Adding a backup fuel quantity indicator?

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farmrjohn

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farmrjohn
I have an Alon A2 with two wing tanks joined with a tee that feed via a fuel pump into a header tank that then gravity feeds the carburetor. The header tank has a float gauge and the two wing tanks have a single float gauge in the left tank. The tank gauge is very difficult to see/read in flight, requiring extensive gymnastic or yoga moves in order to see it. It does read fairly accurately in its defense (when you can see it). Would it be possible to add in a pressure sensing sensor like the Belite Radient sensor http://tinyurl.com/y4ldlb96 to an added tee just down stream of the tank line junction such as http://tinyurl.com/y6mr8kke to feed an auxiliary fuel gauge such as http://tinyurl.com/y2ahxwh7 ? This would keep the certificated indicator but provide an easier to read indicator on the panel. Would the fact that the fuel pump would be drawing fuel from the joined fuel line impact the head pressure the Belite sensor would detect, and hence the quantity reading?
 

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farmrjohn said:
Would it be possible to add....
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Anythings possible, but regardless which direction you wish to pursue it will be at least a major alteration so perhaps talk it over with your AP/IA for more specific info.
 
Truthfully, I wouldn’t see the need for as much headache as it’s likely to create.
 
farmrjohn said:
I have an Alon A2 with two wing tanks joined with a tee that feed via a fuel pump into a header tank that then gravity feeds the carburetor. The header tank has a float gauge and the two wing tanks have a single float gauge in the left tank. The tank gauge is very difficult to see/read in flight, requiring extensive gymnastic or yoga moves in order to see it. It does read fairly accurately in its defense (when you can see it). Would it be possible to add in a pressure sensing sensor like the Belite Radient sensor http://tinyurl.com/y4ldlb96 to an added tee just down stream of the tank line junction such as http://tinyurl.com/y6mr8kke to feed an auxiliary fuel gauge such as http://tinyurl.com/y2ahxwh7 ? This would keep the certificated indicator but provide an easier to read indicator on the panel. Would the fact that the fuel pump would be drawing fuel from the joined fuel line impact the head pressure the Belite sensor would detect, and hence the quantity reading?
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The most effective fuel indicator is a clock. Even though it is required under IFR, most airplanes have them hidden away in some corner of the panel. Given the number of fuel exhaustion accidents that happen, I am surprised that we don't have a large visible clock that ticks down, and then starts screaming at you when you dip into your reserves. Even my $500 drone has that, and will refuse to fly if the battery is too low.
 
While the clock is important it is not an "indicator" It's perfectly accurate so long as everything is as it's supposed to be but the value of the clock and indicator combination is that when something is wrong it will cause you to ask yourself "why is it doing that?" The indicator doesn't even have to be that accurate but will have a known and expected behavior.
 
Ive always flown with a backup, a good chrono watch, heck even a cheap watch or egg timer would work
 
Why not just guess slightly high on fuel burn, and as others said, time it. If for example you have 50 gallons useable, and typically burn 9.7 gph, round it up to 10 gph, so you have 5 hours until empty, or 4.25 hours with 0.75 reserve.
 
Actually I do use a clock (time) as a back up, but timing won't detect a leak or poor engine leaning, and a fuel flow totalizer won't detect a leak prior to the totalizer. Back to my second question, would the fact that the fuel pump would be drawing fuel from the joined fuel line impact the head pressure the Belite sensor would detect, and hence the quantity reading?
 
This is an Ercoupe, correct? Pretty basic airplane. Run the wings to the fuselage tank. Once the fuselage indicator starts to drop, you know you have xx amount of fuel left.
 
I had a student that bought a Alon A2 years ago. We were on a dual x-country and I noticed the fuselage tank level was going down. We should have had plenty of fuel in the tanks. We lost the fuel pump, had to stop for fuel a couple of times on the way home to fill the fuselage tank. The fuel pump moves fuel from the wing tanks to the fuselage tank.
 
farmrjohn said:
Actually I do use a clock (time) as a back up, but timing won't detect a leak or poor engine leaning, and a fuel flow totalizer won't detect a leak prior to the totalizer. Back to my second question, would the fact that the fuel pump would be drawing fuel from the joined fuel line impact the head pressure the Belite sensor would detect, and hence the quantity reading?
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Farmer John, you’re a wee bit overthinking this.

Rule of thumb on the conservative side and a watch.
 
bobmrg said:
Right. It is "time in the tank," not "fuel in the tank."
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Time = Quantity/rate If you don't have a means of measuring rate, you can't solve time to see what time is in the tank. The plane is not equipped with a flow meter/totalizer, and that still would not account for possible leaks prior to a flow meter, ie. leaking tank, line, or venting cap. Using an assumed flow rate doesn't account for incorrect leaning in cruise or change in engine performance.

Clip4 said:
Might be simpler to buy a different airplane.
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Simpler? Selling the current airplane and finding another? I don't think so considering the hassle of selling the current plane and finding another. I don't see the difficulty in adding a tee to the existing plumbing, connecting the sensor, and running the wires to a gauge.

That said, I suspect the fact the electric pump will be drawing fuel from the line will reduce the head pressure the Belite sensor registers, making the auxiliary gauge reading inaccurate while the electric pump is running. I don't want to cycle the pump to get a fuel reading so will leave well enough alone. Timing and the header tank float gauge will be good enough.
 
farmrjohn said:
Time = Quantity/rate If you don't have a means of measuring rate, you can't solve time to see what time is in the tank. The plane is not equipped with a flow meter/totalizer, and that still would not account for possible leaks prior to a flow meter, ie. leaking tank, line, or venting cap. Using an assumed flow rate doesn't account for incorrect leaning in cruise or change in engine performance.



Simpler? Selling the current airplane and finding another? I don't think so considering the hassle of selling the current plane and finding another. I don't see the difficulty in adding a tee to the existing plumbing, connecting the sensor, and running the wires to a gauge.

That said, I suspect the fact the electric pump will be drawing fuel from the line will reduce the head pressure the Belite sensor registers, making the auxiliary gauge reading inaccurate while the electric pump is running. I don't want to cycle the pump to get a fuel reading so will leave well enough alone. Timing and the header tank float gauge will be good enough.
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Dude, you are overthinking yourself into a bad spot IMHO

I’m all for getting fancy, but this is kinda silly
 
I have yet to fly an airplane that has fuel gauges that I'd trust enough "in-flight" to make that even a thing. A dip stick and a watch are my fuel qty gauge.
 
wilkersk said:
I have yet to fly an airplane that has fuel gauges that I'd trust enough "in-flight" to make that even a thing. A dip stick and a watch are my fuel qty gauge.
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That is so extremely true, they are at best, a bad guess.
 
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