Based on the G100UL fuel leak thread what's your position?

[mluvara]

For those that don't regularly partake in FAASafety or FAASTeam Wings seminars, I noticed that some Eagle representatives are presenting at one tomorrow (Saturday Feb 22nd).

"Join us for A VIRTUAL cup of coffee, a donut, and a LIVE WEBINAR as representatives of EAGLE, an initiative consisting of the aviation and petroleum industries, and other interested parties, all working toward the transition to lead-free aviation fuels (UL AvGas) for piston-engine aircraft by the end of 2030 without compromising the safety or economic health of the general aviation industry.

 The speakers will explain the “big picture” from developing and authorizing a UL AvGas replacement to its distribution, storage and sale at airports. They will also provide the most current status of the three replacement UL AvGas that are at various stages of development, testing, distribution and sale.

Aviation safety will be discussed, and is central to the content of this presentation."

Details here:

https://www.faasafety.gov/SPANS/event_details.aspx?eid=134442&%26caller%3d%2fWINGS%2fpub%2faccreditedactivities%2factivitySearch.aspx

Edited February 21 by mluvara

[EricJ]

1 hour ago, gabez said:

sorry I meant resealed. just corrected it. I resealed the tanks and have not been leaking post fix. I gave them 2-3 weeks with 100LL in it. 

Did you reseal them or have somebody do it?   Since that's something people are always looking to get done, can we ask who did it?

 

[gabez]

16 hours ago, EricJ said:

Did you reseal them or have somebody do it?   Since that's something people are always looking to get done, can we ask who did it?

 

I didn't do it. i just fuel the plane and fly it. United Flight Services did it in KWVI. 

[Pinecone]

On 2/20/2025 at 5:38 PM, A64Pilot said:

An R-1340 is allowed to pull I believe 36” of boost from its Supercharger. It has again from memory a 6 to 1 compression ratio and it can do this on 87 Octane car gas. Now car gas and Aviation fuel Octane ratings are different, 100LL I believe if rated as car gas would be more than 100 Octane, likely the reason why we don’t just switch to 100 Octane unleaded race gas. It’s been around for years and I believe even higher than 100 Octane exists https://www.sunocoracefuels.com/fuels/fuel/ss-100 apparently as high as 109 https://racefuel.boostane.com/products/109-octane-fuel

 

The Sunoco SS-100 race fuel is 96 MON.  Car MON is close to Aviation Lean rating.  So, it is about UL96.  Not a big difference over UL94.

The race fuels over 100 MON are either leaded or HIGHLY oxygenated, typically with a lot of ethanol.

Unleaded, no ethanol seems to be around MON of 92.

So even the race gas people have not managed to scale this mountain.

[A64Pilot]

There is 109 Octane unleaded race gas

https://racefuel.boostane.com/products/109-octane-fuel

Oxygenated is good for power production, back in around 1980 when I was drag racing turbo bikes when we set a record, on the way back to the starting line they would take a turkey baster sample of fuel to make sure the fuel was legal, must not have been a difficult test.  I think it may have just been specific gravity like you test antifreeze maybe?

Has anyone actually tested the Gami fuel for octane? Does it claim to be 100 Octane?

Is the requirement to be 100 Octane or just pass detonation testing?

Edited February 23 by A64Pilot

[N201MKTurbo]

I seem to remember that ADI keeps your cylinders and exhaust clean too.

[N201MKTurbo]

https://pubs.acs.org/doi/10.1021/acs.energyfuels.1c00912
 

[Immelman]

On 2/22/2025 at 9:04 AM, gabez said:

I didn't do it. i just fuel the plane and fly it. United Flight Services did it in KWVI. 

Gabe - was the job a full strip/reseal or a patch of areas that were known to be leaking? (I am also at WVI, you'll find me in A-3, and a United Flight customer). We've done several patches over the years but no full reseal.

I am curious if the G100UL degraded your sealant throughout the tanks, went through a vulnerable area, or something else. Happy to chat in person sometime if we can find a mutually agreeable time.

[gabez]

On 2/23/2025 at 9:34 AM, Immelman said:

Gabe - was the job a full strip/reseal or a patch of areas that were known to be leaking? (I am also at WVI, you'll find me in A-3, and a United Flight customer). We've done several patches over the years but no full reseal.

I am curious if the G100UL degraded your sealant throughout the tanks, went through a vulnerable area, or something else. Happy to chat in person sometime if we can find a mutually agreeable time.

ping you on the DM 

[Aaviationist]

1 hour ago, gabez said:

ping you on the DM 

This seems like good public information. Not sure why it needs to be a PM. 
 

as bad as your tanks were leaking, and as old as the sealant was, AND due to the deteriorating effects you state this fuel had, it’s mind blowing to me you didn’t send it to one of the well known specialists in this area. 
 

I'm willing to bet you did the bare minimum. And without taking it to one of the well known tank experts, we are never going to know the TRUE effect. 

[Schllc]

8 minutes ago, Aaviationist said:

This seems like good public information. Not sure why it needs to be a PM. 
 

as bad as your tanks were leaking, and as old as the sealant was, AND due to the deteriorating effects you state this fuel had, it’s mind blowing to me you didn’t send it to one of the well known specialists in this area. 
 

I'm willing to bet you did the bare minimum. And without taking it to one of the well known tank experts, we are never going to know the TRUE effect. 

While you often make fair points, you package them in a shit sandwich, then wonder why no one wants to take a bite. 
How about you take your own advice and not be ugly in your responses. 
If you were a bit more tactful and circumspect you may actually persuade a few folks. 

[varlajo]

49 minutes ago, Aaviationist said:

it’s mind blowing to me you didn’t send it to one of the well known specialists in this area. 

United is a very well known and respected shop with deep Mooney experience. Look them up on Google Maps and you'll see almost exclusively Mooneys parked around their hangar. Terry is recommended by no other than the MSC that start with LA and ends with AR. 

There are indeed reseal-only shops, but their wait lists are years long (ask me how I know), and the OP's plane is not going to last that long with seals dissolving in real time. 

[A64Pilot]

On 2/23/2025 at 12:02 PM, N201MKTurbo said:

I seem to remember that ADI keeps your cylinders and exhaust clean too.

Our Grandfathers would dribble it into the carburetor of a running engine at high idle and gunning it every so often.

This was back in the day when pulling the head and de-carburizing an engine was recommended.

If there is sufficient water it will clean, but I don’t know if ADI is of sufficient quantity.

From this Avweb article Tecnam is going to build an aircraft with ADI. Will they? I don’t know but think there is a market, but maybe mostly in Europe? Haven’t seen many Tecnam’s around here.

I believe the T means turbo, never seen one but seems to be the engine we have been crying for? IE electronic controlled, variable timing etc.

https://www.avweb.com/features/the-return-of-anti-detonation-water-injection-adi/

“Air Plains isn't the only company exploring ADI. At least one European manufacturer, Tecnam, will reportedly use ADI in a new twin called the P2012. Powered by Lycoming's new TEO-540-A1A, Tecnam says the airplane will be operable on mogas. Another Lycoming-powered aircraft, Grumman's pilot-optional Firebird drone, will also have ADI, presumably to operate in theaters where 100LL isn't available but mogas is.”

Edited February 24 by A64Pilot

[N201MKTurbo]

41 minutes ago, A64Pilot said:

Our Grandfathers would dribble it into the carburetor of a running engine at high idle and gunning it every so often.

This was back in the day when pulling the head and de-carburizing an engine was recommended.

If there is sufficient water it will clean, but I don’t know if ADI is of sufficient quantity.

From this Avweb article Tecnam is going to build an aircraft with ADI. Will they? I don’t know but think there is a market, but maybe mostly in Europe? Haven’t seen many Tecnam’s around here.

I believe the T means turbo, never seen one but seems to be the engine we have been crying for? IE electronic controlled, variable timing etc.

https://www.avweb.com/features/the-return-of-anti-detonation-water-injection-adi/

“Air Plains isn't the only company exploring ADI. At least one European manufacturer, Tecnam, will reportedly use ADI in a new twin called the P2012. Powered by Lycoming's new TEO-540-A1A, Tecnam says the airplane will be operable on mogas. Another Lycoming-powered aircraft, Grumman's pilot-optional Firebird drone, will also have ADI, presumably to operate in theaters where 100LL isn't available but mogas is.”

This article is from 2013. I wonder if any of this was ever done?

[A64Pilot]

50 minutes ago, N201MKTurbo said:

This article is from 2013. I wonder if any of this was ever done?

I doubt it, but assume if they said they were going to it was both possible and Lycoming was OK with it.

My SWAG is liability from saying you can burn Mogas, mostly including me think that means Auto pump gas, but does it really? Does Mogas even exist anymore? By that I meant the fuel that was Certified to burn in the Peterson and EAA STC’s in the 80’s isn’t what is at the pumps nowdays.

Plus I think the target market fir the airplane is Part 121. Would that matter for Auto fuel? I don’t know not having personal experience with Part 121, but finally Auto fuel just isn’t available at airports

I don't think Lycoming is the stick in the mud most seem to think as they allow and of course Certified a 540 for Embraer to burn pure Ethanol for Brazil.

So I think Lycoming will allow ADI, by allow I mean not deny Warranty etc.

Its astonishing when you think about it that the FAA allows a fuel that no manufacturer tested, or none that I know of, both airframe and engine.

It would seem to me that puts the FAA into a liability problem, Cirrus says don’t use it, FAA says it’s fine, your million dollar aircraft becomes unairworthy, who is paying?

Edited February 24 by A64Pilot

[N201MKTurbo]

1 hour ago, A64Pilot said:

I doubt it, but assume if they said they were going to it was both possible and Lycoming was OK with it.

My SWAG is liability from saying you can burn Mogas, mostly including me think that means Auto pump gas, but does it really? Does Mogas even exist anymore? By that I meant the fuel that was Certified to burn in the Peterson and EAA STC’s in the 80’s isn’t what is at the pumps nowdays.

Plus I think the target market fir the airplane is Part 121. Would that matter for Auto fuel? I don’t know not having personal experience with Part 121, but finally Auto fuel just isn’t available at airports

I don't think Lycoming is the stick in the mud most seem to think as they allow and of course Certified a 540 for Embraer to burn pure Ethanol for Brazil.

So I think Lycoming will allow ADI, by allow I mean not deny Warranty etc.

Its astonishing when you think about it that the FAA allows a fuel that no manufacturer tested, or none that I know of, both airframe and engine.

It would seem to me that puts the FAA into a liability problem, Cirrus says don’t use it, FAA says it’s fine, your million dollar aircraft becomes unairworthy, who is paying?

It would let us burn UL94. 

[Aaviationist]

15 hours ago, varlajo said:

United is a very well known and respected shop with deep Mooney experience. Look them up on Google Maps and you'll see almost exclusively Mooneys parked around their hangar. Terry is recommended by no other than the MSC that start with LA and ends with AR. 

There are indeed reseal-only shops, but their wait lists are years long (ask me how I know), and the OP's plane is not going to last that long with seals dissolving in real time. 

Again, if the entire argument was that the fuel degraded the sealant why would you do the bare minimum of patching. Seems to me if the fuel destroyed the sealant I would want new sealant all around. 
 

then, keeping the work done to repair back to airworthiness a private matter after being so public about your problems?  Something’s not adding up. 

[A64Pilot]

12 hours ago, N201MKTurbo said:

It would let us burn UL94. 

Yes, that’s what I’m thinking too, 94UL is of course a “fit for purpose” Aviation fuel, refined etc under I think an ASTM spec etc. should I think not have any vapor loc issues etc that car gas does, 94UL won’t “eat” composites or nitrile, fuel tank sealer, paint etc.

It would let you burn car gas too, but car gas has its own problems with different formulations existing and changing seasonally etc.  So it might be difficult, not saying you couldn’t make it work, just it may require even more airframe mods and tomorrows car gas likely won’t be what we test and Certify today.

Without being any kind of expert from what little I know is ADI would allow unleaded fuel tomorrow without any problems and my bet is the engine and airframe manufacturers would test and sign off on 94UL if they haven’t already. In my opinion it’s very important for the manufacturers to approve any alternate, to require a product they don’t test and approve is at a min irresponsible. Only the high compression and turbo motors would need ADI, the majority of GA would be fine just switching over to 94UL. 

There is a solution for those that think we need one, we don’t need a Magic fuel mixed from Lord only knows what with unknown health consequences etc.

 

Edited February 25 by A64Pilot

[N201MKTurbo]

94UL is just 100LL without the TEL. It should have zero compatibility issues, and the refiners already know how to make it.

[Marc_B]

2 hours ago, Aaviationist said:

then, keeping the work done to repair back to airworthiness a private matter after being so public about your problems?  Something’s not adding up.

There are many that appreciate field reports from actual users. But there aren’t many that have been posting positive field reports and the ones who have issues are grilled and vilified by some.  It makes people hesitant to share. Which is unfortunate ALL the way around because it also disincentivizes those who might have a positive field experience  

The group that could do the best to inform ongoing details would be GAMi since they are the one introducing a new fuel with new components to the market. But you don’t see a ton of info there either.

Thanks to everyone who posts field reports and experience with any new alternative fuels coming to market. It helps us all determine how best to navigate this dramatic change to general aviation more successfully in the long run. 

[redbaron1982]

33 minutes ago, Marc_B said:

Thanks to everyone who posts field reports and experience with any new alternative fuels coming to market. It helps us all determine how best to navigate this dramatic change to general aviation more successfully in the long run. 

This... imagine how things would have been different if nobody shared any issues with G100UL. By this time, we would most likely have 100LL banned in California.

I'm grateful for having early adopters willing to share their experiences, as well as for @mluvara for doing so many tests and share the results with all of us.

[mluvara]

3 hours ago, A64Pilot said:

Without being any kind of expert from what little I know is ADI would allow unleaded fuel tomorrow without any problems and my bet is the engine and airframe manufacturers would test and sign off on 94UL if they haven’t already. In my opinion it’s very important for the manufacturers to approve any alternate, to require a product they don’t test and approve is at a min irresponsible. Only the high compression and turbo motors would need ADI, the majority of GA would be fine just switching over to 94UL. 

 

 

ADI comes with its own set of pros and cons. The first issue is that it is another system to manage and carry. When that system quits under conditions where it is necessary, then you are likely to have a problem (detonation). Just ask all the Unlimiteds at the air races what happens when it fails under high power. And then you you are carrying a water/methanol mix and associated components. One can't just use water because it will freeze in some scenarios and there are rust/material considerations. The addition of methanol changes the freezing point of the mixture, hence compatibility with cold or high altitude operations. It also affects the mixture and might require mixture compensation at different stages of power.

 

2 hours ago, redbaron1982 said:

This... imagine how things would have been different if nobody shared any issues with G100UL. By this time, we would most likely have 100LL banned in California.

I'm grateful for having early adopters willing to share their experiences, as well as for @mluvara for doing so many tests and share the results with all of us.

Thanks! I'm just trying to transparently show observations. 

[mluvara]

Piper issued a customer information letter.

"Piper has not evaluated any STC fuels, including GAMI G100UL, for use in any Piper airplane model. Piper does not have sufficient information to evaluate the chemical properties of the fuel and how it may interact with materials throughout the fuel system, including but not limited to: the airframe surfaces and structures, fuel tanks (materials, sealants, bladders, gaskets, etc.), fuel quantity gauging components, fuel lines, and other fuel system components (pumps, valves, sensors, etc.)."

https://www.piper.com/wp-content/uploads/2025/02/CIL-2025-002.pdf

Edited February 25 by mluvara

[A64Pilot]

5 hours ago, mluvara said:

ADI comes with its own set of pros and cons. The first issue is that it is another system to manage and carry. When that system quits under conditions where it is necessary, then you are likely to have a problem (detonation). Just ask all the Unlimiteds at the air races what happens when it fails under high power. And then you you are carrying a water/methanol mix and associated components. One can't just use water because it will freeze in some scenarios and there are rust/material considerations. The addition of methanol changes the freezing point of the mixture, hence compatibility with cold or high altitude operations. It also affects the mixture and might require mixture compensation at different stages of power.

 

Thanks! I'm just trying to transparently show observations. 

ADI wise.

Failure is or could be easily made to be extraordinarily unlikely, the injection plate is just that, no moving parts with several injection holes. Then there are two pumps and surely both are tested on run-up, Separate electrical systems is as easy as a battery back-up like several current instruments. Have a pressure switch like one that runs many hobbs meters will tell you it’s on via a light, and or a failure light is dead easy, heck add a horn if you think it necessary, if the electronics fail it fails to the on position, or you have a switch that merely turns the power on, it’s not modulated it’s just on or off.

Real easy to make it orders of magnitude more reliable than our engine, When I Certified the MVP-50T in the S2R-H80, it’s first installation in a Certified airplane. I spoke with Rob Roberts EI’s owner a little concerned about what if it quits, because if it does you lose everything, ALL engine instrumentation, fuel flow, fuel quantity, even voltage and amps, prop RPM, everything.

I forget the number but he had to prove to the FAA that the likelihood of failure was if memory is correct over a million to one. How do you prove that I have no idea, but the FAA required it. So he can make electronics stupid reliable and he’s set to build the electronics for ADI.

Using Unlimited’s as an example is a little silly, it’s like comparing a normal car to Top Fuel. If ADI fails in truth most likely nothing will happen but you will have time to either turn on the manual switch or reduce power. I know people that run our motors on 93 Octane pump gas and IO-540’s too, Experimentals do as they please, some run one tank 100LL for T/O and some don’t.  I’m not abdicating running car gas or 94 UL, just know some that foolishly do. 

You think we have hot start issues, you ought to see how bad it is with car gas, that stuff vapor locks the moment you turn it off, you can hear it frying.

Methanol mix handles freezing concerns, a tiny bit of oil handles corrosion concerns, but what do you think is going to corrode? I imagine a Rotomolded plastic tank, the pump can handle water, use an RV water pump if you think it’s necessary, the hose is rubber and the injection tube could be stainless.

Windshield washer fluid is 30% to 50% Methanol, ADI wants %40 https://carfluidguide.com/how-much-methanol-is-in-windshield-washer-fluid/

• Methanol Content: Windshield washer fluid typically contains 30-50% methanol, critical for preventing freezing and enhancing cleaning effectiveness

Leaves the engine, Methanol is going to exist in it for milliseconds so I can’t see Corrosion there. But finally there is decades of actual experience with ADI from the Military, Airlines back in the day and hot rodders, they often use windshield washer fluid which is apparently Methanol and water, and I’ve never heard of corrosion from windshield washer fluid and I’m sure it doesn’t contain any oil.

No need to modulate it, it’s only on at high power and the amount your spraying is way in excess to what’s needed as until you start spraying a stupid amount excess isn’t harmful. I assume size of the injector will likely be based on HP of the engine?

If we accept that lead is a health concern and has to go (I don’t myself) but that only leaves a few options (Magic fuel) that has eluded smart people for decades? A new engine that I can assure you all in is over $100K, or scrap our aircraft, add maybe a low compression motor STC, maybe possibly low compression pistons and or cylinders and live with the power loss with our existing engines?

Or ADI and 94UL

Now to be clear, I do NOT want ADI, I want to keep 100 LL, but if forces beyond my control take it away from me I don’t see anything viable but ADI.

Do you?

Edited February 25 by A64Pilot

[A64Pilot]

I do feel this way and hope to convince as many of you as I can.

IF Gami gets to keep selling their fuel and or somebody else does their fuel

We as in all us Pilots and Owners need to lobby as hard as we can with AOPA and all the type clubs that before ANY alternate fuel is required that it has to accepted by both the Airframe (where one exists) and the engine manufacturer (where one exists) 

This FAA awarding STC’s with no testing is BS, by no testing I mean the FAA didn’t test, they review the STC applicants testing and accept that. But it’s insane to allow a fuel be put into an aircraft that both the engine and airframe manufacturer warn against, this contributes to safety, how?

Cirrus saying that they have Airworthiness concerns on their aircraft that have the Gami fuel in it should raise Huge concerns in the FAA.

I wonder what new Cirrus wings cost?