MOGAS STC and Ethanol... ???

[SIG600]

I was posting a comment in the RV thread, and it led me to a question. Do guys with MOGAS STC's, or people pursuing one.... how does the implementation of Ethanol affect the STC, or the use of E85. Will fuel lines, gaskets, and o-rings stand up to the punishment Ethanol puts on them?

 

[flyboycpa]

The internals don't stand up to the ethanol. This ethanol issue is a major concern for those using autogas nowadays. I have a Globe Swift (not eligible for Mogas w/ 210hp engine) and a Stinson 108-1 that has the STC already in place. I use autogas in a 75:25 ratio (mogas:100LL) in the Stinson. This is essentially the same amount of lead as the old 80/87. 100LL has approx 2 grams of Lead/gallon and 80/87 had .5 grams/gallon.

Anyway, I keep a tester in my truck and test the fuel at locations when I fill up my truck to ensure that locations don't yet have ethanol as an ingredient so that later I can fill up my 5 gallon cans to use in the Stinson.

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[Berkut]

how does the implementation of Ethanol affect the STC, or the use of E85.

I've never seen an STC that will allow you to use ethanol.

Since we are having this discussion in the experimental/homebuilding forum, chances are you won't have to worry about an STC anyway. A homebuilt doesn't have a type certificate to supplement.

 

[SIG600]

Right, no STC for homebuilts.... but still the same bits, pieces, engines, etc.

There's no STC for Ethanol, because when the STC was come up with Ethanol wasn't the main additive in gasoline. But with the nationwide implementation of it since May '06, it should be damn near impossible to find automotive fuel that dosen't have Ethanol in it. I can't think of the additive that Ethanol replaced. Like MDHC or some wierd acronym like that. Personally I think Ethanol is crap and a total mistake.

 

[Berkut]

But with the nationwide implementation of it since May '06, it should be dang near impossible to find automotive fuel that dosen't have Ethanol in it.

I have never even seen it around here (Nashville), although I must confess I'm not exactly looking for it. I know there have been a few airplanes that have been modified to burn it.

It will trash certain soft components in your fuel system. But, even when you solve the issue with soft parts compatibility, it still has a lower vapor pressure and might have a tendency to vapor lock.

 

[flylowman]

Check out EAA.org They hold the STC Mogass and have some good articles on the use of alternate fuels

 

[~~~^~~~]

One problem with Ethanol, as I understand it, is that the engine will run very lean and hot. The flex fuel cars are engineered with this in mind and capable of providing much higher fuel flows to compensate. There is also the issue of water contamination since alcohol will absorb water and the different volitility rates which apparently can lead to vapor lock at atltitude.

I think the articles I read were in Flying Magazine and there are good articles in Car and Driver discussing the fuel and the adjustments car manufacturers have had to make to adopt to its use. Here is a link to one article with a good simple test method at its conclusion.

http://www.eaa.org/education/fuel/knopp_alcohol.html

 

[flyboycpa]

I have never even seen it around here (Nashville), although I must confess I'm not exactly looking for it. I know there have been a few airplanes that have been modified to burn it.

It will trash certain soft components in your fuel system. But, even when you solve the issue with soft parts compatibility, it still has a lower vapor pressure and might have a tendency to vapor lock.

Do you fly GA around Nashville? My planes are based in Lebanon (M54).

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