snipped: So if we find issues with either the GAMI fuel or Swift Fuel, we may end up living with the problems with no recourse. Lycoming isn't going to change, it won't add automation to improve manufacturing right now.
Not entirely true. Vans recently announced that all Lycoming FI engines sold by them will no longer have a choice of which fuel injection system to use. All will come with the Airflow Performance system. AFP has for decades supplied their products with seals, O-rings and diaphragms made of fluorosilicone [generic Viton]. Use of these components negates this issue, as regards engine components of the system.

What is Fluorosilicone?
 
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Not entirely true. Vans recently announced that all Lycoming FI engines sold by them will no longer have a choice of which fuel injection system to use. All will come with the Airflow Performance system. AFP has for decades supplied their products with seals, O-rings and diaphragms made of fluorosilicone [generic Viton]. Use of these components negates this issue, as regards engine components of the system.

What is Fluorosilicone?
And the nitrile rubber fuel hose, and the nitrile rubber orings in the fuel selector, and the nitrile ruibber in the mechanical fuel pump, and what rubber type in the boost pump. etc etc.

Sorry,but do not believe that having an AFP setup protects you from this issue. And even if it did, unless you welded your fuel tanks, it is a moot point as you can't hold fuel long enough to feed the engine.
 
And the nitrile rubber fuel hose, and the nitrile rubber o rings in the fuel selector, and the nitrile rubber in the mechanical fuel pump, and what rubber type in the boost pump. etc etc.

Sorry,but do not believe that having an AFP setup protects you from this issue. And even if it did, unless you welded your fuel tanks, it is a moot point as you can't hold fuel long enough to feed the engine.
I didn't say it did. Don't know about the fuel selector, more than 1 available. For rubber fuel lines, use automotive fuel injection hose, or better yet, Teflon lined hose. For the O-rings, you would need to replace them with Viton units.
 
I found this Youtube video from Blancolirio about the effect of GAMI 100 UL fuel causing damage on a Cirrus aircraft.
The damage is more extensive than what I had read. He also describes the degradation of the sealant in the fuel tanks. I am assuming the Cirrus uses the same Proseal as our RV for the fuel tanks looking at the video.

 
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I found this Youtube video from Blancolirio about the effect of GAMI 100 UL fuel causing damage on a Cirrus aircraft.
The damage is more extensive than what I had read. He also describes the degradation of the sealant in the fuel tanks. I am assuming the Cirrus uses the same Proseal as our RV for the fuel tanks looking at the video.

Our local EAA Chapter visited GAMI last Fall, and they had said they had purchased a fuel tank wing section from a wrecked Cirrus and were doing their own tests on that; so will be interesting to see what they find out...

Doug
RV-7A w/180 hp Renesis (942 hrs.)
RV-9A w/RX-7 13B (7 hrs. ground run time)
 
Our local EAA Chapter visited GAMI last Fall, and they had said they had purchased a fuel tank wing section from a wrecked Cirrus and were doing their own tests on that; so will be interesting to see what they find out...

Doug
RV-7A w/180 hp Renesis (942 hrs.)
RV-9A w/RX-7 13B (7 hrs. ground run time)
I can't believe this sort of testing wasn't part of the development lifecycle from day one. Paints, primers, hoses, sealants, o-rings, gaskets...all should have been part of the validation process for any new fuel, and it seems incredibly irresponsible, if not outright amateurish, for them to not have done thorough compatibility tests.
 
I think the bottom line here is that there is just no way to make 100 octane (~130 MON?) fuel without tetraethyl lead, or high proportions of aromatic solvents. The general public, and even many pilots, have made general aviation out to be the bad guy because to them it looks like "only" 100 octane, which is "only" 6-7 points higher than the premium gasoline they're able to buy at the pump everyday. In reality, it seems to be a level of knock resistance that engines have not required in a very long time.

The Achilles heel to our ancient airplane engines really does seem to be primarily the lack of electronic fuel injection. Once you have electronic control over spark timing, mixture, and even manifold pressure, the absurd octane requirements should go away. For safety, we need to have huge antiknock margins when the CHTs are hot, the mixture is too lean, and we're climbing at maximum manifold pressure for 20 minutes straight.

GAMI may have messed up here, but more than likely, achieving the required octane without using xylenes, or something else that abuses old rubber and paint, is just impossible.
 
I expected a huge multinational oil company would be behind the effort to develop unleaded aviation fuel, not some random guy out in his shop. No offense to George as I admire his passion to see this through - especially since the "big boys" apparently aren't interested. I just had no idea one person in a (relatively) tiny company could develop a fuel used by airplanes. The testing is also shocking to me. I thought somebody would have at least a couple dozen different types of engines running basically around the clock with hundreds of thousands of hours of test data. And don't get me started with materials testing....sheesh. As much as I'd like to use a cleaner burning fuel in my brand new engine when it arrives, I will not be running G100UL based on what I've seen to date.
 
The Achilles heel to our ancient airplane engines really does seem to be primarily the lack of electronic fuel injection.
EFI is a step not far enough. I would hope that in some dark corner at Lycoming someone is working on a transforming our traditional engines to direct injection and end the problem. We could be flying high compression engines on 93 octane pump gas.

Carl
 
If what I've seen in that video is actually true, I certainly wouldn't touch it.

Sorry,but do not believe that having an AFP setup protects you from this issue. And even if it did, unless you welded your fuel tanks, it is a moot point as you can't hold fuel long enough to feed the engine.
I've been holding 91 E10 for nearly 800 hours, ( 12 years), not sure what you are talking about?
AFP FI, Andair fuel valve, Tempest mechanical fuel pump, teflon hoses.
No leaks, no paint damage and no seal issues and probably cheaper than G100UL.
 
EFI is a step not far enough. I would hope that in some dark corner at Lycoming someone is working on a transforming our traditional engines to direct injection and end the problem. We could be flying high compression engines on 93 octane pump gas.

Carl
Direct injection might give the normally aspirated engines a bit more margin (they can run on pump gas already with a little care). But it won't cure the problem for forced induction engines (Big twins, SR22T, ect).

93 octane pump gas has methanol. That's still a problem for the majority of GA. If it wasn't 100+ octane "pump gas" is readily available.

It's a 2 part problem; 1. maintain detonation margin. 2. don't damage the soft components of the certified fleet fuel system. 1. is easily solvable with readily available fuels if the soft components in the aircraft are modernized. Relatively easy and in-expensive for the experimental fleet. But the cost to modernize a legacy airframe (legally) would essentially send those airframes to the scrap pile.

I suppose the root problem is the perception that leaded fuel is the devil trying to kill us all lol.
 
I think the bottom line here is that there is just no way to make 100 octane (~130 MON?) fuel without tetraethyl lead, or high proportions of aromatic solvents.
Swift and Lyondell both believe they can make 100 octane. I believe that both rely on ETBE in their formula. ETBE is widely used in auto fuel (but not in the US) versus ethanol. We should let this play out.
 
GAMI may have messed up here, but more than likely, achieving the required octane without using xylenes, or something else that abuses old rubber and paint, is just impossible.
not according to swift. The have stated that their 100ul has no aromatic solvents. Watch the video posted above. Sounds like they have done a lot of testing.
 
I can't believe this sort of testing wasn't part of the development lifecycle from day one. Paints, primers, hoses, sealants, o-rings, gaskets...all should have been part of the validation process for any new fuel, and it seems incredibly irresponsible, if not outright amateurish, for them to not have done thorough compatibility tests.
Not really surprising when you accept specialized boutique fuel formulated by a very small business that specializes in making metal fuel injectors. We really should leave this task to petrochemical companies that know what they are doing and actually employ chemists and chemical engineers. I put this blunder squarely on the faa.
 
I've been holding 91 E10 for nearly 800 hours, ( 12 years), not sure what you are talking about?
AFP FI, Andair fuel valve, Tempest mechanical fuel pump, teflon hoses.
No leaks, no paint damage and no seal issues and probably cheaper than G100UL.
That comment was related to g100ul, not e10 fuel. I was referring to the fact that even if you had special rubbers that could handle it, it would still eat away the proseal in your tanks and therefore still unusable.
 
If what I've seen in that video is actually true, I certainly wouldn't touch it.


I've been holding 91 E10 for nearly 800 hours, ( 12 years), not sure what you are talking about?
AFP FI, Andair fuel valve, Tempest mechanical fuel pump, teflon hoses.
No leaks, no paint damage and no seal issues and probably cheaper than G100UL.
The situation is bad enough that the Cirrus Aircraft company came out and said its airplane can only use 100LL. Cirrus knows a lot about the non-lead avgas from the testing.
Also from another of my posts regarding the interview with Gami and Swift fuel. Both of these guys sound like they are selling snake oils. When asked about the details of the tests performed, they all clamped up and said the testing was proprietary. WTF moment.
 
I do not believe that methanol is in pump gas in the US. If true I would be surprised.
You are correct, it is ethanol. That is what the E in e85/e10 stands for. Methanol would be a far better product to add to our fuel, but you can’t easily get it from corn, so not happening in america.
 
You are correct, it is ethanol. That is what the E in e85/e10 stands for. Methanol would be a far better product to add to our fuel, but you can’t easily get it from corn, so not happening in america.
Larry, do you remember the original "gasohol"? It was what the U.S. was converting too in the 1990's and was a gasoline methanol blend. Methanol production for auto fuel use came to an end when underground fuel tanks started leaking it into the groundwater. Hundreds if not thousands of tanks were dug up and replaced. Many gas stations went out of business because they couldn't afford the installation of double wall tanks with leak detection. Methanol is not environmentally friendly. It is a volatile organic compound and can cause blindness among other health issues. It also burns with a clear flame which is hard to see in daylight, which complicates fighting fires.

Joe
 
Larry, do you remember the original "gasohol"? It was what the U.S. was converting too in the 1990's and was a gasoline methanol blend. Methanol production for auto fuel use came to an end when underground fuel tanks started leaking it into the groundwater. Hundreds if not thousands of tanks were dug up and replaced. Many gas stations went out of business because they couldn't afford the installation of double wall tanks with leak detection. Methanol is not environmentally friendly. It is a volatile organic compound and can cause blindness among other health issues. It also burns with a clear flame which is hard to see in daylight, which complicates fighting fires.

Joe
I believe you are confusing methanol with MTBE, methyl tertiary butyl ether. Very different chemicals. MTBE was used as an oxygenate. These fuel tanks were leaking before mtbe but in that mtbe is water soluble and has a very low odor threshold it was noticed in the aquifer. It continues to be used in large quantities in car gas but just not in the US.
 
I believe you are confusing methanol with MTBE, methyl tertiary butyl ether. Very different chemicals. MTBE was used as an oxygenate. These fuel tanks were leaking before mtbe but in that mtbe is water soluble and has a very low odor threshold it was noticed in the aquifer. It continues to be used in large quantities in car gas but just not in the US.
Hi Steve,

I was intentionally trying to keep the conversation simple and related to Larry suggesting the use of methanol instead of ethanol as a fuel additive, so that lay people could easier understand that we had been there and done that. I guess I should have been more detailed, but I didn't want to side rail the thread too much. You are correct in that MTBE was the final product. I had a career in a chemical refinery which produced methanol (which was used in formulating MTBE). We made methanol by the railcar load. Neither it nor MTBE is environmentally friendly. If you research the health effects of methanol, they are much the same as MTBE and you don't get MTBE in large quantity without producing methanol. Bottom line: replacing 100ll needs to be looked at from the big picture and the total environmental impact from product manufacture on and not just focus what comes out our tail pipe.

For anyone interested here is a link with good information from the EPA:
EPA link

Joe
 
Hi Steve,

I was intentionally trying to keep the conversation simple and related to Larry suggesting the use of methanol instead of ethanol as a fuel additive, so that lay people could easier understand that we had been there and done that. I guess I should have been more detailed, but I didn't want to side rail the thread too much. You are correct in that MTBE was the final product. I had a career in a chemical refinery which produced methanol (which was used in formulating MTBE). We made methanol by the railcar load. Neither it nor MTBE is environmentally friendly. If you research the health effects of methanol, they are much the same as MTBE and you don't get MTBE in large quantity without producing methanol. Bottom line: replacing 100ll needs to be looked at from the big picture and the total environmental impact from product manufacture on and not just focus what comes out our tail pipe.

For anyone interested here is a link with good information from the EPA:
EPA link

Joe
Swift's 100 octane fuel relies on ETBE instead of high aromatics. It's smell is even more potent than MTBE so I'm curious how they think it's not dead on arrival in California where MTBE is banned for making drinking water unpalatable.
 
MTBE is banned for making drinking water unpalatable.

You are being too kind.
MTBE was found to contaminate ground water and could not easily be removed.
It is potentially carcinogenic and the cause of other major health problems.
More studies are needed to confirm or refute such evidence. Sure we do....
 
Swift's 100 octane fuel relies on ETBE instead of high aromatics. It's smell is even more potent than MTBE so I'm curious how they think it's not dead on arrival in California where MTBE is banned for making drinking water unpalatable.
Lead is also banned in California. We have been using it there for decades since being outlawed and it’s horrible effects are well documented . We are not getting 100 octane fuel without using something that someone iss not going to like. Good news is that the FAA seems to have the authority to do whatever they want. Even the epa can’t get them to do anything.
 
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Not really surprising when you accept specialized boutique fuel formulated by a very small business that specializes in making metal fuel injectors. We really should leave this task to petrochemical companies that know what they are doing and actually employ chemists and chemical engineers. I put this blunder squarely on the faa.

You mean like Mobil Oil did when they came out with Mobil 1 synthetic for aviation years ago?

Skylor
 
The airport we base at decided to pass on GAMI G100UL given all the recent set of issues with it. They're waiting for Swift UL 100R instead, which uses a different octan booster. As with many other airports, they went around the airport and the surrounding area and tested for lead, but found no detectable levels. The lead scavenger in 100LL is Ethylene Dibromide (EDB), so the going theory now is that lead actually gets vaporized during the combustion process and become undetectable. After testing for lead, our airport manager is not as motivated in moving to UL until Swift UL 100R becomes certified and available.
 
I expected a huge multinational oil company would be behind the effort to develop unleaded aviation fuel, not some random guy out in his shop. No offense to George as I admire his passion to see this through - especially since the "big boys" apparently aren't interested. I just had no idea one person in a (relatively) tiny company could develop a fuel used by airplanes.
Not really surprising when you accept specialized boutique fuel formulated by a very small business that specializes in making metal fuel injectors. We really should leave this task to petrochemical companies that know what they are doing and actually employ chemists and chemical engineers. I put this blunder squarely on the faa.


And also not surprising considering how much of a niche market avgas is, compared to Jet-A and especially auto fuels. Most petro companies would probably prefer to drop avgas production of any type entirely.
 
As with many other airports, they went around the airport and the surrounding area and tested for lead, but found no detectable levels.
This is the key point. Other than making you change your oil every 50hrs leaded fuel doesn't hurt anything.
 
I expected a huge multinational oil company would be behind the effort to develop unleaded aviation fuel, not some random guy out in his shop.
I think the fact that oil companies haven't is telling. Every refinery has a lab and a pile of chemical engineers on staff. The previous refinery I was at makes something north of 40 different blends. The majority of them are blended in the pipelines. And they can pipe from Texas to California. Avgas isn't very high volume but the margins are high.

All that said I suspect they've all looked into a lead free, high octane fuel, without ethanol or some other hazardous chemicals, and found it isn't feasible.
 
I watched a series of You Tube videos called "the True Story of AVGAS" that Scott Perdue (FlyWire) produced. The most interesting one was George Braley discussing and demonstrating the O-ring swelling issue, with 100LL. Turns out you can get batches of 100LL with the same high proportions of aromatics that cause O-ring swelling as G100UL and that the issue has been known for decades. One of the most interesting discussions was about 100LL formulation and the fact that there is no exact recipe for what goes in it. Depending on which refinery blended your 100LL and where it was distributed to, you can have high, low, or medium levels of aromatics in it. I am curious why that fact has never come up in any PAFI/EAGLE discussions and what they consider the 100LL baseline for material compatibility testing vs any UL formulation. You would hope the highest aromatic version of 100LL would be the one they selected for a baseline.


No dog in this fight as I have hauled about 3,000 gallons of 93 non-ethanol from the local WalMart Murphy station to the airport. Given the $3.69/gallon cost I do not see that changing even if G100UL or Swift 94/100 is available.
 
I watched a series of You Tube videos called "the True Story of AVGAS" that Scott Perdue (FlyWire) produced. The most interesting one was George Braley discussing and demonstrating the O-ring swelling issue, with 100LL. Turns out you can get batches of 100LL with the same high proportions of aromatics that cause O-ring swelling as G100UL and that the issue has been known for decades. One of the most interesting discussions was about 100LL formulation and the fact that there is no exact recipe for what goes in it. Depending on which refinery blended your 100LL and where it was distributed to, you can have high, low, or medium levels of aromatics in it. I am curious why that fact has never come up in any PAFI/EAGLE discussions and what they consider the 100LL baseline for material compatibility testing vs any UL formulation. You would hope the highest aromatic version of 100LL would be the one they selected for a baseline.


No dog in this fight as I have hauled about 3,000 gallons of 93 non-ethanol from the local WalMart Murphy station to the airport. Given the $3.69/gallon cost I do not see that changing even if G100UL or Swift 94/100 is available.


Careful, though 100LL is not pure standard one off recipe, the high aromatic of G100UL is NOT nearly 100LL's normal range. Bias raises eyebrows. It may be the Amines also, not just the high aeromatic xylene content causing G100UL issues. Just "high aromatic" 100LL is a distraction, showing bias in the who not the what...

My bias- I use only the % of 100LL for my required lead content, which is a conservative 50/50 with no ethanol, 90 octane mogas .

Take out or at least cut the lead to just what you need . Problem? Yup- winter blend Rec 90 is too light of vapor for warm spring.

Solution? No Lead Avgas, 100LL sans TEL. Too logical for aviation and government . Add to 100LL or better yet add TEL at the plane, same as adding TCP to fight the lead salts.

Rocket science won't always outstrip common sense, but it does cause leaks.

 
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