Ethanol, the EAA and Aviation

[Hank Levin]

The EAA (Experimental Aircraft Association) grants STC's (special certifications) to builders of experimental aircraft allowing the use of automobile gas, not normally allowed in general aviation aircraft. However, there are warning about using any gas that has ethanol in it. They list the reasons in the following announcement:

http://www.aviationfuel.org/autogas/test_kit.asp

(Note also the link to the FAA Airworthiness Information Bulletin PDF.)

Do these warnings have merit? Some (though not all) of the concerns would impact automobile use.

[Ron Fisher]

could you post a working link? this one seems to be broken...

[Ron Fisher]

I found and read the story about ethanol on the site you referred to...

I am not in aviation however in Brazil ethanol has been being used for aviation fuel in planes with auto type motors and some aviation motors with conversions...

Most of the issues the story brings up are true...ethanol can damage rubber parts, clean fuel systems of dirt and absorb water...I am not sure about aviation parts but you can buy ethanol resistant fuel system parts for autos...what the story fails to deal with is the fact that modern auto gasoline will also do most of this with no ethanol added...damage to fuel systems parts from modern auto gas is common due to volatiles in the fuel. These volatiles will ruin rubber parts, damage plastic parts, and once they evaporate will leave you with poor quality fuel that will degrade into gum and lacquer if it sets in the fuel system for to long...alcohol will not ruin your fuel system by coating it with gum and lacquer...Diolefins: An ingredient of gasoline which contributes to gum and lacquer has become a real problem with gasoline.

Modern gasoline has been subject to formulation restrictions that now make it able to sit only 4 to 6 weeks after manufacture before its usefulness as a fuel is compromised due to reduced combustibility. The biggest issue is the fact that the “volatiles” in this new formulation evaporate very quickly. so by the time you buy gasoline it is degraded in quality as fuel...some gasoline that has not been setting for a month before you buy it has been seen to boil in the gas tank due to the fact that the volatiles boil at low temperatures and can start to boil in the gas tank under high heat conditions like sitting in the sun...this has caused fires in parking garages and parking lots...

I will leave it to you to consider but I feel ethanol is a better, safer, cleaner fuel...you may need to get used to how to best use it in a plane, however it is good fuel...even with a little water in it...many folks have used ethanol with up to 15 percent water and had few problems with performance...most of the issue with water is related to electrolysis pitting metal parts like fuel injectors...if alcohol fuel gets more water than you want in it you can add "dry" alcohol to absorb the water and you will be back in good shape...

In 1942 more than 500 million gallons of alcohol was used for aviation fuel according to government reports due to shortages of aviation fuel from traditional sources...it was also used as torpedo fuel! I guess folks nowadays just can't do the stuff we could do in world war II for some reason?

[Hank Levin]

Thank you, Ron, for a well-informed and articulate reply. (Sorry I've been offline so long---I'm just seeing it a month later!) --Hank