Ethanol (full strength) as a fuel is not a new idea.

[GAHorn]

From Baylor University: http://www.baylor.edu/bias/index.php?id=4556

The Case for Ethanol
1. Secure Supply
In 1973, the Unites States was subjected to its first major fuel supply interruption by the Arab Oil Embargo. At that time oil imports in the U.S. represented approximately 37% of the domestic annual oil consumption. Congress debated then, among other measures, cutting off or rationing fuel to general aviation. Today, the U.S. imports over 60% of its petroleum, considerably increasing the vulnerability of the country to fuel disruptions. In light of the deteriorating situation in the political scene of the Middle East, it would seem not only highly desirable to develop domestically produced transportation fuels, but the only rational course of action to pursue in order to secure the country's energy independence and the long term survival of general aviation.

Ethanol can be produced from anything that contains starch, sugar or cellulose. There is virtually limitless supply of feedstock available in the United States to produce ethanol. This feedstock is renewed on an annual basis. The amount of ethanol produced in the United States is approximately 1.7 billion gallons and the production capacity is growing continuously. Thus, it would not be difficult for the ethanol industry to supply the fuel needs of the general aviation community, insuring that its fuel demands will always be met. Domestic production of ethanol will never be subject to supply interruptions as a result of international disputes.


2. Economics
Today the cost of ethanol delivered to the FBO is between $1.20 and $1.30 per gallon. (Moderator's Note: This article was obviously issued about 10 years ago. This would mean that Baylor has worked on this matter now for over 25 years!) The cost of Avgas varies considerably more than that of ethanol, but it is, currently, at least 50 cents per gallon more than ethanol and in some cases even higher than that.

A technological revolution in the production of ethanol is currently underway. It is possible to produce ethanol economically from any substance containing cellulose. Municipal solid waste (approximately 60% of which is cellulose) together with many types of industrial and agricultural wastes can now be used as feedstock for the production of ethanol. In addition, the U.S. Department of Energy has been working with private industries to develop energy crops that can be grown on lands currently not used for agriculture. This new technology, as estimated by the DOE, will soon result in a bulk price for ethanol in the range of 67 to 80 cents per gallon.

During the first certification of an engine on ethanol, the results of the endurance test showed considerably less wear on ethanol than on avgas. These results prompted the FAA project engineer and the DER to estimate that the TBO on ethanol could easily be extended by 100% over avgas. This would represent a considerable saving in operational cost and would more than offset the fuel cost difference (assuming a range reduction on ethanol/ETBE) even at current prices.

Lead will soon be unavailable as an octane enhancer, and any replacement, other than ethanol, with adequate octane, will be at least as expensive and in all probability more expensive, increasing the cost of a future fuel at the pump.

Again, at the current prices and at the existing state of technology, the economics of ethanol used as an aviation fuel are already competitive.

The nature of the increased quality control requirements for aviation gasoline coupled with the dedicated transportation system required and the relatively low consumption of Avgas in this country, results in a fuel far more expensive than automobile gasoline. In the United States, the current production of ethanol is approximately 5 times the annual consumption of aviation gasoline. Thus, general aviation is a perfect niche market for ethanol, and the economics are a good match at this time, and will improve in ethanol's favor over the near future.


3. Environmental Compatibility
The use of ethanol significantly reduces the CO2 burden when compared to the use of any fossil fuel. This is because ethanol is a biomass fuel, and most of

the CO2 emitted to the atmosphere by its combustion is sequestered by the plants used to produce it. Only the fraction of fossil fuels used in the production of the ethanol adds to the CO2 burden (it is possible to eliminate this fraction by using renewable fuels in the entire cycle of ethanol production).

The preliminary analyses of the emission testing of ethanol, ETBE and aviation gasoline show higher levels of NOx and lower levels of Hydrocarbons and CO for ethanol and ETBE when compared to aviation gasoline. With the final demise of lead and other heavy metals from aviation fuels, catalytic exhaust after treatment becomes feasible. Such treatment has already proven to be very effective in ground transportation for reducing NOx emissions.

Another significant advantage is the fact that VOC's are substantially reduced as a result of ethanol not being a hydrocarbon-based fuel. Most recently, research on the issue of toxic emissions from fossil fuel combustion shows that they are cause of great concern for human health. Ethanol does not contain any benzene or other aromatics.

The most compelling environmental benefit in the short term for ethanol is the fact that it has more than adequate octane without the addition of highly toxic substances such as lead or MMT (needed by Avgas).


4. Technical Characteristics
Ethanol is a high octane, high oxygen content fuel that burns more completely than gasoline in the combustion chamber. With simple modifications to the fuel system to allow more fuel flow, ethanol burns cooler and cleaner, it resists detonation and it produces higher thermal efficiency and power than combustion of gasoline in a conventional engine. The only drawback associated with ethanol is a slight reduction in range (20 to 10 percent depending on engine compression ratio) due to its lower caloric content. Because of its chemical simplicity, ethanol characteristics as a fuel are far more consistent and predictable than avgas.

Octane: While some of today's aircraft piston engines can run on fuel with an octane number lower than 100, a large portion of the total hours flown in general aviation depends on engines which are octane critical. In all of the detonation tests performed during certification tests carried out under carefully controlled conditions and FAA supervision, ethanol produced more power and it had superior anti-detonation properties when compared to Avgas.

Performance: The increased power is attributed to the higher latent heat of vaporization resulting in natural supercharging and leading to a higher charge density in the cylinder. As compression ratios increase, the relative increase in available horsepower over aviation gasoline increases in ethanol's favor.

An example of the power increase was exemplified in the certification testing of the O-235 Lycoming on ethanol. The version of the engine undergoing testing had a compression ratio of 9.75:1. This engine is rated at 125 HP on Avgas. The tests were conducted on a test stand owned by Engine Components, Inc. (ECI). This test stand was routinely used for certification projects and was approved by the FAA for this purpose. The full power tests on ethanol showed that the engine developed 150 HP, an increase of 20%. This is using a compression ratio that Avgas can still operate under. However, ethanol can operate at higher compression ratios than Avgas, meaning that the potential efficiency of ethanol as an aviation fuel can be improved substantially.

Material Compatibility: Key properties of the fuel were tested during various projects. To obtain independent, authoritative characterizations, the Fuels and Lubricants Research Division of Southwest Research Institute (SWRI) was engaged to conduct tests and data analysis on E-95. Samples of fuel-wetted materials were subjected to soak tests to determine material compatibility. SWRI concluded that no materials compatibility problems existed with E-95.

Lubricity: Using the widely accepted Ball-on Ring Evaluator (BORLE), SWRI found that E-95 has slightly better lubricity than gasoline and is within the range considered acceptable for aeronautical systems. This result was corroborated by the post endurance test engine inspection. Prior to the endurance test the engine was disassembled and all parts subject to wear as a result of the fuel were measured under FAA surveillance. The engine was then reassembled and installed on the test stand. After the endurance test the engine was removed from the test stand and the measurements were repeated. The wear measurements indicated that all components were within service limits. The wear exhibited during this test on all components was less than or equal to that experienced in the same test using avgas.

Oil Analysis and consumption: FAA requires periodic fuel and oil analysis during the test. All results of these tests were satisfactory. Additionally, the report of the DER stated that oil consumption during the test was almost nil.

Luminosity: Flame luminosity was measured by a United Detector Technology Model 40X Optimeter System. Luminosity of E-95 was adequate to insure safety.

Energy Density: The single drawback encountered in the use of ethanol is its reduced heating value that results in a reduction in miles per gallon. Gasoline has 125,000 BTUs per gallon versus 75,000 BTUs per gallon for ethanol. If the thermodynamic efficiencies of ethanol and avgas were the same, a range reduction of 40% would be experienced using ethanol. The higher thermodynamic efficiency of ethanol reduces the loss of range to between 7% to 25%. This figure is the result of extensive flight test data taken using a variety of aircraft.


5. Safety
The decision concerning the next fuel for General Aviation must take into account all aspects related to the choice of a fuel. Clearly, safety is the paramount issue in aviation. Safety includes all parameters of performance of a fuel, plus the health hazards associated with its production, handling and usage.

Reid Vapor Pressure (RVP): The RVP of denatured ethanol is 3.0. Avgas is required by ASTM specifications to fall in the range of 5.5 to 7.5. The higher the RVP of the fuel, the more likely it is for vapor lock to occur. In the case of ethanol, a variety of chemicals can be used to denature it. The type and percentage of the denaturant can be tailored according to the desired RVP of the final product.

At RAFDC, the denatured ethanol, as produced today by the distilleries, with a RVP of 3 has been used since the beginning of the program. The lower Reid Vapor Pressure causes difficulty in starting in temperatures below 65 degrees F. The solution adopted at RAFDC to overcome this problem is very simple. A small canister containing Avgas is installed on the firewall and in cold weather, the engine is primed with a small amount of gasoline to start it. This system is very simple and inexpensive and has the additional advantage that the lower RVP of the fuel affords greater protection against vapor lock than Avgas.

Due to its relatively high RVP, gasoline is subjected to venting loss during flight. This can cause miscalculations leading to overestimation of range capabilities. Ethanol, with a substantially lower RVP, has far less tendency to evaporate when tanks heat up during flight.

Quality Control: The quality control of ethanol is very simple and effective. Ethanol is a single compound, C2H5OH, as compared with gasoline that consists of literally hundreds of components. Except for the denaturant, which is usually 2-5% unleaded gasoline, the very simple chemistry of the process insures that the end result of the distillation is always the same. As ethanol exits the distillation tower, it is already a high-octane fuel not requiring toxic additives such as lead or MMT to achieve adequate performance characteristics. All of the combustion characteristics of ethanol are measured as a single point as compared to gasoline where the characteristics are reported in a range (as in RVP). This also means that ethanol is almost completely stable in storage. When evaporation does take place, which happens at a far slower rate than gasoline, the fuel remaining is exactly the same as the original fuel.

Water Absorption: Anhydrous ethanol has a tendency to absorb water but the water that can be absorbed from the atmosphere is limited to a small percentage and will not separate out of solution. In fact, as far as safety and performance is concerned, hydrous ethanol is a slightly better fuel in every respect (except specific fuel consumption since water does not provide any caloric content). Small quantities of water absorbed in the fuel, result in a slight increase in power caused by the higher latent heat of vaporization of the fuel. In conclusion, there is no danger associated with water injection in an engine when using anhydrous ethanol as a fuel. Practical evidence of this characteristic of ethanol is the use of anhydrous ethanol in automobiles as a drying agent for fuel tanks in which water is suspected. All of the STCs granted for ethanol call for anhydrous ethanol as defined by ASTM specifications.

In contrast, gasoline's fuel condensation, from the inside of the fuel tank, can cause enough water to separate from the fuel to induce engine stoppage in flight.

Handling: Another safety issue in handling and using ethanol is its toxicity. The fumes from ethanol have a very low toxicity level compared with those from gasoline. In particular, the benzene component of gasoline is a carcinogen, as are other constituents. Clearly, the low-toxic nature of ethanol is evidenced by the fact that in its undenatured state it is a common component of potable beverages.

Performance: Ethanol produces more power and runs cooler than gasoline in the engine. Both of these benefits, when used with appropriate safeguards increase safety margins during operation.

The development of renewable aviation fuels has been underway at Baylor University for 20 years. The simple modifications enabling an aircraft engine to operate on ethanol, developed in 1980, have been continually improved over the years. The project has never been one of "research for research's sake". The initial motivation was the development of a renewable aviation fuel that could be domestically produced. The goal was the certification of an engine and airframe on neat ethanol. The Cessna 152 was chosen because it was the most common training aircraft. This goal was achieved and in the past years, a Cessna 152, certified on ethanol, is being used as part of RAFDC's air pollution investigation program conducted under a contract with the state of Texas. RAFDC research has always been aimed at implementation.

There is general agreement in the aviation community today that the lead will come out of the currently used aviation gasoline. The issue is "when". Environmental as well as economic considerations are urging the development of an unleaded aviation fuel.

Ethanol and ETBE have been proven by RAFDC to be outstanding replacement fuels for general aviation.

RAFDC is the most experienced organization working in the area of renewable aviation fuels. The experience of its personnel gained during two decades of testing, developing and certifying alternative fuels for aviation, coupled with the availability of dedicated facilities, are invaluable to the advancement of this research. These resources would be utilized to determine the full potential of ethanol and Avgas blends.

RAFDC appreciates the role the FAA has played in the development of its research facility. The additional investment represented in this proposal will enable RAFDC to evaluate all aspects of existing and future renewable candidates as replacements for 100LL.

[jrenwick]

I don't think the oil companies need to lift a finger here. I went to http://www.eaa.org and searched for "ethanol," and didn't find anything positive. (The first link that pops up on that search is http://www.eaa.org/autofuel/autogas/art ... 20mix_.pdf)

I suppose you could achieve similar results by searching http://www.cessna170.org, but I didn't try that.

[hilltop170]

This sounds too good to be true! I could use another 25hp in my 170.

The industry claims it's cheap to make, the farmers are making the money instead of OPEC, the tree huggers claim it's good for the environment and they'll love us for using it. What is everybody waiting on? Let's start using it while the government is still subsidizing it!

George, is this a cruel delayed April fool's joke?

[bsdunek]

Maybe it is a delayed joke. Look what's happening today.
1. Alcohol production has to be subsidized, as it is not economical to make.
2. The energy is only about 65% compared to gasoline - think about your range limitation.
3. No mention of vapor pressure - vapor lock at altitude anyone?
4. With today's technology, it takes as much or more energy to make it as you get back from it.
5. Water? Alcohol loves water - even if there's not enough to cause freezing, it further reduces energy.
6. Corrosive - the entire fuel system would have to be redesigned to use it.
I'm not saying that alcohol might not have a place in our fuel supply, but not for aircraft, and not yet for anything, IMHO.

[GAHorn]

Gasoline also has it's shortcomings, and those problems contributed to critic's fears in the early years. (Explosion hazards of production, storage, handing by the public, health, etc. In fact, the health issues strongly argued for ethanol. The fact that Prohibition was in full swing, and the fears of prohibitionists and temperance movements probably accounted more for the demise of alcohol-based fuel research than any other.) Economics played an important part in encouraging researchers to address those issues.

Henry Ford actually planned for ethanol to be the basic fuel for automobiles. It is renewable and can be produced less expensively than some of the hype that crtics of ethanol-as-an-additive frequently quote. During the early years of auto development, oil was so cheap that it was selected as the primary source of fuel. Those days may be numbered.
The problems of ethanol use can be overcome. It's a matter of economics. (Remember when the cost of converting the entire fleet of autos to unleaded fuel was the Chicken Little problem of the mid-seventies?)

My choice of original subject line for this discussion was prompted by my belief that corporations, of any industry, will behave protectively and in their own interests. The primary interest of all corporations is money, and how more of it can be garnered, and I believe that their money-goal will interest them far more than the long-term public good. History supports that conclusion. I changed the subject line because it made someone who works for an oil company uncomfortable. I apologize.

There may be other alternative fuels in the future.

[Lopez]

I am currently running E85 in my Jeep Wrangler. I'm up to 65% E85 with good results and no loss in mileage. I love the idea of saving $1 per gallon and getting more power. Next thing to do is advance the timing to enjoy the benefits of the higher octane.

[Bruce Fenstermacher]

George I'm still not over the shock that you posted information that is pro ethanol for airplanes given your position on MOGAS and MOGAS with ethenol.If I'mrecalling correctly you have lectured us in the past how ethanol will just not work well in airplanes for many reasons.

[GAHorn]

I am not "promoting" ethanol for use in current model airplanes that are not specifically designed for such fuel. The problem with using mogas or any other fuel with ethanol in it, is that our airplanes are not designed/modified to properly use such fuels. This discussion is not about that (completely) different issue.

This discussion was only about how research and development produced gasoline for a fuel for the "masses" and that other fuels can also be researched/developed successfully.... as long as certain corporations who are heavily invested in oil... do not fight or otherwise suppress such development out of fear they will lose market share.

[jrenwick]

I imagine that in Henry Ford's time, the demand for engine fuel was a tiny fraction of what it is now. Ethanol might have been easy and cheap to produce on that scale -- but what about today's demand? One problem I see at today's scale is that ethanol competes for land with the production of food, where oil does not. If ethanol is the fuel of the future, I hope we can find a way to produce it that does not increase the price or reduce the availability of food crops.

[hilltop170]

John-
I agree with you that we should not be making fuel out of food but as long as Congress is mandating its production and giving our tax dollars as subsidies for its production, we/G.A. ought to be taking advantage of the situation. If the conversion could be done cost effectively and converting would guarantee supply from now on, I would be willing to accept the loss of range for 20% more horsepower (according to the article above). The uncertain future of 100LL without a good replacement once lead is banned is not a very desirable situation either.

I don't know the exact numbers but I've heard total ethanol production is currently about four times the total avgas production so there is already more than enough production to take care of all of G.A. If we were going to look at it environmentally, eliminating lead in avgas would probably be of more value than diluting unleaded mogas for cars. So using current production for aircraft should be a better use than for auto fuel.

I would question whether the conversion from avgas to ethanol could be done very cost effectively and would also question future supply availability knowing we could be just one more congressional mandate away from no fuel or too-expensive fuel if the subsidies were cut off.

[webmaster]

Here's a recent article in the Washington Post that should be of some interest. It addresses the "Food for Fuel" issue.

http://www.washingtonpost.com/wp-dyn/co ... 02040.html

[jrenwick]

Thanks, Dale, that's an interesting story. I'm a skeptic by nature, and I'd like to hear the full story -- not just what the ethanol marketers want to tell us. Especially, I'd like to understand how an ethanol process (or multiple processes) can scale up to satisfy the needs of the country's fleet of cars and trucks, and what that would mean to our agricultural economy. I'll bet it's complicated, without easy answers.

Does the ethanol economy depend on government subsidies to get it started? If so, can it become self-sustaining without them? I've heard that a new ethanol plant now pays for itself in one year because of government input. If that's true, it sounds absurd to me -- normal businesses get started and prosper on a much longer-term plan than that every day.

If we shift toward ethanol because it's cheaper than oil (and I mean not artificially cheaper because of US government subsidies), then so will the rest of the world. Do we then become self-sufficient in ethanol production, or do we import some of it from, say, Brazil? The question really has to be answered on a global scale, not just for our country alone.

I don't know the answers to these questions. They don't seem easy to find, but the world is full of people who want me to hear just one side or the other of the story. It must be tremendously difficult for those in government who have to try to come up with a sane, workable policy.

[GAHorn]

....the world is full of people who want me to hear just one side or the other of the story. It must be tremendously difficult for those in government who have to try to come up with a sane, workable policy.

I don't know about that... Seems there's already two sides of the story being presented.... in this thread at least.

I guess you could be right, tho'..... there might be some who might like only one version of a story ....

[jrenwick]

....the world is full of people who want me to hear just one side or the other of the story. It must be tremendously difficult for those in government who have to try to come up with a sane, workable policy.

I don't know about that... Seems there's already two sides of the story being presented.... in this thread at least.

I guess you could be right, tho'..... there might be some who might like only one version of a story ....

George, I wasn't accusing anyone here of being one-sided; I was thinking more of the Washington Post story that Dale pointed to. It quoted two people from the ethanol industry, who both sounded 100% positive on producing ethanol without impacting the food supply. It left me wondering what the rest of the story was, because I'm pretty confident those guys are also lobbying for government support for their operations, and they're going to talk mostly about the up side -- seldom about the problems they need to solve, unless somebody knows how to ask the really pointed questions.

A lot of what I read in the mainstream media is like this -- reporters writing up stuff that's fed to them by one advocacy group or another, and never addressing the big questions that aren't raised by those experts. It's just very hard to get all sides of any story with this much political loading in a way that doesn't leave really important questions hanging out there.

[thomasmorley]

hey folks,

ethanol is being used as avfuel in brazil right now. all of these doubts and question are already answered.
in use, there are as far as i know, three problems;

corrosion- etanol does have water in it. i belive the fuel here is 96% ethanol and 4% water. aluminun and water don't work
well together. this can be delt with by changing all of aluminum parts to stainless or with vigilant maintenace and
removing the ethanol and flushing with avgas when the plane will not be flown. this is not as bad as it seems because an
ethanol motor can still be run on avgas. you can also treat the aluminum parts with a coating, but that doesn't really work
in tubing and pump bodies.

compatability- some rubbers don't work with ethanol. this must be solved on a case by case basis.
for example i hear that the diaphram in the fuel distributor of the lyc. io-540 must be changed but
in a conti io-520 the original is good to go

fuel quality- this is nothing new but with ethanol it just works different than avgas.
you need to keep an eye on the density because water does mix right in there. but a good desity meter is
not hard to find, or keep with the plane.

the long term (but maybe not long) problem is the cost. ethanol -for now- costs far more than avgas to produce, especialy
in the US. the current price is only because of huge subsities from the feds. there is no good crop to use
for making ethanol in the US. here in brazil they are making it from sugarcane and that process is something
like 4 times as efficient as the current corn method in use in the states.

the global ramifications of the corn subsidy are far reaching. they have helped drive the cost of all basic
food through the roof lately. this is helping the rich folks all around the world and starving poor people.
for countries that are net importers of grain this extreamly destabilizing. but in a country that is a net exporter,
well, thats great unless you were already poor.....

so, yes ethanol as a fuel is old news but its future is anything but settled.. .. ..