Vans fuel gauge calibration ?

[Larry DeCamp]

I have read the discussion about meaningless values due to dihedral etc. So I resolved to use accurate tank dipsticks and fuel totalizer to manage fuel ( of course burn rate and clock are always in play ). Because RV's must switch tanks left to right for balance, you don't know for sure where all the fuel is until it gets quiet. Before declaring the gauges worthless, I thought why not calibrate them so they are accurate at some minimum level for reserve planning.

Can any electrical types suggest how to install calibration trim pots (with ohm value) to set a minimum reading accurately. I believe the float is 30 to 240 OHM.

[Doug]

Frankly, I wouldn't bother, but they are certainly not worthless.

I don't know about the '3 but in my aeroplane I can swing the indicated quantity shown on the gauge by more than half a tank by simply stepping on the rudder pedals and displacing the slip ball its own width either side. Remember the same force acting on the slip-ball is also acting on the fuel and with the delay in the fuel passing through the tank baffles you will need to fly precisely in balance for quite a few seconds to have a close to accurate fuel quantity indication dihedral issues aside.

Because of their location close by the fuel pick-up, the real value of the fuel gauge is that they show the actual level of fuel above the fuel pick-up, so irrespective of the quantity of fuel in the tank or if you are inadvertently flying out of balance (I know, nobody ever does that!) the gauge will tell you at least where the level is relative to the fuel pick-up.

In terms of fuel quantity the fuel totaliser does a a pretty good job. I validate that by tracking fuel added to fuel consumed according to the totaliser and having now tweaked the coefficient rarely have to make any adjustment to indicated quantity.

In flight I manually log time on each tank for a running tally - if the panel goes dark at any time this is my redundancy.