It's a growing problem for aviation, I think oil companies should start producing av spec 82UL, basically auto fuel that is guaranteed not to contain alcohol or other addititves. I fire off emails every once in awhile to EAA about this, but it's another chicken/egg problem. FBOs won't stock it until there is some "demand". I would like to see this fuel available at airports just because it is a hassle while travelling to get mogas at airports, it's almost nonexistent onfield in the west.
I've burned approximately 5500 gallons of mogas in my plane over the last several years and probably 1/3 to 1/2 of that contained 10% ethanol (winter gas). I think all mogas in Oregon is now 10% ethanol year round.
I verified with composite guru Gary Hall several years ago that 10% ethanol would not harm my composite fuel tanks. I've seen no problems with it so far. I keep my plane hangared so water in the fuel is not a problem and I fly often.
You should check the specs or do some testing on whatever seals your fuel tanks.
disclaimers: my experience is limited to a rotary engine application in an experimental category composite airplane. the mogas stc for certificated aircraft does not allow the use of mogas containing ethanol.
Perry
---original message-----
To anyone who has encountered this situation:
Ethanol-free autogas is getting more and more difficult to find. For those of you who are already flying your rotary-powered kitplanes, what has been your practice regarding the use of autogas? Has anyone been using fuel that contains ethanol? If so, what percentage? Have you seen any actual damage from use of autogas containing ethanol, or is this just another myth - not applicable to rotary engines? After all, the engines seem to run just fine in cars using ethanol-based autogas.
Thanks for your input.
Bob J. Rogers
13B powered Mustang II, almost ready to fly