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Swift Fuel: Is It for Real?

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With everyone worrying about both the cost and availability of leaded avgas, the reporting we've done on Swift Fuel, a proposed replacement, has generated plenty of interest, not to mention questions. The lead-off query: Is this stuff for real?

From the outside looking in, it's always difficult to judge the credibility of projects like this. People directly involved in them are perpetually on the sunny side of the street and they'll tell you what they truly believe or what they think you want to hear. With that caveat, my impression is that yes, Swift Fuel is a legitimate industrial development project, albeit one that's still a long shot.

First, what is this stuff? It's a biofuel generated from cellulosic feedstock rather than starch feedstock. That means Swift will use switchgrass or sorghum rather than corn to ferment acetone from which it then manufactures a 100-plus octane fuel. As we reported last week, the FAA has done proof-of-concept testing on Swift Fuel and finds that it has more energy content than 100LL and excellent anti-detonation margin. That's good news. What the FAA tested is the chemistry-set version of Swift Fuel, what one petrochemical chemist we know calls the "$65 gallon of avgas." The real stuff, squeezed out of the biomass, hasn't been made yet, at least in volume. (For all the details on this, see our extensive analysis in the April 2009 of Aviation Consumer available in about two weeks.)

Swift estimates a manufactured cost of about $2 a gallon. That's the refinery out number, by the way, not the pump price. Add taxes, transportation and FBO margin and you're somewhere north of $4. Again, that's realistic if Swift's basic numbers are correct. But there are good reasons to believe they're a little optimistic. For one, you never hear this phrase in developmental projects: "Detailed testing has revealed that our estimates we're incorrect. Our product is much cheaper to make than we originally thought." It's always the other way around.

The challenges facing Swift Fuel are substantial. Yield from the biomass will be critical. To achieve its stated economics, Swift will have to evolve its chemical process to yield more of the chemicals it needs and less of those it doesn't and on a massive scale. This is easier said than done. It will also have to show that the biomass-generated fuel is free enough of impurities and unwanted byproducts to perform as well as the lab-made version. And that real-deal fuel will have to worm its way through the certification process.

Then there's the raw, commodity-driven blackhole of petroleum economics. The whole thing is tied to the price of oil which, at $40, isn't providing much encouragement for alternative fuel development. In the unlikely event that Swift Fuel proved cheaper on an equivalent octane basis than oil-based hydrocarbons, the refinery trade will buy up every drop of it for blendstock or otherwise bid up the price. One solution to this, says Swift's John Rusek, is to isolate the new fuel from the petroleum trade by marketing and distributing it through agricultural channels, as an aviation-only product. Well, maybe. Just because that hasn't been tried doesn't mean it couldn't work.

In Swift's favor are two things: Tetraethyl lead won't be around forever and the oil industry interest in using it to make avgas may be waning. We've been saying that about lead for nearly three decades now, but just as sure as the sun will explode into a red giant, TEL will eventually disappear. Even if it doesn't, if the oil companies decide they don't want to fool with avgas anymore—a real possibility because of falling demand—Swift could have a perfectly timed opening.

The fact that it's cellulosic rather than starch-based is a plus, for I predict that the country will eventually wake up and realize how utterly stupid the U.S. corn-based ethanol program has been. Energy yields from corn are pathetically low and the direct subsidies have been as much as $1.45 a gallon. The cellulose lobby hasn't done as well for itself and one hopes that it never will, except for research and seed money. If these alternative energy sources can't stand on their own economically, they shouldn't stand at all.

Coming full circle, that means that if Swift Fuel's real manufacturing cost is $3 a gallon and that translates to $5 or a little more at retail, they've got a player. GA in the U.S. can and has adapted to $5 avgas. If Swift can deliver, this project could have legs.

Comments (72)

Yeah, great. I have adapted to $5.00 gas. I fly less.

Posted by: Stuart Baxter | March 9, 2009 7:53 AM    Report this comment

You are right on about the economics. The 2$/gal. is fluff to attract interest and research money. Nobody selling Swift fuel or any other competitor to gasoline will sell below the equivalent petroleum based price. That is just the way commodity prices work. Back in the 1880’s we used biomass (wood) for fuel and it spawned a new industry, wood cutting for trains and steamboats. Made finding a tree difficult however. Growing fuel for your own use is easy, but you also have to grow it for the rest of us!

Posted by: Dick Merrill | March 9, 2009 8:25 AM    Report this comment

Although Swift are very cagey about their process, it sounds much like the ABE (acetone-butanol-ethanol) process invented by Chaim Weismann back in 1916. Using the bacteria clostridium acetobutylicum, biomass is fermented in to a brew of acetone, butanol and ethanol.

Unfortunately our reseach has indicated that, although acetone is an excellent fuel component, it is voraciously corrosive to plastics, elastomers, composites and aluminum. So, using a fuel containing acetone as a straight replacement for avgas in unmodified aircraft is a pipe dream.

Posted by: Chris Martinus | March 9, 2009 8:34 AM    Report this comment

It is being touted as non-corrosive so it would then follow that it would be some other process.

Posted by: Stuart Baxter | March 9, 2009 8:51 AM    Report this comment

What kind of land useage are we talking about to grow all this switchgrass and sorghum, and how's that going to affect the price of food?

Posted by: Mike Holshouser | March 9, 2009 2:44 PM    Report this comment

>> Unfortunately our reseach has indicated that, although acetone is an excellent fuel component, it is voraciously corrosive to plastics, elastomers, composites and aluminum.

>> It is being touted as non-corrosive so it would then follow that it would be some other process.

If you read Swift's patent application, available on the web, you'll see indeed that it is Chaim Weismann's process they intend to use. They then dimerize and trimerize the acetone. The don't mention how they get rid of unreacted components, or side-reactions that create undesirable for avgas materials. More to come, one hopes.

Posted by: Paul Millner | March 9, 2009 4:58 PM    Report this comment

>>They don't mention how they get rid of unreacted components, or side-reactions that create undesirable for avgas materials<<

Now that is an entirely new angle on the impact of using plant material or food production waste for a base for conversion to fuel - what happens to all the "undesired" or even "harmful" disposal material? One would assume that at some point the cost of the resultant fuel would need to cover the entire systems cost - including cleanup of the unused portion. Interesting as we have all been concerned about how a bio-fuel would be certified or distributed and have the same content anywhere we get it - this disposal aspect is very concerning! We should even ask what happens to contaminated fuel - can it be burned in ( name your local FBO piece of auto gas fueled equipment) or is it now a hazardous waste itself?

Posted by: d newill | March 9, 2009 5:27 PM    Report this comment

>> what happens to all the "undesired" or even "harmful" disposal material

Typically, one doesn't dispose of such material... it's either converted to something that's compatible with the desired fuel, through some chemical reaction, or it's converted to something that can be separated from the desired fuel at reasonable cost. Any separated stream, like the butanol already mentioned in the patent application, is then sold to secondary markets, whether mogas, chemicals, etc.

Posted by: Paul Millner | March 9, 2009 9:48 PM    Report this comment

Even if the manufacturing process can be perfected, the distribution problem would be enormous. Without processing plants scattered all over the country, tanker trucks would be required to criscross the country trying to get the fuel to every FBO/airport. I don't see any relief for 10 to 15 years even if the process could go into production immediately.

Posted by: Enoch Nicewarner | March 10, 2009 8:01 AM    Report this comment

If we are going to get this Country out of the ditch we had better start thinking about ways to get them done instead of all the reasons that something can't be done and that includes some solution before the guy in the big office just writes one of his memos and says no more lead.

Posted by: Stuart Baxter | March 10, 2009 9:10 AM    Report this comment

We will get out of the ditch by informed discussion like this. Thats how we got to the moon and how we got the bomb. the guy ithe big office does not have a clue what lead in fuel is even for. Has TEL been shown to be a major pollutant?

What we need is a new engine system that will burn unleaded fuel. GAMI has such a system but the FAA (I think the guy in the big office is their boss) is the hold up.

Posted by: Dick Merrill | March 10, 2009 9:27 AM    Report this comment

AVWEB says to stick to the subject and if the subject is aviation fuel, I would like to put in my two cents worth on auto unleaded fuel and the ethonol issue. I know lots of pilots that use auto fuel even ones with bladder tanks that have had no problems using auto fuel with ethonol adder. I wonder if it is just a ploy to discourage us from using auto fuel.

Posted by: Enoch Nicewarner | March 10, 2009 10:01 AM    Report this comment

I would highly recommend responders read AOPA's "Good-by Big Blue" which has an excellent explanation of the situation - both from a chemistry and supply point of view.

As for distribution - it will need to be via a set of trucks as it cannot be run through the current industrial pipelines ( Like 100LL cannot )

Finally, cost and price are not strongly related - most of the cost of fuel -any type - has some large element of tax involved. One could assume this would as well.

Posted by: d newill | March 10, 2009 9:25 PM    Report this comment

SwiftFuel does not appear to be a viable replacement for 100LL for several reasons. 1. Manufacturing Cost. I don't believe they can economically make the blend shown in their patent, which is a mixture of ethyl acetate, 2-methyl furan, mesitylene, n-heptane and corn oil for $2 a gallon. If they could, they could sell these on the open market for considerably more than they would fetch as a fuel. 2. Why not go the compromise route and remove lead and replace it with BioButanol? This butanol does not phase separate with water like ethanol does and it has 83% of the energy content of gasoline, whereas ethanol only has 66%. This stuff is being investigated by BP and DuPont. 3. Lead is in 100LL as a valve seat protectant (as well as raising the octane rating), what is done to fix this if lead is removed?

Posted by: Chris Lowery | March 11, 2009 4:19 AM    Report this comment

>>3. Lead is in 100LL as a valve seat protectant (as well as raising the octane rating), what is done to fix this if lead is removed?<<

I've seen the claim made before and have looked for the documented engineering data to support it. Can you point me at any? The question comes up frequently. In Europe, engines are running on 91/96UL without valve problems that we're aware of.

Posted by: Paul Bertorelli | March 11, 2009 5:59 AM    Report this comment

Lead as a valve protector, is an old wifes tale that goes back to flat head Fords without valve seats. Some think of it as a valve lubricant but if you have ever picked that stuff out of a sparkplug or valve guide you would never think "lubricant".

Posted by: Dick Merrill | March 11, 2009 7:11 AM    Report this comment

Lead tends to prevent valve seat recession on "old" low compression engines. At a certain point this problem was fixed by metallurgy; a harder valve seat. I don't know enough about this area, perhaps someone else could chime in. I agree with the comment that lead causes a lot of problems and if the octane rating of the fuel could be raised by blending in the right kind of feedstock then the resultant fuel would be a lot better.

Posted by: Chris Lowery | March 11, 2009 9:18 AM    Report this comment

Aircraft engines all have steel valve seat inserts in aluminum heads. In anticipation of unleaded aviation fuels, I understand that both Lycoming and Continental have used hardened valve seats since 1978. So, any Lycont which has been manufactured or overhauled (including top-end overhauls) since 1978 should have no problems.

There do not seem to be any reports of valve-seat recession from unleaded mogas users or the IO-540s which are certified for operation on ethanol in Brazil.

Posted by: Chris Martinus | March 11, 2009 9:42 AM    Report this comment

In Sweden we have flown without lead in Lycoming and Continental engines since 1981 -yes that is 28 years and with no problem. Engine manufacturers changed valves and valve seats mid 1970 to accomodate the 100 L fuel (was before 100 LL) and to be hard enough to crack certain combustion deposits. When they did so they without knowing it also got a system that operates without lead.

Posted by: Unknown | March 11, 2009 9:46 AM    Report this comment

Benefits of lead. 1. It acts as a biocide and prevents fuel from going bad. 2. It drastically raises the octane of fuel better than any other known substance, save a few extremely expensive exceptions. 3. It slows the flame front propagation of a burning fuel/air charge. This is know as the "lead bonus".

We burn so little leaded avgas each year it is silly to me that we even consider phasing it out. The benefits far outweigh the risks from an aviation perspective. In fact, even if GAMI were able to certify a system to allow unleaded usage in current engines, it would still be of benefit to use lead.

The known toxic qualities of lead are easily avoided by even the most casual, carefree, and ignorant avgas user. The risks to the environment in the quantites burned by GA each year are impossible to measure, in fact there is no documented harm whatsoever, save an isolated gas spill here or there or pure speculation.

Until a real product becomes available at the pump for GA to seamlessly replace leaded avgas we should all campaign to keep it around.

Posted by: Brad Vaught | March 11, 2009 12:27 PM    Report this comment

Lars,I guess you are the man behind Hjelmco who manufacture unleaded 91/96UL?

Posted by: Chris Martinus | March 11, 2009 2:19 PM    Report this comment

Chris - that is right. I invented the 91/96 UL. Brad. To manage one single unique leaded product in an else unleaded world is expensive and is going to become even more expensive. Many people speak about lead -- the most toxic part of the leaded fuel is the scavenger. The scavenger is also an ozone depleeting substance. The second most toxic substance in 100 LL the benzene, a carciogenic proven to give blood cancer. The good thing about benzene is that it can be removed by a qualified refiner. The Swedish AVGAS 91/96 UL has 0,00 vol % of benzene.

Posted by: Unknown | March 11, 2009 4:02 PM    Report this comment

Lars,

Isnt there more benzene in the unleaded car gas that we use here in the US than in avgas? How can ethylene dibromide be an ozone depleating substance? Its heavier than air and binds with lead during the combustion process and falls to the ground.

Posted by: Brad Vaught | March 12, 2009 7:41 AM    Report this comment

Brad, Car gasoline in Europe used to have up to 3 % benzene. It is now limited to 1 %. There is harm to environment and humans of using fuels. For humans or living objects, lead is toxic , the scavenger is so toxic that we need special permit from authorities to handle it and benzene is toxic. When you look to the environment there are other things we look at. As to the scavenger, bromide molecyles are released during the combustion process. They move around is the same manner as other ozone depleating substances and eventually make their way up in the atmosphere. It is all complex but proven.

Posted by: Unknown | March 12, 2009 8:25 AM    Report this comment

Lars, This is very interesting stuff. The ethylene dibromide misses some of the lead because what is not caught by it and blown out the exhaust as lead bromide is deposited in the combustion chamber and on the spark plugs. That's why there is an aftermarket for TCP containing additives like Alcor and Decalin. These mop up the remaining lead and convert it to a phosphate. Decalin also contains an extra ingredient for preventing deposits in the combustion chamber.

Posted by: Chris Lowery | March 12, 2009 8:44 AM    Report this comment

I too would like to see an informed discussion of the use of auto fuel containing Ethanol. I've heard/read a lot of anecdotes about the many ways that its use can kill you in an airplane. Seems to me that if it can be made to work safely in millions of cars, it can work in an airplane too. Burning the same fuel in an airplane that is burned in millions of cars every day certainly solves the distribution, infrastructure, and economic issues associated with a custom boutique fuel used by less than 1% of the nations fuel consumers.

Posted by: Mike Wills | March 12, 2009 2:16 PM    Report this comment

>> How can ethylene dibromide be an ozone depleating substance? Its heavier than air and binds with lead during the combustion process and falls to the ground.

Not all of it combines with lead. Some evaporates during fueling, or from tank emissions. Some doesn't react. That said, the numbers are so small, that all the US pollutant inventories I've Googled show the annual numbers at zero. I think Lars concern about benzene may be a red herring... though it's dangerous to get into a fish discussion with a Swede, eh? The only benzene one would expect to find in avgas would be from reformate; but reformate benzene levels have been reduced by an order of magnitude to comply with mogas regulations... and reformate doesn't fit well into the avgas pool if you're making 100LL. Pretty much zero.

To Mike Wills point, there's much been written on the problems with ethanol in aircraft. We don't need to reproduce it all here. Airplanes are different than cars.

Posted by: Paul Millner | March 14, 2009 2:08 AM    Report this comment

Paul: every producer of hazardous products has to make a Material Data Safety Sheet (MSDS) and list dangerous components according to certain rules.So if the scavenger and benzene are present they are listed. Google MSDS AVGAS 100 LL and you will find certain producers allowing them to have up to 5 % of benzene. Benzene is not regulated in the AVGAS standard ASTM D910 but the freezing point of AVGAS usually puts a restriction of its content. Also Google benzene and you will find how dangerous it is - it is proven to give blood cancer. When we speak about environmental impact as said before the are two dimensions -- the influence on people handling and using the fuel and the influence on the environment (mother earth) in a greater sense. So to Google US pollutant inventories will not give an answer about the hazards the people handling the fuel such as pilots, mechanics etc are exposed to. The discussion cannot move forward if not everyone understands that leaded AVGAS is a very dangerous product. I guess it is labelled with "scull and crossbones" also in the US by law and not only elsewhere. Please read this MSDS in detail and come back with your comments. http://www.petroleumlogistics.co.nz/forms/avgas_100.pdf

Posted by: Unknown | March 14, 2009 5:39 AM    Report this comment

Lars, The New Zealand (!) MSDS you cite does not convince me that there is benzene in US avgas. For completeness sake, as you know, many things are LISTED in an MSDS for a blended product that rarely or never appear there. Due to the requirements of blending mogas with very low benzene levels, and the transition to 100LL which requires higher octane blendstocks than found in the refinery gasoline components that contain even low levels of benzene, there's just no practical way to end up with significant amounts of benzene in avgas.

If you take a look, for example, at Chevron's avgas MSDS (a US avgas manufacturer) you'll see that it lists benzene, but at less than 1%, similar to mogas. http://www.chevronglobalaviation.com/docs/aviation_gas.doc

But again, practically speaking, I don't think you'll find benzene in US avgas... when you blend alkylate, toluene, and butane to make avgas, there's no source for benzene... unless you've somehow found the world's *worst* toluene supplier! :-) And even then, we're talking trace amounts, not 1% in avgas.

Paul

Posted by: Paul Millner | March 15, 2009 9:45 AM    Report this comment

For a good technical overview of aviation fuels (not for you, Lars, but for the lurkers), see:

http://www.chevron.com/products/ourfuels/prodserv/fuels/documents/aviation_fuels.pdf

What skull and crossbones labeling requirement for avgas are you speaking of? I'm not aware of any such, and I've never seen a skull and crossbones on avgas in my 31 years of flying, or 34 years working in an oil refinery.

I guess I'm not willing to stipulate that leaded avgas is a very dangerous product... We've been using it with relative safety for many decades. So perhaps, as you say, the discussion cannot move forward.

Paul

Posted by: Paul Millner | March 15, 2009 9:45 AM    Report this comment

Paul, that is very useful information, thanks.

Chris L.

Posted by: Chris Lowery | March 15, 2009 10:53 AM    Report this comment

Paul - I have only been flying for 40 + years - here is an 100 LL poster with scull and crossbones. http://www.hjelmco.com/pages.asp?r_id=13394

There are very many ways to make AVGAS not only the one you indicate. It is up to the refiner. Also the US is not the world and AVGAS is a world commodity. Perhaps US producers are better than others but I don,t think so in general. Refiners take what the have to put things together and cost of production is important. No one puts things into a MSDS if the things are not present. It is also illegal. As long as there is no restriction in the ASTM D910 standard, refiners will use the opportunity if needed.

Posted by: Unknown | March 15, 2009 1:12 PM    Report this comment

Paul, thanks for dismissing me out of hand and focusing on your agenda. Much has been written about Ethanol use in airplanes both pro and con. Most of it is anecdotal with no factual content. There are plenty of folks flying Mogas containing Ethanol with no adverse issues. The Vangaurd RV Squadron flies an airshow routine burning pure ethanol. Mogas may not be a 100% solution, but it may be a 75% solution for little investment in retrofit to existing aircraft. I dont have specifics and thats why I asked for info. I've done a fair amount of reading on the subject and all I see on the con side is it cant work, with no effort put into explaining how it might be possible. One thing is clear to me - burying your head in the sand and stating that lead poses no problem so we should stick with the status quo is a non-starter. Lead in fuel is on borrowed time whether for real environmental issues or for political or economic reasons.

Posted by: Mike Wills | March 16, 2009 10:59 AM    Report this comment

I agree with Mike Wills. I was always told that you couldn't burn ethanol in old tractor engines on the farm. Well I did for ten years and they were all still running just fine when I got out of farming. A lot of the negative comments about ethanol added fuels is just plain not true and accurate.

Posted by: Stuart Baxter | March 16, 2009 4:42 PM    Report this comment

I also don't understand why motor fuels can't work for airplanes. I get that ethanol is particularly nasty, caustic stuff. It attacks a large variety of rubbers and other materials. The automotive industry has started using materials which are not as vulnerable to it and the average car you buy today is able to run fuel that's up to 85% ethanol. It seems like it should be possible to retrofit fuel systems for airplanes so that they can run the typical 10-15% blend in pump gas.

I also can't understand why aviation engines require such high octane fuels. They are typically extemely low compression and should be much less vulnerable to detonation than the 11:1+ compression ratio automotive engines that seem to be perfectly fine on 92. If it's an issue of combustion chamber design and poorly engineered cooling systems, the solution isn't to run leaded fuel forever, it's to redesign the heads and switch to liquid cooling.

Exactly how is aviation, as an application, so radically different from other applications for four stroke, internal combustion gasoline engines that it requires special fuel?

Posted by: John Cuyle | March 16, 2009 8:18 PM    Report this comment

Best to focus on what's written, rather than on the writers' supposed motivations... see "keep it civil" below.

Ethanol is incompatible with certain materials in aviation fuel systems. Does that mean it's incompatible with a given bugsmasher 200 that you or I fly? Don't know... but it will take research, and a certification effort to get approval for different materials. Ethanol requires signficantly greater quantities of fuel to generate the same horsepower, so fuel metering requires adjustment, with attendant certification headaches, as well as new performance tables for the now shortened range aircraft. Most troubling to me, ethanol varies considerably in water soluability with temperature, and of course, water can't be drained from the tanks on the ground as water and ethanol are miscible. So as you climb into cooler air, or even fly from a warm place to a cold place, as the ethanol in your tanks cools, it drops out water. Maybe there's enough to snuff combustion in the engine, maybe not. But if it's below freezing, the water can freeze, blocking fuel flow to the engine. I hate it when that happens.

Do folks fly with ethanol and get away with it? Sure. Is it safe and legal? Well, maybe not.

Being opposed to ethanol doesn't mean being for lead. An unleaded fuel that doesn't require significant certification and modification cost for the existing fleet is a very doable thing, whether or not acetone can be made into an acceptable unleaded avgas.

Paul

Posted by: Paul Millner | March 16, 2009 8:56 PM    Report this comment

Ethanol is not caustic. It is alcohol. That's one of the myths. It does not attack a large number of rubbers and plastics. That is precisely what I am talking about. If it was caustic could you drink it without serious damage other than to your sobriety?

Posted by: Stuart Baxter | March 16, 2009 8:58 PM    Report this comment

>> here is an 100 LL poster with scull and crossbones. http://www.hjelmco.com/pages.asp?r_id=13394

Thanks for sharing that from your website. 90% of the world's avgas is made and consumed in the US, I believe... and we've been discussing the difference in US mogas and avgas content. So I'm not certain that a Swedish avgas poster is on point... but there it is! :-)

>> There are very many ways to make AVGAS not only the one you indicate.

Pretty much, Lars! Take a look at the Coordinating Research Council 100 Unleaded working papers, I know you've been in touch with that group. I didn't see a single 100LL formulation there that had benzene.

>> Refiners take what the have to put things together and cost of production is important.

Of course. But there's no gasoline component stream available to US refiner blenders that has that much benzene in it, hence the need for you to identify a New Zealand example, where there's one refinery in the country with significant challenges... a whole different story.

>> No one puts things into a MSDS if the things are not present.

Actually, in our litigious society, they do, if there's any chance it MIGHT be present. Note that the MSDS says less than 1%. Zero is less than 1%.

>> It is also illegal.

No, not actually.

>> As long as there is no restriction in the ASTM D910 standard, refiners will use the opportunity if needed.

If they had such a stream... but they don't. :-)

Paul

Posted by: Paul Millner | March 16, 2009 9:02 PM    Report this comment

>> Ethanol ... does not attack a large number of rubbers and plastics.

Aviation fuel systems have rubber, cork, and leather (accelerator pump piston) parts, and of course many parts, including tanks, are aluminum. Per the EPA website, high ethanol concentration fuels attack all these materials.

No one who's even mildly liability averse will sell ethanol into the aviation market unless an airplane has been certified for that fuel... and the FAA is going to want to see those vulnerabilities addressed, which won't be easy.

See the EPA's web site for a presentation on ethanol compability, and especially note page 29 for the above information.

http://www.epa.gov/reg3wcmd/Ethanol_Workshop/English_EtOH_Material_Comp_Final_Rev3.pdf

Posted by: Paul Millner | March 16, 2009 9:15 PM    Report this comment

>> I also can't understand why aviation engines require such high octane fuels. Exactly how is aviation, as an application, so radically different from other applications for four stroke, internal combustion gasoline engines that it requires special fuel?

Cesar Gonzalez, retired from Cessna, and participant in the 100UL industry work, had a nice presentation at Oshkosh on why aviation engines have such high octane requirements. Key issues are fixed timing, timing that varies with accessory section gear lash, poor fuel atomization in both carbureted and aviation fuel injection systems, high cylinder head temperatures due to air cooling, CHT hot spots due to uneven cooling, high OAT, pilot ability to select too lean or too rich of a mixture to control temperatures and hence detonation, pilot ability to select an RPM that increases detonation at operating conditions... all these things are fixable, of course. Are they economically fixable and certificable on the existing fleet? Or do we just throw some 50,000 higher octane requirement airplanes away?

It's not an easy problem to solve, logistically.

Paul

Posted by: Paul Millner | March 16, 2009 9:29 PM    Report this comment

The EPA, they are the experts on everything, sure. We need some leading edge people not some government hacks to work on this problem. How about some funding for GAMI to work on this? Assuming they would take any money from Uncle.

Posted by: Stuart Baxter | March 16, 2009 9:39 PM    Report this comment

I looked at page 29. It is referring to E85. At this point I don't think anyone is suggesting that due to it's lower mileage and therefore lower range of travel. Besides it uses the great words of government 'possible'. That means 'be afraid....be very afraid.'

Posted by: Stuart Baxter | March 16, 2009 9:45 PM    Report this comment

>> It is referring to E85. At this point I don't think anyone is suggesting that

Hmmm... read Mike Wills' note, and your note, Stuart, above... you did suggest ethanol in tractors as an example for aviation, no?

The EPA is typically seen as favorable toward alternative, bio-based fuels... but there are others less favorably inclined who also have the same materials compatibility concerns.

GAMI has chosen how they plan to proceed, I think... they're working with Lars, represented here, and others on conventional hydrocarbon solutions to an unleaded avgas. I'm sure they're eyeing any feasible solutions.

Posted by: Paul Millner | March 16, 2009 9:50 PM    Report this comment

There were sort of two points to my post. The first is the unfortunate reality that automobile gasoline now contains ethanol. I don't like the stuff either and wish it wasn't in automotive fuels, for a variety of reasons from poor performance to the subsidies that go into producing it. It'd be nice if aviation engines could simply run on the same gas as cars, but that may not be practical.

The second is, ethanol aside, it seems like airplane engines ought to be able to run on lower octane. All of the issues you listed, fixed timing, inaccurate timing, poor fuel atomization, high CHT, uneven cooling, have been solved by automobile engines. Electronic ignition and fuel injection systems and liquid cooling take care of most of it.

Given that engine overhauls must be done regularly anyway, and that the cost of a complete overhaul approaches the cost of a new engine the logistics of retrofitting the fleet would largely be taken care of over time.

The issue really isn't the technical challenge, or even the logistical one, it's that the FAA's rules for certifying powerplant and airframe modifications are so strict that it is not economically practical to develop an aviation powerplant using technology that has been standard in automotive engines since the 80's or earlier.

Posted by: John Cuyle | March 16, 2009 9:52 PM    Report this comment

>> The issue really isn't the technical challenge, or even the logistical one, it's that the FAA's rules for certifying powerplant and airframe modifications are so strict that it is not economically practical to develop an aviation powerplant using technology that has been standard in automotive engines since the 80's or earlier.

Well, that's kind of a chicken and egg thing... are we going to change the FAA, or figure out how to change the airplanes? I have an idea how to do the latter. I'm not so sure about the former!

Paul

Posted by: Paul Millner | March 16, 2009 10:08 PM    Report this comment

Paul You have made comments to my comments about benzene. I don,t agree with your comments and it will just take too much space to present the facts to you. I have 30 + years of experience in production of AVGAS and have seen many refineries both in the East block before the iron curtain fell and in the west. Here you have a link to where AVGAS is produced today. http://www.hjelmco.com/news.asp?r_id=3871 90 % of all AVGAS is not produced in the US and there is not only one producer in Australia.

To move things forward: This blog is about the Swift fuel. I am interested to learn more about that fuel.

Posted by: Unknown | March 17, 2009 2:00 AM    Report this comment

>> I have 30 + years of experience in production of AVGAS

Well then! I have 34 years experience; does that make my observations somehow better? :-) Even in the absence of the data that's too space consuming? A web link would work, Lars.

90 % of all AVGAS is not produced in the US

That's very odd, since 50% of the world's piston aircraft are in the US.

>> there is not only one producer in Australia

Actually, Lars, your comment, and my reponse, were about New Zealand, a different country, isolated by a lot of water from Australia.

>> I am interested to learn more about that fuel

As am I... if they're really figured out a way to control the byproducts of dimerization and trimerization, then that's significant news to the industry beyond merely avgas production. But since many, many have attempted this, and Swift doesn't even claim that they've accomplished this in their patent application, it's a mystery how they plan to make such high quality gasoline from a process inherently beset with less desirable by-products. So I hope we hear the rest, soon...

Posted by: Paul Millner | March 17, 2009 9:56 AM    Report this comment

The problems faced by Swift seem to be largely economic. Bulk acetone tends to be a bit more expensive than mogas on the open market. Processing it into mesitylene and 2-methyl furan is gonna cost money. So, the intermediate material has more market value than the end-product.

On top of that, the environmental impact of these substances and their by-products are an unknown at this time.

Posted by: Chris Martinus | March 17, 2009 10:14 AM    Report this comment

Paul. See the link http://amtulld002.bp.com/alignmsds/oavfin.nsf/webprodcurairbp?OpenView&Start=1&Count=30&Expand=17.2#17.2 and take MSDS from various regions in the world. See that they vary the MSDS if it is < 0,1 % of benzene and if the blend is > 0, 1 %. So it is the choice of the refiner. Sorry about New Zealand -- but as far as I know New Zealand does not produce AVGAS it is coming from Australia -- thus my point.

Chris Acetone tend to be corrosive. How could that be handled? Ethyl Acetate attracts water. How is that handled ?

Posted by: Unknown | March 17, 2009 10:47 AM    Report this comment

Paul Milner,

Thank you for your fact based and well written posts. You are an asset to the aviation community. The time you spent on your accurate posts may well lead some of the ignorant down a more balanced path.

Posted by: Brad Vaught | March 17, 2009 10:49 AM    Report this comment

Brad, I second your comments. Paul Milner is a real asset here.

Posted by: Chris Lowery | March 17, 2009 11:08 AM    Report this comment

>> Per the EPA website, high ethanol concentration fuels attack all these materials.

I'll take issue with this, Paul. This misconception arises from the fact that methanol, acetone and other ketones are natural fermentation by-products and are highly corrosive to many materials - as well as your health.

Any moonshiner worth his salt knows that the first part of the distillation run should be discarded, unless you want to go blind and rot your gut.

ASTM-D4806, which standardizes ethanol for blending with fuel, places generous limits on these impurities - so high concentrations of ethanol in fuel will rot your rubbers and corrode tanks, fuel lines etc.

Posted by: Chris Martinus | March 17, 2009 12:20 PM    Report this comment

I dont recall advocating the use of E85 or pure Ethanol. I cited the Vanguard Squadron as an example of a successful use of a fuel containing Ethanol in an aviation application. If they can make it work then it would seem the technological barriers to using Mogas containing 5% - 10% Ethanol should be relatively trivial. Fixed timing, poor atomization, etc...? What makes more sense? Spending untold amounts of cash to develop a new boutique fuel or spending those dollars to bring the typical aircraft engine a little closer to the 21st century? I'd agree with you that as far as I can tell there is currently no legal means to fly your certified aircraft on any fuel that contains Ethanol. But the current general aviation fleet now contains a significant number of Experimental aircraft and they are perfectly legal to fly on Mogas containing Ethanol. Quite a few of them are doing so with no problems at all. Comments about water dropping out of suspension and snuffing out an engine or freezing are the kind of anecdotal references that I find particularly frustrating. If you've got some data that shows that running Mogas containing 10% Ethanol has ever caused an engine stoppage in flight due to this I'd like to see it. Otherwise it's just scare mongering. I dont believe I posted anything less civil than your dismissal of my comments. I believe any blog about 100LL alternatives should include discussion of Mogas as a viable alternative so I think this is on topic as well.

Posted by: Mike Wills | March 17, 2009 12:29 PM    Report this comment

Mike, the main problem with ethanol/hydrocarbon blends is the risk of phase separation where there may have been water contamination. It is not really a problem for automobiles, but phase separation can well occur where the temperature drops as an aircraft climbs to altitude. What happens is that the hydrocarbons and the "wet" ethanol separate into distinct layers.

Baylor university in Texas managed to trash a Lyc IO-540 testing this about 20 years ago. The surging that resulted from separated fuel sloshing into the engine was enough to cause significant damage.

Straight ethanol will not separate at all and it is quite safe to run with about 10% water in it.

There are STCs to operate a few aircraft on straight denatured ethanol, namely the Cessna 152 and the Piper Pawnee. A couple of aircraft are also STCd to run on AGE-85.

The Embraer Ipanema crop sprayer is certificated in Brazil to run straight ethanol. It uses a Lyc IO-540 engine.

Posted by: Chris Martinus | March 17, 2009 1:46 PM    Report this comment

AVGAS is a world wide commodity. You can take a plane in Northern Europe Sweden and fly around the globe. The AVGAS fuel will find will do its job without any changes to the engine and regardles of latitude. If you take pure ethanol or a high ethanol content in the fuel you have to retailor the engine to accomodate the higher fuel consumption. On the latitudes where I live the engines will hardly start in the winter nor will they reach sufficient engine temperature in flight because they will run too cool. Ethanol is good for flying if it resides in ethanolether, ETBE.

The Swift patent says that one important component in that fuel is ethyl acetate of about 13%. Litterature says that Ethyl acetate is very good to attract water. Does any one have opinion about this? Shouldn,t this component also be able to cause phase separation as Chris Martinus says about pure ethanol?

Posted by: Unknown | March 17, 2009 2:43 PM    Report this comment

I fly an experimental aircraft, a Glastar that I built myself. I put in a Subaru engine and reduction gearbox, I'm now at 311 hours. I run autogas with the ethanol in it which I buy at Costco. I check the Reid Vapor Pressure using a Petersen Aviation tester. The engine runs very happily on it. But then, it has fuel injection, an anti-knock sensor, a fully mapped ECU controlling the ignition timing and all the goodies modern cars take for granted. This is what it might take on conventional aircraft engines to solve this fuel problem. I had a great flight this morning, burning gas at $2.06/gallon.

Posted by: Chris Lowery | March 17, 2009 3:34 PM    Report this comment

"...the main problem with ethanol/hydrocarbon blends is the risk of phase separation where there may have been water contamination. It is not really a problem for automobiles, but phase separation can well occur where the temperature drops as an aircraft climbs to altitude." Why not? It gets cold on the ground too.

Posted by: Mike Holshouser | March 17, 2009 4:42 PM    Report this comment

I've read some of the literature on phase seperation. Google Ethanol phase seperation and you'll get a list including a pretty good paper on the subject. Very little specifically addresses aircraft application and it appears to me that the reason for that is the just say no approach the FAA has taken. I accept the fact that phase seperation can happen. I also see from what I've read that there are ways to minimize or prevent the risk. I've still seen no documented cases of an actual in flight problem directly traced back to phase seperation. I guess I'm a show me kind of guy and weigh the examples such as Chris Lowery's against the total lack of examples on the other side of the argument. Guys like Chris (I know others as well) prove that it can be done.

Posted by: Mike Wills | March 18, 2009 10:22 AM    Report this comment

I echo Mike Wills comments. I may have misspoke when earlier I talked about ethanol when I meant gasohol. There is no evidence about problems of using gasohol in aircraft that I can find. There is no evidence of gasohol melting rubber, plastics, felt, aluminum or other stuff in the fuel systems of tractors or airplanes or cars. Please if we are going to keep talking about this, show me the beef.

Otherwise let's get back to Swift Fuels.

Posted by: Stuart Baxter | March 18, 2009 4:05 PM    Report this comment

I understand there was an open forum regarding SwiftFuel about a week ago......Is that subject still being discussed?

Posted by: Greg Morton | March 19, 2009 10:17 AM    Report this comment

>> SwiftFuel ... still being discussed?

Sure, Greg. What are your thoughts? Summary is that mesitylene and isopentane would no doubt make an acceptable aviation fuel, with some caveats. However, we have no information yet on what the actual yield from dimerized and trimerized acetone would *really* look like.

Posted by: Paul Millner | March 19, 2009 10:58 AM    Report this comment

Mesitylene (1,3,5-trimethylbenzene)is extremely poisonous stuff. IHL-RAT LC50 24 mg/m3/4h. Mesitylene plays a significant role in aerosol and tropospheric ozone production, (according to Wikipedia) so I don’t see how this is an environmentally friendly solution. This would be jumping out of the frying pan containing lead into the fire lit by the FOE and the EPA. SwiftFuel would contain 45 to 60% of this stuff and I don't think I'd want to be anywhere near it.

Posted by: Chris Lowery | March 19, 2009 11:15 AM    Report this comment

>>we have no information yet on what the actual yield from dimerized and trimerized acetone would *really* look like.

You are correct. I understand,as we speak,SwiftFuel is undergoing long term testing (150 hrs) by the FAA, TCM and Lycoming. Once these tests are completed and reports are issued we will have more data to evaluate the relvance of SwiftFuel.

Posted by: Greg Morton | March 19, 2009 11:42 AM    Report this comment

>>I understand,as we speak,SwiftFuel is undergoing long term testing (150 hrs) by the FAA, TCM and Lycoming<< I attended a presentation by Swift Industries a couple of weeks ago - unless I missed something, Lycoming donated a 540 engine (turbocharged?? unknown) that is headed for GAMI and they will do testing there. The FAA / NASA test stands in NJ are not being used at the moment - and there was no indication they would be scheduled soon to begin testing. Swift wants to file for application as a fuel that meets whatever the new ASTM fuel specification will be ( 92 -93- 94- 95UL ) which is to take place this summer. They must match whatever the consortium of Aviation fuel suppliers come up with so that they are not a different certification. I am still not sure that will make them acceptable - just proves their chemistry passes the same tests as the "94UL" spec. For what it is worth - their senior guy is pretty sharp. Some of the rest of the team seemed just a bit too enthusiastic for most of the elderly pilots in the crowd, not sure it was their youth or manner of speech -but it did not build confidence in the FBO operators I was sitting with.

Posted by: d newill | March 19, 2009 8:19 PM    Report this comment

The world abounds nowadays in IWWOKS. Some where along the way we seem to have lost the can do philosophy. The it won't works seems to be a lot more prevalent than let's make it work. At least the testing is going to be done at GAMI some of our brighter bulbs than by the FAA who even if everything worked will decide than twelve more years of study are required before we more on to the next stage of study.

Posted by: Stuart Baxter | March 19, 2009 9:19 PM    Report this comment

>> I understand,as we speak,SwiftFuel is undergoing long term testing (150 hrs) by the FAA, TCM and Lycoming

I believe that's the $65/gallon test fuel made by blending pure isopentate with pure mesitylene that is being tested. That will tell us if such a blend would work, and I expect that it will. It won't tell us whether a Swift fuel actually made by fermentation and dimerization/trimerization will work... they need to build more than a bench top facility to generate adequate volumes for such testing. And the devil is in the details of what the co-products are, and the properties of those co-products, intermingled in the fuel.

Posted by: Paul Millner | March 20, 2009 12:22 PM    Report this comment

Paul, I plan giving a presentation Forum on Fuels at the Golden West Fly-In at Marysville, California in June. I would very much like to confer with you on some of the issues being discussed here. Could you email me at decalin@sbcglobal.net if you are willing to share your thoughts.

Posted by: Chris Lowery | March 20, 2009 1:17 PM    Report this comment

>>The FAA / NASA test stands in NJ are not being used at the moment - and there was no indication they would be scheduled soon to begin testing.

I understand there has been a delay in the delivery of the Lycoming engine to the FAA facility in N.J. for the endurance testing to be conducted under the Cooperative Research Development Agreement (CRDA) and the FAA. The FAA had requested and has received the needed SwiftFuel at their N.J. facility and will continue testing once the engine has arrived. I’ve also learned, although GAMI previously had been testing SwiftFuel, for now, they are not involved in the testing. TCM has also been sent SwiftFuel to be tested at their Alabama facility. It seems as if all or most of the major players are involved. We shall see.

Posted by: Greg Morton | March 23, 2009 10:17 PM    Report this comment

The Swift fuel is said to have a density of > 820 grams/liter at + 15 degr. C. That is about as diselfuel How will that make it with the floatation gear in the carburettor? You might set it for that density -- but then you fly to an other field where the fuel is having a normal density of approx 720 grams/liter. You cannot reset the floatation gear in the carburettor when refuelling at various sites.

Posted by: Unknown | March 27, 2009 5:34 AM    Report this comment

Can anyone give me a clue as to what these last two posts are about?

Posted by: Dick Merrill | March 29, 2010 8:26 AM    Report this comment

I think you may have seen some spam comments, Dick. We've been keeping a close eye out for them on the blogs lately — but if any of you guys come across them in your reading of the blogs, don't hesitate to use that "report abuse" link to send us a note.

(We don't say it often, but you readers are tops. Thanks for everything — including the spam reports!)

Scott Simmons
webmaster

Posted by: Scott Simmons | July 10, 2010 5:59 PM    Report this comment

It definately sounds like a case of marketing being over optimistic. It's the start of a plan, except it to differ (north of $4 at pump) by the time realisation.

Thanks Gary Corbett

Posted by: Gary Corbett | April 20, 2011 12:30 PM    Report this comment

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