Gasoline Whitepaper by Gold Eagle

[Anticept]

If you want to know a bit more about automotive gasoline, this is a fantastic read!

 

http://www.goldeagle.com/UserFiles/file/STA-BIL%20files/White_Paper_Ethanol_%20Blended_Gasline.pdf

 

Of note related to ethanol:

 

 

A gallon of gasoline comprised solely of hydrocarbons can hold only 0.15 teaspoons of water (at 

60°F) before the water will separate. A gasoline blend containing 10v% ethanol would require almost 

4 teaspoons of water before phase separation would occur. Therefore in routine operations, ethanol 

is more likely to suspend moisture and carry it out of the fuel system than hydrocarbon only fuels.

 

Keep in mind the part about ethanol drawing moisture from the air, so just because ethanol holds more moisture, it doesn't necessarily mean it's better.

[Doug G.]

So, having never suffered phase separation, does it show up as water observable in the sump?

[Anticept]

The bottom is the ethanol/water.

 

 

 

To put a note forth: I honestly think that the worry about ethanol phase separation is overblown, but awareness of it is nonetheless a good thing. Your plane would have to sit for a long long time before it gets to look like the above.

[Doug G.]

OK, a follow up question. After phase separation, is the fuel OK if you dump off the separated water? (I agree about the unlikelihood of this happening when the plane is flown on a regular basis.)

[Doug G.]

Makes sense Roger, thanks.