J

JohnF

Well Known Member
What do you plan to do with the coming 15% ethanol auto fuel? I was thinking about going to 100LL with Decalin, but am not crazy about that either. This is on the immediate horizon; what are you planning?
 
15% ethanol!

I dont think that this will be a worry anytime soon. Read this article here:http://www.sun-sentinel.com/business/os-auto-scscolumn-102410-20101023,0,174593.column
Also at OSH this summer it was noted by Rotax reps that in Brazil the 912 was running on 30% ethanol with out any problems. My feeling was if the US market goes to a higher ethanol count in its fuel then Rotax will allow this fuel to be used in its engines.

John
RV12 N1212L
 
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EPA has approved E15 for newer cars, MY20001+ IIRC. However, this doesn't mean we're going to see E15 replacing the current E10 any time soon. Unfortunately, the coming shift in the political climate looks like we're going to see more mandates for ethanol.

Rotax has approved 10% EtOH. From the E-LSA perspective, this doesn't matter; run what you want. If you're flying a S-LSA, you can only use what your manufacturer approves.

TODR
 
For whatever it's worth, the Rotax seminar I went to at OSH addressed the question of the ethanol problem (and to answer rv9av8tr, ethanol = corn = Iowa = votes) by saying that the engine itself has no problems with ethanol. According to the presenter, the problems people have seen with ethanol usage in the past were related to plastic fuel lines that couldn't tolerate it.
 
I plan on building a small "distillery" to remove the ethanol before it goes into the plane.
 
the_other_dougreeves said:
As I am fond of saying "There are no environmental problems, only political problems." Many of the environmental regulations have no bearing on the scientific realities. Ethanol is no different.

TODR
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Right - in fact, one of the main reasons the ethanol lobby is pushing for 15% is only because they can't sell the amount the govt. has mandated they sell at only 10%. Wonderful logic there....

Once we do get pushed into it, yes, we'll be forced once again to deviate from Rotax's minimum of 10% - we won't really have any choice (I don't believe for 5 minutes E10 will persist alongside E15 ;)). And we'll have to go through this whole thing again waiting for Rotax to approve the higher concentration.

But even at 15%, ethanol will be vastly less hard on our 912's than the lead in 100LL over the long-term. I plan to just run the E15 once we run out of the lesser stuff....

LS
 
szicree said:
Doesn't removing the ethanol lower the octane?
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Ethanol does have a slightly higher octane rating from what I am able to determine through some basic research. I don't know what the octane rating would be of the remaining pure gasoline after I remove it but I can not see there being too much of a difference. Its interesting that E85 fuel (85% ethanol/15% gasoline) has a higher octane rating than premium grade gasoline (according to Wiki), yet auto fuel economy suffers greatly using it.:confused:
 
9GT said:
Ethanol does have a slightly higher octane rating from what I am able to determine through some basic research. I don't know what the octane rating would be of the remaining pure gasoline after I remove it but I can not see there being too much of a difference. Its interesting that E85 fuel (85% ethanol/15% gasoline) has a higher octane rating than premium grade gasoline (according to Wiki), yet auto fuel economy suffers greatly using it.:confused:
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The octane rating of pure ethanol is 113. That means if you removed the ethanol from E10 93 octane fuel, the result would be E0 fuel at 90.77(repeating) octane.

Octane rating has nothing to do with the power involved in the fuel, it is an 'anti-knock index' (what AKI stands for!). Basically, it means that you can run it at higher boost/compression levels before it will cause detonation.

The reason 92/93 octane fuel seems to give more power than 87 is because the engine can be more efficient due to higher compression and boost. IN actuality, 92/93 octane pump gas has LESS energy in each gallon than 87!

Ethanol has a very high octane rating (research shows 113) however it has a much lower amount of energy, thus why the result is lower fuel economy.
 
Pretty darn good explanation Erich! I learned more from your small statement that I have been able to get out of countless sources of info. Thank you.
 
30%???

Are the Rotax 912's in Brazil approved for aircraft use with 30% ethanol? and if so, to what altitude/temperature?

Bevan
 
We can only guess on this one!

Bevan, Sorry but all that you ask is an Unknown at that this point in time.

John
RV12 N1212K
 
has nobody tried

just taking some small sample of auto gas adulterated with ethanol at 5, 10, 15, 30 percent, disolving as much water as possible at a warm temperature, then cooling to the lowest temp a naturally-aspirated craft might encounter and see if any precipitation happens?

If not, is there any plan to do so and does anyone have a guess as to how to avoid the chance of precipitation in tainted fuel?

Does Rotax address the temperature/water issue in fuel with alcohol?
 
I suspect Delusional is referring to Phase Separation. The phenomenon where an amount of absorbed water in ethanol will, under given atmospheric conditions, separate from that ethanol. It is my understanding that those given atmospheric conditions are not constant. Dan
 
guccidude1 said:
I suspect Delusional is referring to Phase Separation. The phenomenon where an amount of absorbed water in ethanol will, under given atmospheric conditions, separate from that ethanol. It is my understanding that those given atmospheric conditions are not constant. Dan
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That's about it. Sorry for the jargon. Here's the plain english:

Take some gasoline and add a little water. The water mostly does not dissolve in gasoline so it sits at the bottom, hopefully near a drain where it can be drained off by the pilot during preflight. No problem.

But now, add some drygas, aka alcohol. Then add a little more water. The water will disolve, which is how the EAA test kit works, no rocket science here. So far so good if you gaskets and other compnents don't dissolve just like the water, or swell or soften etc.

But now comes the scary part. Remember what happens to water vapor in air when you cool the air off? First clouds then rain if you cool the air enough. Well, the same thing _could_ happen in gasoline with enough water dissolved in it because the solubility of water in fuel depends on temperature. Take a little warm auto gas with 10% ethanol, add some water and shake until water is all dissolved. Then cool the fuel just as it would say during a winter flight up to 8000. Will "clouds" or "rain" form in your tank during flight?

Follow up questions:
How does Rotax know this is not a problem? Are they assuming that the aircraft they run in only stay low where temperature gradients aren't so steep? Then what are the limits? Or maybe they know something that renders this theory pointless?

Or, maybe they are just relying upon the fact that nobody has reported any such incidents and they just figure they'll wait until one of us "proves" this is another real problem with ethanol in your fuel.

There is more on this subject in this thread http://www.vansairforce.com/community/showthread.php?t=62947
 
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EASA Report

If anyone suffers from insomnia I can send you a report commissioned by the European Aviation Safety Agency on the impact of ethanol on mogas in aircraft. The PDF runs to 280 pages.

I'm trying to get my aircraft legally approved for use with E10 in the UK. Don't hold your breath...

Cheers...Keith
 
My EAA ethanol test kit came yesterday. I checked out my premium fuel (91-93) today. The reading is zero ethanol in the fuel. It seems to me I read somewhere that ethanol is only being added to regular gas. Anyone out there know if that's true?
Dick Seiders 120093
 
dick seiders said:
My EAA ethanol test kit came yesterday. I checked out my premium fuel (91-93) today. The reading is zero ethanol in the fuel. It seems to me I read somewhere that ethanol is only being added to regular gas. Anyone out there know if that's true?
Dick Seiders 120093
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Could be in your area but here in MI, they add the ethanol to all grades,,,10%.
 
Mix it up Baby!

I agree with 9gt. It depends on you geographic location in the USA. Here in the DFW area all our fuels weather it is regular or premium it has Ethanol in it. If you go out away from the city to the more rural areas they use little or no Ethanol.

John
RV12 N1212K
 
Airframe and Alcohol

The one question I have regarding ethanol is whether the entire fuel supply system in the RV12 is designed to withstand the long-term affects of alcohol? I know it can do bad things to the system in my 35 year old certificated plane. Are the materials in the 12 optimized to withstand the inevitable? Just curious. One of many questions this newbie will surely be asking!

Bob
NW IN
 
Hey Bob

Don't think there is any problem with Ethanol in the RV-12 system. I have had some in, and you can't tell any difference. I used it in my last plane for years. No problem. Old systems, yes, it loosens up 'stuff' in the system.

John Bender
 
Ethanol!

All the parts in the airframe of the RV12 fuel system are made of metal. The Rotax engine is approved for 10% ethanol so there is no problems in the 12.;)
 
dick seiders said:
> ... It seems to me I read somewhere that ethanol is only being added to regular gas. Anyone out there know if that's true?
Dick Seiders 120093
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Definitely NOT true. What you may have read is that in those few states that have mandatory E10 laws, four active with Florida joining them at the end of the year, there are exceptions in the laws for marine, aviation, off road vehicles and small engines and those exceptions are fulfilled by allowing some premium unleaded ethanol free gasoline to be sold in the state. But in NONE of those states or anywhere else, for that matter, is there statutory language that requires that ethanol free gasoline be made available, and by the end of next year, or early 2012, there will be no ethanol free gasoline in the U.S. If you want to know why: www.e0pc.com

Your only choice is to ask your state legislators to pass a law prohibiting the blending of ethanol in premium unleaded in your state or asking the EPA administrator to prohibit the blending of ethanol in all premium unleaded gasoline. Please sign our petition to the EPA administrator: http://www.thepetitionsite.com/1/keep-pure-gas/ and write a letter to the FAA and EPA like the one I did here: www.flyunleaded.com You have about one year left to try to change this madness.
 
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