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Ethanol's Effect

R

RV7ator

Well Known Member
E10 91 mogas slows my -7 around 4-5 mph at cruise.

For the grins of it, I A/B compared 100LL from one tank to 91 mogas ruined with 10% ethanol from the other tank. The lower energy density of ethanol through a volumetric measuring device like a carburetor assures you can't make the same horsepower. In my case it's about 12-13 hp or so lost to the corn lobby. The numbers at 8,500 ft/21.5 in/2400 rpm/100 ROP: 100LL = 198 mph, E10 = 193-4 mph. Nothing calibrated, it's all wet-thumb-to-the-wind rigorous, but the trend is right.

When MTBE was the Greenies darling, my 172 lost ~2 mph.

What was more interesting is the time it took for the different fuel to make it from the selector to the engine: 3 1/2 minutes! I couldn't believe there was that much volume in the system to keep the mill turning at cruise power for so long. Think about that if you ever start sucking contaminated fuel. Changing tanks may not help before you run out of airspeed/altitude/ideas.

John Siebold
Boise, ID
 
I was reading an article in Aviation Week recently where Embraer converted a Lycoming IO-540 over to run on E96 ethanol for their EMB 202A AG plane. Resulted in 20 more hp but a 40% reduction in range. Price of the fuel there is 1/4 that of avgas. This is the only production aircraft to use alcohol fuel and over 60 have been produced now. Initial tests indicate cooler running and very clean chambers, valves plus very lower carbon contamination rates on the oil. (Pierre, this thing has a 2094 lb. hopper capacity and electrostatic spray system).

Some of the new studies and pilot plants producing ethanol from discarded bio mass, algae and sugar cane show great promise. A new plant in Ontario is now producing 1 million gallons of cellulose ethanol from non crop sources per year with plans to be even bigger in the future.

Brazil has massive sugar cane crops (more efficient than corn by far) to power their ethanol industry and the majority of vehicles there are either flex fuel or ethanol fueled. It shows it can easily be done on a very large scale- people just have to get off their butts and do it.
 
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Alcohol is capable of making more HP than gasoline, provided the rest of the engine is optimized for it.

Look at the difference at the drag strip.

IIRC, it has to do with octane----resistance to detonation. But, to actually get the improvement, a lot of things have to be done to the engine. Compression, timing, and fuel flow the main ones. Also, cut back on cooling capacity.

Oh, by the way-----fuel flow goes up a bunch----40% seems to stick in my mind.

To just switch tanks as John did, the results could be expected. If he had been running more than just 10% etoh, then the loss would have been greater.
 
Mixture setting?

Did you richen the mixture when switching to the tank with ethanol? Ethanol is use as an oxygenator in auto fuel, if you did not richen the mixture you would have been way below peak power. The engine should make the same horse power but burn about 8% more fuel. So the speed shouldn't change.
 
Engine guys often argue about why alcohols make more power than gasoline in engines. One thing not often mentioned is that as ethanol or methanol is vaporized, it gets very cold, absorbing heat from the intake charge and increasing its density. This is clearly evident if you have ever run alcohol in race engines on a humid day, frost can form on the intake runners downstream of the injectors- even when the ambient temp is well above 70F.

In Porsche's Indy car program, engineers measured intake charge temperature drops of up to 80C!

Another thing to consider in the power equation is that the sheer mass of alcohol decreases the amount of air than can be inducted as a percentage of the charge mass. This may be offset by released oxygen.

One thing is clear from dyno testing and track use of alcohol, engines make 5-15% more power than on gasoline and it is a wonderful fuel for high compression or turbo engines. I ran a couple of turbo street cars on M85 for two years. The range sucked but you could run full boost without any ignition retard. Great fun.:cool::D
 
I agree

LOP opearations seems to cost me about 5mph but I can't lean to 7gph at 2400 sq like i could with 100LL..&.5 GPH seems to be the minimum with E10.

I when I get some time I will do a side by side test.

mind you at mogas at less than $3 and 100LL at over $5, I'm not too dissappointed with the performance loss.

Frank
 
A little OT: My auto mechanic races dragsters & we were talking about alcohol a couple days ago. He runs a 500 HP engine, gets about 7 seconds in the quarter mile, peaking at 197 mph, using 4.5 gallons in those 7 seconds! Carb jet is over .200 in diameter to get that fuel flow. He says he use about twice as much alcohol as he would gas, but wouldn't go as fast with gas.
 
Which is why you probably...

RV7ator said:
.....
What was more interesting is the time it took for the different fuel to make it from the selector to the engine: 3 1/2 minutes! I couldn't believe there was that much volume in the system to keep the mill turning at cruise power for so long. Think about that if you ever start sucking contaminated fuel. Changing tanks may not help before you run out of airspeed/altitude/ideas.

John Siebold
Boise, ID
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...should not switch tanks just before take-off...

Use the fuel that worked in the taxi and run-up phase for take-off....:)
 
One of the main reasons that Alcohol produces more power is that you can burn more of it. As Ross said it cools the intake charge but you can run a much richer mixture. I can not remember the exact number but I think it is around 9.5 lb air to a lb of alcohol. Gasoline's richest mixture is around 12 :1.
Nitro-methane is even more drastic at about 2 lb air to 1 lb of nitro. This more than makes up for the lower heating value of alcohol and nitro-methane.

I read a paper on some research done by the EPA on a pure alcohol engine. They were running a compression ratio of 18 : 1 using port injection and spark ignition. They were able to get the same volumetric (ie mpg) as gasoline. The engine produced approximately the same power as gasoline. They were not trying for more power but the same fuel economy with equivalent emissions. Their reasoning that E85 at higher cost and more fuel consumption would be a hard sell to consumers seems logical.

The high compression ratio produced a more efficient engine and recovered the power loss from alcohol. Yes there is a power loss if running at stoic but it looks like you maybe able to run richer and still meet emission standards so some alcohol blends can make more power than gasoline. I thought when I read it that the engine would be an interesting aircraft engine.

I will try and find the paper and post the link, it is an interesting read.

Bob Parry
 
Even on an unmodified engine, power is always slightly higher on alcohol over gasoline, certainly on methanol which I've run many engines on, we saw 5-15% depending on injector configuration. Higher CRs naturally make more power and this is a good way to recover some lost mileage as well. Stoichiometric mixtures for gasoline are around 14.7, 9 for ethanol and 6.4 for methanol.

I think most people have come to the conclusion that making ethanol from straight corn crops is not a great idea but using the discarded cellulose from stalks, leave,s clippings etc. is a really good idea as this stuff is normally just wasted.

I'll put forth one more thought on water in ethanol fuels- I think this is a complete non-issue. Water simply stays in suspension and goes though the engine with a slight power loss. It would take a tremendous volume of water in the fuel to cause serious problems. People add alcohol here in Canada in the winter months to supposedly keep water in fuel lines from freezing. It never happens anyway but the stuff works for that purpose.

The Brazilians replaced fuel lines with stainless and installed larger injectors primarily on the Lycoming. RV fuel tanks would need some work with aluminum not great for alcohols and Proseal an unknown in prolonged contact with ethanol. Obviously the RV group who has been running ethanol for years has the answers to all this.
 
Thanks Ross for the AFR for alcohol, I did not have them at hand.

During a meeting on methanol direct fuel cells I attended it was mentioned that the only source for methanol in the quantities required for auto use is natural gas. This did not make much sense from an energy standpoint, but this also applies to making ethanol from grain, corn and other bio-waste. Another problem with converting bio mass to alcohol is the amount of water used in the process. I have read as much as 3 liters water to produce 1 liter of alcohol. Not a problem here on the wet coast but other locations it can be a big issue.

Methanol for aircraft use would be a nice alternative. The quantities are not huge (compared to automotive) and the systems could be adapted. Seals, tubing and tank lining would have to be addressed. Doable, expensive especially for existing aircraft, new production would not be a big deal at least on the experimental side.

The sooner lead is removed from the fuel the better the engines will be. I was not big on it when it was first removed from auto fuel, but it did not take long to see that the engines were better for its removal.

Bob Parry
 
rv6ejguy said:
>...
I'll put forth one more thought on water in ethanol fuels- I think this is a complete non-issue. Water simply stays in suspension and goes though the engine with a slight power loss. It would take a tremendous volume of water in the fuel to cause serious problems.
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The problem remains. There are many ways to get water into airplane gas tanks, especially since they are vented. Leaving an airplane out during the winter when it is wet, is the same problem that watercraft face. The problem is that once you reach phase separation it is irreversible and the muck that is created is even more corrosive than the ethanol gas mixture that is sitting in your tank all the time.


People add alcohol here in Canada in the winter months to supposedly keep water in fuel lines from freezing. It never happens anyway but the stuff works for that purpose.
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Anybody can do that, even in an airplane. It is legal. But that alcohol mixture results in less than E1, at least that is the limit for aircraft.

>...Obviously the RV group who has been running ethanol for years has the answers to all this.
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Yes, but you notice that they never document their results. I have never read anything about the conversion that was necessary to run their aircraft on high levels of ethanol. And I believe that they have never performed in those aircraft other than in the summer in the Midwest. Obviously the airplanes would be almost impossible to start in the winter. I have also heard that they have clear fuel header tanks to start the aircraft all the time and they fly between performances on clear gas, after all where could they get ethanol gas on airports on cross countries? I would love to know what they did to their airplanes if anybody has a reference.
 
I Hate Ethanol & It's Politics

The reason I tried E10 was simply curiosity regarding how badly it would affect performance. Too bad it's being crammed down our throats by the fools east of the Potomac. I would never seek it out in lieu of petroleum.

Someone mentioned enrichening the mixture to regain lost h.p. Wrong. I intentionally selected best h.p. EGT for gasoline. Dumping in more to accommodate the ethanol would reduce gasoline derived h.p. as well as waste fuel.

Brazil: a socialist economy that heavily subsidizes ethanol production through taxation - same as the USA except on a grander scale. (They are a net oil exporter.)

If we were serious about saving the (insert favorite Green fetish here), we'd drop tariffs that exclude importing Brazil's cheap sugar ethanol, and eliminate subsidies here that favor redirecting feed to fuel.

But why use ethanol at all? It started as an oxygenate, now no longer necessary as emission controls are so good. So now it's "renewable" and "energy independence", a chasing after the wind. African tribeswomen scrounging twigs for cooking fires are also energy independent. He who has the energy wins, and we have abundant resources other than food crops at our disposal. Innovation and market forces will save our bacon, if only the pols would get out of the way.

Energy density is the name of the game, most obvious in consumer products like cell phones, and it's the anchor restraining vehicle electrification. In aircraft it's precious. If you were to convert your bird to 100% ethanol, you'd give up useful load (.79 s.g. vs. .73 for gas), and be landing to refuel before you had to land to pee. That's really going backwards, let alone the complications of adapting infrastructure and operations to ethanol and mitigating its hazards.

Long live petroleum. I hope this ethanol nonsense is only temporary on the way to developing what's already known, and in the labs, for energy that's truly sustainable, clean, cheap, and chock full of btu's.

John (I hate ethanol) Siebold
Boise, ID
 
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N1593Y said:
The problem remains. There are many ways to get water into airplane gas tanks, especially since they are vented. Leaving an airplane out during the winter when it is wet, is the same problem that watercraft face. The problem is that once you reach phase separation it is irreversible and the muck that is created is even more corrosive than the ethanol gas mixture that is sitting in your tank all the time.



Anybody can do that, even in an airplane. It is legal. But that alcohol mixture results in less than E1, at least that is the limit for aircraft.


Yes, but you notice that they never document their results. I have never read anything about the conversion that was necessary to run their aircraft on high levels of ethanol. And I believe that they have never performed in those aircraft other than in the summer in the Midwest. Obviously the airplanes would be almost impossible to start in the winter. I have also heard that they have clear fuel header tanks to start the aircraft all the time and they fly between performances on clear gas, after all where could they get ethanol gas on airports on cross countries? I would love to know what they did to their airplanes if anybody has a reference.
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My goodness, I hope you don't treat your RV like this. If you reach phase separation, you simply sump the tanks just like with gasoline- which you should be doing anyway.

I think I was discussing using higher proportions of ethanol here rather than E10. Obviously there is no ethanol fuel infrastructure in place for aircraft at this time. This could change if people wanted it to.

Aircraft engines with updraft carbs would be difficult to start below 10C most likely. Fuel injected engines, no problem. As I said, I drove two cars for about 3 years running M85 winter and summer -35C to +35C. Worked just fine. Had to use a block heater below -10C for about 20 minutes though. I had to change the rubber line from the fuel pump to the supply line because of swelling. I went to a stainless fuel filter as the methanol attacked the glue on the original paper element. Water and corrosion were never an issue in either car.


The auto OEMs offer flex fuel cars these days capable of running on gasoline or E85. Obviously they know exactly what is involved to make it work under all conditions. Not rocket science, there are hundreds of thousands of these vehicles driving around today and I see little difference applying it to aircraft. People just whine that it is too hard. Building an airplane is hard. Converting an engine to run on alcohol is comparatively easy. I think we could learn a lot from the ethanol RV squadron, especially about tank mods- they are actually doing it. I'm always amazed at the resistance to new ideas. Burning ethanol IS being done successfully on a massive scale already.

Technical issues aside, the big question is does it make sense? The energy density of petroleum is superior so range will suffer but we would still get to fly at least if there was no more petroleum around. We could produce gasoline from coal as Sasol is doing now with jet fuel but it still isn't renewable. Petroleum is a superior fuel for weight critical applications like aircraft- no argument there. The waste biomass cellulose ethanol isn't a bad idea for the environment but lots of infrastructure would need to be put in place to make this change. Realistically, I don't think there is the will to make this happen.

If governments in North America would stop screwing around and take the environment seriously, they'd just commit the billions needed to launch the industries to build solar and wind facilities to generate enough power for ground use and leave the petroleum based stuff for mobile transportation like cars, aircraft, ships and trains. For the amount we spend on imported oil, we could be self sufficient for ground use in less than a decade. If anyone here believes that oil is not heavily subsidized already in one way or another by the Canadian and US governments- please remove your rose colored glasses. We continue to do what we do because it is easy and it is again, for the moment, relatively cheap. We'll have to wait for oil to top $120+ a barrel again before panic sets in again about finding alternate energy sources. I don't get it...
 
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Not to worry

There will be other, better, fuels available when the time comes.

Here is an example of a Designer Aviation Fuel May Provide Cleaner, Greener, Cheaper Alternative: SwiftFuel© is comprised of synthetic hydrocarbons derived from biomass.

Designer Aviation Fuel May Provide Cleaner, Greener, Cheaper Alternative
WEST LAFAYETTE, Ind.--(BUSINESS WIRE)--Swift Enterprises Ltd. has unveiled a new general aviation fuel that is less expensive, fuel-efficient and environmentally friendlier than any on the market, said co-founder John Rusek.

The general aviation industry includes all flights other than military and scheduled airline flights, both private and commercial. Data on Swift Enterprises’ 100 percent renewable general aviation fuel was presented April 28 at an annual meeting of an international committee that oversees aviation fuel standards. Unlike current biomass fuels, SwiftFuel© is comprised of synthetic hydrocarbons derived from biomass. Rusek said it can provide an effective range (distance between refueling) greater than petroleum while its projected cost is half the current petroleum manufacturing cost.

The innovation by Swift Enterprises’ propulsion and energy researchers meets or exceeds the standards for aviation fuel as verified by nationally recognized laboratories, said Rusek, a professor in Purdue University’s School of Astronautics and Aeronautics Engineering.

Swift Enterprises, founded seven years ago at Purdue Research Park, is led by Rusek and his wife, Mary, who have been involved in the field of energy more than two decades. The meeting was held by the Coordinating Research Council of ASTM International in Alexandria, Va. ASTM International is one of the largest voluntary standards development organizations in the world.

“Our fuel should not be confused with first-generation bio-fuels like E-85, which don't compete well right now with petroleum,” Rusek said. “For general aviation aircraft, range is paramount. Not only can our fuel seamlessly replace the aviation industry’s standard petroleum fuel, it can outperform it.”

The general aviation industry each year uses nearly 570 million gallons of 100LL aviation fuel, which is toxic, increasingly expensive and non-renewable. In contrast, testing has shown SwiftFuel© is 15 to 20 percent more fuel efficient, has no sulfur emissions, requires no stabilizers; has a 30-degree lower freezing point, introduces no new carbon emissions, and is lead-free, John Rusek said. In addition, he said, the components of this fuel can be formulated into a replacement for jet/turbine fuels.

The aviation industry has been the only form of transportation to use leaded fuel (tetraethyl lead) since an Environmental Protection Agency ban went into effect 30 years ago. However, that lead-free exemption will cease in less than two years.

“The general aviation industry, both domestic and foreign, is demanding a solution to this dilemma,” said Mary Rusek, Swift Enterprises’ president. “Our new, patented technology can provide the 1.8 million gallons per day required by the industry in the U.S. by utilizing only 5 percent of this country’s existing bio-fuel plant infrastructure.”

“John and Mary Rusek have devoted their lives to coming up with practical, renewable energy,” said Joseph B. Hornett, senior vice president, treasurer and chief operating officer of the Purdue Research Foundation, which manages the Purdue Research Park. “This fuel could change aviation history and be an economic boon for the state of Indiana and the Midwest, where we can abundantly grow the resources to produce SwiftFuel©.”

Swift Enterprises officials are in discussions with the Federal Aviation Administration, which has initiated a cooperative agreement with the company to evaluate the fuel.



Contacts
For Swift Enterprises Ltd.
Cynthia Sequin, media relations, 765-494-4192
765-413-6013 (mobile)
[email protected]
OR
Swift Enterprises Ltd.
John and Mary Rusek, 765-464-8336
[email protected]
[email protected]
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RV7ator said:
But why use ethanol at all? It started as an oxygenate, now no longer necessary as emission controls are so good.
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Sadly, the answer is "politics". Making ethanol, particularly from corn, is a high dollar business and spends a lot of money to lobby. EtOH isn't really needed for on-road vehicle emission control any more, but vehicles seem to able to run on E5/E10 without major problems, just reductions in MPG. It doesn't really do anything for our aircraft engines with 1950s era emissions controls (basically none).

As for airplanes, I don't see the positives that EtOH brings, and it has problems with its use, particularly with older airframes and engines. IMHO, we should be focusing our efforts on getting a replacement for 100LL, which is a more pressing problem. I don't see how using EtOH helps us achieve that goal.

TODR
 
Brazil - some numbers -

RV7ator said:
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Brazil: a socialist economy that heavily subsidizes ethanol production through taxation - same as the USA except on a grander scale. (They are a net oil exporter.)

If we were serious about saving the (insert favorite Green fetish here), we'd drop tariffs that exclude importing Brazil's cheap sugar ethanol, and eliminate subsidies here that favor redirecting feed to fuel.
......
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Brazil is a net oil exporter because they actually have been drilling more holes in the ground (more precisely in the ocean floor), something that is not really happening in the US - and yes, the Brazilian oil is "offshore oil", just like a lot of the US oil.

Oil production has almost doubled in the last 10 years, and they are #2 producer in S. America, rapidly catching up with Venezuela.

The ethanol they are producing is for mainly for autos - the countries internal consumption of oil is six times greater than that of ethanol - IIRC, their trucking industry is still diesel based.

Some actual figures here....

http://www.eia.doe.gov/emeu/cabs/Brazil/Oil.html

-- check the Brazil oil consumption vs. production curves, it appears they were a net oil importer in 2007 - if they became a net oil exporter since then, I'm sure it's because the production bit went up...:)

gil A - believing in the drill here, drilll now theory....:) -- just like Brazil
 
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Not much of an Ag plane

rv6ejguy said:
I was reading an article in Aviation Week recently where Embraer converted a Lycoming IO-540 over to run on E96 ethanol for their EMB 202A AG plane. Resulted in 20 more hp but a 40% reduction in range. Price of the fuel there is 1/4 that of avgas. This is the only production aircraft to use alcohol fuel and over 60 have been produced now. Initial tests indicate cooler running and very clean chambers, valves plus very lower carbon contamination rates on the oil. (Pierre, this thing has a 2094 lb. hopper capacity and electrostatic spray system).
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That's less than 300 gallons in the hopper.
We build 'um lot's bigger in the USA!
http://www.airtractor.com/at-802a
And it'll run on Jet A, diesel, and probably french fry oil.
 
A lot of talking about Brazil's experience, so I decided to post my coments. First, let me introduce myself: My name is Andre, from Brazil and I'm building an RV9A that's almost ready to fly (just waiting the FFW Kit). My previous aircraft was a Tecnam ECHO P-92, powered by a Rotax 912S, that was sold to my hangar partner, so I still fly it. We always used auto gas on our rotax. Auto gas in Brazil has 89 OCT and 25% of ethanol and the little engine never complained. In fact, we can't notice the difference between auto gas and 100LL. The engine has now 700 hr and we always do the regular inspections and never noted anything wrong. So far so good. In our last annual, we found a few problems that are related to ethanol: a fuel valve leak - maybe the rubber seal - and a tank leak trought a rivet. Our aircraft is 10 yrs old. A lot of people use auto gas in Brazil, becouse only a few places has 100LL and using auto gas save us 45%. I wish I could use it in my new Superior IO-320, but I'll not take the risk.
 
Putting out dry material..

rv6ejguy said:
I'm guessing most other 300hp class AG planes haul about the same load, obviously not gonna compete with PT6 power.
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....like seeds and fertilizer are the main reason for the big hoppers. They're fluffy with a lot lower density than liquids. The Cessna Agtrucks with Conti IO-520's/300 HP, had 280 gallon hoppers but on a hot day, they'd have a tough time getting off with 200 gallons. You could fill them up with either rye or fertilizer and they'd be much lighter than 200 gals of water/chem mix.

Regards,
 
rv6ejguy said:
My goodness, I hope you don't treat your RV like this. If you reach phase separation, you simply sump the tanks just like with gasoline- which you should be doing anyway.
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You clearly do not understand phase separation. If your E10 fuel were to phase separate practically all of the ethanol and water, 10% of your fuel supply would separate and sink to the bottom of your tank as a highly corrosive blob. Phase separation is not incremental. If this were to happen you would have to know it immediately and completely pump your tank out because of the corrosive properties and because E10 is usually manufactured with a suboctane blending stock. The gasoline left after phase separation probably will not have the proper AKI rating for your engine. Regular unleaded, 87 AKI gasoline, is usually made with 84 AKI blending stock, it is here in Oregon. Premium unleaded 92 AKI E10 can be made with 89 AKI blending stock.
 
N1593Y said:
You clearly do not understand phase separation. If your E10 fuel were to phase separate practically all of the ethanol and water, 10% of your fuel supply would separate and sink to the bottom of your tank as a highly corrosive blob. Phase separation is not incremental. If this were to happen you would have to know it immediately and completely pump your tank out because of the corrosive properties and because E10 is usually manufactured with a suboctane blending stock. The gasoline left after phase separation probably will not have the proper AKI rating for your engine. Regular unleaded, 87 AKI gasoline, is usually made with 84 AKI blending stock, it is here in Oregon. Premium unleaded 92 AKI E10 can be made with 89 AKI blending stock.
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I've been blending race fuels and brews for a long time using Xylene, Toluene, Methanol, Ethanol, Acetone and gasoline and think I have a pretty good idea of what stays mixed with what and in what proportions. Depending on base stock gasolines that we have up here in Canada and the proportion of aromatics therein, phase separation like you describe has never been a problem that I have observed. There is a big difference in the proportion of alcohol which will stay in solution based on brands of gasoline here and the aromatic content. If you were purposely to pour a lot of water into the fuel, you might get what you describe. It just does not happen in regular automotive usage in my experience and our climate here can have shifts in temperature exceeding 20C/ hr. in the winter, probably the worst case for condensation in fuel tanks.
 
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rv6ejguy said:
>... It just does not happen in regular automotive usage in my experience and our climate here can have shifts in temperature exceeding 20C/ hr. in the winter, probably the worst case for condensation in fuel tanks.
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Apparently we are talking about two entirely different applications. I thought this was an airplane forum, not a car forum. I agree that this would be extremely rare in cars, especially modern cars with closed fuel systems. I was talking about airplanes with open vented fuel systems, especially airplanes that could be stored for long periods outside in wet climates, using commonly available E10 mogas, not high ratio racing blends, which I would agree would be very unlikely to phase separate.
 
If I had gas caps on my RV which leak water (which I do) I'd change them or tape them over when storing the plane outside. It would be madness to rely on sumping the tanks to get rid of water that I could have prevented from getting into them in the first place.

The convoluted vent system in my 6A would only permit minute amounts of humidity to enter the tanks over a very long period of time and would be a non-issue IMO.

I bring out the auto side of ethanol fuels because there is vastly more experience in using it with millions of flex fuel cars worldwide. It could certainly be applied to aviation. An interesting link: http://en.wikipedia.org/wiki/Flexible-fuel_vehicle

People keep bringing up this hypothetical water issue with alcohol fuels. I don't see this being any more serious than water in avgas on a carbed engine and maybe even less serious since normal low amounts simply remain in suspension.
 
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rv6ejguy said:
>...
I bring out the auto side of ethanol fuels because there is vastly more experience in using it with millions of flex fuel cars worldwide. It could certainly be applied to aviation.
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In order to be applied to aviation it would require a fuel injected engine with a computer that could alter mixture and timing and have sensors in the gas line to determine the level of ethanol and an oxygen sensor in the exhaust to sample the result of burn to modulate the fuel injection. That is what is in a Flex-Fuel car. You are proposing to haul all of that extra complex electronic equipment around, which will require redundancy, so that you can use a fuel with much less energy content that gives you much less range and is corrosive to aluminum and at high ethanol blends requires special pumps at the airport? (And we can't even get mogas pumps and tanks at our airports.)

People keep bringing up this hypothetical water issue with alcohol fuels. I don't see this being any more serious than water in avgas on a carbed engine and maybe even less serious since normal low amounts simply remain in suspension.
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People keep bringing it up because it is one of the known problems with ethanol blended fuel and it is one of a number of reasons that no STC allows ethanol blended fuel. Neither EAA nor Cessna nor Petersen could see a way to make an ethanol blended fuel STC economically feasible: http://www.aviationfuel.org/faqs/ethanol_blends.pdf please pay particular attention to Section 11 on page 10.
 
Get The Ethanol Out

For those of you who haven't connected the dots about ethanol in airplanes, here's a link to the latest Idaho Aviation Association newsletter. Pages 2 and 3 have articles. It fairly succinctly sums up the issues, and why we need to have access to ethanol-free mogas.

http://www.flyidaho.org/newsletters/November 2008.pdf?menuID=48~48
Four important points aren't emphasized in this thread:
1. $.51/gallon of your tax money is feeding this contentious issue and skewing market forces.
2. Though some of us don't care because experimentals have no fuel restrictions, the vast GA fleet must have an STC to use mogas without ethanol.
3. Don't expect help from the FAA. They've done nothing to head off this ethanol nonsense that's obviating STCs; even less likely are they to push back against new powers being elected tonight who think GA is a state.
4. The modifications and hugely complex machinations needed to field something beside 100LL will take years to implement.

John Siebold
 
I've made it pretty clear that I don't think ethanol will become the fuel of GA in the future, just that it could be done if we were faced with no petroleum alternatives. My comments were intended to show that this could be done as the Brazilians have done with their certified Ag aircraft using modified mechanical injection.

I believe modified tank materials or coatings, stainless lines and larger injection nozzles would be required so this would be some trouble to retrofit. In the case of using multiple fuels, EFI with tank sensors would probably be the best bet. For experimentals, inexpensive EFI already exists to run multiple fuels- I've been doing this for 15 years. There is no redundancy in a single carb. Modern EFI has proven to be at least as reliable as a carb though electrically dependent.

I do agree that low amounts of ethanol in auto fuel is a negative thing for stock carbed aviation engines.

My contention here is simply that ethanol based fuel can and has been successfully used in aviation and the technology is available should people have the will to make the step towards it. It isn't rocket science. I'd mention that another pilot has been flying aerobatic routines in a Pitts for many years running on Ethanol: http://futurshox.net/aeroview.php?level=image&id=6194

http://www.ethanol-gec.org/fall96/eafal9604.htm

http://www.baylor.edu/bias/index.php?id=4555

A technical discussion here: http://www.baylor.edu/bias/index.php?id=4556

All this doom and gloom about ethanol not working in a suitably modified aircraft/ engine is nonsense.
 
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rv6ejguy said:
>...
All this doom and gloom about ethanol not working in a suitably modified aircraft/ engine is nonsense.
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Strange, you left out one key word in your argument "economically", as shown by EAA, Cessna and Petersen. It is rather suspect when the only way ethanol can compete in the energy market is with government welfare.

There are a couple of companies doing research on biofuel production for which the result is hydrocarbon similar to gasoline, instead of alcohol. Supposed to have a higher octane than 100 LL and isn't corrosive to AL. Hope it works soon.
 
N1593Y said:
People keep bringing it up because it is one of the known problems with ethanol blended fuel and it is one of a number of reasons that no STC allows ethanol blended fuel. Neither EAA nor Cessna nor Petersen could see a way to make an ethanol blended fuel STC economically feasible: http://www.aviationfuel.org/faqs/ethanol_blends.pdf please pay particular attention to Section 11 on page 10.
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I would voice my agreement with RV6ejguy on this issue of water in fuel. I whole heartily agree that there are serious issues associated with the use of Ethanol in our current internal combustion (IC) engine configurations (regardless of the purpose of the work the engine is producing). However, water in fuel is not one of those serious issues!

Prior to just a few years ago, when we had this change of mind about injecting specific amounts of alcohol in our fuels, anyone who knew they had water in their fuel system would be ecstatic to find they could pour a measured amount of alcohol in their fuel tank and instantly get that water out of their tanks. Alcohol has historically been used just for such a purpose as removing water out of fuel. Now, all of a sudden, everyone is scared to death that one molecule of alcohol in their fuel source is going to destroy their engine because it bonds with water molecules. The fear of this happening is totally unfounded!

No matter what problems may exist to be argued concerning Ethanol in gasoline, the issue of Ethanol bonding with water is not one of them that should be touted. It flat out is not an issue. Any discussions of water in the fuel have dealt with planes left out in the weather for long periods of time and having open fuel systems that can have water introduced in them. Well, I am sorry but it will not matter if there were Ethanol in the fuel or not in these circumstances. Regardless of the fuel this scenario is the same in every situation. Meaning that the issue is not with the fuel in the tank but instead lies with the methods used for protecting that fuel that matters.

Anyone who wishes to remove Ethanol from our fuel source has some legitimate concerns and should address them appropriately. However, by perpetuating a non-existent problem does not address these concerns and only serves to fuel educated opposition to the bigger battle of controlling what fuels we have available for use.

As always, Live Long and Prosper!
 
N1593Y said:
Strange, you left out one key word in your argument "economically", as shown by EAA, Cessna and Petersen. It is rather suspect when the only way ethanol can compete in the energy market is with government welfare.

There are a couple of companies doing research on biofuel production for which the result is hydrocarbon similar to gasoline, instead of alcohol. Supposed to have a higher octane than 100 LL and isn't corrosive to AL. Hope it works soon.
Click to expand...


There is no doubt that mechanical changes are required to safely use high ethanol content fuel in existing carbed Lycomings, no argument there again but if we didn't have a petroleum based alternative you'd either have to spend the bucks to make the changes, go electric or stop flying.

I too believe that some type of gasoline will be the future aviation fuel for piston engines. I just don't like to hear all this "couldn't be done" talk.
 
RVbySDI said:
I would voice my agreement with RV6ejguy on this issue of water in fuel. I whole heartily agree that there are serious issues associated with the use of Ethanol in our current internal combustion (IC) engine configurations (regardless of the purpose of the work the engine is producing). However, water in fuel is not one of those serious issues!
...
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Then I guess this article is bogus: http://www.epa.gov/oms/regs/fuels/rfg/waterphs.pdf and phase separation has no basis in fact and the EAA ethanol test kit doesn't work?
 
N1593Y said:
Then I guess this article is bogus: http://www.epa.gov/oms/regs/fuels/rfg/waterphs.pdf and phase separation has no basis in fact and the EAA ethanol test kit doesn't work?
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No, that is not at all what I am saying. What I am saying is that water phase separation in fuel that contains Ethanol is not as serious an issue as say the economic or safety aspect of decreased range is when arguing against Ethanol use as a fuel. Or, the incompatibility of Ethanol with specific components associated with the delivery and use of fuel in IC engines.

When discussing the issue of phase separation of water in Ethanol the truth is that Ethanol is much, much, much (did I say much already?) better at holding water in solution that any other fuel. Especially gasoline. For that reason alone is why I say discussing water phase separation in Ethanol is a non-issue. It would take a HUGE amount of water (somewhere in the neighborhood of a PINT of water in our standard RV size tanks) in a fuel tank before it would separate from the Ethanol. Because of this, if one has that much water in their tank they have a much more serious problem to contend with than having Ethanol in their tanks.

There have been many threads discussing Ethanol on this forum in the past. During several of them I have had the fortune to read this article. Click on this link http://www.epa.gov/OMS/regs/fuels/rfg/waterphs.pdf to read some very interesting information on phase separation.

I agree with you on many points concerning the use of Ethanol as a fuel. However, I do not agree with you concerning the idea that water phase separation as it is associated with Ethanol is something anyone should be using to argue against Ethanol. The truth is Ethanol is a very effective vehicle for preventing water phase separation in fuel.
 
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RVbySDI said:
>...
There have been many threads discussing Ethanol on this forum in the past. During several of them I have had the fortune to read this article. Click on this link http://www.epa.gov/OMS/regs/fuels/rfg/waterphs.pdf to read some very interesting information on phase separation.
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Yes, that is why I posted it ... maybe you meant another article?
I agree with you on many points concerning the use of Ethanol as a fuel. However, I do not agree with you concerning the idea that water phase separation as it is associated with Ethanol is something anyone should be using to argue against Ethanol. The truth is Ethanol is a very effective vehicle for preventing water phase separation in fuel.
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Unless the phase separation happens to you.
 
N1593Y said:
Yes, that is why I posted it ... maybe you meant another article?

Unless the phase separation happens to you.
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I am sure my posts will make little difference in your opinion of the hazards of water in an Ethanol blended fuel so this will be my last post on this thread. From the article that both you and I have posted for differing reasons comes this quote:

"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 which will cause phase separation in the 90/10 ethanol blend."

As I have already stated, there are many reasons to be concerned about using Ethanol blended fuels but water phase separation is not one of them.

I am done here.

Live Long and Prosper!
 
RVbySDI said:
I am sure my posts will make little difference in your opinion of the hazards of water in an Ethanol blended fuel so this will be my last post on this thread.
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No problem, take your ball and go home.
"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 which will cause phase separation in the 90/10 ethanol blend."
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And that 3.8 teaspoons of water will pull 0.1 gallon of ethanol, 10% of your fuel, out of solution that will then sit on the bottom of your fuel tank as a very corrosive irreversible blob. The entire tank will have to be drained and inspected for damage. The other examples that you give can be sumped easily and are not corrosive, even if the amount is much larger than 3.8 teaspoons of water.
As I have already stated, there are many reasons to be concerned about using Ethanol blended fuels but water phase separation is not one of them.
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Unless it happens to you. Murphey's law applies here.
 
N1593Y said:
No problem, take your ball and go home.

And that 3.8 teaspoons of water will pull 0.1 gallon of ethanol, 10% of your fuel, out of solution that will then sit on the bottom of your fuel tank as a very corrosive irreversible blob. The entire tank will have to be drained and inspected for damage. The other examples that you give can be sumped easily and are not corrosive, even if the amount is much larger than 3.8 teaspoons of water.

Unless it happens to you. Murphey's law applies here.
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I've had ethanol fuel in my tanks for over 4 years flying with Subaru, so far the inside tank skin is bright and shines like new. If there is corrosion, it is not apparent on the surface of the skin.

I am no fan of ethanol or the government supported production of it, but perhaps before making such statements about it's cause and effect in a fuel system, one should do some testing to see if it is true. I too believe water is a non issue just as vapor lock is a non issue with a bit of common sense. I've said this here before, E85 tests almost as good as 100LL with the Hodges meter, not that any of us will be using E85. Fifteen percent ethanol does not make the fuel any more vapor prone than without it. That being said, auto fuel does test all over the board for vapor pressure and it must be tested each time it is loaded in, at least that is what I did when using it and did not experience a vapor lock in operating in temps up to and including the high 90's. I had other problems but vapor lock was not among them.

As some of you know, I am re-engining to Lycoming at this time. It's fuel system will be AFP FI with a continuous electric pump for pressure going forward of the firewall. Fuel under pressure generally will not lock up, 100LL or properly tested auto fuel. The weakest link with AFP is from the FM200 controller up to the flow divider where pressure is just 1 to 3 psi. But I am assured it works, especially with proper use of the purge valve. The weak, weak link with a Lycoming installation is just before the mechanical pump if no boost is used coming through the firewall.

Murphey's law does apply as always, but with a little care and diligence it does not make an appearance too often. :)
 
Takes a lot of water

If I did the math right 3.8 teaspoons per gallon works out to 1.66 cups of water in a 21 gallon tank, that is far more than any airplane should be accumulating.

I did a little Hillbilly science experiment the other day. I took about 8 oz. of e10 gas in a clear container and added water one drop at a time,(if you imagine the 8 oz. of gas as a fuel tank a drop is quite a bit). The gas will absorb the first bits of water and look normal. I then put the container in my freezer to see if it would separate, nothing happens. However as you add water the gas will "cloud" up, at that point freezing it will cause the water to fall out. It seems a simple visual inspection of the gas before you buy it and before you fly would be adequate to prevent water problems.

But I am the first to admit that I am no scientist so this may may not prove anything. But ethanol is not going to go away so it would be nice if we could learn how to live with it. Might turn out to be the only game in town?
 
Let's refocus: ethanol is the problem, not water. That's why we have sumps. Bantering about absorption misses the point.

Remember, the majority of GA is in a far worse predicament than experimenters.

We of the experimental community are a small minority of general aviation. Modifying our fuel system requires no FAA permission (if it were even possible to live with ethanol). Yet tens of thousands of certified aircraft can't use ethanol-laced auto fuel. Many of these pilot/owners purchased and operated under STCs now made worthless by ubiquitous ethanol. Adapting to tolerate ethanol through hardware modifications and recertification is prohibitively expensive. Thus the sword of Damocles hangs over GA: the ruination of auto gas and the eventual demise of 100LL. While we wring our hands about 100LL's future and hope for a silver bullet out of the labs, a viable immediate and near-term alternative for lower compression engines is ruined by political mandate.

Still, viton o-rings and teflon fuel lines do not get experimenters out of the woods. The one particularly vulnerable fuel system component is the engine driven fuel pump. NO manufacturer I've consulted says the diaphragms are ethanol-tolerant. One said the way So. Americans deal with ethanol is to regularly replace the entire pump before it deteriorates to failure (How long would that be?). Lycoming's attempting to create a 91 mogas-based fuel spec that would segregate gas for aviation at the source before it is ruined by blending with ethanol (or other proprietary branded additives). What's left out in the no-fuel cold would then be a few very high compression engines that actually need something approaching 100 octane. Good luck war birds and Piper Navajos.

We could help matters immensely by pushing back against ethanol, not just accepting the situation by bending over and lubing up. Write, phone, inundate your representatives to get the ethanol out, surely from 91 octane, and I opine (ethanol's a bad idea from the get-go) from all fuels.

John Siebold
 
Randy Walls said:
>...
But ethanol is not going to go away so it would be nice if we could learn how to live with it. Might turn out to be the only game in town?
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Aviation never has to learn to "live with ethanol". It is not, and never was, the only game in town. Unleaded mogas is an aviation fuel, blessed by the FAA, per the STC process. As such, any commercial entity on an airport can order unblended mogas for aircraft use in every state in the country, whether that state has a mandatory E10 law or not. There is no state or federal law that can change this fact. Since ethanol is blended at the terminal, all terminals have unblended gas that can be ordered by commercial aviation entities. If we had more mogas operations on our airports this problem would never have occurred. It is only the fact that we could self-fuel our airplanes by going to the corner service station that has brought this on. It is only now that federal RFS mandates and a few state mandatory E10 have made it untenable to self-fuel, that we are seeing a "problem" with ethanol.

BTW, there might be a new game in town. I posted the news about a new DOD request to ASTM for a 91 octane avgas here: http://www.vansairforce.com/community/showthread.php?t=35785
 
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Randy,

You're correct as far as blending at the terminal goes, and, as I mentioned above, it is Lycoming's approach to an alternative fuel. But, it will die aborning, just like the 82UL spec of a few years back, without a delivery system in parallel to 100LL. Without a 100LL replacement that can be used by all aircraft, the entire aircraft fuel chain will not go to the expense of providing mogas at airports along with 100LL. I suspect the few that do sell mogas (mostly in the mid-west, and for little less $ than 100LL) have retained their old 80 octane plumbing. Therefore, ethanol is the problem. It is in essence a contaminant, and we're rapidly running out of sources of clean mogas.

John Siebold
 
RV7ator said:
Randy,
>... Without a 100LL replacement that can be used by all aircraft, the entire aircraft fuel chain will not go to the expense of providing mogas at airports along with 100LL. ...
John Siebold
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So you don't think FBO's are going to be jumping at the chance to install infrastructure for the new DOD 91 octane avgas to refuel all of the DOD and DHS drones that are going to be plying our skies ... watching us? ;)
 
Ethanol Powered Airplanes

I am a brazilian agricultural pilot and i have been flying ethanol powered airplanes for some time. In Brasil we have been flying the ethanol powered Lycoming IO-540 K1J5D for the last 4 years (it is allowed just in agricultural aircrafts). I will describe what it looks like:
We dont get all that power improvement we use to see in theory. When flying, it looks like the plane has the same power as it had before. The engine burns 26 gph at 75% power, on take off the fuel flow must be at least 35 GPH. It has one advantage, it runs very,very cold all day long. When flying with avgas we had the CHT ranging from 390 to 430 degrees but now, even in the hottest days, it is hard to see more than 360, so there is no problem whith LOP operations. But, if you lean too much, lets say 25 inches MAP and 20 GPH, the engine becomes very rough.It seems that there is a fuel imbalance problem due to the new noozles installed in the engine. We haven't had any reliability problem with these engines but Lycoming says that if you burn ethanol in your engine you loose your warranty. It is difficult to start in cold days (10 to 15 celsius degrees) and we have a kind of primming system that puts some avgas in the engine just to make it fire, than it starts burning ethanol.

The conversion is very simple. All alluminum parts in the fuel system are replaced by stainless steel parts, including the fuel selector,electric boost pump,mechanical fuel pump, etc. The fuel tanks are painted internally with a special product.The engine fuel injection system is replaced by another one that can deliver the higher fuel flow needed for ethanol work, changing even the fuel noozles. The mags timming is the same.

We are paying US$ 6.00/gal of avgas and US$ 2.42/gal of ethanol so this conversion is very profitable for aircraft owners and operators.
 
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WRT to the comments about low-grade gasoline stock being blended with Ethanol to raise "Octane" ratings, I've been testing the 93 Octane sold in N. Dallas for my Rotax.

Exxon: Usually 5%, has ranged from 4 to 7% at the same station
Chevron: One test, right at 10%
Wal-Mart 93: 3%

My question: If the distributor is skimping on ethanol at the terminal, is the supposedly 93 Octane not really 93 because half the ethanol is missing?

I've been using the Exxon most of the summer with no problems.
 
adrianolsantos said:
I am a brazilian agricultural pilot and i have been flying ethanol powered airplanes for some time. In Brasil we have been flying the ethanol powered Lycoming IO-540 K1J5D for the last 4 years (it is allowed just in agricultural aircrafts). I will describe what it looks like:
We dont get all that power improvement we use to see in theory. When flying, it looks like the plane has the same power as it had before. The engine burns 26 gph at 75% power, on take off the fuel flow must be at least 35 GPH. It has one advantage, it runs very,very cold all day long. When flying with avgas we had the CHT ranging from 390 to 430 degrees but now, even in the hottest days, it is hard to see more than 360, so there is no problem whith LOP operations. But, if you lean too much, lets say 25 inches MAP and 20 GPH, the engine becomes very rough.It seems that there is a fuel imbalance problem due to the new noozles installed in the engine. We haven't had any reliability problem with these engines but Lycoming says that if you burn ethanol in your engine you loose your warranty. It is difficult to start in cold days (10 to 15 celsius degrees) and we have a kind of primming system that puts some avgas in the engine just to make it fire, than it starts burning ethanol.

The conversion is very simple. All alluminum parts in the fuel system are replaced by stainless steel parts, including the fuel selector,electric boost pump,mechanical fuel pump, etc. The fuel tanks are painted internally with a special product.The engine fuel injection system is replaced by another one that can deliver the higher fuel flow needed for ethanol work, changing even the fuel noozles. The mags timming is the same.

We are paying US$ 6.00/gal of avgas and US$ 2.42/gal of ethanol so this conversion is very profitable for aircraft owners and operators.
Click to expand...

Welcome to VAF. Thank you for your real world experience with Ethanol fuel.:)
 
opticsguy said:
WRT to the comments about low-grade gasoline stock being blended with Ethanol to raise "Octane" ratings, I've been testing the 93 Octane sold in N. Dallas for my Rotax.

Exxon: Usually 5%, has ranged from 4 to 7% at the same station
Chevron: One test, right at 10%
Wal-Mart 93: 3%

My question: If the distributor is skimping on ethanol at the terminal, is the supposedly 93 Octane not really 93 because half the ethanol is missing?
Click to expand...
No. Refineries will only go to suboctane for blending when all of the terminals in a large geographic area will blend at the 10% level. It is the 10% level that guarantees that the AKI is raised enough. If the pump says 93 AKI, it has to be 93 AKI minimum. And it has to be whatever the pump says for the duration that the gasoline is in the tank at the service station. If a dept. of weights & measures person comes around and tests the gasoline, it better meet at least what is on the pump label or they can shut down the gas station.

When the mandatory E10 law in Oregon was totally implemented, the refineries on the Olympic pipeline from Seattle to Portland started shipping 84 AKI suboctane to Oregon, because they knew that every terminal in Oregon had to blend at the 10% ethanol level. We are waiting for the other shoe to drop on premium unleaded, dropping it to 89 AKI. We have heard rumors that it is coming, but because of the exemptions that we have in our law for aircraft and watercraft, they are waiting to see if we are going to be successful in repealing our mandates and prohibiting ethanol blending in premium unleaded.

It turns out that during this changeover period a lot of gasoline suppliers are "giving away performance", since higher AKI gasoline is usually priced higher because you think it is giving you better performance. During the changeover, refineries are still producing 87 AKI regular and 91-93 AKI premium. If the terminal blends at 10%, all of that gasoline is going up 3 AKI, so the regular is really 89 AKI, which is mid-grade in most states and your 93 AKI is now 96 AKI, but you don't know that because there is no hand held tester you can buy to find out what AIK they are delivering to your tank.

There was a scam going on in the Midwest that made the newspapers awhile back in some of the corn states that pumped a lot of E10 early on. The station operators knew that the regular E10 (87 AKI) they were getting was really 89 AKI with the ethanol in it, so they pumped that from their mid-grade pump and charged folks the extra 10 cents for mid-grade, but it was no different than their regular. Point is the economic dislocations and unintended consequences of this mandatory ethanol program are huge and there is a new game created every day, just like in our financial markets. There is an interesting test of wills going on now in North Carolina and South Carolina between the dealers and the big brand name oil companies. You can read about it at http://www.eopc.com and clicking on North Carolina at the bottom of the page. Hope you will join our coalition and ask the Texas legislature to prohibit ethanol blending in premium unleaded gas.
 
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