A couple of concerns: 1. The mix of gasoline and ethanol is not necessarily homogenous, meaning that the total in a gas station tank may be 10 % ethanol, but the portion you actually pump out may have considerably more, or less, than 10 % ethanol. That will take all the predictability out of mixing it with avgas to keep the ethanol to less than 5 %.
2. I may be wrong, but I am not sure there is approval for a mix of mogas and avgas. I like the idea, but would be concerned about insurance picking up on it and denying an engine failure related claim. Anybody knows? Sorry for raining on the parade... Eliacim > Here are a few things that I have found out about fuel in the past > few days. Since the Mogas STC does not allow for automotive gasoline > that contains ethanol, the question was asked about where you can > get gasoline that does not have Ethanol. I thought my sport pilot > instructor had a source in California. That was partially true. > Apparently "all" gasoline sold in California has between 4% and 6% > Ethanol. Through the Ultralight forums, there is a list of the exact > amount of ethanol in the gasoline that each company is producing. > Right now Mobil is low and ARCO is the highest in California. My > instructor buys from Mobil and mixes 100LL aviation fuel to reduce > the Ethanol percentage. The Rotax engine can tolerate up to 5% which > is the same percentage that is listed in the EAA STC for mogas as > the absolute-don't-use-it maximum. > > In some states, only E10 (10% ethanol blend) is available by law. > Some states have passed laws that the premium grade of automotive > gasoline contains no ethanol. In California, there is a mandate to > move to E10 by 2010 but the refineries will need to invest in their > transportation and handling infrastructure to support that. > > Relate to this discussion is the news that TCP will begin production > of TCP again around April of this year. They had some problems with > their packaging that tended to leak. The EAA recommended that > people use the auto fuel STC in the meantime. They also suggested > mixing 100LL with auto fuel to provide the same benefits of STC with > respect to lead fouling. They recommended a mixure of three-fourths > autogas and one-fourth 100LL which would contain the same lead > content as was allowed in the 80/87 octane aviation fuel (suitable > for the Ercoupe). > > So it seems that mixing 100LL and ethanol-blended auto gas will > solve both the lead problem and the alcohol problem. If you only > have E10 available, it looks like you would have to mix 50-50 to get > the percentage of alcohol down to 5% or lower. At that point the > lead content is half as bad but not yet done to the level of 80/87 > avgas (no longer available). A higher mixture of mogas can be used > if the actual alcohol content is less than 10%, but it will require > some research and/or testing to know what the content is to ensure > that the mixture does not contain more than 5% alcohol. > > Of course the use of 100LL is the other option which will need TCP > available to mitigate the risk of lead fouling. WOW we practically > have to make our own fuel to provide the right fuel for our birds. > > Frank Nelson > N51DV 415C > TOA/California > > >
