Since last posting I found on the Fight Design (makers of the CT LSA) a detailed bulletin on using ethanol on ther Rotax powered LSA.
Note they do NOT say "don't use it" but give clear detailed explanation if the considerations and conditions.
http://flightdesign.com/files/Service%20Notification/SN-ASTM-CT_-06-en.pdf
And
http://flightdesignusa.com/wp-content/documents/SB-ASTM-CT2k-04.pdf
Important reading, IMO, for anyone using ethanol added fuel in any Rotax who wants straight useful info rather than rumors
As for preventing and dealing with the very rare, although troublesome, possibility of the phase separation I mentioned in my earlier post and that link from CT... Here are some tips/notes I have picked up:
Phase separation doesn't just strike randomly at unlucky pilots or boat owners who have ethanol-added gasoline it their tanks...thre are conditions that provoke it.
A significant amount if water must get into the fuel.
Ethanol E10 fuel handles small amounts of water better than straight gasoline...up to a point.
Get a tablespoon of water condensationin alcohol free gas and it sinks straight to the bottom of the tank intact.
If it isn't' caught in the preflight (like what if that little puddle isn't right AT the drain valve because plane is slightly titled or whatever?) it can do all sorts of mischief... Get in the carb's fuel bowl sitting there indefinitely causing the bowl bottom to corrode, or get get further down stream and cause a stutter or stall during takeoff or worse.
In contrast,wWith 10% ethanol in the fuel that attracts and combines with minor water contaminationand dilutes out the water evenly and burns perfectly well with that trace of water.
In fact adding alcohol to gasoline is the traditional way to get rid of water in fuel system (usually isopropyl alcohol ...sold under names like drygas or gasoline-antifreeze.
But get TOO much water bonded into the alcohol and the Phase separation occurs:
" As an example, at 60 degrees F, water can be absorbed by a blend of 90%
gasoline and 10% ethanol up to a content of 0.5 volume percent
before it will phase separate. This means that approximately 3.8
teaspoons of water can be dissolved per gallon of the fuel before
the water will begin to phase separate."
The real irony is that regular gas without alcohol is MORE subject to phase separation than the ethanol-10% stuff:
"Since MTBE [which is in mogas that does not have ethanol] has much less affinity for water than does ethanol, however, phase separation for MTBE/gasoline blends
occurs with only a small amount of water, as shown in Figure 2.
A blend of 85% gasoline and 15% MTBE can hold only 0.5 teaspoons
at 60 degrees F per gallon before the water will phase separate.
For comparison, one gallon of 100% gasoline can dissolve only
0.15 teaspoons water at the same temperature. These figures are
far below the 3.8 teaspoons per gallon which will cause phase separation in
the 90/10 ethanol blend."
Both quotes above are from from
http://epa.gov/otaq/regs/fuels/rfg/waterphs.pdf .
In short you have to get quiet a bit of water into that tank of E10 fuel before worrying about phase separation.
The ways that could happen could include leaving aircraft in the rain with something about location and design of filler cap unexpectedly funneling water into tank, leaving external fuel filler cap off (yes, that has happened) or, more commonly though still rare..condensation on inner walls of a fuel lank that is not full.
Scenario: tank is half empty. Humidity is on the high side. Temperature drops at night, air in tank contracts and sucks in outside humid sir, temperature drops further at night inside the tank to below the dew-point, small amount of water condenses on walls of tank. Plane sits in hanger for two months adding a small amount of water this way each night until there's enough water in ther to trigger phase separation.
Prudent countermeasures include ..
If not flying plane for long oeriod fill tank to 95% . Good practice regardless what kind of fuel you use.
When doing the pre flight drain fuel sample check...especially if not flown for long period....really check what that clear looking fluid in the bottle IS: does it look AND smell like gasoline. (For god's sake sniff cautiously at a distance...gasoline fumes are toxic.. Alcohol fumes not as toxic but not nice.)
This is from one site addressing boat owner ethanol concerns
(Boats are at more risk because the are kept in locations of high humidity...on or near water):
"Preventing Phase Separation Do's and Don't's
DO
Add Stabilizer[such as Sta-bil]
Top off the tank (to about 95% full)
Use your boat frequently during the season so that gasoline doesn't go stale in the tank
DON'T
Leave the boat's tanks partially filled
Let the boat sit idle for months over the summer."
I'm not a fuel, safety, or aviation expert, I'm passing on this as the best and most reliable info IMO.
I have used E10 gas in our 912 UL aircraft for over 400 hour three years. So have many others.
Make your own call.
Al
P.S., After posting this I talked to tech support at the Sta-bil makers of Sta-bil additive for stabilizing fuel, and fuel with ethanol.
http://www.goldeagle.com/products/10_oz_ethanol.aspx
The tech explicitly said it will prevent the rare but worrisome phase separation.
I will check and see it they'll put that in writing.
As said, earlier, phase separation happens only if you get significant amounts of water in the fuel, and that is rare even if ignorant of that possibility and preventable if you understand how it happens.
P.P.S., here's written confirmation/claim from makers of Sta-bil additive that it will prevent possibility of phase separation in fuel that includes ethanol. Note that using this additive would add about 25-cents per gallon, but in most locations using alcohol free mogas, if you could even find it, would add about $1.50 per gallon to fuel price and using avgas would add about $2.50 per gallon to fuel price compared to using E10 mogas):
From: MARKETING <MAC1@goldeagle.com>
Date: December 19, 2013 at 11:53:11 AM PST
Subject: RE: GoldEagle.com - Contact Us Response
Hello Al,
Thank you for contacting Gold Eagle Company. Regular use of STA-BIL(r) will absolutely help prevent phase separation. My recommendation would be to use STA-BIL(r) Protection when you run your small engine equipment or car regularly and to use STA-BIL(r) Storage when you store your equipment from 30 days to 12 months. If you have any further questions or comments please do not hesitate to contact us.
Have a great day,
Tyler Rossdeutcher
Customer Development/Consumer Contact Associate
Gold Eagle Company
(773)326-6334
trossdeutcher@goldeagle.com
