Fuel Level at Top of Tank

[cperry]

In my RV-9A, and probably most aircraft with wing tanks, my fuel level sensor (mounted at the wing root) can't reach the top of the tank (5ft up the wing), so when it reads 15 gallons, there could be anywhere from 15 to 18 gallons in the tank.

I've decided I can set the tank capacity to 15 gallons, which would show the tanks full for anything above 15 gallons, or I could set the capacity to 18 gallons, which would never show the tanks full even when they are. Of course we should always dip our tanks before every flight, so it really is just an indication that is only accurate when the prop stops...

Has anyone decided on their "most ideal" way to deal with this?

 

[dynonsupport]

Actually, you don't get to choose. The number you give it at the beginning of the calibration is a number the calibration routine uses to divide up your pours into a reasonable amount of increments (usually 1 or 2 gallons for most small aircraft). Once the float pegs high, the routine figures out where it stopped, let's say at 15.x, and then says 15+ in usage for all capacities above that.

That's the way you want it, though. If you actually have 18 gallons but it's reporting 15+, no biggie. But if it's reporting 18 and you only have 15.8, that's bad news. You want your gauge to be conservative when the ACTUAL reading isn't available.

 

[robertc]

I actually have the opposite problem. I have the Van's capacitance plates in an RV-7. When I calibrated the tanks, they reported no change for the first 6 or so gallons. The level seems to be very acurate at the top of the tank, but it runs out of fuel when recording 3 or so gallons remaining. HELP!!!

Bob

 

[cperry]

lol Yes, Bob's problem is much bigger than mine!

 

[dynonsupport]

Is fuel hitting the plates in those first few gallons? If not, that definitely explains it.