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Alcohol content in fuels


Kennith

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Posted

Like we've said here before... the effects of alcohol go beyond a "Rotax" issue... in Pipistrel's case, it looks like the wing-tanks themselves don't play well with alcohol. For others, it's connectors, gaskets, fuel-lines, or filters.

To my knowledge, CTs have been checked-out end-to-end, and are OK with (up to) 10% alcohol. OK... except for that nylon fuel filter thing.smile.gif

Tim

Posted

Here is a link to an important study done by Pipistrel on the effects of alcohol in the fuel:

 

My link

 

 

Thank you for posting this link.................. it is a big deal I think. If we can't use gasoline with alcohol without damage to the air frame, and we can't use 100LL without damage to the engine, we're screwed.

Posted

I agree this is one of the more perplexing issues for me in CT world right now, as we burn more alcohol out west. I am running a mix of 100LL with decalin and mogas, and I try to warm the oil at least once each week. But there is no way to really understand the tradeoff between the deleterious effects of alcohol and lead. What's a fellow to do?

 

WF

Posted

My background is in the auto industry. I recall how hard is was in the earyly '60's to re-engineer car engines and the fuel delivery systems to accept fuel with alcohol. All cars now accept fuels with mixtures of alcohol up to 15% (E85). None of the present day autos have any problems with this mixture. I have now been using mogas in my CTSW for the past year and a half. I use full synthetic oil (Mobile 4T). I have had absolutely no problems with the use of mogas in my CT. I fly in a climate that has large variances in both temperature and humidity. I put on 200+ hours in 2010 so I pumped a lot of fuel thru my CTSW. Rotax, like all automakers, produces engines that have been designed and developed to accept fuels containing alcohol. Flight Design has designed and developed aircraft that appear to accept fuels with alcohol. The only problem I have ever personally witnessed regarding the use of alcohol fuel in a CT was a partially melted plastic fuel filter. These plastic filters and no longer used by FD and all old plastic filters should have been thrown away and replaced with an aluminum filter per a FD SB. Two things I personally do to insure that I don't experience problems using mogas:

 

I always buy from large, clean gas stations that pump a lot of fuel .

If the airplane is going to sit for more than 3 months, I will remove mogas or run the tanks down and fill the tanks with 100LL.

  • 1 year later...
Posted

Dick, You bring a question to mind for me. I use 91 octane without ethanol nearly all the time. Since our winters up here are pretty significant I don't use nearly enough fuel to keep it "fresh" (which is a hard word to quantify, I guess.) This winter I started using Stabil fuel stabilizer in both the plane's tanks and the 75 gallon transfer tank in my truck.

 

Good old hindsight: was this a good thing to do? I haven't had any problems so far this winter. I'd appreciate an opinion.

Posted

Hi Ron. Jim is correct, I incorrectly labeled 15% alcohol fuel as E85. You have the best of all worlds for your Rotax if you have access to 91 octane non alcohol Mogas. This will have a fraction of the lead that 100LL contains and the ability to be stored for long periods of time with very little absorption of water. My CT doesn't sit more than one to two weeks thru the winter so I am running fresh fuel thru it. I have not had any issues with use of 93 octane ethanol Mogas in the 2 1/2 years I've used this in my CT. Note that I also check for percentage of alcohol content in my fuel frequently with the simple but effective EAA alcohol tester (this can also be used to determine if the fuel contains water):

http://www.eaa.org/a...as/test_kit.asp

 

Regarding the use of Stabil, this is claimed by some to work well while others, like me, are not convinced of this. In Michigan, we have no choice but to buy E15 Mogas fuel. All grades sold contain 15% alcohol. At one time I used Stabil but still found that this did not prevent gunked up carbs on my watercraft after wnter layup. The best I have found for watercraft is to completely drain the fuel and run carbs dry and drain the float bowls if there are bowl drains. Start the new season with fresh fuel and dont' leave fuel tanks exposed to the weather during the boating season. I don't think that you'll need to do anything with your fuel. If it sits for a few months, Roger's suggestion to drain and add fresh fuel is good advice. In addition, I would try to drain the carbs too if this is the case. Adding Stabil in the winter is your call based on your experience with this. It may prevent solvent build up in carbs but I don't think that it will prevent or eliminate water from collecting.

Posted

Dick, You appear to have the same situation as Minnesota, e.g. all fuel sold in the state has 10% alcohol in it. However, we also have "boat gas" that is sold through selected stations. They market it as "non-oxygenated fuel" for boat motors, snowmobiles, and classic cars. What it is, actually, is 91 octane fuel with no ethanol. Being in Michigan I would think that you can find this fuel at selected stations as well. Here it is about 35 cents a gallon higher but still $2.00 less a gallon than 100LL. I am also fortunate to find 91 octane with no ethanol in Fargo, ND, just 45 miles west. One would think that someone would offer this fuel somewhere in every state (wishful thinking, maybe??)

 

Here is a link to ethanol-free gas locations in each state: http://pure-gas.org/

 

This website lists 63 stations in Michigan alone.

 

Good suggestions from you all, thanks!

Posted

Hi Roger. I'm sure that you discuss this fuel issue on the other forums and know that you are actively involved with maintenance and repair of aircraft almost daily. Due to this, I consider your observations and comments regarding the results of using alcohol fuel very important and find it reassuring to know that you do not see any concerns with use of this fuel provided percautions are taken regarding the storage of it. Although I would welcome the day that a 91+ octane non alcohol and non leaded fuel would become available for us to use, I am forced to continue to use 93 octane E15 mogas and do so without any concerns to date. A note to forum members who may read this is that two of my friends visited with the team that is working on high octane non leaded and alcohol free bio fuel at Swift a few months ago. According to my friends, the Swift team indicated that it was close to delivering fuel to the market in octane ranges up to and above 100 with a price equal to present 100LL.

  • 10 months later...

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