Calif. auto gas users

Doug Echelberger · Post by **Doug Echelberger** » Mon Feb 10, 2003 6:17 am

Anybody using auto gas in California should be aware that our Governor has made it manditory that MTBE be phased out by the end of this year. The replacement oxygenator will be alcohol.
I found a news release on the Chevron corporate web site stating that Chevron is implementing the change starting with So. Calif. and expects to change over in No. Calif. by the end of this year. The full text can be found on the Chevron web site. Other brands are follwoing suit. Right now ARCO and Shell have made the change from MTBE to alcohol. I gather from the release that it may take longer to make the change over, but the fact it that when fully implemented auto gas will no longer be an option for use in airplanes.

Doug

wa4jr · Post by **wa4jr** » Thu Feb 13, 2003 2:19 am

I've been reading as well that 100LL will be on the way out in the next few years. As I understand it, the only parts in the O-300 that may be damaged by the alcohol are the rubber seals in the fuel system. Perhaps it is time we started looking for replacements for these seals that are made of current technology materials? I know this may be a bear of a job, but seems to me our aircraft engines should have fuel system seals at least as durable as the automotive industry has had for the last 15 years or so. If we can get good synthetic seals in our fuel systems, we will not have to worry so much about fuel addititves.

zero.one.victor · Post by **zero.one.victor** » Thu Feb 13, 2003 6:21 am

Yeah,what is it in our airplanes that are so allergic to alcohol? Cars seem to do OK on it,at least they're not placarded against it. Or is it the tendency of alcohol to bond with water,and vice versa?

Eric

DensityDog · Post by **DensityDog** » Fri Feb 14, 2003 4:34 am

Eric,
I think the problems with alcohol are:
1. Bad for the rubber parts. The seals in our fuel systems are made from material that is not resistant to the alcohol. There are rubbers or synthetics resistant to alcohol, but I dont know if they are available in the std parts like o rings and (non-metal) carburetor floats, and hoses.

2. Alcohol does not produce nearly as much BTU when burned compared to gas, either Mogas or Avgas. Therefore, your engine makes less power burning fuel containing alcohol. I know EAA and possibly others are working on ethanol as an alternative fuel for piston planes, but the main tradeoff besides less power is less range, as well.

Anyone else have more info on alcohol? I am certainly not an expert and it would be great to hear more on this subject!

Max

blueldr · Post by **blueldr** » Fri Feb 14, 2003 5:23 am

Do you really think that they make two kinds of fuel hose and "o"rings for fuel systems? The aircraft market is so infintesimal compared to the automotive market that I can't immagine a manufacturer setting up for it. Especially since the automotive product must also be compatible with straight gasoline. I don't believe I've ever seen any warning on any type of "rubber" fuel hose, gaskets or seals that warned about possible deterioration if exposed to alcohol enhanced fuels or even alcohol itself.

DensityDog · Post by **DensityDog** » Fri Feb 14, 2003 5:23 pm

Well, I have never seen any warning on an aircraft fuel system part against the use of ethanol or methanol either. But Cessna has put out warnings.
Here is a link to an EAA web page that has Cessna's warnings against using it, they sound like good enough reasons to me. Granted, they are not all applicable to Cessna 170's:

http://www.eaa.org/communications/eaane ... essna.html

I am going to keep researching the topic, if I learn anything of interest I will let you all know.
Max

Larry Holtz · Post by **Larry Holtz** » Fri Feb 14, 2003 7:25 pm

The Cessna warning against the use of "alcohol based fuels." At the present time alcohol is being used at not more than 10%. The deterioration of the the rubber parts will occur in an auto that is old and has not been on alcohol fuels since new. The big difference is the that the accumulation of deteriorated rubber in the fuel system of an auto is not life threatening.
My question is: Will the moisture that the alcohol has absorbed become ice crystals in extreme cold weather?

Larry

blueldr · Post by **blueldr** » Sat Feb 15, 2003 4:31 am

The Cessna Service Bulletin mentioned above refers to AGE85 which is 85% alcohol. Normally, an engine set up for gasoline would not run at all, or possibly very feebily, on a fuel that rich on alcohol. It would require considerable modification of the fuel delivery system.
I still believe that a gasoline fuel using the amount of alcohol needed to "oxygenate" it would work adequately in most of our engines. It seldom runs more than ten to fifteen percent ethanol.

zero.one.victor · Post by **zero.one.victor** » Sat Feb 15, 2003 7:12 am

I'm sure that none of us are burning car gas without the benefit of an appropriate STC. The EAA STC paperwork includes an Approved Flight Manual supplement,that sez,among other things,"do not use fuel containing alcohol". The required fuel tank placards are supposed to say that too. Reading on further,they cite alcohol as causing problems with vapor lock,due to it's increasing the volatility of the fuel, also with alcohol attacking some seal materials & varnishes on components in the fuel system. Also "excessive entrained water" mixed with the alcohl causing problems.
I remember that the Petersen STC has the same prohibition re: alcohol.

Eric

wa4jr · Post by **wa4jr** » Wed Feb 19, 2003 11:59 pm

I think bluldr has a point. Why, in 2003 would manufacturers be going to the trouble to use inferior pure rubber compounds in the manufacture of fuel seal components? There is part of me that thinks aircraft manufacturers have some ulterior motive in keeping all of us in the fear mode regarding automotive fuels. Some points in the Cessna bulletin regarding AGE85 fuel make sense...I'd like to know how the Texas Skyways fleet is doing operating on this fuel. But what I would really like to hear are comments that substantiate this fear of auto fuel in our airplanes. I hear a lot of "it may" or "it might" or "it has the potential for" and the like. I want to hear evidence from anyone of damage to their aircraft that is attributable to the use of auto fuel. Concrete evidence. Are we being subjected to a smoke and mirror show from the manufacturers regarding auto gas in low compression engines? Are our fuel system sealing components REALLY pure rubber like the stuff used in the early 1900s?

DensityDog · Post by **DensityDog** » Thu Feb 20, 2003 8:21 am

Hi wa4jr,
I think we may be getting a little off track here. If I said â€œrubberâ€ in my last post I did not mean natural rubber, of which there is certainly none in our fuel systems. (If my books covering aircraft materials & processes from A&P school long ago are correct, our fuel systems will use synthetic rubbers like Buna-N and Neoprene. Natural rubber has no resistance to fuel, let alone alcohol)
The topic here was initiated by Doug, thoughtfully pointing out that Mogas users in California may soon find it hard to obtain Mogas without any ethanol in it, since that state is replacing the oxygenating compound MTBE with its alternative, alcohol. This could eventually affect all of us who want to use Mogas in our airplanes, since alcohol in the fuel is illegal, even if not proven to be harmful.
The relative merits of using Mogas VS 100LL is being thrashed elsewhere on this list, to the amusement of many!
The plane I am flying now, a 1958 Cessna 180, was flown for 22 years by its previous owner using nothing but Mogas (without any ethanol) with absolutely no problems, other than a very black exhaust stain on the belly.
It's OK with me if you want to run Mogas, just make sure you consecrate with holy water and do the hokey pokey with MMO! See Eric for further instructions!
But I cringe at the thought of using Mogas with even 10% ethanol, if for no other reason than it makes my car and pickup run like crap. Add to that the possibility of ruining my $expensive$ â€œrubberâ€ fuel tanks and Lord knows what other components.

So we need someone who knows the answer to the alcohol question to pipe up here on this topic so we know if we are really being subjected to the smoke and mirrors from the manufacturers!

Max

zero.one.victor · Post by **zero.one.victor** » Thu Feb 20, 2003 6:04 pm

Currently out here in the wilds of northwest Washington State,I'm paying anywhere from $1.54 (Costco) to $1.75 for a gallon of regular. 100LL is holding steady at my airport at around $2.42.
I just saw on the TV news a day or two ago that people in California (LA?) are paying over $2 for regular! I wonder what the avgas prices are doing in those areas?
Look like the price advantage of cargas is fading fast.

Eric

wa4jr · Post by **wa4jr** » Thu Feb 20, 2003 11:47 pm

Yes, I have noticed the stability of the avgas prices while auto gas prices fluctuate rapidly. This seems to prove my theory that the profit margin on avgas is so incredibly high that the retailers can afford to keep the prices steady and not take too much of a hit on their bottom line. The profit margin on auto gas is incredibly small so the vendors have no choice but to raise their costs to the end user. Yes, a bit off topic perhaps, but at least we keeping the discussion to gasoline!

Post by **GAHorn** » Sat Feb 22, 2003 9:36 pm

Although alcohol is certainly corrosive to fuel system components (primarily to aluminum and certain synthetics) it's real hazard in aircraft fuel is it's affinity for water. Once it has become saturated with water, and you fly to altitude and drop the temp a few degrees, the water precipitates out and can overwhelm your gascolator. I had an A&P buddy in DAL who tried to fly one night (after the temps had fallen) in his 182 which was a mogas-only operation. He suffered the engine failure on the takeoff roll (Thank God!) rather than after lift-off. It seems his Texaco dealer had recently changed (over several months) to a new supplier on the spot market which had ethanol in the fuel. Gary had not checked the fuel for alcohol for the last several months because he thought Texaco stations got their fuel only from Texaco refiners and had some sort of "standard" for their products. Silly fool.

flyguy · Post by **flyguy** » Thu Mar 06, 2003 12:16 pm

TEXACO? I don't think any of the original "Mo-Gas STCs" ever named "Texaco" as a reliable supplier of fuel to be considered for use in aviation. The "Watered Gasoline" debacle in California a couple of years ago, has turned many people away from ever using Texaco product in their cars or trucks, much less their airplanes. The "It 's not our fault. Our retailers were----" line from Texaco officials, was just another example of the corporate "profit over honesty" flim-flam mentality. Maybe that all CA fuel suppliers have joined that parade?

There are some reasons to "NOT" use Mo-Gas but with care and attention to detail, good quality fuel can be found. If the fuel is already "leaned" with emulsified water, and other additives, it becomes doubly dangerous in an airplane. The mixture of water and alcohol can lower the efective btu to un-acceptable levels, then, throw in extreme weather, both hot and cold, and the equation changes dramaticly.

'KEROSENE' - KEROSENE' - YEA YEA YEA--- ?

The International Cessna 170 Association