Ethanol ConsiderationsEthanol Considerations and and

The Future of Aviation FuelsThe Future of Aviation Fuels

The fuels we will use today and in the future will not The fuels we will use today and in the future will not be the same as the ones we used even last year.be the same as the ones we used even last year.

Automobile gasoline formulation is changing greatlyAutomobile gasoline formulation is changing greatly 100LL will be a fuel of the past, just as leaded 100LL will be a fuel of the past, just as leaded

automotive gas is todayautomotive gas is today

WHAT ARE SOME OF THE WHAT ARE SOME OF THE REASONS FOR CHANGE?REASONS FOR CHANGE?

The mandated use of Ethanol has increase greatly in The mandated use of Ethanol has increase greatly in the US and is now being required in European auto the US and is now being required in European auto gasoline's.gasoline's.

There is significant pressure throughout the world to There is significant pressure throughout the world to find alternatives to gasoline and jet fuels.find alternatives to gasoline and jet fuels.

There is only one supplier of tetra ethyl lead left in the There is only one supplier of tetra ethyl lead left in the western worldwestern world

Leaded automotive fuels are no longer used in, North Leaded automotive fuels are no longer used in, North America, Europe, Australia, New Zealand and some America, Europe, Australia, New Zealand and some parts of South America, Asia and Africa.parts of South America, Asia and Africa.

Starting in 2000 North American , European, Starting in 2000 North American , European, Japanese and Korean new car production Japanese and Korean new car production became exclusively unleaded vehicles.became exclusively unleaded vehicles.

World wide use of 100LL is declining, causing World wide use of 100LL is declining, causing production and distribution costs to riseproduction and distribution costs to rise

EPA wants eventual end to use of leaded fuelEPA wants eventual end to use of leaded fuel

One hand gives the other takes away

Last year the government:– Removed the oxygenate requirement for

reformulated fuels (Meaning Ethanol was no longer mandated in reformulated gasoline)

– Added a requirement that a minimum amount of ethanol be used gasoline sold in the US

The result is that more automotive gasoline contains Ethanol than ever before.

What are the Issues with Ethanol?

Engines– For most non-injected aircraft engines

there are no major issues. Airframes

– Most if not all aircraft fuel systems have major issues with fuels containing ethanol.

FAA says do not do use it. – SAIB CE-07-06 October 27, 2006

ENGINES Common misconception that aircraft engines in

general have problems with gasoline's that contain ethanol

Use of ethanol in gasoline does pose material compatibility issues for some fuel injection components

Fuel flow is a significant issue as it must be increased as the amount of ethanol added increases

Oil “washing” is a concern particularly for engines that are not operated for extended periods of time.

Accumulation of water in engine crankcase an issue for two stroke engines that are not operated often.

AIRFRAME

Material compatibility ethanol Vapor Lock Phase separation

– Water – Temperature– Octane lost (leading to detonation)

Material compatibility with water/ethanol mix Cleaning

The FAA cites numerous reasons alcohol and airplanes do not mix. Alcohol:

Adversely affects the volatility of auto gasoline, which could cause vapor lock.

Is corrosive and not compatible with rubber seals and other materials used in aircraft, which could lead to fuel system deterioration and malfunction.

Is subject to phase separation, which happens when the fuel cools as an aircraft climbs to higher altitudes. When the alcohol separates from the gasoline, it may carry water that has been held in solution and that cannot be handled by the sediment bowl.

Reduces the energy content of fuel. Methanol has approximately 55 percent of the energy content of gasoline, ethanol 73 percent. More alcohol equals reduced range.

Effects of Ethanol takes time

No not think you are OK just because you have not had a problem yet.

Except for vapor lock ethanol related issues occur over time

Ethanol

Autogas is generally sold with 10% or 85% ethanol.

For conventional type certified aircraft testing has indicated that 3% ethanol is the maximum an aircraft system can safely handle.

What should you do Always test for Ethanol Do not store fuel for long periods

– When you buy it use it Do not store fuel in metal containers If you do not have a sump drain add one Use your sump drains Consider using an aircraft style gascolator Experimental and LSA aircraft can mix 100LL

and autogas to reduce percentage of ethanol Follow additional maintenance schedule for

ROTAX engines using a leaded fuel

Testing for Ethanol Using a glass or chemical resistant plastic (such as

TPX) container, mark ten equally spaced volumes. A graduated cylinder is ideal; however, a non-tapered glass jar, such as a large (quart) olive bottle, will work. 

Add one part water (approximately 100 ml) into the container, fill to the first mark, and then add nine parts (approximately 900 ml) of automobile gasoline, fill to the top mark. Shake thoroughly, let stand for 10 minutes or until automobile gasoline is again bright and clear. Mark the apparent level of the line between the automobile gasoline and water.

If alcohol is present, the water will absorb it, and the amount of water will appear to increase.

Fuel Test Kit (15$ from EAA)

                                           

When you start talking numbers at the end of the presentation it can be a little confusing. Like 91/97, 98-108 MON, 91 grade, 87 UL mean what, octane, MON, RON, AKI. You know this all get a little confusing. Another question you might face is I have a 912, Rotax says when using 100LL you have increased lead deposits which are bad, what is the lesser of 2 evils, using autogas with alcohol or using 100LL? That is a tough one that you can not answer but I have had that question over the phone. Some of the ultralight/light plane fuel tanks are fiberglass with polyester resin and the alcohol is a real problem for these. Suggestion for those that have no choice but to use alcohol autogas is to completely disassemble and inspect/clean/replace as appropriate, fuel system every 6 months. Another suggestion for 2-cycle engines is to use mineral based oil instead of synthetic based oil. Mineral based oil is typically 50:1 where as synthetic is 100:1, twice as much mineral oil coating internal engine components while the engine is in the hangar. Also, mineral based oil clings better to surfaces, synthetic has lower coefficient of friction and will not cling to part as well, when the engine is in the hangar.

What is in the future

Regular autogas will continue to have high levels of ethanol

Unleaded Aviation fuels have been developed

Market place will drive changes– LSA’s are starting to be a market factor– Increased use of jets putting pressure on

remainder of fleet to transition to unleaded fuel

Who are the Players

ASTM International is involved with ASTM International is involved with writing the new fuel specificationswriting the new fuel specifications

The Coordinating Research Council The Coordinating Research Council (CRC) is helping organize basic (CRC) is helping organize basic research on new fuels componentsresearch on new fuels components

The same organizations belong to both ASTM The same organizations belong to both ASTM and the CRC fuel groupsand the CRC fuel groups

EAA, FAA, ROTAX, Cessna, Ethyl, EAA, FAA, ROTAX, Cessna, Ethyl, ExxonMobil, TEXACO, Philips, AIRBP, and ExxonMobil, TEXACO, Philips, AIRBP, and Chevron are currently the most active Chevron are currently the most active participantsparticipants

Recently proponents for an Aviation E85 fuel Recently proponents for an Aviation E85 fuel have also become much more engagedhave also become much more engaged

Fuel components being examined as a Fuel components being examined as a replacement for lead include:replacement for lead include:-Ethers (MTBE, ETBE)-Ethers (MTBE, ETBE)-Amines -Amines -MMT (Ethyl corp)-MMT (Ethyl corp)-Ethanol-Ethanol

A Short lesson on Numbers

AKI, MON, RON, Rich Ratings, 100/130, 80/87, 82UL, 100LL – What does all this mean to you?

HOW MUCH TIME DO WE HOW MUCH TIME DO WE HAVE UNTIL WE SEE THESE HAVE UNTIL WE SEE THESE

NEW FUELS?NEW FUELS?

No one knows for sureNo one knows for sure 82 Grade is available 82 Grade is available 91/98 Grade Aviation Gasoline can be 91/98 Grade Aviation Gasoline can be

made unleadedmade unleaded Autogas is no longer the safe alternative Autogas is no longer the safe alternative

for the low end of aviation (ultralights, for the low end of aviation (ultralights, homebuilt, Katana type trainers)homebuilt, Katana type trainers)

100LL will go away100LL will go away

WHAT HAS BEEN WHAT HAS BEEN DEVELOPED TO DATE?DEVELOPED TO DATE?

A Swedish refiner is selling 91/97 unleaded A Swedish refiner is selling 91/97 unleaded aviation gasolineaviation gasoline

Oil companies have unleaded test fuels available Oil companies have unleaded test fuels available in the 98 to 108 MON rangein the 98 to 108 MON range

GAMI is developing engines controls they hope GAMI is developing engines controls they hope will allow the most demanding opposed engines will allow the most demanding opposed engines to operate on 91 grade fuelto operate on 91 grade fuel

Cessna has successfully developed and flight Cessna has successfully developed and flight tested a ETBE fuel.tested a ETBE fuel.

E85 Ethonal based fuel has been STC’ed.E85 Ethonal based fuel has been STC’ed. EAA, Cessna and ROTAX working on a new 87 EAA, Cessna and ROTAX working on a new 87

UL aviaiton gasoline based on premium autogas.UL aviaiton gasoline based on premium autogas.

References

EAA autogas STC website www.aviationfuel.org

EAA SPORT PILOT MAGAZINE– June 2006 “Power On” Ethanol and Rotax

Engines by Phillip Lockwood.