When do you drain fuel?

mulligan said:
Anyone know why so many sumps? I liked the older 172 where you pull a handle for under the engine sumps and looked for evaporation and anything left behind. The new plane has 13 and the 10 on the wings are easy but I hate getting down on my knees on the Tarmac to check the three under the engine. Will still do it for safety but will moan and groan during the process
Click to expand...

Yet another reason I prefer the Cherokee to the 172 :). Three and done.
 
timwinters said:
Have you ever tested MoGas for ethanol using a clear jar? This is done by putting about an inch of water in the bottom of a jar, mark the level with a sharpie. Then fill the jar with gas. Shake, shake, shake, shake. Set it down. If the gas has ethanol in it then it will migrate into the water and the water level will rise.

If you had ever done this test then you'd have seen that the water has settled out of the gas and the level is back to the line in 3 to 5 seconds and it won't fluctuate from there even if left to sit for another hour.

I've always been amazed at how quickly it re-separates.

Yes, fuel tanks are larger and it might take a bit longer but I have no doubt that any water you pumped into your tanks while fueling will have settled out before you even get the hose reeled up.
Click to expand...


Yeah, but it think it's a little different when you're pouring fuel on top and in a larger scale.

For work it's just a do it when you show up at work for your daily flight check, and don't pump fuel if you don't know it's quality, otherwise white bucket test it.
 
mulligan said:
Anyone know why so many sumps?
Click to expand...

The old 172s had aluminum tanks inside the wings. Those tanks had smooth bottoms so that the water could easily flow to the sump. The restart 172s have integral tanks, which just means that the old tank cavity in the wing has been designed and sealed to act as a tank, but it still has the hat-section stiffeners across it inside, top and bottom, and those on the bottom act like dams that will trap water. So there are five sumps in each wing tank, four of them in strategic low spots where ribs and stiffeners meet and the last in the usual corner.
 
oldShar said:
If you have to hold the jar against a white background to determine the color, I would highly suspect the fuel.
Maybe if you are sumping MoGas, but the blue in AvGas is so blatant that any background other than light blue should make the color obvious.
Click to expand...
Depends where you are. The fuel at my airport has almost no dye in it. Sometimes it's clear enough that I smell it to be double sure.
 
You must log in or register to reply here.
Back
Top