Flex Fuel engines

[Bighorn]

I know thw Rotax 912 will burn up to 10% Eth are there any others? Is anyone with a o-200 or o-235 burning up to 10% Eth?

[steveinindy]

Not that I'm aware but you might try finding a sales rep for the various engine manufacturers you are considering and ask them. That would be your best source of information rather than going off of hearsay, vitriol and anecdotal reports on an internet forum. If a stock engine is going to tolerate the presence of alcohol without serious issue, the manufacturer will be the one to know about it first in most cases.


That said, I will point out that mentioning any tolerance or acceptance of ethanol in fuel tends to produce a very marked reaction around here. Put on your asbestos undies and buckle up my friend. This might get pretty rough.

[FlyingRon]

Well the engine manufacturers don't even admit to wanting you to be able to run auto gas in them.
If you're in a certificated bird, neither of the STCs for auto fuel allow any amount of ethanol.

If you are talking the academic exercise of putting it in your experimental aircraft, then it's up to you to be the engineer and test pilot. I only have passing interest in this in the Aviation area but I'm a boater so I can tell you what I've learned there. E10 while taking blame for a lot of ills really doesn't seem to be that big of a problem especially in an area where you can expect a lot of hydroscopic pickup like in a boat. E85 however is another story entirely. There's definitely issues with corrosion and such (which is why even the cars the stuff is designed for need to be specifically "Flex Fuel" vehicles.

I'm not even going to get started on the ecological and economic disaster that ethanol currently is. Suffice it to say, the only ones really benefiting from the current system is Archer Daniels Midland.

[Dana]

10% really isn't properly considered "flex fuel"; it's just an additive (many would say contaminant). E85, now that's a different fuel requiring a flex fuel engine.

The big problem is compatibility of ethanol with the rubber parts in the engine and fuel system, i.e. seals, hoses, etc. Rotax uses ethanol resistant rubber compounds in their newer engines, but the older engines don't... and because they're certificated, it's difficult for the manufacturer to change them.

Corrosion is another issue, but not so much on an engine that's run frequently.

[steveinindy]

Well the engine manufacturers don't even admit to wanting you to be able to run auto gas in them.
If you're in a certificated bird, neither of the STCs for auto fuel allow any amount of ethanol.

If it's not supposed to have auto gas run through it, why are you trying to use it then? That's my biggest question to the folks who point at the word "certificated" and go "See! That doesn't apply to us".


If you are talking the academic exercise of putting it in your experimental aircraft, then it's up to you to be the engineer and test pilot.

The problem is that most homebuilders aren't exactly the best qualified to be doing such testing since a lot of us get so excited that our creation is airborne that even the basic flight testing gets put aside in place of a glorified solo joyride.


There's definitely issues with corrosion and such (which is why even the cars the stuff is designed for need to be specifically "Flex Fuel" vehicles.

No offense intended but...

Imagine that, a vehicle designed for the fuel it will be using. I never really thought of that being a good idea. ;)



I'm not even going to get started on the ecological and economic disaster that ethanol currently is. Suffice it to say, the only ones really benefiting from the current system is Archer Daniels Midland.

Thanks for leaving it at that. It's the political BS that gets dragged in whenever this gets brought up that makes these threads more or less pointless because it turns into a big circle jerk.


Corrosion is another issue, but not so much on an engine that's run frequently.

Which is to say that it's a significant problem for most GA aircraft because of the infrequency with which people fly. I often wonder how many of these problems could be averted simply by pulling the plane out of the hangar every (or every other) weekend and running it for a few minutes to get the oil circulated through the engine.

[Bighorn]

. Put on your asbestos undies and buckle up my friend. This might get pretty rough.[/QUOTE]

ooooppppppsssss! was just a passing thought that slipped out.:)

[Mike M]

Well the engine manufacturers don't even admit to wanting you to be able to run auto gas in them.

well, not QUITE true any more: Lycoming Service Instruction No. 1070Q

http://www.google.com/url?sa=t&rct=j&q=lycoming%20service%20instruction%201070&source=web&cd=1&ved=0CFwQFjAA&url=http%3A%2F%2Fwww.lycoming.com%2Fsupport%2Fpubl ications%2Fservice-instructions%2Fpdfs%2FSI1070Q.pdf&ei=uBazT6bMKMSWtwe34oTRCA&usg=AFQjCNHn85pUZbORoj_JLIlERx7bhtt0kw&cad=rja

see also:

http://www.fuelandfiber.com/Archive/Fuel/Research/AGE85/age85.html

http://www.google.com/url?sa=t&rct=j&q=alcohol%20fuel%20aircraft%20south%20dakota&source=web&cd=1&ved=0CF8QFjAA&url=http%3A%2F%2Fwww.tc.faa.gov%2Flogistics%2Fgran ts%2Fpdf%2F2002%2F02-G-029.pdf&ei=fRWzT7_NNMnEtgeH4uHrCA&usg=AFQjCNHBwezawUk6t1bkwxTCVHFDgx113A&cad=rja

http://www.google.com/url?sa=t&rct=j&q=alcohol%20fuel%20aircraft%20south%20dakota&source=web&cd=4&ved=0CGcQFjAD&url=http%3A%2F%2Fwww.sdcorn.org%2Fuserfiles%2Ffile s%2FNAAA%2520Aviation%2520Grade%2520Ethanol.pdf&ei=fRWzT7_NNMnEtgeH4uHrCA&usg=AFQjCNHbJpuWL3J8JXRmfSgLHvoW92BXNw&cad=rja

http://www.txskyways.com/about_us.htm

your mileage may vary.

[FlyingRon]

If it's not supposed to have auto gas run through it, why are you trying to use it then? That's my biggest question to the folks who point at the word "certificated" and go "See! That doesn't apply to us".

I don't know what point you're trying to make. People have been running AutoFuel in airplanes for years now even though Lycoming and Continental do not recommend it. The FAA approves it and it is arguably better for those planes that were designed for 80 octane than trying to run them on 100LL avgas. Similarly the manufacturers wouldn't probalby admit that you can run non-factory parts on the engine, yet the FAA approves them and people have been flying legally and safely for 60-70 years with aftermark stuff.



Which is to say that it's a significant problem for most GA aircraft because of the infrequency with which people fly. I often wonder how many of these problems could be averted simply by pulling the plane out of the hangar every (or every other) weekend and running it for a few minutes to get the oil circulated through the engine.

While I agree with you that inactivity is an issue (and this is certainly a problem with autofuel versus avgas, avgas is designed for this). It's n ot going to help with E85. Running the engine isn't going to keep the fuel tanks and other components from corroding. There's no "oil" running through any of those parts. The only place there is likely to be oil and fuel mixing togother ought not to have fuel "sitting" in it while parked.

[steveinindy]

The FAA approves it and it is arguably better for those planes that were designed for 80 octane than trying to run them on 100LL avgas

This is technically correct. I always forget about the 80 octane engines because they had been phased out of production before I was born (or at least for the most part) so they aren't something that jumps to mind.

The point was that if you have an engine (and as you pointed out, a fuel system) designed for one fuel and you're most likely parked somewhere where that fuel is generally more readily available than the alternatives, I can't see anything (other than a flimsy "economic" argument which falls apart when you really examine it; there's also a general "screw you" attitude that motivates some because they simply can "get away with it" but that's thankfully the minority of pilots and that tree tends to be somewhat self-pruning due to other activities that attitude tends to predispose towards) that justifies tankering in automotive gas.

As for the FAA giving it their blessing, I don't know if that's really the best argument to use either since most of the time people on here are grousing about how the FAA doesn't have a clue. They approve all sorts of things that are pretty questionable when it comes to safety or reliability so long as the paperwork is in the right order.


Running the engine isn't going to keep the fuel tanks and other components from corroding. There's no "oil" running through any of those parts. The only place there is likely to be oil and fuel mixing togother ought not to have fuel "sitting" in it while parked.
Point taken but the comment was made about the engine. I was simply looking at that end of it. The other point I would make given that this forum caters to the experimental community is that if someone really wants to run autogas through their system, why don't they take the time and effort to switch (or build in the first place) the tanks and other parts in a way that can handle it. I have a good idea as to the answers to this but it's not socially acceptable to point them out on here.

[FlyingRon]

This is technically correct. I always forget about the 80 octane engines because they had been phased out of production before I was born (or at least for the most part) so they aren't something that jumps to mind.

Darn younsters.


The point was that if you have an engine (and as you pointed out, a fuel system) designed for one fuel and you're most likely parked somewhere where that fuel is generally more readily available than the alternatives, I can't see anything (other than a flimsy "economic" argument which falls apart when you really examine it; there's also a general "screw you" attitude that motivates some because they simply can "get away with it" but that's thankfully the minority of pilots and that tree tends to be somewhat self-pruning due to other activities that attitude tends to predispose towards) that justifies tankering in automotive gas.

Not everybody has to tanker in auto gas and since when is wanting to spend less money a "screw you" attitude? Even premium autogas is still running over a buck cheaper than the cheapest 100LL I can find around here. If my plane would run on auto fuel, I'd definitely give it consideration. You haven't made any technical reason that autofuel is a bad idea other than you believe that 100LL is some sort of magical potion. This is EXPERIMENAL aviation after all. What you call a "screw you" and "get away with it" attitude is the the experimental aviation idea of innovation and independence.

You haven't made the least bit of technical explanation as to why people should NOT deviate form 100LL.

[steveinindy]

since when is wanting to spend less money a "screw you" attitude?

That's not what I was getting at and you're combining two separate points. Some folks in the aviation community tend to have the perception that they need to thumb their nose at the FAA/manufacturers/etc as much as they can. A lot of these folks (at least around here) tend to be the same ones who crow about how they love running gasoline so they aren't under the "thumb" of the 100LL racket. That is, right up until their engine pukes or their fuel lines start leaking. Then it's a massive government conspiracy which is about the time I start to tune them out. These guys tend to rapidly move off the local airport to a grass strip when they realize that the cost of having a separate system for their automotive gasoline at the field is prohibitive in many cases (in other words, they get pissy with the airport management for not catering to their minority and either leave or are told to do so because of their hostility; one guy here was escorted off the premises in cuffs by the local PD because of he was being so bellicose) or otherwise remove themselves from the local pilot population.


Not everybody has to tanker in auto gas

I know a lot of people who have to run off the airport to get it and bring it back to their plane. It seems like a lot of extra work for something that's likely to damage the seals, gaskets, etc of the aircraft.


You haven't made the least bit of technical explanation as to why people should NOT deviate form 100LL.

You mean besides the fact that the fuel systems and most of the engines were designed to utilize 100LL and that the ethanol in gasoline is causing problems? That's a pretty good set of them in my book. That's not to mention it's a heck of a lot easier to just taxi up to the 100LL pump and fill the tanks. I'll pay a little more for the convenience factor alone.


What you call a "screw you" and "get away with it" attitude is the the experimental aviation idea of innovation and independence.

Well, when the same stuff isn't working and people are complaining about the damage it's doing, that doesn't exactly sound like "innovation" to me. When you're ruining your engine, that's not really "independence" now is it? Aviation has never been "independent" but we sure like to tell ourselves that (just like how we like to blow smoke about it politically, etc). Show me a plane with a motor that can be literally built by someone (not a corporation) with no input from an outside source and isn't beholden to the oversight and input of numerous other folks and then we will talk "independence".

Ethanol in gasoline isn't going anywhere anytime soon and instead of grousing about it maybe folks should start building their aircraft to accommodate it rather than trying to skate by with the older designs. How many of the folks do you see on these threads that are developing modifications to their fuel tanks, lines and engines to run the stuff without destroying them? I can't recall any of them. Instead, we get people whining about politicians and how they need to be booted out of office for supporting this. The problem is the next crop will go right into the pockets of the ethanol lobby, the oil lobby, etc. I might be a little less pessimistic about the automotive gas as an aviation fuel crowd if they banded together and said "Here's the problem, here's the practical solution we need to make this work. Let's get to it" instead of sitting around howling like a bunch of cats in a room full of rocking chairs and licking their wounds. If we're supposed to be "innovating" and "independent" then damn it, people need to start acting like it instead of just talking about it.

We need more folks who have the education, knowledge and experience to fix these issues. The problem is that the average homebuilder is chasing his tail by not innovating. In one way, this is good because most of us (including myself at the moment) are not engineers or expert mechanics. In another, it makes the "idea of innovation and independence" little more than a slogan and has caused us to stagnate into a bunch of copycats. Very few people in "experimental aviation" are really experimenting. It's simply called that because of historical context and the FAA classification of our aircraft. The average homebuilder buys a kit or a set of plans and build someone else's design. Sure, it's an "experiment" by definition but unless they did something really boneheaded, most aircraft will fly. I love the RV series and the rest of the popular kit aircraft are great too but the average homebuilder isn't innovating at all. Trying to pin that medal on every last one of our lapels is doing a disservice to aviation as a whole. Recognize those who are and hold them out as an example (which is why Rutan was honored a couple of years back at Oshkosh). The rest of us need to abide by the old Chrysler marketing slogan: "Lead, follow or get out of the way".

[FlyingRon]

You keep making unsubstantiated claims and bouncing around. Nobody is seeing damage to seals or gaskets from (non-ethanol) auto fuel. There's just nothing you have said that makes any credible statement why people with the STC or experimentals which have been reasonably determined to be in a similar situation, should not run autofuel.

The jury is out on 10% ethanol. For certain, it is illegal under the STC. There are mixed evaluations on certain things like gascolator gaskets, but a lot of the other alleged issues are pretty much unsubstantiated.

What makes you think people are NOT working on higher-concentration ethanol tolerant designs? It's not true that it's not happening. There's a group of guys that were flying RVs on 100% ethanol. But you don't get that by jumping up and down and arguing you shouldn't ever put anything other than 100LL in a Lycont or that a experimental owner shouldn't be allowed to tinker with their designs.

[steveinindy]

Nobody is seeing damage to seals or gaskets from (non-ethanol) auto fuel

Yeah, but good luck finding gasoline without ethanol in large swathes of the country. Around here, I can't tell you the last time I saw a pump that didn't have one of those "contains up to 10% ethanol v/v" stickers. There are a couple of motorcycle shops that specialty stock the stuff but it's more expensive than 100LL because they know they can gouge the RUBs.

For all intents and purposes in the Midwest, gasoline is going to equal 10% ethanol blend unless you really go out of your way to find the few places that stock the old blend. That's why I think you're looking at me like I've got my head on backwards. When I say "gasoline" that's what I'm talking about not the pure gas blend that is going the way of the dodo bird.


What makes you think people are NOT working on higher-concentration ethanol tolerant designs?

There are a few folks working on it no doubt just as there are a few of us working on designs intended for increased safety in the event of a crash. The point I am trying to make is that if even half or a third of the people whining about the subject on this forum would put the same amount of effort into fixing their aircraft to make them function just fine , we would probably have a solution to it in very little time.


. But you don't get that by jumping up and down and arguing you shouldn't ever put anything other than 100LL in a Lycont or that a experimental owner shouldn't be allowed to tinker with their designs.
I said it's probably not a good idea given all the issues with ethanol that people keep pissing and moaning about. If they want to do the homework and put in the effort, go for it. It's the people who are looking for the easy way out when there probably isn't one (either politically or from an engineering standpoint) and whine when this is pointed out. The easy solution for those who can't or don't choose to refit is 100LL (or whatever unleaded replacement for it comes down the pike). You don't write regulations or make suggestions to the smartest or most dedicated person out there. Think about the guy who can't be trouble to check his fuel for water before takeoff and then can't figure out why he had to put it down in a field right after takeoff. You really think he is thinking about the effects of the cheaper gas (as in ethanol/gas blend) on the gaskets, etc? There's a guy at one of the local airports here that has a death pool among his fellow pilots on when his poor judgment is going to cause him to bite it.


but a lot of the other alleged issues are pretty much unsubstantiated.

A lot of them seem to be more or less a convenient excuse for shoddy maintenance or the result of the owner trying a "home brew" to remove the ethanol from gasoline. I'm not enough of an "engine guy" to try anything other than calling my friends who are A&Ps and following the manufacturer's recommendations. My own distrust of my abilities and knowledge of anything firewall forward is a major reason why I honestly wonder anyone would chance it when there is an easy alternative that doesn't have any of these reputed problems.


that a experimental owner shouldn't be allowed to tinker with their designs.

I'm advocating for people tinkering with the designs (within reason of course). I pointed out that most of us don't which is why you see a ton more RVs and VariEzs than you do the one off designs that used to really warrant the term "experimental aircraft".

[Dana]

Steve, I think you're missing a couple of points:

The autogas STC's weren't just thrown out there because somebody in the FAA found the paperwork in order. There was a lot of testing by various groups, under a wide range of conditions, before the STC's were approved.

The STC's do not allow autogas with ethanol. Period. Any arguments about the safety of ethanol in a certificated and STC'd aircraft engine are moot because you can't do it (legally).

Autogas (without ethanol, of course) is a lot closer to the 80 octane fuel those older engines were designed for than 100LL. The A-65 my Taylorcraft simply required "73 octane minimum". And there are still a lot of those engines operating today.

Autogas without ethanol is admittedly hard to find today. It depends on the state, of course, but many states only mandate it for highway vehicles. Depending on the local distribution system, airports, marinas, etc. may be able to get ethanol free gasoline or they may not.

On non certified engines like Rotax, etc. ethanol may be used, though people debate about it. Rotax allows up to 10% ethanol. These engines suffer from lead fouling on 100LL; they're made for autogas. 2-strokes need a jetting adjustment since ethanol runs leaner, an owner who doesn't adjust the jetting may blame ethanol for problems. I've seen no problems that I could relate to ethanol in any of the 2-strokes I've operated.

[steveinindy]

The autogas STC's weren't just thrown out there because somebody in the FAA found the paperwork in order. There was a lot of testing by various groups, under a wide range of conditions, before the STC's were approved.

The STC's do not allow autogas with ethanol. Period. Any arguments about the safety of ethanol in a certificated and STC'd aircraft engine are moot because you can't do it (legally).

Oh, I know how difficult it is but at the same time a lot of people seem to forget (or ignore) the point you and Ron both brought up: that the presence of ethanol negates the STC. This is one of the problems here locally and it seems to be causing problems with the various "gaskets". Which ones, I'm not sure...the mechanics just talk about the ethanol messing with "the gaskets" and that pilots often chime in with "but the engine is STCed for this!".


an owner who doesn't adjust the jetting may blame ethanol for problems

Yeah, I saw that during my time flying ultralights. It's like the old squawk list joke about the problem not being with the headset but rather what's between it.


I've seen no problems that I could relate to ethanol in any of the 2-strokes I've operated.
Neither have I but then again my n=somewhere between 300 and 400 hours in mostly 2-stroke powered aircraft is a drop in the bucket compared to some.


Autogas (without ethanol, of course) is a lot closer to the 80 octane fuel those older engines were designed for than 100LL. The A-65 my Taylorcraft simply required "73 octane minimum". And there are still a lot of those engines operating today.

One of my acquaintances has a little L-bird and I can't remember which model but it takes the lower octane fuel. The stuff isn't apparently easy to find around here and he jokes that it will soon be cheaper to figure out how to put a turbine on it and base it at IND (where Jet-A is something like $7.00+ a gallon). The one marina I know of here that has it happens to be really close to an airport and they peg their prices to the price of 100LL to take advantage (as in "bend over and grab your ankles") of the pilots who want to buy ethanol free mogas.

The guys who need a lower octane fuel are the ones who are really getting screwed over here. The rest of have other options for the most part.

[Aaron Novak]

Anyone that thinks automotive fuels are "the greatest thing since sliced bread", apparently know little about them, and dont realize what a luxury a fuel like 100LL is. Not from the chemistry perspective per se, but from a control standpoint. Auto fuel is all over the map, and ethanol is only one of the variables. It is some of the nastiest, most uncontrolled buch of garbage ever made. From an engine designers perspective, I wish all fuels were 100LL or 98UL.

[WWhunter]

Why is it that anytime someone asks a simple question concerning ethanol we seem to get the same people saying the same things. Every single one of these types of threads on the various forums end up with the same pi$$ing and moaning matches with the pros and cons coming from the different proponents of these fuels. Can't we ever have a thread that doesn't drift into these spats?

Can anyone just answer Bighorns question with a direct answer?

Willie....I have an O-235 in one of my planes as you know and I have burned auto fuel in it when I had to but I always bought non-oxygenated so it was sans ethanol.
Now in my O-300 powered plane I unknowing used some fuel with ethanol in it for quite a while and never had an issue. This happened in a southern state many years ago when the pumps there were not marked as the fuel containing ethanol. I was lacks in checking because when I had asked the fuel station if they had ethanol they had said the state did not have it in any of the gas. I had checked and he was correct. Well, over the next few months it had been phased in an I didn't know it had been done so was still buying my fuel at the same place as always. One of the other pilots at the airport I was based at informed me the local station was now getting their fuel with ethanol and had been for several months. I quit using it because the STC states I can't......but the engine never knew it had it nor did I have any problems.
I feel as long as a person plans for its use in an experimental and makes all the appropriate modifications to the fuel system there shouldn't be any issues.
Keith

[Aaron Novak]

Keith,
Simple answer to your question is this, Passion Without Education, or PWE for short. Seems to crop up frequently on the internet.
-Aaron

[Bighorn]

[QUOTE=WWhunter;16171]Why is it that anytime someone asks a simple question concerning ethanol we seem to get the same people saying the same things. Every single one of these types of threads on the various forums end up with the same pi$$ing and moaning matches with the pros and cons coming from the different proponents of these fuels. Can't we ever have a thread that doesn't drift into these spats?

Can anyone just answer Bighorns question with a direct answer?


Thanks WW

As you know I have been looking at LSA or ELSA and just was wondering what was allowed for options. I do agree that 100LL stores for some time longer. Going forward does one look at the newer style engines that may be easily adapted to other fuels or the good ol standbys like your o-235 that are tried and true.
Didn't mean to open up a can of worms just looking at what is....and someday may be.

Thanks again

[Aaron Novak]

BigHorn,
To answer your qustion simply, the engine is not in itself the issue, but the application and operating conditions are. "Flex Fuel" opens up so many variables that while not critical to automotive use, could be real issues in aviation. Big differences are the storage intervals, ambient pressures and temperatures etc. Right now there are so many serious long term durability issues with ethanol blends its not funny, and the non-aviation engine manufactures are doing everything they can to try to make things work well enough to get by. Its not as pretty as it appears on the "outside".

[Frank Giger]

How many of the folks do you see on these threads that are developing modifications to their fuel tanks, lines and engines to run the stuff without destroying them? I can't recall any of them.

Ahem.

Aluminum tank.
Braided line on the fleshy side of the firewall, automobile fuel line on the noiser side.
Fuel filter in addition to the gascolator.

Then again, my engine isn't certified and is designed to run on automotive fuel in the first place. I'm fortunate that we have a high test ethanol free gas station convenient to the airfield, but I'm sure at some point some 100LL is going to go into the tank. If I need some juice at some distant field I'm not scavenger hunting; I'm gonna put up to ten whole gallons of Super Aviation Fuel in and go!

[steveinindy]

Aluminum tank.

Not to add fuel to the fire (pun not intended), but I believe you know my opinion of bare aluminum fuel tanks and their limitations with regards to my particular field of work. If I'm mistaken, shoot me a PM and we'll discuss it to avoid a further derail of this thread.


Then again, my engine isn't certified and is designed to run on automotive fuel in the first place. I'm fortunate that we have a high test ethanol free gas station convenient to the airfield, but I'm sure at some point some 100LL is going to go into the tank. If I need some juice at some distant field I'm not scavenger hunting; I'm gonna put up to ten whole gallons of Super Aviation Fuel in and go!

Yeah, the whole fuel debacle (including the current uncertainty of the 100LL replacement efforts should the EPA get a wild hare up its collective arse) is another primary reason why I decided to go with a Jet-A powered engine for the second design (the LSA being the first design) we have been working on.

[Aaron Novak]

Ahem.

Aluminum tank.
Braided line on the fleshy side of the firewall, automobile fuel line on the noiser side.
Fuel filter in addition to the gascolator.

Then again, my engine isn't certified and is designed to run on automotive fuel in the first place. I'm fortunate that we have a high test ethanol free gas station convenient to the airfield, but I'm sure at some point some 100LL is going to go into the tank. If I need some juice at some distant field I'm not scavenger hunting; I'm gonna put up to ten whole gallons of Super Aviation Fuel in and go!


Frank,
Aluminum tank not a wise choice when going with ethanol blends, unless its 1100 or 3003, and even then you have to be VERY careful selecting fitting alloys. Automotive applications that use various ethanol blends typically stick to polymers (plastics), steel ( believe it or not ), certain nickle based alloys, and pure aluminum for their systems. What do you mean by "automotive fuel line" anyway?

[Joe LaMantia]

Interesting topic!

I think there are some key elements that get the conversation going in different directions. First off we in the aviation world have a EPA problem with 100LL, we also have a cost problem due in part to technical issues and driven by a very low volume customer base. One solution that started off the thread was the fact that some Rotax 912 engines are available that can use current auto gas, i.e. 10% ethanol. Let's assume we could develop a whole series of new aviation engines that would run just fine on the current auto gas. That would satisfy EPA and bring the fuel cost per gal closer to what we are paying to drive our cars. That would be great for all the guys who can afford to buy a new airplane or have their current "old bird" upgraded with a new fuel system and engine. We'd still have a huge number of folks left out to dry simply because they can't afford to do that big a modification. Then there's the distribution thing. Today most airports carry 100LL and Jet A, if you can fly (legally & technically) with current auto gas you still have a big problem finding it at any airport. Now if the whole GA fleet could magically operate on today's auto gas then all the 100LL tanks and pumps could be "changed" to auto gas and we'd all be happy.

Unfortunately, we don't have many engines today that can run on auto gas with 10% ethanol, and there are a whole bunch of segments in GA outside of us "low and slow" guys who really need high performance fuel. I think EAA in the form of it's membership is doing what it can do to experiment with aircraft and engines using something other then 100LL. Steve is going Jet-A and Frank is lucky enough to have auto fuel near his home base. Both are good examples of homebuilders finding solutions that work for their missions. The rest of us stuck with older certified aircraft are flying on 100LL and hoping that a solution is found that will allow us to continue to fly at some sort of affordable cost.

Joe
:eek:

[Jim Heffelfinger]

As this is not a new thread and has had many iterations over the last few years. I comment in brief.<br>
1. Anyone thinking they have mogas that is alcohol free better not make any significant bets on that. Nearly all US auto fuels have ethanol. Assume it does and be surprised if it does not. Asking the gas station will get an unreliable answer. Test for it.
2. Ethanol is being used by the blenders because it's really less expensive - Because subsitities that were designed for infrastructure development for the supposed huge shift to flex fuel auto sales - that didn't happen. We now have a mandated (Feds) glut of ethanol in the US and high corn prices.<br>
3. If 91 octane fuel was available at the pump without ethanol it would solve a number of issues . Not only allowing the planes with STC for mogas to use it but also all the Rotax and other Rotax type engines would be happier. That includes boaters, off road vehicles and 2 cycle garden equipment. The high performance boat guys are going to the airport and buying 100LL because it doesn't have ethanol.
4. Airports that had Mogas have stopped carrying it as the ethanol free fuels are hard to find if not at all available. One ethanol-free fuel would bring back those airport services.
5. Don't expect to see a true flex fuel engine in a plane - ever. No one is going to invest in that technology for such a tiny market. (auto-conversions excluded)<
6. The world wide supply issue for 100LL has a number of engine manufacturers looking at Jet A for piston power.
7. Flex fuels have less power per volume and dramatically effect HP/pound.

[Joe LaMantia]

Jim,

Lots of good thoughts! I might take issue with item 2, the real cost of ethanol is understated if your just looking at a cost per gallon comparison of with vs without ethanol. Everyone who buys food that contains any corn product is subsidizing the ethanol program. It's another cost pass through to the average consumer, the price of corn has gone up a whole lot since the ethanol program started. Now there are a bunch of plus and minuses that are really hard to track on this one so you can take any position on it and find figures to support that position. That was actually pointed out to George W. when the issue came up and his response was that this would be "short-term" while we switched to "switch grass". The idea being that you can produce ethanol from just about any plant and using Brazil as the model, you could produce the rare material without investing in fertilizer and expending a lot of fuel to acquire that material. Since we know have established corn-based ethanol, we've also established a political constituency to keep this in place.

As of now, I think that converting to Jet-A is the only viable solution for GA, but it kills most of the current fleet.

Joe