Andair mid position

What would happen with the Andair in the mid position with one side being close to empty. If you were low on one side and switched to the other and stuck mid position since we have arrived that it would suck from both sides the low side would run dry at some point correct?

If this happened would the sucking of air from the empty side cause the engine to sputter and quit?
 
Low Pass said:
Actually, the valve in question did fail. It didn't deliver fuel from the selected tank to the engine when called upon.
.
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I'm afraid that you're unfortunatley ignoring the facts, and misledaing people. The valve HANDLE failed (not part of the valve that Van's sells), not the valve. It could be accurate to say the the overall fuel delivery system failed - but not the component that you cite.

Jamie said:
Has anyone actually tested Van's valve to see if it cuts off fuel flow entirely between L and R positions? .
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Yes...once in flight ;), and several times on the ground the next day!
 
JonJay said:
... I have never heard of an incident or accident caused by the standard valve and handle being left in a mid position cutting off fuel flow. I suppose it could happen....
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Do the research, it can and has happened.

While I was building, a two time offender told me the valve in his RV-6A failed at 100 hours, its replacement failed at 150 hours in a position that partially off. He couldn't move it and landed at the nearest airport where he put in a third valve. When he returned home, he grounded the plane until he installed new fuel lines and an Andair valve.

He told me this story just as I was about to install the Van's valve and it was enough to make me open my wallet for the Andair.

DarylT said:
What would happen with the Andair in the mid position with one side being close to empty. If you were low on one side and switched to the other and stuck mid position since we have arrived that it would suck from both sides the low side would run dry at some point correct?

If this happened would the sucking of air from the empty side cause the engine to sputter and quit?
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Yes, you would suck air and the engine would stop. As part of any engine out procedure, you should check your tanks and fuel valve postion and hopefully you would turn the selector to the fullest tank prior to any takeoff or landing.

Andy, from Andair told me that he tested the 90* valve and that it will deliver full flow regardless of position. I do not recall what he said about the others as I was only interested in the 90* valve which I installed in my RV.
 
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FAR on Fuel Selection

I'm too new to have any opinion on this Andair vs Vans fuel selector debate, but I'm learning from both sides. I noticed via the Andair site that FAR 23.995 discusses these issues (highlighted portions by me):

Fuel valves and controls.

(a) There must be a means to allow appropriate flight crew members to rapidly shut off, in flight, the fuel to each engine individually.
(b) No shutoff valve may be on the engine side of any firewall. In addition, there must be means to--
(1) Guard against inadvertent operation of each shutoff valve; and
(2) Allow appropriate flight crew members to reopen each valve rapidly after it has been closed.
(c) Each valve and fuel system control must be supported so that loads resulting from its operation or from accelerated flight conditions are not transmitted to the lines connected to the valve.
(d) Each valve and fuel system control must be installed so that gravity and vibration will not affect the selected position.
(e) Each fuel valve handle and its connections to the valve mechanism must have design features that minimize the possibility of incorrect installation.
(f) Each check valve must be constructed, or otherwise incorporate provisions, to preclude incorrect assembly or connection of the valve.
[(g) Fuel tank selector valves must--
(1) Require a separate and distinct action to place the selector in the "OFF" position; and
(2) Have the tank selector positions located in such a manner that it is impossible for the selector to pass through the "OFF" position when changing from one tank to another.]

Amdt. 23-29, Eff. 03/26/84
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These requirements apparently don't apply to Experimentals, but they obviously originated from post-incident analysis, and it's interesting to me that they seem to directly address both the handle installation issue, and the problem of having any setting between Left and Right (whether labeled Off or not) in which fuel doesn't flow.

--
Stephen
 
N941WR said:
Do the research, it can and has happened.

While I was building, a two time offender told me the valve in his RV-6A failed at 100 hours, its replacement failed at 150 hours in a position that partially off. He couldn't move it and landed at the nearest airport where he put in a third valve. When he returned home, he grounded the plane until he installed new fuel lines and an Andair valve.

He told me this story just as I was about to install the Van's valve and it was enough to make me open my wallet for the Andair.
Click to expand...

Caution needs to be used so as to avoid generalizing, which can cause confusion. RV kits have not always been supplied with the same fuel valve (though they both look very similar).
The early valve (supplied until about the mid 90's) had only three ports (two in, and one out), and they were all on the sides of the valve. The valve body and movable spindle were both made of brass. It was common that as they aged, the lube would be washed out by the fuel, and the brass spindle would begin to gall in the body. Because RV builders in general are not aircraft mechanics (or plumbers) and since these are home built airplanes, it was not common knowledge that they required periodic maintenance (be lubed with fuel lube no less!).
About that time a new valve was introduced that has a fuel resistant, self lubricating plastic spindle. It has three inlet ports (on the sides)and one outlet port (on the bottom). It is not a direct replacement for the early valve so often when people had problems with the early valve they simple replaced it with a new one of the same type (much less work), but if they failed to do the regular lubrication maintenance they were destine to have a repeat of their original problem.
The early valve worked fine if properly maintained, but I will admit that it wasn't the best choice.... lubing the valve required that the fuel level in each tank be lower than the valve elevation... and just the hassle of doing it.
As far as I am aware, there has not been any service difficulties with the newer style valve. I have never had to replace one. They work!

(A little bit of RV history/trivia... Old Blue, the RV-6A prototype is still flying, doing transition training with Mike Seager. It now has almost 4700 hrs and still has the early style fuel valve installed. How? It has been properly maintained!)

Bill, I am not meaning to say that it is obvious that your friend was dealing with an early style valve... just pointing out that it is a possible explanation, and that the current valves should not be condemned just because of his experience.

But my main point is... That sometimes we need to look at things through a wide angle lens instead of a microscope.
 
My take on Van's valve. First, if you have one and question it's ability to perform as required, before you run off to spend an unneeded amount of cash for an upgraded valve, take the brass valve apart and see how it works.
For what the valve is asked to do, it doesn't get any simpler than this valve. But this valve does have one problem....... The spring that keeps the cone seated is too long and too strong. A weaker spring from ACE cut so you can lift the select handle about 1/8 inch will make the valve work like silk.

Second. When someone at Van's decided that it would make more sense to have the handle instead of the pointer point to the selected valve created the problem that you ended up with. Not only did you have to cross plumb to install the valve with the handle pointing to the tank, the after market people had to allow for the variation.

I installed my valve with the pointer (painted red) pointing to L or R. It works fine and I don't have to reach over the valve for leverage to change it. But another RV pilot might get confused.....

In the picture above, I see you have the valve plumbed so the stock pointer will point to the tank. One way you could have a safe selector handle is to use the stock one and alter it's looks and shape with some rectorseal EP200 epoxy putty. Mold it and shape it the way you want then paint it. The stock handle is safe. Even without the screw, it is a press fit onto the D shaft.

I also purchased the red handle and did not install because of the set screw. I would at least double set screw it. 2 set screws 7/16" long. Set the first one and then grind the second one down till when installed, it ends up just flush to the surface of the handle.

Van's fuel valve can be set to switch tanks in 1/4 turn with just a slight overlap where both tanks would feed at the same time. Van's valve can be rebuilt for less than one dollar without removing it from the plumbing. It also has far less parts then the Andair.
 
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rvbuilder2002 said:
Caution needs to be used so as to avoid generalizing, which can cause confusion. RV kits have not always been supplied with the same fuel valve (though they both look very similar).
The early valve (supplied until about the mid 90's) had only three ports (two in, and one out), and they were all on the sides of the valve.
...

Bill, I am not meaning to say that it is obvious that your friend was dealing with an early style valve... just pointing out that it is a possible explanation, and that the current valves should not be condemned just because of his experience.

But my main point is... That sometimes we need to look at things through a wide angle lens instead of a microscope.
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Scott,

Thanks for the clarification. I didn?t realize the valve was changed.

However, I still stand by original post; the Andair valve is of much better quality than the valve supplied with the kit and is worth every penny of the $250.
 
I just verified through testing that there is no change in fuel flow or EGT at any position between Left and Right on my fuel valve. Andair with Left and Right 180 degrees apart and Off is aft.

Jeremy Constant
 
I did the same today with a Andair valve. With the engine at 1700 rpm I positioned the selector halfway between left and right. No variation at all with fuel flow or pressure. Left it that way for about 3 minutes.

George
 
I just did the same 2 hours ago with the Van's stock valve set between left and right tanks (1/4 turn) and ran at 2600 at 7500 ft for about 5 minutes and no change in fuel pressure. left is at 10:00 right is at 2:00 and off is at 6:00.

When people complain about it costing over $75000.00 for an RV7, you can bet it has an ANDAIR valve in it. It is just an example of cost creep!......

Van's is not the worlds largest kit manufacturer because he purchased the most expensive part for the job, he purchased what would get the job done. And this valve is well proven.
 
So am I understanding that some of the Van's fuel selectors are "Off" between Left and Right and others are "Both" in the same in-between position? That would be a really good thing to know which you have:eek:

Thanks for bringing this to everyone's attention Paul, although I agree with Alex...:eek:

All Best

Jeremy
 
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