Concerns about corrosion issues over ethanol is simply no longer an issue.
This obsession with ethanol free gas is all based on the catastrophic effect of early ethanol blended gasoline and I do agree it was a very valid concern.
Phase separation:
Highly unlikely if you keep your fuel tanks closed and fly a lot with fresh fuel.
Even less likely to happen in mid flight.
Vapor lock:
Design a fuel system to prevent it:
Either fuel pumps pushing fuel to your fuel controller or constant flow return,
both work, different concept. Fuel injection preferred, High fuel line pressure
is your friend when it comes to vapor lock.
All fuel system components must be ethanol tolerant.
AFP fuel injection system takes care of that.
Rubber o ring on tank drain replaced with Viton o ring ( 10 cents)
Mechanical fuel pump is the only wild card in my system and the only reason I carry Avgas. No one will tell me if the rubber components in that pump are ethanol compatible and I choose to park the aircraft with avgas in the system so as to minimize exposure of those rubber parts to ethanol. I do know from unnamed sources that rubber used in those fuel pumps is not a concern for ethanol. In todays litigious world one is better off listing a thousand things that can go wrong and not mention what actually works.
As to flying on mogas with ethanol:
I have tested as many scenarios as I could think of using mogas only and in
2 years and 260 hours of flying have not seen or noticed a stumble, burp, or anything else running the engine throughout it's power envelop in any and all conditions.
Many of us are using mogas with ethanol some without any modification but most are smart enough not to spread it all over the internet
From an engineer at the forefront of development:
Quote:
BillL
Join Date: Sep 2007
Location: Chillicothe, IL
Posts: 881
Quote:
Originally Posted by ronschreck
<snip> BTW, are there not some corrosion issues with running ethanol-blend fuel?
Since this thread has been revived . . .there are real facts and data behind elimination of modern ethanol corrosion issues. They were very real and very bad. It is true that they have been eliminated at the manufacturing plant.
The early ethanol plants (circa 1994) were not required to have a continuous monitoring system for acidic content. Cargill and ADM made 90% of all ethanol as an additive at that time. The manufacturing process adds acid to accelerate the mash fermentation process (like the old batteries in hillbilly stills) then a water wash process removes the acid. Some plants did not have good controls and allowed the acid laden ethanol out on the market. My engineering group worked with Cargill and ADM to propose, and get, the ASTM testing standard modified to make it a continuous process measurement rather than the batch process being used. This change pretty much eliminate all corrosion due to the ethanol content over the following 12 months that the standard allowed for compliance.
More background: At the time (mid 1990's) my engineering group was developing catalysts for large diesels that sprayed pure(denatured) ethanol in front of a catalyst bank to reduce NOx by 90%. We had field testing sites that purchased 10,000gal tanks of ethanol. The first one was ok, but then we started to eat up everything. Pumps especially. We had a 5 gal can of the stuff shipped back to us and it dissolved the chrome off the pull out spout of the 5 gallon can, and in the process of eating the container neutralized itself. Struggling for a while, I sent a guy with a glass container and brought a sample back. It was 500 times over the acid limit of the standard. yes, five hundred. So- the old tales of corrosion were true and were nearly impossible to trace. The large batch sizes and the fact that we stored it in stainless steel tanks kept the acid from neutralizing itself in normal steel tanks, allowing the team to get to the root cause.
PS: one must still ensure that elastomers are compatible and pressure/temp of fuel is adequate to prevent vapor formation, but corrosion should not be a concern.
__________________
Bill Lane
Building 7 tipper. QB,Canopy : on hold
G3X/GNS 650 Panel, Built by SteinAir
IO-360 M1B, Hartzell CS Composite
Wiring 98% sans FWF. FWF: Fitting SJ Cowl
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stc
I'm loving the Experimental world so far but still having a hard time with some of the justification that I see others make, but no disrespect to anyone and not judgement on anyone, it's just not for me. To each it's own, fly safe and enjoy
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