Auto Gas & Engines

[PilotRPI]

I see a lot of Auto Gas STCs and LSA engines that actually prefer to run on Auto Gas (Rotax). I believe that in almost all these cases, Auto Gas meant as E-0, alcohol free automotive gas.

Are there any engines that can use E-15 pump gas found at most stations, or does anyone know of any engine companies looking at modifying their designs to accept E-15? I love the idea of auto gas in engines, but it doesn't seem to make much sense if no airports offer it and I can't even get it at local car stations.

Thanks everyone!

P.S. - not looking to restart the debate on intelligence of ethanol in gasoline

[TwinPOS]

There are no engine or airframe stc's with ethanol approval. While some engines might be converted to use it easily, the delivery of ethanol fuels to the engine will be the weak link in getting approval. Ethanol and other additives have perishable part detioration, and Vapor locking issues. Ethanol free fuel is available around the country with a little research and effort. Its half the price of 100ll in my area so its like cutting my fuel burn in half ie. well worth the trouble.

[Savannah-Tom]

Rotax now approves E10 for it's engines. There are a number of them running much higher ethanol percentages in Brazil, but this is all without Rotax approval.

Here's more than you probably want to read: http://www.evektor.cz/pdf/support/bulle ... nglish.pdf

tom

[Zzz]

The guy who develops an aircraft fuel system that can safely handle E10 or E15 consistently and predictably, will do well.

Rotax may approve use of E10, but the variables of fuel systems and the fuel itself are too many accept that as okay. Even a Rotax 912 cannot run on water that has fallen out of suspension in an ethanol blended gasoline.

I don't think you'll be able to divorce this topic from the ethanol debate in general, it's just too closely related. I do often wonder though how my Toyota engine has never once stuttered having run E10 for 85,000 miles. Is it an advantage of fuel injection and real time combustion analysis (oxygen sensor?) It's easy to make a fuel system less prone to corrosion from water suspended or emulsified in ethanol, but how to make a fuel system that can handle water that is out of suspension? Centrifugal filter? Some sort of fancy gascolator?

[fern_hopper]

I do often wonder though how my Toyota engine has never once stuttered having run E10 for 85,000 miles.

Thats a good point. E10 seems to be more suitable for newer auto engines though. My 1996 Toyota T100 with 189k miles runs like a champ on clear gas, while it sputters and has a noticeable MPG drop with E10 unless I run E10 premium. On the other hand I used to have a 2004 Tacoma. Same engine, just different generation then the T100. That Tacoma could care less whether it burns E10 or clear gas.

[Zzz]

I do often wonder though how my Toyota engine has never once stuttered having run E10 for 85,000 miles.

Thats a good point. E10 seems to be more suitable for newer auto engines though. My 1996 Toyota T100 with 189k miles runs like a champ on clear gas, while it sputters and has a noticeable MPG drop with E10 unless I run E10 premium. On the other hand I used to have a 2004 Tacoma. Same engine, just different generation then the T100. That Tacoma could care less whether it burns E10 or clear gas.

Matt, I did run my Toyota Tundra on clear gas quite a bit in the beginning, but in recent years it's just hard to find. I noticed the MPG drop too, but never a sputter.

[PilotRPI]

I searched a few of those sites and couldn't find any ethanol free stations in jersey. If that is the case, then the rotax may become my new best friend. I'm considering a few rotax friendly kits. It would be worth switching out bits if necessary in the fuel system to be alcohol compatible, especially if gravity feed is used.

[Stol]

I am speaking from the experimental side of aviation...

The first 20 hours I ran 100LL just to be on the safe side since my 'creation' was a complete unknown. Then I switched to 91 octane auto fuel sold at the local Smiths store and supplied by Flying J. I knew ethanol was coming so I designed my fuel system to handle the corrosive nature of it. At about the 70 hour mark on the hobbs Flying J introduced 10% ethanol. I have done EXTENSIVE testing on the performance and I am impressed at the ability of my unique situation to utilize alcohol in auto fuel. I test every load I pump in the plane and it has been anywhere from 7% to 16 %. My motor is water cooled, carburated and the timing is set at a conservative 33 degrees total advance. No hiccups, misfires, stumbles and it has been up to 17,999 MSL and no sign of vapor lock at all. Been in temps of 95 f all the way down to -37 f. Unless something comes along to persuade me otherwise I am somewhat happy. Also remember,,, Ethanol is considered a oxygenated fuel so that does help up high as it adds a little to the power to the engine as the air gets thinner.. Think of it a chemical supercharging to a slight degree. YMMV.

Ben.
www.haaspowerair.com

[Mongo]

The guy who develops an aircraft fuel system that can safely handle E10 or E15 consistently and predictably, will do well.

Rotax may approve use of E10, but the variables of fuel systems and the fuel itself are too many accept that as okay. Even a Rotax 912 cannot run on water that has fallen out of suspension in an ethanol blended gasoline.

I don't think you'll be able to divorce this topic from the ethanol debate in general, it's just too closely related. I do often wonder though how my Toyota engine has never once stuttered having run E10 for 85,000 miles. Is it an advantage of fuel injection and real time combustion analysis (oxygen sensor?) It's easy to make a fuel system less prone to corrosion from water suspended or emulsified in ethanol, but how to make a fuel system that can handle water that is out of suspension? Centrifugal filter? Some sort of fancy gascolator?

The sock filters in the fuel tank will filter out water.


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[180Marty]

Zeolite. At the ethanol plants, distillation gets it to about 190 proof or a little better. The last few percent of bound water gets removed in the molecular sieve. It looks like 1000 gallon propane tanks standing on end and are filled with zeolite. If I remember right, the pores in the zeolite are 3 angstroms and water is smaller so fits into the pores. Ethanol is to big to fit. The mole sieves are in series so when one fills to capacity with water, the 190 proof flow is switched to the next one, and the first is regenerated by putting a big vacuum on it and boiling the water out. There are usually 3 or 4 sieves. I did find out the other day that the ethanol that is being exported to Europe has to be drier when it leaves the plant since it will pick up a little bit of water on the trip over. The way they make it drier is to slow the flow through the sieve. So to maintain capacity, more sieves have been installed. Not sure what would happen if ethanol blended gas was run through a mole sieve since gasoline has so many different hydro carbon molecules---ethanol is consistently the same. Sealing the vents system in between flights would sure cut down on the flow of air in and out of a tank. Here is what a boat mechanic in Florida has to say about E10 . The thread was about Yamaha fuel stabilizer which used to be 95% alcohol. This guy doesn't use stabilizer.

Think about the reality of have one in every 10 gallons of your fuel being a straight gallon of pure alcohol. Now what are the chances that there exists an additive that can eliminate that alcohol, add back the octane that alcohol supplies, burn safetly in your engine without having its own problems, and come in a concentrate so strong that a small bottle will treat an entire gas tank? Not to even mention all the other claims like increased performance, economy, etc.
If this were the old west, this stuff would be called tonic and sold by men in covered wagons.
There are some benefits to using stabilizers for storage but the rest, IMO, is unsupported marketing BS.
The other side of the coin is, ethanol does have some advantages and that is why it is present in so many of these products. Ethanol is a great cleaner and carbon reducer. I regularly pull apart carbs and since the introduction of E10 those carbs are usually spotless. Carbon buildup on valves and in combustion chambers has been greatly reduced. Again, IMO, I really see no need to decarb since the introduction of E10.
Well, thats my take on the whole thing. I am not going to argue it, just keep doing things the way that has worked very well for me. Only add fuel to the tank when I am ready to burn it. No additives. My boat just sat for almost three months with no additives but less than 1/4 tank. I put 60 gallons in and ran the boat all day. Any water that had accumulated/separated was re-absorbed by the fresh fuel and safely passed through my engine.
Our best hope for a resolution to E10 is improved materials to handle the fuel without deteriorating. It probably wont be long until we see closed fuel tank ventilation systems like those we see in automobiles. We also may see smart fuel systems that will calibrate mixture according to the type of fuel being used.

[180Marty]

Another thing, in Brazil they mix dry anhydrous ethanol with gasoline to make ~E25. That's the minimum ethanol content down there. Lots of cars down there run E100 that is called hydrous ethanol. It is distilled to 190 proof but no mole sieve so the engine is burning 95% ethanol and 5% water. Even if it picks up a bunch of water, it really doesn't matter since 160 proof will burn and you won't have any phase separation problem. I have a friend in Brazil that sent a picture of his sons with their water ski boat. I think it is interesting that their outboard motor uses E25 but up here E10 or maybe E15 is the end of the world.

[Zzz]

Let's keep this limited to how to run our current E10 blend in existing engines. There are plenty of ethanol egghead threads floating around.

[TwinPOS]

Experimentals are different, I am not aware of an STC that allows ethanol. The big issue being certifying, a whole new fuel for a relatively small number of airframes. Remember that the airframe and engine in certified models must both pass the test for the FAA to grant an STC. I would be careful experimenting with blended fuels at altitude or in warmer temps after being left on the ramp in the sun. This is very close to the worst case scenario testing that the FAA submits planes to.
This being said, when STC'd, I love using Mogas, and wish you the very best of luck with your project.

PS try boat guys, and classic car guys and calling jobbers in the area to see if clean gas is being sold locally, you might have a good close by resource.

[Stol]

Experimentals are different, I am not aware of an STC that allows ethanol. The big issue being certifying, a whole new fuel for a relatively small number of airframes. Remember that the airframe and engine in certified models must both pass the test for the FAA to grant an STC. I would be careful experimenting with blended fuels at altitude or in warmer temps after being left on the ramp in the sun. This is very close to the worst case scenario testing that the FAA submits planes to.
This being said, when STC'd, I love using Mogas, and wish you the very best of luck with your project.

PS try boat guys, and classic car guys and calling jobbers in the area to see if clean gas is being sold locally, you might have a good close by resource.

You answered the question quite perfectly... The FAA needs a constant, repeatable and realiable source of fuel to conduct testing.. It seems every fuel distribution network has its own "special" blend. Hence the comment I made about the variability of Ethanol percentages I found at my local station... There is NO way a STC can be issued when the end user cannot be assured that the fuel he buys meets the STC spec..

In my opinion the airframe is the biggest drawback...... Motors are pretty tolerant of various blends of fuels. For instance,, the vapor lock issue keeps coming up, but all summer long, in the summer heat, passenger cars and light trucks drive to the top of Pikes Peak at over 13,000 msl hundreds of times a day and the rate of vapor lock happening is almost nil. YMMV.

Ben.

[TwinPOS]

Thanks Ben,
I agree with you about engines being pretty forgiving with blended fuels but airframes, and environments that we use these engines being the problem as far as ethanol use goes. Here is an excerpt from Peterson about ethanol:

"Run the ethanol test on all the gas you buy.

DO NOT burn fuel with ethanol in your airplane. Revert to 100LL if ethanol free gasoline cannot be found.

Gasoline blended with ethanol can be corrosive and damaging to aircraft fuel systems. Range is less with ethanol blended gasoline. It has an affinity for water and can pull moisture from inlet air on humid days to an extent which has lead to engine malfunctions. Allowing it to sit for extended periods of time has resulted in the need to replace carburetors, hoses and gaskets. It has also been reported to clean the interior of fuel tanks, leaving the accumulated sludge in the screen. If you cannot find gasoline that you are certain is ethanol free then you must revert to using avgas.

It has become increasingly difficult for many pilots in the US to obtain ethanol free gasoline. In some areas of the country it is impossible while in others it is not. This is primarily due to Federal requirements now hard coded into EPA regulations which require ever increasing quantities of ethanol to be blended into the nations gasoline supply. Oil companies are required to do it or they face hefty fines. Pilots must be vigilant when purchasing fuel to make certain that it is conventional, non ethanol gasoline. Be certain, before ordering an STC, that you are able to purchase conventional, non-ethanol gasoline.

Marathon Oil Company is marketing a 90 octane unleaded non-ethanol gasoline as a recreational fuel for boats. This fuel is perfectly suited for use with 87 octane auto fuel STC's. In some locations it is one octane point higher, 91 octane. 91 octane is suitable for use with all auto fuel STC's. "

[hotrod150]

......Marathon Oil Company is marketing a 90 octane unleaded non-ethanol gasoline as a recreational fuel for boats. This fuel is perfectly suited for use with 87 octane auto fuel STC's. In some locations it is one octane point higher, 91 octane. 91 octane is suitable for use with all auto fuel STC's. "

Never heard of Marathon & don't know where they're located, but I doubt marina's ahere in the PNW are gonna be bringing in gasoline from texas for example. They'll either go with E10 (or whatever) or quit selling.
Speaking of which, if and when my local source of E-zero cargas craps out, the local marina be the next place I look.

[TwinPOS]

http://pure-gas.org/index.jsp?stateprov=WA

Try these guys for ethanol free gas in Washington. I highly recommend their tester too.

Other States:

http://pure-gas.org/

Hope it helps

[NineThreeKilo]

I used to go to the little gas station next to Harvey in Shnohomish, buy a bottle of water, chug all my the last 10th of it, fill the bottle up with gas, but the cap back on, shake and see if the seperation level between the water and gas increased, that was my tester.

After getting a huge chunk of info and doing some math, I run 100LL through my Stinson, quite frankly car gas vs av fuel not half as good, the time it takes for it to break down while sitting, the QC, etc, etc.

If you're running a lawnmower engine, or a rotax or a subaru engine, or one of those half VW units, then it might not be as bad, just seems like a cheap way to make a expensive problem in a certified AC

[180Marty]

Here is a mfg. that approves E10 in their planes with Rotax power.
http://www.pipistrel.si/news/si-2009-se ... hanol-cont

We have conducted tests of the complete fuel system on all Pipistrel Aircraft (Sinus/Virus/Taurus/Apis-Bee/Trikes) and we have discovered no problems when usinfg E10 fuel, which has 10% Etahnol content.

[senior]

Up here our Gov't has mandated all gas to have a % of Ethinol.
Auto fuel Pumps all have a sticker stating "up to 10%"

We know ethinol will seperate if mixed with water, so what's the chances of figuring a method of removing the stuff?? Maybe even a big can to mix a larger quantity of water with Auto gas then simply siphen the fuel off the top after a period of settlement time. For all the avi fuel I use 100av would be fine, but it's far from an ideal fuel in our old 65Cont engines. My logs show the motor had been de-carbonized almost once a year because of build-up It runs so clean on a mix of 4/1 auto fuel/Av.