D120 Aux Fuel Tank setup question

[blueflyer]

I have aux wing tanks in my airplane that do not have fuel level senders installed in either tank. These aux tanks feed my main tank, and my engine is fed strictly from the main tank. I have my D120 setup to show my main tank fuel level, fuel burn, etc. I would like to do the following in my D120: I want to manually input the total amount of fuel in my aux tanks which will display on my D120 aux tank indicator. Then, when I pump the fuel from the aux tank, I want to go into the D120 and manually adjust the amount of fuel remaining the the aux tank. Is that possible to do?

 

[DougD]

Without a sensor, the display will be nonsense. Why not just use the totalizer function to keep track of the total fuel on board and fuel used. I presume your main tank stays full until the aux tanks are empty, or at least tracks linearly with the main tank until they are empty. So, your totalizer will show more fuel than the tanks until they match and then just track down together.

 

[jakej]

Although I personally don’t trust that an electric ( read facet) pump will work when I need to transfer fuel.
in your situation I’d just add the total fuel to the computer (providing you’re satisfied with the fuel flow & bowser use match up) & just run each main down enough that the aux tank quantity will fit or lower. then, as the fuel is pumped into the main tank it will increase the gauge level by close to that level especially if you use the other mains while the transfer is being done.
Also installing an optical sensor ( Aircraft Extras have them) using a regulated DC/DC 12volt out converter (really cheap to buy/assemble) connected to a light on the panel with a miniature on/off switch, to disconnect power after the light is on due to low fuel level,- ) you don’t want the light staying on while continuing flying). HTH