Why can't we use Ethanol

[blue eagle]

Dear Mooniacs,

Would it not be nice to sit in the cockpit and flying on bio Ethanol knowing that only carbon dioxide and water is leaving the exhaust. Also that your Lycoming or Continental engine is running cooler, giving more horses and never ever fouling your spark plugs again. Your engine is running with a full synthetic engine oil making it last longer and you are able to fly for many years with your same current engine.

 

Let's go over some topics to make this dream come thru:

 

- Octane number of ethanol is around 105 MON, this is much higher than that of 100LL making it a perfect replacement (this is also why top fuel (drag)racers are using ethanol as fuel). 

 

- Energy density is slightly lower compared with Avgas, so the mixture needs to be adjusted to a higher value. This can be done exact the same way as we do it today by leaning and using the EGT as parameter. Our Lycoming and Continental engines are a perfectly designed for this and we can use the same procedure as always.

 

- Ethanol can be solved in water, so it is not (easy) to detect if there is water in your fuel. I hear you saying that is a risk and therefor don't use Ethanol as a aviation fuel. I disagree, let me explain : If water is soluble  in Ethanol it makes it a homogeneous mixture. So If I would use it I would always have the same fuel and no pockets of water that could kill my engine if I switch tanks. When I perform a run up prior to releasing the brakes, I actually execute a performance test. With pitch fully fine and throttle fully forward I know what MAP and RPM I have to expect. If these values are off I would abort the take off and go check what is wrong. Now if I  would take of with ethanol after a good performance check I know that I will get the same power because the fuel is exactly the same. With Avgas this is a different story, I know I have now good fuel and power but if there is a pocket of water because I failed to drain all the fuel point in my pre-check, I could loose my engine. The Question is what is safer? There were many accidents were engine power was lost just after take off caused by water in the fuel. I would prefer ethanol.

There are some other things you should know, tests have revealed that there needs to be a considerable amount of water in the ethanol fuel to have a noticeable drop in power. We are talking more than 20 percent water content. Water content can be determined by measuring the specific gravity (talking a sample of 1 pint and weighing it precisely (like battery acid). This could be performed every morning by the Ethanol Supplier as some kind of batch release that day.  So there are solutions to mitigate risk concerning the use of Ethanol as a aviation fuel. It is a small effort to execute a more precise power check prior to the take off and perform a daily ethanol batch release with tight specifications (e.g. less than 1 % water content).

 

- Pure Ethanol burns with less visible flames compared to Avgas (because it is cleaner). Top Fuel racers know this problem and act accordingly. With some additives the flames could be made visible if that is what some would like.

 

- Compatibility with materials is different between Avgas and Ethanol. Ethanol can cause swelling of some hydrocarbon materials. I did some internet study on the materials in my 1998 Mooney M20J turbo-normalized (M20-turbos) with following interesting results:

+ fuel cap o-rings need to be replaced by viton o-rings + polysulfide kit used to deal the wet fuel tanks is approved for ethanol + 303 aeroquip hoses made from synthetic rubber are approved for ethanol + fuel selector seals and o-rings need to by replaced by piton o-rings + electrical fuel pump can be replaced by ethanol approved item + Lycoming engine fuel pump is not approved and there are no efforts to do so + Injection throttle body seals are not approved for ethanol + fuel divider seals are not approved for Ethanol + injectors  (with pressure lines from intercooler) o-rings need to be replaced by viton o-rings.

 

- Ethanol price is now around (€ 1.55 per liter) U$ 7.90/ Gal. For the US this is expensive but for Europe it would be cheap if only sales taxes would be applied. Bio ethanol is as green as a hydrogen cell engine and even greener than an electrical propulsion because there are no batteries with all kinds of toxic materials. On top of that ethanol is providing a environmental solution for all the existing engines out there and freeing the world from leaded fuel.This would be good arguments in Europe to only apply sales taxes on the bio ethanol.

 

If bio ethanol would be produces in large quantities from bio waste materials, there would be no competition with crops. Also it will make us less and less dependent on foreign oil. The ethanol price also will go down due to the scale of economics.

 

Now the Question is why are we taking so long solve the above mentions items, and instead spending a lot of money in finding petroleum based alternatives for 100LL. The next question that comes to my mind is why are the main engine manufactures not active in finding, certifying and offering ethanol approved fuel system components and let the end Customer decide if he or she will use a petroleum based 100LL lead free alternative or green Bio ethanol. Oil companies had their fair share in finding solutions for alternative fuels. They have chosen to pursue petroleum based road and were blocking green alternatives (Shell killed a solar panel activity and Mobil killed a algae project to grow bio diesel/kerosine). 

 

My final Question to you is how can we get together and form a front in forcing the aircraft industry and the governments of many countries to get ethanol in as a perfect green alternative, by approving and offering aircraft owners components to convert our existing aircrafts in an easy and cheep way (it is just a bunch of seals, o-rings and diaphragms).

Looking forward to your reaction.

 

Regards,

 

Bue Eagle

[Geoff]

Are you serious are is this just bait to try to get certain people banned?

  

[Yetti]

It's all fun and games till the alkeehal eats the o-rings in your fuel system and then the pieces try and go through your injectors.   Alkeehal also absorbs moisture, so you would be draining the whole plane load of fuel and replacing it after a rain storm or several heating and cooling condensation cycles. Ask the motorcycle guys who store their bikes for the winter and then have to drain the tanks to get them to run

[blue eagle]

In the experimental class there are examples of running a Lycoming IO360 on pure ethanol for many years. Because they were able to replace the engine fuel pump by an electrical pump approved for ethanol. We are not able to do this with our certified airplanes. Otherwise I would have converted my plane a long time ago. It is just getting this from the experimental world into the certified world.

 

Blue Eagle

[chrisk]

I'll take the bait.

http://www.generalaviationnews.com/2011/02/easa-warns-again-about-ethanol-in-mogas/

 

http://www.enertechlabs.com/fuel_phase_separation_in_ethanol.htm

 

And something to think about.  The energy density is lower for ethanol.  Does your fuel system have the capability to give full power on take off?  Are you going to be happy with 30% more GPH?

 

On a slightly different topic.  Does anyone know why a mogas STC is not available for Mooneys?

[N601RX]

You might want to read up on phase separation and how temperature affects phase separation of water and ethanol. At higher temps (on ground) all the water is absorbed in the ethanol.  At lower temps (cruise altitude) the water is going to separate again and settle to the bottom of the sumps.  Hopefully you can figure out what happens next without actually trying it.

[Shadrach]

I'll take the bait.

http://www.generalaviationnews.com/2011/02/easa-warns-again-about-ethanol-in-mogas/

 

http://www.enertechlabs.com/fuel_phase_separation_in_ethanol.htm

 

And something to think about.  The energy density is lower for ethanol.  Does your fuel system have the capability to give full power on take off?  Are you going to be happy with 30% more GPH?

 

On a slightly different topic.  Does anyone know why a mogas STC is not available for Mooneys?

Compare the MSDS of Mogas to that of Avgas, I believe it's a vapor pressure issue.

[BorealOne]

Alternative fuels are a huge interest of mine, and N601RX is bang-on - there's not an obvious solution to ethanol phase separation in our application, not to mention the other challenges. Swift and the other 100LL replacements seem to be better solutions.

 

http://fuelschool.blogspot.ca/2009/02/phase-separation-in-ethanol-blended.html

 

http://www.sciencedirect.com/science/article/pii/S0378381204004388

 

 

http://www.eaa.org/news/2010/images/Swift-Study.pdf

[blue eagle]

We have to clearly distinct items from each other. Ethanol in Avgas is bad for the not compatible materials were seals are made from (e.g natural based rubber). Ethanol will cause swelling of these materials and causing fuel flow problems or leaks. That is main reason why ethanol should not be in your Avgas fuel for now.

 

Because petroleum based fuels with ethanol cannot be checked on water content easily now, the EASA warns for it because there are no procedures yet to check. That's is why I do suggest to implement a daily batch release with a water content measurement by measuring the specific gravity.

 

Like mentioned earlier if you have a homogenous mixed fuel ethanol saturated water content with a E15 fuel you will hardly notice the difference in power, but you have at least always power.

 

regards,

[1964-M20E]

Ok so change the O-rings to be suitable for ethanol easy enough to do.  Diaphragms maybe a little more difficult but doable and any other rubber part in the fuel system.

 

Ethanol has a lower BTU content than gasoline (76,000 vs. 116,000 BTU) and diesel has a higher BTU content than gasoline.  So gallon for gallon you get less heat, less work and less power form ethanol.  Ethanol is 6.59 lbs./gallon and AVGAS is 6.02 lbs./gallon (note looking around I found some variations in these weights).

So less power per gallon with more weight per gallon equals less performance. 

 

Not to shun the idea I like it but there are some drawbacks like any other engineering solution.  We could then be green aviators.

[N601RX]

I don't think you are understanding phase separation.  At higher temps ethenol will absorb lots of water and the engine will burn it as long as it is absorbed.  As you climb higher and the ethanol cools it is no longer able to hold the water and will release it back to the bottom of your sump. Suddenly the engine is only getting water and is no longer making any power.

[Yetti]

While we are on the topic of green fuels.  It would be easier to use bio diesel and start producing the Packard Radial Diesel .   About the same weight as a 580 and 225 horsepower.   Burning used french fry oil would be pretty cool.

 

http://www.lcbamarketing.com/packard_radial_diesel_aircraft_e.htm

[Cruiser]

It is clear that a new fuel must be developed for use in GA engines. Many obstacles exist that must be overcome.

 

First, the fuel must perform in the environmental extremes of the airspace and the physical conditions of the engine/airframe. 

Second, Certification and regulatory hurdles must be overcome. 

 

I encourage anyone interested to become involved and contribute POSITIVELY to a solution.

[BigTex]

God only knows what Ethanol would do to my fuel bladders...

[ChrisH]

But, if a water pocket does strike in flight, at least you can take a cool drink of fuel on the way down. Note to self, add fuel test line to cockpit with mixing station. 

[pinerunner]

I wouldn't want to have the spend the money to convert my engine to ethanol so I'm glad its unlikely. Both Swift and GAMI have unleaded replacements and it looks like the only hurdles to having G100UL are regulatory so we can get away from lead. From what I recall the Swift fuel has a bio-based sourcing so that might seem more green but I'm not so keen on devoting a LOT of acreage to growing fuel instead of food.

 

In one of the sites blogging about thorium based nuclear power and molten salt reactors (LFTR's for Lithium Fluoride Thorium Reactors), of which I'm a big fan, one bloggers mentioned that with cheap energy one could synthesize hydrocarbon fuel from CO₂ in the air and water, that is just run the combustion reaction backwards, adding in energy instead of getting it out.  As a chemist I know its easy to get hydrogen by electrolysis of water and that catalytic hydrogenation of CO₂ is easily done (I ran a GC-FID that used that process to detect CO₂ and CO (converted to methane), which would otherwise have been invisible to the flame ionization detector). A bit of googling brought up a few references to catalytic generation of fuel from smaller molecules instead breaking down larger as is done in catalytic cracking of crude oil. So it appears to be possible to make our favorite hydrocarbon fuels using carbon currently in the atmosphsere which would be green and smart in my book. You would just need cheap energy and some R and D. The petro companies are already the ones who know the most about such catalysts so they wouldn't even lose money.

 

Short term G100UL. Get the lead out at the FAA so we can have it out of our fuel and off our spark plugs and valve stems.

 

Long term ..... we'll see but we could do much better and still have our current levels of energy consumption. It doesn't have to reintroduce old dino-carbon (yeah I know it mostly came from algae) into the atmosphere. I'm not in denial about global warming. 

 

I'm not with you in hoping for ethanol in my Mooney even though I believe it would be possible, even if the conversion were free.

 

Dave

[danb35]

35% less energy content than avgas with a greater mass.  That's enough reason in my book.

[flight2000]

God only knows what Ethanol would do to my fuel bladders...

 

Guess you'd have to go back to wet wings...    

 

Sorry, couldn't resist...

 

Brian

[BigTex]

God only knows what Ethanol would do to my fuel bladders... Guess you'd have to go back to wet wings... Sorry, couldn't resist... Brian

There's no doubt that the wings will be wet

[blue eagle]

Let me react on 2 items :

- Corrosion of aluminum is caused by destruction of the oxide layer. This is because of contaminant solved in water making the water acidic or alkaline. If we control the water content these contaminants cannot perform their destructive work. If you take the water away the chemical reaction stops.

Mentioned already earlier that the water percentage should be as low as possible when the ethanol is being produced, stored or transported as the percentage of contaminants. Water vapor in your tank also will be absorbed by ethanol in the tank, this is very clean water and will not cause any problems if the ethanol is also pure.

 

- Phase separation is not an issue because it is not there. We are talking about pure ethanol with possible a very small amount of water (caused by water vapor absorption inside the fuel tank), this will never ever separate as with fuel/ethanol mixtures due to water content. Or did somebody see a bottle of whiskey separate into water(mixed with some other stuff) and ethanol (= alcohol), or sugar getting separated from your coffee. The only way out is to cook is out (distillate) or with some very special nano filters to block distinct larger molecules and letting only water thru. So with ethanol you will never have suddenly only water as mentioned before it will remain a homogeneous mixture.

 

I know there are issues with pure ethanol as a fuel but all these issues can be solved without complex technical solutions. And therefore I would like the engine companies to change some seal and diaphragm materials to ethanol compatible materials. What is stopping them?

 

Regards,

 

Blue Eagle

[kmyfm20s]

But, if a water pocket does strike in flight, at least you can take a cool drink of fuel on the way down. Note to self, add fuel test line to cockpit with mixing station. 

Fill tank 1/2 way add favorite mixers, hit light turbulence to lighlty shake and enjoy.

[carusoam]

I like the optimism of youth....

In summary.

We should use alcohol, because it...

(1) has no flame color...

(2) top drag fuel cars use it...

(3) has less energy per gallon

(4) has a history of corroding engine parts

(5) has a history of being un-nice to rubber

(6) costs more than traditional fuels

(7) stabillity

(8) vapor pressure challenges during cold starts

(9) dry distribution challenge

OK, I get it, Blue Eagle=troll

At least the avatar make sense.

Did I miss something?

-a-

[BorealOne]

Let me react on 2 items :

 

- Phase separation is not an issue because it is not there. We are talking about pure ethanol with possible a very small amount of water (caused by water vapor absorption inside the fuel tank), this will never ever separate as with fuel/ethanol mixtures due to water content. Or did somebody see a bottle of whiskey separate into water(mixed with some other stuff) and ethanol (= alcohol), or sugar getting separated from your coffee. The only way out is to cook is out (distillate) or with some very special nano filters to block distinct larger molecules and letting only water thru. So with ethanol you will never have suddenly only water as mentioned before it will remain a homogeneous mixture.

 

I know there are issues with pure ethanol as a fuel but all these issues can be solved without complex technical solutions. And therefore I would like the engine companies to change some seal and diaphragm materials to ethanol compatible materials. What is stopping them?

 

Regards,

 

Blue Eagle

 

 

Sorry - that's the least complex part of the challenge. Changing a few seals and diaphrams in the engines isn't going to guarantee anyone anything - the critical challenge as I see it would be ensuring that we have a pure anhydrous supply of ethanol at source, and maintaining the purity of that supply right through the distribution system until it reaches my tank.

 

In my area of operation (Northern Canada) that'd be a huge challenge - AVGas is often brought in bulk trucks or ships, transferred to fuel farms and may well sit for a year or two until it reaches the end user. We know that water gets into the system, and have designed solutions for that. Consequently, I'm pretty confident that the guy operating the fuel truck has drained any water from the fuel he's pumping into my tank. I can check my own tanks to see if there's any water in them, and I can drain that myself if it is present. It doesn't matter if its +30C or -30C on the ground or in the air - I don't need to worry about water content. 

 

With ethanol, we'd need to integrate testing and drying systems throughout the fuel supply and delivery chain, and come up with a solution for pilots to test for and to remedy water content. I don't believe that would be easy or cheap.

 

Oh - and then there's this - ever try to start an engine at cold temps with E85?? The experimental planes that have done 'real world' flying (ie over the Atlantic) all had dual fuel systems so they could start on AVGas and then switch to ethanol.

 

Worries about contaminated fuel? Dual fuel tanks on my plane for cold starts? Ethanol seems like another problem, not a solution.

[jetdriven]

The biggest thing I see is stability in storage. The E10 in my lawnmower won't run right, or hardly start after 90 days. It picks up too much moisture from the air and goes stale. I couldnt imagine the nightmare it would make in my aircraft wing tank. Its unstable. 100LL, for contrast, is guaranteed good for a year, and actually is good for 7 or 10 years.

 

Then there is the cost, the energy value, airplane compatibility, vapor pressure, mixture settings, et al.

[BigTex]

There's a reason the fuel distributors have to splash blend Ethanol in the trucks as they head out to the gas stations.  So the E10 is ~ E10... Could be E20 depending out how well it's bended en route.