Unuseable fuel: FA Dodge 30.5 gal tanks

[Speedo]

I ran my right tank until the engine stumbled. After landing I removed the Saf Air drain to replace it and was surprised that two gallons of fuel drained out - I'd only expect a quart or so. So, between the two tanks the unusable fuel is at least 4 gallons, and probably a bit more since there is still some fuel between the drain and the aft wall of the tank. That's at least 30 minutes of flying in my plane (a PA-12 160).

Next task is to fill the "empty" tank and see how close it comes to 30.5 gal. Stand by for news.

I'm curious to know what others have found.

 

[Cubus Maximus]

I fly a PA-12-160 a few times a year. It has the 30.5 Dodge tanks and electric gauges :-? (I despise these electric gauges!!) When they read empty there is still 11.5 gallons per side. Hard to check this visually or with a stick at 3 point due to the shallow tank angle. Did I mention I can't stand these gauges!!

Brad

 

[mike mcs repair]

was surprised that two gallons of fuel drained out - I'd only expect a quart or so. So,.............................

more than likely.... the tank installer didn't follow the directions and RE-route/move lower the rear fuel line properly to be below new tank outlet which sit lower...

very common on left side (new position of fuel line will be above/against rear window frame BEHIND upright tube.. not in front of tube as was original)

 

[5139Y]

finally a topic i can reply to without risking being offensive. 39y has dodge tanks, flush caps, unhooked elec gauges, sight tubes. i just walked in from the hanger after replacing the fuel line from the rear header to the rubber coupler under the left d window. it took on water last fall after freezer filler season while sitting, water ran to the low point, froze in the line and broke it. f.a. dodge makes a raised adapter for their old tanks and 39y will be getting them soon. kracky will also be blanking off the sending units. i have flown the right tank dry several times trying to estimate remaining fuel. this is done very high off the ground. i can count on slightly over 20 minutes of fuel after the tank indicates empty, if i input a little right rudder. i do this for a couple of reasons, to learn my cub a little better, and to know if the tank is switched when it reaches empty, if i really need it there is a little time in that tank. i don't plan on that fuel though. dodge tanks are tough to read, and how they read depends on the instal. i love them and hate them, you are always fat on fuel, great unless it is tight. i am considering installing the left tank from 87c in 39y then installing the dodge tank in the left wing of 87c with a sight window installed in the aft section for better info when running light . this would be exp. of course. sorry for running long. chris

 

[aviationinfo]

Speedo---

I'm very interested in what you find out; I have the same setup.

I spoke to Steve at FAD last year and he said there's not really supposed to be any unusable fuel. Although he may be technically correct I'll bet that most installations have some.

As far as my tanks go I do know that the sight gages are calibrated conservatively and get less accurate at very low fuel quantities.

Andrew

 

[Speedo]

. . . RE-route/move lower the rear fuel line properly to be below new tank outlet which sit lower...

very common on left side (new position of fuel line will be above/against rear window frame BEHIND upright tube.. not in front of tube as was original)

Thanks for the heads up. I'll check the routing to see how the lines are run. It would be nice to reduce the quantity of unusable fuel!