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1 Gallons of AvGas

Clipper1

Active Member
Quick question. How did you determine/measure a Gallon of gas in order to perform a fuel calibration as accurately as possible?

TIA!
 
Pump Meter

I used a five gallon plastic (translucent) can and added one gallon at a time from the pump dispenser. Mark the outside of the container as you proceed.

Don
 
What is a gallon of Avgas

Quick question. How did you determine/measure a Gallon of gas in order to perform a fuel calibration as accurately as possible?

TIA!


It kind of depends on exactly what you are calibrating. If it is the fuel flow gauge then you need to find something of a specific volume that you trust. I used a five gallon gas can that I had previously calibrated with a large glass flask to a specific spot on its neck so I knew I was within a quarter cup.

But the rub is that Avgas has a pretty good coefficient of expansion so you have to pick one temperature to do all this stuff if you are going for accuracy..
 
I cannot add much to what has already been said, except that I have 4 plastic fuel containers (5 Gallons each) for ONLY AvGas since new. Very handy for draining fuel if you need to do any work on the fuel system. Comforting to know you have containers that have absolutely NO contamination. AvGas is far too expensive to discard these days.....
 
I used the gauge on the fuel pump, and added 5L at a time as accurately as I could with the displayed gauge and my squeezing capability on the handle. It's accurate enough for me, and agrees with the fuel totalizer (red cube flow rate) when I fill up. Never been more than one litre off in 72 on a fill... That's 2 minutes' worth at cruise fuel flow.
 
To get really accurate, you can use a paint mixing cup since they include an ounces measurement along with the various mixes on the side. They typically hold a quart, which is faster to measure.
Use it to measure out a gallon into your favorite jug and mark a line with a sharpie at one and two gallon increments. (128 oz to a gallon US or 4 qts to a gal)
It might take a few minutes to get done but is about as accurate as you can get.
 
I used the gauge on the fuel pump, and added 5L at a time as accurately as I could with the displayed gauge and my squeezing capability on the handle. It's accurate enough for me, and agrees with the fuel totalizer (red cube flow rate) when I fill up. Never been more than one litre off in 72 on a fill... That's 2 minutes' worth at cruise fuel flow.

Exactly my experience. The red cube has been very reliable and accurate to tenths of a liter tested by filling to the top in both tanks, flying, and then refilling.

Once floats come off their tops, and show something less than "max" which is 17 gallons on my EFIS, the numbers seem to match pretty well what the red cube says, so I use it as a sanity check.

For taildraggers, it's an extra step to raise the tail at the fuel pump for the calibration fill-up, but if you plan right, it shouldn't disrupt others too much.
 
When I calibrated my fuel gauges I emptied the tanks by removing all three drain valves. I then did a new weight/balance, replaced the valves with new ones, then refilled the tanks 2 gallons at a time from a bucket that I had measured and marked at the FBO. I refilled through a water-straining filter, calibrating the tanks for the EFIS gauge as well as recalibrating my dip tube.

I’m satisfied with the accuracy of the EFIS gas gauge, although it doesn’t really start moving off “full” until I’m down to about 14 gallons/tank. I use the gas gauge as a confirmatory check on my fuel computer, which thus far has been accurate to 0.1 gallon.
 
With tanks completely empty and plane in "level flight attitude", I called the local fuel truck.

The truck's pumped MUST BE calibrated so I get the fuel crew (at a quiet time) to come out and put in the incremental amounts as needed until I fill the tanks.

To me it is safer and more accurate than what I would otherwise do.
 
Oh ya ...

Be safe out there
 

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Might be wise to check compatibility of the ABC extinguishers.

If it's not Halon/Halotron or CO2, might soon become the insurance company's airplane anyway.
 
Quick question. How did you determine/measure a Gallon of gas in order to perform a fuel calibration as accurately as possible?

TIA!

I measured temperature (once) and used a scale. I recorded the approximate gallons then corrected for temperature at home.


Edit: It did not work for me (snow on the ground, leveling the plane recording the data etc), but the fuel station / truck method is by far the most accurate!!!
 
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Might be wise to check compatibility of the ABC extinguishers.

If it's not Halon/Halotron or CO2, might soon become the insurance company's airplane anyway.

Please tell me there are no type A extinguishers anywhere inside the fences near planes.
 
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