Eats Imron Paint!

I put some auto fuel, 93 octane, 10% ethanol in my tanks. It started leaking out some seams. We pressure tested these tanks but we believe the seals were damaged/opened up while trying to align the attach bracket to the fuselage. The leaking fuel left yellow streak marks on my nice white imron paint. I some areas where it was saturated it actually bubbled up some of the paint.:eek:Not good! All other things appear to be fine and the engine is running great. The AC is also working!!! So far the paint is the only thing not ethanol proof!:mad:
 
frankh said:
I can understand the o rings in the fuel drains...but the orings in the caps are brown in colour...To my knowledge brown indicates the material is Viton and I thought Viton was resistand to ethanol...

I have a materials compatibility database at work so i can check that out...Am I correct in thinking brown o ring = viton?

Can we get viton (or whatever the compatible material is) o rings for the fuelt ank drains??

Thanks

Frank
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Frank,
Check with your local industrial bearing supplier. MSC and McMaster-Carr both sell them. The down side from the last two is that they sell them in lots of 50 or 100. They don't sell in "onesies and twosies" :(
I believe you are correct about brown indicating Viton. I suspect that somewhere along the way, Vans supplier changed the material of the O-rings on the caps.

Charlie Kuss
 
chaskuss said:
Frank,
Check with your local industrial bearing supplier. MSC and McMaster-Carr both sell them. The down side from the last two is that they sell them in lots of 50 or 100. They don't sell in "onesies and twosies" :(
Click to expand...

That's no problem. Order 50, and at the next fly-in just trade one O-ring for one beer - you'll have enough takers to keep you happy for more than one weekend!
 
ethanol

Greg Poe is using ethanol in his airshow aircraft-Lyc IO 540 powered MX something. gregpoe.com, also fageninc.com, his sponsor. Fagen claims to be the largest producer of ethanol in the US. Years ago there was a group of RV's I think from S. Dakota that was running ethanol fuel. The MX whatever is all composite, probably composite tanks. Water is also present in jet fuel. While most jets have fuel heaters, the ones that do not must use Prist.
 
ethanol

Dr. Max Shauck of Baylor Air Science has been using ethanol fuel in aircraft since 1980. He flew airshows (including Oshkosh)for years in a ethanol powered Pitts S2B, Lyc IO 540 power. He flew an ethanol powered aircraft round trip from Waco to Paris(France not TX) A google search using "Max Shauck" will produce lots of info.
 
Updated information?

So, has anybody yet done the test on proseal and ethanol? Todd, how are your tanks holding up?

I used to be able to get mogas without ethanol here, but now everybody's gone to the 10% in winter. I'm certain that my setup is ethanol-proof at this point except for the proseal in the tanks. One of the other guys here in Reno has used ethanol for the past several winters with no ill effects so far...

Anyway, would be good to hear any updated info that might be out there.

greg
 
Been running 10% ETOH for over a year..from memory..so far no issues on the proseal. I have flourosilicone tank drain orings.

I saw "somewhere" that the mechanical pump diaphram won't withstand etoh....I can't confirm that however..and I don't run a mechanical pump, partly for that reason.

Frank
 
Seal Colour may not be indicative

This is a very interesting post and very long. I did not read every post so if this has been mentioned I'm sorry.

Viton is brown but they can add carbon black to the seal, I think to make it conductive for some applications. Nitrile is normally black but I have seen it white when the carbon black is not added.

I can see how this would be a difficult thing to sort out in the shop. A black nitrile and a black viton seal would look and feel the same.

Teflon would be resistant to alcohol but it has a tendency to creep in my experience and I do not like using it for sealing purposes if anything else will do.

I hope they sort out this no lead and alcohol situation soon as this is causing too much difficulty to everyone.

Bob Parry
 
They do applaud

Jeff R said:
........Heck, I read in the paper this morning that the Missouri legislature is thinking of banning ethanol in fuel for the reasons I indicated. I figured pilots would applaud this.
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At least eliminating a mandate for it. Seems like when the government touches something, they break it. So, I'm not sure if I like banning ethanol. Just let the market decide.

Bottom line for pilots is that 100LL is an endangered species.

My personal preference is to run diesel / jetA because that is not ever going away. I'm hoping an appropriate engine of the right size/weight/power range will become available in the not to distant future.
 
frankh said:
Been running 10% ETOH for over a year..from memory..so far no issues on the proseal. I have flourosilicone tank drain orings.

I saw "somewhere" that the mechanical pump diaphram won't withstand etoh....I can't confirm that however..and I don't run a mechanical pump, partly for that reason.

Frank
Click to expand...

Hey Frank,

You heard that from me I think (about the fuel pump). I have been doing some serious research on the 10% ethanol thing and come to the conclusion (after actually talking with many of the manufactures of the parts in my fuel system in detail) that the mechanical fuel pump is the only item that would really be effected by ethanol (the o rings on the fuel drains as well but it's not a big deal to change them out as you know). My pump is made by Tempest and those guys tell me that the diaphragm is the item that would eventually go. They say they have had people run fuel with ethanol in it and they typically see failures around 50 hours. They have looked in to purchasing a material that would be impervious to ethanol but they would have to purchase it in such huge quantities to make it financially viable that they can't justify it now. The FAA has some strict rules about shelf life and they think that they would end up throwing half of it away. So, the way to go is to either find a fuel pump manufacturer that uses a material that ethanol won't eat in their mechanical fuel pumps or go with an electric setup like yours.

For now; I'm just gonna pay for 100LL in the winter when they put ethanol in the fuel here. It would be a big job to rig my plane up to use an all electric system I think (plumbing return lines, extra alternator, battery etc.) so I can't be bothered with that. If anyone out there hears of a mechanical fuel pump that is resistant to ethanol then please let me know and I will reconsider very quickly.

Thanks,

Mark
RV-7 500+ hours
 
Proseal and Ethanol

I wrote Linda Smith at Flamemaster and enquired about ethanol and Proseal compatibility. I got a carefully qualified answer. A long disclaimer that seems somewhat standard fare these days. Regardless, we are in the experimental catagory, and the burden is on us, no?

She attached a nice little summary of some compatibility data they have culled from "Chemical Resistance Guide For Elastomers", written and researched by Kenneth M. Pruett.

No specific CS 3204 data (if that's not what your are using for tank sealing, please comment), but Flamemaster suggests that most of their products are polysulfide polymers and they reported the following compatibility between polysulfide polymers and the below components. I'm passing on the ethanol and gasoline compatibilities, there are others listed.

All were "to 70 deg F" which suggests the compatibility was not tested at higher temps so they are not making statements one way or another for high temps.

Rating definitions-
A = Excellent, little or no swelling or softening or surface deterioration
B = Good chemical resistance, minor chemical attack, swelling, softening or surface deterioration
C = Limited Chemical resistance Moderate chemical attack Conditional Service

Volumetric Swelling and Loss of Tensile Strength are defined.
A = Less than 15% in 30 days to 1 year
B = Less than 30 % in 30 days to 1 year

Ethanol- A

Autogas- A

They also list 3 octanes of avgas, maybe not real useful considering we only have 100LL these days, but: 65, 100, and 130 are all listed as an A/B compatibility

Out of the three, avgas is the lowest rated with the A/B. Please regard this as another data point, not an end all answer for Proseal and ethanol. What is unanswered, how do combinations of the above interact with polysulfide polymers? Sometimes combinations can bring unexpected results. Need some more testing :D !

My tanks are fine, so I don't have Proseal laying around, but I'd be willing to start a few bottles with various combinations of fuels, and toss them in the flamable liquids cabinet for later inspection. If you've got some interest and proseal laying around, please PM me and we'll see what we can get going.

best
 
Go to the source

I called Tempest and here is what I learned.

Carbs: They are OK running up to 10% ethanol. Above that they worry about vapor lock.

Engine driven fuel pump: They will deteriorate over time when used with ethonal. He went on to say that the South Americans use ethonal laced fuel and replace their fuel pumps as needed. They are working on ethonal tolerant fuel pumps and said to watch for the press release in the next year or two.
 
RVP and Vapor lock risk go down with increasing ethanol

N941WR said:
I called Tempest and here is what I learned.

Carbs: They are OK running up to 10% ethanol. Above that they worry about vapor lock.
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While I'm sure the Tempest folks have an area of expertise, I don't think auto fuels is one of them. They're vapor lock understanding is backwards. Case in point, the 10% blend is in the neighborhood of where RVP's are the worst. Ethanol and autogas mixtures are complicated. Ethanol has a very low RVP of about 2.3 psi and the autogas in the 7 or 8 range. If it were simple, we'd mix the two, and the ethanol would pull down the RVP in the mixture, right? Well, that's not what happens. As some of us know from experience, vapor lock of E-10 can be a problem, and sure enough, the RVP according to test data goes up at low ethanol concentrations. This is why the 5 to 10% ethanol concentrations causes the refiners heartburn, as they've got to adjust their gasoline components to keep the RVP within a reasonable range when there fuel is later mixed with the ethanol.

Well, it stays interesting. Continue climbing in ethanol concentration beyond the usual low level blends and the RVP slowly and in a linear manner comes down, and ultimately ends up at the very low 2.3 psi. of pure ethanol :) So, bottom line, when Tempest reports vapor lock risk rises beyond 10% blends, that doesn't jive with the technical data, and I doubt it even jives with anecdotal evidence. There is the Vanguard Squadron, Greg Poe, the AGE-85 folks and I don't recall hearing any complaints.

A good read is "Technical Issues Associated with the USE of Intermediate Ethanol Blends (>E10) in the U.S. Legacy Fleet: Assessment of Prior Studies"
 
Anecdotal evidence

Have close to 500 hours on an 8.5.1 Lyc clone running mostly mogas...about 200 and two years on 10% ethanol.

So far no problems with the modified fuel system.

Frank
 
nomocom said:
...So, bottom line, when Tempest reports vapor lock risk rises beyond 10% blends, that doesn't jive with the technical data, and I doubt it even jives with anecdotal evidence. There is the Vanguard Squadron, Greg Poe, the AGE-85 folks and I don't recall hearing any complaints.

A good read is "Technical Issues Associated with the USE of Intermediate Ethanol Blends (>E10) in the U.S. Legacy Fleet: Assessment of Prior Studies"
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Stan,

I'm only reporting what I was told.

As for the Vanguard Squadron, the only information on their web site about what modifications they have made is "Ethanol adds power and performance to the Squadron's aircraft without any major engine modifications."

What the members of this forum want to know is what "minor engine modifications" they had to make. I wouldn't call changing a carb or fuel pump a major modification. While other might call changing the pistons a minor modification as well.

As for me, get that junk out of my fuel!

It bothers me that the use of ethanol has become so political rather than based on good science. I feel like the only reason there is ethanol in our fuel is because the corn growers have a good lobby.
 
Tempest and Vanguard Squadron

N941WR said:
Stan,

I'm only reporting what I was told.
Click to expand...

Bill,
I believe I understand your position and I appreciate your many posts. Don't see my post as critical of you, it was intended to insert some research based information into the discussion to go along with the Tempest advice. If I get similar advice and you've got contrary information, I trust you will do the same.

I think we are on the right track on communicating what needs done to run autogas. There's lots of informative posts on how builders have built vapor lock resistant fuel systems and there are links and mention of fuel resistant materials.

I have chatted with the Vanguard lead flyer and he seems very willing to share their setup, though before I post on it, he will proof it, so standby on that.

best regards
 
nomocom said:
Bill,
I believe I understand your position and I appreciate your many posts.
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Not to worry, I didn't take it as an attack.

This is a good thread and it will be helpful to get as much info out there as possible. (Even if I'm not a fan of ethanol and hope I never have to burn that stuff in my car, truck, plane, lawnmower, etc.)

nomocom said:
I think we are on the right track on communicating what needs done to run autogas. There's lots of informative posts on how builders have built vapor lock resistant fuel systems and there are links and mention of fuel resistant materials.
Click to expand...

Why no discussion about working with he EAA & AOPA to get their lobbyists to work towards the removal of ethanol from mogas?

nomocom said:
I have chatted with the Vanguard lead flyer and he seems very willing to share their setup, though before I post on it, he will proof it, so standby on that.
Click to expand...

That will be very helpful!
 
Since the one area I was particularly lazy about in school was chemistry, I need someone who plays a chemist in real life to help me out. Every pilot fears vapor lock & ethanol is often mentioned in the same sentence when pilots discuss it. However, reading outside the aviation community I seem to read something different. Is this more an issue with Mogas than with ethanol? Below are numbers I pulled off various internet sites, & converted to 'normalized' units using an engineering website at
http://www.engineeringtoolbox.com/pressure-units-converter-d_569.html

water VP: 0.96 psi/49.7mm hg @ 100F, boil point 100 C
ethanol VP: 2.51 psi/130mm hg @ 100F, boil point 78.4 C
avgas VP: 5.5-7psi(Reid VP)/285mm hg @ 100F, boil point 70-170 C

Now, there are all kinds of chances for errors in my numbers due to unreliable internet sources, conversion mistakes, etc, but based on the numbers above, it looks like ethanol is less likely to vaporlock than avgas. It's interesting that the MSDS on the internet for avgas is noticeably different from company to company, & all have that rather large range of boil point (one site actually listed it as 24-170 C).

What am I missing?

Charlie
PS:
For what it's worth, I've been running premium autogas (no ethanol) in a 160hp RV-4 for a couple of years, with no issues except *possibly* minor fuel tank leaks in this 20 year old a/c. There were minor leaks (repaired) even before auto fuel was introduced, & it's quite possible that these are just age-related leaks, or that the very old version of tank sealant used back in -91 wasn't auto fuel-proof; some of the older sealants weren't resistant to auto fuel even without ethanol. I've avoided ethanol because of rubber in the gascolator, stock mechanical pump, etc.
 
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I spoke with the Vanguard people a couple of years ago when i was building my RV-8, and it was a simple change. They have FI engines, and they sent the fuel components to Don at Airflow Performance to set them up for ethanol use. I don't recall what they did to the airframes of the 3's, I wasn't interested in that info and am not familiar with the fuel system of a 3.

I sent my fuel components in to Don to set up for use with ethanol, and have been using E98 mixed with 100LL since I started flying it a month ago. I have run up to a 50% mix of straight ethanol and 100ll. I have about 30 hours on the plane as of today.

The differences I have noticed are a different exhaust smell, slightly higher fuel flows when the EGT is the same, and a slightly elevated idle speed when running on the E-98 mix. I cannot tell if there is a power difference, the plane is new to me so a comparison is hard to quantify. When I started mixing, I left one tank with straight 100LL for comparison.

Hopefully nomocom will post the info, because I may have forgot the details in the last couple of years.
 
O-rings

Can the "stock" O-rings in the fuel drains put up with Ethanol?

There is a post about someone who had one go bad on their gascolator (not ethanol related) and it made me wonder if three leaking fuel drains could be bad.

I realize they are easy enough to replace but the question is, should they be replaced?
 
Bill, I'm pretty certain that the stock o-rings are NOT ethanol tolerant. They last a while but eventually deteriorate. You can get ethanol-tolerant ones at auto parts stores (some places, anyway) or order through McMaster or similar outlets.

greg
 
Fuel caps also

I spoke to someone in Van's about this, a long time ago. Not only the o-rings in the drains, but also the o-rings of the fuel caps will not tolerate ethanol. Although, normally the fuel caps will not be submersed in fuel very much, so I doubt that that will be a problem.

Something that I have not seen mentioned here is the fuel lines themselves, they are made of rubber, will they cope with ethanol?

I was going to use Mogas after the engine is run in, but it makes sence to me to try to find a source without ethanol.

Regards, Tonny.
 
Yes, replace them.

N941WR said:
Can the "stock" O-rings in the fuel drains put up with Ethanol?

I realize they are easy enough to replace but the question is, should they be replaced?
Click to expand...

The stock o-rings won't last indefinitely with avgas or ethanol. They start to drip. Replace them when they do, or even better, every few years. Might as well get a capable elastomer on hand, that works on just about anything.

Different thread, "leaking fuel drain repair" Squeak suggests these.
Squeak said:
Got my O-Rings from McMaster-Carr part # 9464K11. They work great and hard to beat the price ($4.48 per 100).
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Greg Arehart said:
Bill, I'm pretty certain that the stock o-rings are NOT ethanol tolerant. They last a while but eventually deteriorate. You can get ethanol-tolerant ones at auto parts stores (some places, anyway) or order through McMaster or similar outlets.

greg
Click to expand...

I mentioned in an earlier post that I've been running E-free mogas with no issues other than (possibly) old style tank sealant. I need to make a slight correction/addition. My old style/material fuel cap o-rings & drain o-rings eventually swelled(sp?) up under the influence of mogas (no ethanol). Someone turned me on to a supplier who had the right size cap o-rings, & I found a kit of literally hundreds (dozens of sizes) from that supplier for not much more than the price of a couple at one-zies prices. I'll try to find the link if anyone's interested. No issues for at least a year.

Charlie
 
proseal fyi

We run adi in our race planes at Reno and have had no issues with the proseal reacting. Adi is 49% water,49% alcohol and 2% fish oil. We seal up our tanks with proseal and sometimes convert our fuel tank to run adi then flush and put 100ll back into it. No problems all these years. Marc. reno crew
ma II and Furias
 
Anti-detonation injection

drakerv said:
We run adi in our race planes at Reno and have had no issues with the proseal reacting. Adi is 49% water,49% alcohol and 2% fish oil. We seal up our tanks with proseal and sometimes convert our fuel tank to run adi then flush and put 100ll back into it. No problems all these years. Marc. reno crew
ma II and Furias
Click to expand...

Is the alcohol methanol or ethanol?

http://en.wikipedia.org/wiki/Water_injection_(engines)
 
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another option for some.........

here in stuart there is a place called martin co petroleum and they carry a non ethanol fuel called recreational fuel. i believe it is 91 rated. my bonanza buddy had fuel bladder problems with ethanol fuel and now uses rec fuel only. no problems. he is paying $3,10/ gal. this may help some of you if u can find it.

my experience with car gas mix with 100ll has been ok. 50/50 take off & land tank, 5/1 cruize tank.marvel added too. been doing this for over 7 years now.
 
rv7charlie said:
Since the one area I was particularly lazy about in school was chemistry, I need someone who plays a chemist in real life to help me out. Every pilot fears vapor lock & ethanol is often mentioned in the same sentence when pilots discuss it. However, reading outside the aviation community I seem to read something different. Is this more an issue with Mogas than with ethanol? Below are numbers I pulled off various internet sites, & converted to 'normalized' units using an engineering website at
http://www.engineeringtoolbox.com/pressure-units-converter-d_569.html

water VP: 0.96 psi/49.7mm hg @ 100F, boil point 100 C
ethanol VP: 2.51 psi/130mm hg @ 100F, boil point 78.4 C
avgas VP: 5.5-7psi(Reid VP)/285mm hg @ 100F, boil point 70-170 C

Now, there are all kinds of chances for errors in my numbers due to unreliable internet sources, conversion mistakes, etc, but based on the numbers above, it looks like ethanol is less likely to vaporlock than avgas. It's interesting that the MSDS on the internet for avgas is noticeably different from company to company, & all have that rather large range of boil point (one site actually listed it as 24-170 C).

What am I missing?

Charlie
Click to expand...
The Ethanol will form an azeotrope (a constant boiling mixture) with some of the hydrocarbon components, yielding an even lower boiling point (and higher vapor pressure) for that portion of the mixture.

I have no idea what the actual impact would be on the overall vapor pressure of the mixture, but it would have an effect. That, combined with the normally higher vapor pressure of Mogas by itself might be enough....

FWIW, I've been running Mogas (usually contains Ethanol) for 3 years and 175 hours. I tend to keep one tank full of 100 LL as a general rule, and other than reduced mileage, and greatly reduced spark plug fouling, been pretty uneventful.
 
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