Fuel gauge calibration

[woxofswa]

Apologies if this has been mentioned before.

One of the most frustrating things for me has been calibrating the fuel gauges.

Obviously I'm not a coder, but it seems to me that since the system tracks time, fuel flow, voltage indication of the floats, and start fuel and end fuel from the totalizer, it would be really nice if over a series of flights, it would be able to auto calibrate the gauge adjustment automatically and then indicate its belief that the gauges are as close as they can get.

 

[dynonsupport]

To do this would require that you first get the fuel flow sensor properly calibrated, which can take 5-10 tanks of fuel.

Then you'd need to fly 5-10 tanks of fuel so we could use the fuel flow to cal the tanks. But in any plane that has a fuel selector, we have no idea which tank you are pulling from, and in planes with common tanks, they are often not the same level due to venting, maneuvering, etc. So I'm not sure how we'd deal with any plane with more than 1 tank.

Finally, you'd need to burn ALL the fuel out of the tanks to have any accurate measurement near empty. Are you actually going to fly down to zero gallons?

With all of this, you have to take your first 10-20 flights with no direct measurement of fuel, which at least in the USA is not legal (and is not a good idea anywhere).

We'd love to help you get your tanks well calibrated. What issues are you having? Are you aware that you can go in and edit the calibration after it's done?

 

[tboyett]

Not meaning to hijack this thread, but had a hopefully related question.

When calibrating my tanks to the gauge, I found that the resultant calibration table did not contain the last fuel pour from 18 to 20 gallons.  The table contains the 10 pours from zero to 18 gallons.  Is that the correct outcome?

Thanks,
Tom

 

[dynonsupport]

That is expected. The last pour may not have actually been a full 2 gallons, so we ignore it and extrapolate from the last actual known point (18 gals).

 

[tboyett]

You are correct, the last pour was 1.7 gallons.  Thank you for the quick reply.

 

[airguy]

That is expected. The last pour may not have actually been a full 2 gallons, so we ignore it and extrapolate from the last actual known point (18 gals).

Additional to that, the float is usually located at the wing root, and with wing dihedral the float may well be at the top of its movement range before the last pour begins, so it won't register any movement. This is particularly true on the RV series.

 

[Tuiliere]

Hello Dynon,

One of my friend has an Advanced System and he is able to calibrate his fuel tanks both when the plane is on the ground and when it is in flight. I have a RV7 ( tail wheel ) and it would be very useful to have 2 calibration tanks, the first when I am on the ground and the other when I fly.
Is it possible to add it ?
In advance thank you
Sylvain

 

[Dynon]

It's not currently in our software, but I'll make sure it's in the list for possible future features.

 

[skysailor]

Sylvain,

I have an RV4. The shape of the tanks and the fuel sender placement (using the Vans senders) makes it such that I see no difference in reading between parked in 3 point and level flight. You may want to just calibrate them parked and fly it to see. Mine works great.

 

[Tuiliere]

Hello skylailor,

Information is the same only when the tanks are full. When they are half-filled, you have a wrong information when you are on the ground ( I made my calibration in flight level position). For example if my skyview said 40 liters in each tanks on flour, in fly those numbers change to 27 liters.
This difference has required me to check my tanks manually with a old wood gauge before each flight...
I hope Dynon will make this adding soon because it already exist on the advanced systems and it is the same Company.

 

[skysailor]

Sylvain,

I guess the 4 and 7 are different enough.