Another reason not to run G100UL…

Hang 4 said:
That's not exactly correct. The latest version from Swift requires derating some of the higher HP engines to avoid detonation. G100UL does not. G100UL appears to be a full solution for the octane requirement and fully fungible with 100LL, but potentially has material compatibility challenges.
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Swift has multiple irons in the fire. Derating is for the 94UL that Swift currently makes and has an STC for. The way the STC was written, it will work with the 100R from Swift fuels for which Swift is going dual path last I read. The 100R is going through EAGLE and like the racing fuel company has made it passed the third phase of engine testing and are now into materials compatibility. (memory says it was Phillips 66 that failed at the third stage of engine testing). At the same time, Swift fuels has pursued, and been granted (I think) a very limited STC for 100R to be used on just a few model Cessnas; with a goal of expanding the STC over time to eventually a fleet wide AML.

Tim
 
NealRomeoGolf said:
Random wondering...

If you mix G100UL 50/50 with 100LL does it still strip the paint and cause the other issues? Curious if there is a dilution that would work.
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I don't know about the paint issue, but the video posted above where the guy was experimenting with the o-rings in a fuel selecter did run a test with 50/50 mix and still saw a significant swelling of the o-rings.
 
tspear said:
Derating is for the 94UL that Swift currently makes and has an STC for. The way the STC was written, it will work with the 100R from Swift fuels for which Swift is going dual path last I read.
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94UL is only useable on lower compression engines as listed in the STC. There are no options to run it on higher HP/Compression engines. 100R was going to require modifications to higher HP engines (derating) as it's effective octane did not match 100LL.
At the end of the day, if GAMI "wins", Swift is dead and vice versa. They are both flinging mud at each other as hard as they can. Read the FAQ's on both their websites and it's all about why the other one sucks.
Agee GAMI needs a different spokesperson than Braly. Having said that, I'd run G100UL in my plane if I could. Not for the "children" but for a much cleaner combustion chamber, no valve morning sickness and not cleaning sparkplugs every 25 hours.
 
Jim K said:
According to Mike Busch, Lycoming has been using hardened valve seats for decades. Continental since like 2012 or something.
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So UND experienced valve seat recession with hardened seats?
It just don't add up.
 
AV8R_87 said:
So UND experienced valve seat recession with hardened seats?
It just don't add up.
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It wasn't because the valves were soft and wearing away. I believe it was microwelding and they were eroding away. Iirc the detonation margin wasnt where it should have been.
 
What would be the issue with using MMT in E0 ?
Price?
Parts degradation?
Is MMT snake oil that doesn't actually work?

It was used previously in autofuel.
 
EdFred said:
What would be the issue with using MMT in E0 ?
Price?
Parts degradation?
Is MMT snake oil that doesn't actually work?

It was used previously in autofuel.
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It was removed because of its ground water contamination potential. With a lot of people still dumping sumped fuel on the ground, that might not be an option embraced by the public.
 
EdFred said:
What would be the issue with using MMT in E0 ?
Price?
Parts degradation?
Is MMT snake oil that doesn't actually work?

It was used previously in autofuel.
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MMT is probably worse than TEL from an environmental perspective.

Tim
 
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tspear said:
The problem is one of economies of scale along with certification. Aviation does not have the economics along with a much higher barrier on certification. Makes it very hard to apply automotive processes and thoughts to aviation. You can potentially adopt some of the material insights, but not really the processes.

Tim
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An o-ring material can be changed without a massive disruption or re-certifying. If its supposed to meet MIL-SPEC ZXY then find a material that still meets MIL-SPEC ZXY but also PDQ. How many industries have done this? All of them?

Its HILARIOUS that people think these dinosaurs are perfect an cannot be changed. I firmly believe that 90% of the problem is people, not the materials science.

I mean here is one example https://www.mcfarlaneaviation.com/products/FSS-KT-2/

Also hardware has 100% been superseded MANY TIMES. MS21042 is an authorized replacement for AN364, and the 'B' variant can replace the 'A'. How many AN parts have been superseded by MS parts? Some are just name changes, but many are completely new designs that are 100% compatible.
 
Hang 4 said:
100R was going to require modifications to higher HP engines (derating) as it's effective octane did not match 100LL.
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Any links, I cannot find anything to support this statement.

Tim
 
pfarber said:
An o-ring material can be changed without a massive disruption or re-certifying. If its supposed to meet MIL-SPEC ZXY then find a material that still meets MIL-SPEC ZXY but also PDQ. How many industries have done this? All of them?

Its HILARIOUS that people think these dinosaurs are perfect an cannot be changed. I firmly believe that 90% of the problem is people, not the materials science.

I mean here is one example https://www.mcfarlaneaviation.com/products/FSS-KT-2/

Also hardware has 100% been superseded MANY TIMES. MS21042 is an authorized replacement for AN364, and the 'B' variant can replace the 'A'. How many AN parts have been superseded by MS parts? Some are just name changes, but many are completely new designs that are 100% compatible.
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It is a question of unknown state of the fleet, along with the labor required to inspect and address each plane and part. Never said not solvable, just that it is not practical to solve in a short timeframe. The FAA should have set the stage to solve the TEL problem in 1970. Now, the ship has sailed, and owners (pilots to a lesser degree) are effed.

Tim
 
tspear said:
MMT is probably worse than TEL from an environmental perspective.

Tim
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From Wikipedia - which as we all know is infallible:

In 1994 (reaffirmed in 1998, 2001 and 2010), Health Canada concluded that "airborne manganese resulting from the combustion of MMT in gasoline powered vehicles is not entering the Canadian environment in quantities or under conditions that may constitute a health risk"[24] and confirmed they were taking no action with respect to MMT. Similarly, the 2003 NICNAS report states that the airborne concentrations of manganese as a result of car emissions from vehicles using fuel containing MMT poses no health hazard.[citation needed]

The assessment conducted by NICNAS notes that "[m]anganese, the principle degradation by-product from combustion of MMT, is naturally occurring and ubiquitous in the environment. It is an essential nutrient of plants and animals. Environmental exposure to Mn compounds will mostly arise through the gaseous phase. Eventually, these will deposit to land and waters. The emission of Mn into the environment from use of fuels containing MMT is unlikely to develop to levels of concern and therefore poses a low risk for terrestrial or aquatic environments."

Additional health studies, overseen by the US EPA, were conducted to explain the transport of manganese in the body. In studies published from 2007 through 2011, no significant health effects are anticipated from the use of MMT in gasoline.[25]
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Which is why I asked.
 
cowman said:
I've been skeptical that 100LL is going away from the start and I still am, but...

It would seem like the hose and o-ring issue is not that hard to solve- unless I'm misunderstanding we do have compatible materials. So, unless I'm mistaken isn't that something that can be fixed with off the shelf generic replacement parts and a day or two of shop labor or less depending on the aircraft type? Then we'd just need to figure out a compatible material for fuel bladders/sealant for wet wings right?

Another annoyance/expense for aircraft owners but one that doesn't seem to me like that far out of bounds beyond what we normally deal with anyway. The FAA can just issue an AD and we can take care of that stuff I would think.

I'm more concerned about the reports of valve recession, if that turns out to be legit and it's not something that can easily be avoided by changing engine management techniques I think that's what would sink G100UL.
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AFAIK the valve recession was not with G100UL, but was only with the Swift 94UL product. It has a very different formulation from my understanding. I've not seen anyone report a "running" problem with G100UL, just acusations of paint damage and leaks, not engine damage.
 
Jim K said:
Squarebodu Chevy pickups. Remember when 60 minutes blew one up for a story about them exploding in crashes?
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They were caught having used pyrotechnics to make it "blow up" since the side-saddle fuel tanks apparently wouldn't actually do it on their own in a collision, though they would breach.
 
I would be willing to change orings at annual for this.

I would not be willing to swap bladders.

There may need to be compatibility testing with some of the more popular legacy and modern paints.

And then I’d want to be convinced by user data that the engines can survive long-term.

So how does one “fix” my problem? Legislate 100LL out of existence with a deadline. Lose a few votes, and maybe some financial support, that might net even from other sides. Then I suck it up like a big boy and either upgrade my equipment or sell, both at negative cash. Done.

I don’t really think anyone cares about little me and my hobby plane. Do they? AOPA? EAA?

How would this affect piston commercial ops (training) and global missions? That’s maybe a bit of a “bigger picture” dilemma.
 
455 Bravo Uniform said:
I would be willing to change orings at annual for this.

I would not be willing to swap bladders.

There may need to be compatibility testing with some of the more popular legacy and modern paints.

And then I’d want to be convinced by user data that the engines can survive long-term.

So how does one “fix” my problem? Legislate 100LL out of existence with a deadline. Lose a few votes, and maybe some financial support, that might net even from other sides. Then I suck it up like a big boy and either upgrade my equipment or sell, both at negative cash. Done.

I don’t really think anyone cares about little me and my hobby plane. Do they? AOPA? EAA?

How would this affect piston commercial ops (training) and global missions? That’s maybe a bit of a “bigger picture” dilemma.
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I’d be interested to see what it does to wet wings over a long period of time
 
455 Bravo Uniform said:
I don’t really think anyone cares about little me and my hobby plane. Do they? AOPA? EAA?

How would this affect piston commercial ops (training) and global missions? That’s maybe a bit of a “bigger picture” dilemma.
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Yes, both EAA and AOPA do. I have even talked to a lobbyist from NBAA, they all care about the legacy piston fleet. And they give a lot more than just lip service to it; they actively jawbone Congress and the FAA about the issue.
The reality as I have said before is the FAA should have banned 100LL from new certificates back in 1970. To do so now, would at least be a step in the right direction, but it will take decades for the equipment to age out.

Tim
 
JOhnH said:
Not exactly the same, but there was the "Doctor Killer" ruddervator.
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Not exactly the same because they sold like 18,000+ Bonanzas? I don't remember, were those the 3rd or 4th most popular aircraft ever?
 
tspear said:
Yes, both EAA and AOPA do. I have even talked to a lobbyist from NBAA, they all care about the legacy piston fleet. And they give a lot more than just lip service to it; they actively jawbone Congress and the FAA about the issue.
The reality as I have said before is the FAA should have banned 100LL from new certificates back in 1970. To do so now, would at least be a step in the right direction, but it will take decades for the equipment to age out.

Tim
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The reality since the fall of 2023 is 100LL exhaust is a menace to society and both the EPA and the FAA are legally bound to regulate it away.

The EPA has issued a final determination that lead emissions to air from certain aircraft engines cause or contribute to air pollution which may reasonably be anticipated to endanger public health and welfare. Aircraft that use leaded aviation gasoline are primarily piston-engine aircraft.

With this final determination, EPA now becomes subject to a duty to propose and promulgate regulatory standards for lead emissions from aircraft engines. The FAA is also now subject to a duty to prescribe standards for the composition or chemical or physical properties of aircraft fuel to control or eliminate aircraft lead emissions.
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www.epa.gov

Regulations for Lead Emissions from Aircraft | US EPA

EPA regulations related to smog, soot, and other air pollution from aircraft.
www.epa.gov www.epa.gov
 
AV8R_87 said:
It was removed because of its ground water contamination potential. With a lot of people still dumping sumped fuel on the ground, that might not be an option embraced by the public.
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I thought the ground water contamination was from MTBE.

I thought MMT fouled up catalytic converters. And people were concerny about manganese. But that was more secondary
 
I would love to see a "you can blend alcohol free mogas 50/50 with 100LL and run it in your 8.5 compression or lower cylinder engines without having to do airframe specific testing". That would stretch the 100LL supply, lower lead in the fuel, and likely avoid the vapor lock issues on low wing planes.
 
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schmookeeg said:
Not exactly the same because they sold like 18,000+ Bonanzas? I don't remember, were those the 3rd or 4th most popular aircraft ever?
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And most of those sales came AFTER the tails started falling off, and the problem was resolved. But Bonanza recovered and sold a bunch of them. So I submit it is a relevant comparison.
 
Pinecone said:
How many people here have airplanes with any warranty coverage????
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My engine is under coverage, but Continenal will lie their way out of both warranty coverage and responsibility for engine design problems.
 
JOhnH said:
And most of those sales came AFTER the tails started falling off, and the problem was resolved. But Bonanza recovered and sold a bunch of them. So I submit it is a relevant comparison.
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Wasn't the AD in the early 1980s? for the plane sold from 1947-1982?
 
except the ruddervator problem isn't solved. That recreational market is still running on hope and pool nooddles. Airframes with hangar rash gets scrapped monthly by insurance unable to procure skins. They're still tearing each other up over on BT over carbon fiber pipedreams and the hobby's usual factory default setting poorshaming, latter which in fairness isn't unique to BE-35 owners.

Lyco and TCM aren't friends of aviation, they're rent seekers. I don't think recreational owners of dinosaur engines that need 100LL have much of a political leg anyways. As has been highlighted already, they're just riding coat tails from the flight training space. Will it be enough? I don't think so, but I do understand the gargantuan economic incentive they have in holding on to 100LL, and therefore their simping for Lyco and Conti. No different than housing NIMBYs.

Saying 'ecOnoMies of scAle' over and over as to why we have to accept 2025 production of XXX-540 XXX-550 and downline-subordiante variants, is just beat wife syndrome. And people need to be careful, as it's also taken as a given, but is big time facts not in evidence, that physical primary flight instruction will always be a staple of American flight training. That's an even bigger wishcast than the permanence of 100LL through whatever prototypical GenX aircraft owner holdout's natural lifespan. Ab initio can make that political coalition disappear right ricky tick, and then you will be forced to downgrade to whatever literal lawnmower engine rotax can offer, and if that doesn't fit your use case, welcome to the has-been club.

My poorly researched prognostication on the heavy consumers of 100LL is, the part 134.5s get told to crap or get off the pot, and industry consolidation ushers the JetA retrofitting that should have occurred 20 years ago. The rest fold. Flight training goes diesel and shrinks in size, as most will be done in simulators, as US airlines move into MPL equivalence.

None of this has to mean the end of sport/recreational aviation, but absent auto inspired alternatives, yeah the supra-150hp market is coooked. Lyco and Conti are not going to innovate, they're in full Sears mode now, just waiting on their cue to give you all the final finger.
 
tspear said:
Any links, I cannot find anything to support this statement.

Tim
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Can't find a link that talks about de-rating, but I do remember reading it at some point. This article from April describes where they (Swift) are.

Avweb article

TLDR, talks about the fact they have not done testing yet in higher octane required engines like turbo and high compression

Quoting Chris d’Acosta, CEO of Swift.

Swift’s fuel currently is approved by STC for the two latest models of Cessna 172s, the R and S versions. Both of those aircraft are already approved to use Swift’s 94 UL unleaded avgas and the plan is to expand 100R’s STC availability to the 75% of the fleet already able to use 94UL. Then, Swift will replace the 94UL in its network of FBOs and fuel sellers with 100R. “The first thing that’s going to happen is 100R’s going to step into the footprint of 94, and when we do that, we’ll have 75% of the U.S. fleet able to fly on 100R,” he said.

Swift is now getting ready to tackle that remaining 25% of the market, aircraft with high-horsepower, often turbocharged engines that use about 75% of the avgas sold in the U.S. Almost all those engines must use 100 octane fuel and Swift is expanding its portfolio with a 150-hour endurance test on a six-cylinder engine. “Now we’re moving into the turbocharged world, so we’ve set up a TSIO550K turbocharged engine,” d’Acosta told the forum. According to Continental specs, that model is the only 550, turbocharged or normally aspirated, in that line that can use 94UL. “The turbocharge endurance test is going to open the door to a lot of turbocharged engines becoming approved soon from now, sometime this year,” he said.
 
hindsight2020 said:
except the ruddervator problem isn't solved. That recreational market is still running on hope and pool nooddles. Airframes with hangar rash gets scrapped monthly by insurance unable to procure skins.
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That's a different ruddervator problem.
 
Hang 4 said:
Can't find a link that talks about de-rating, but I do remember reading it at some point. This article from April describes where they (Swift) are.

Avweb article

TLDR, talks about the fact they have not done testing yet in higher octane required engines like turbo and high compression

Quoting Chris d’Acosta, CEO of Swift.

Swift’s fuel currently is approved by STC for the two latest models of Cessna 172s, the R and S versions. Both of those aircraft are already approved to use Swift’s 94 UL unleaded avgas and the plan is to expand 100R’s STC availability to the 75% of the fleet already able to use 94UL. Then, Swift will replace the 94UL in its network of FBOs and fuel sellers with 100R. “The first thing that’s going to happen is 100R’s going to step into the footprint of 94, and when we do that, we’ll have 75% of the U.S. fleet able to fly on 100R,” he said.

Swift is now getting ready to tackle that remaining 25% of the market, aircraft with high-horsepower, often turbocharged engines that use about 75% of the avgas sold in the U.S. Almost all those engines must use 100 octane fuel and Swift is expanding its portfolio with a 150-hour endurance test on a six-cylinder engine. “Now we’re moving into the turbocharged world, so we’ve set up a TSIO550K turbocharged engine,” d’Acosta told the forum. According to Continental specs, that model is the only 550, turbocharged or normally aspirated, in that line that can use 94UL. “The turbocharge endurance test is going to open the door to a lot of turbocharged engines becoming approved soon from now, sometime this year,” he said.
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The tsio- 550k can already run on 94. So I guess I'm failing to see how that helps testing the 100r
 
So I'm wondering something about octane... my IO-540-k15d has a compression ratio of 8.7:1 according to what I'm able to look up.

I know automotive engines with higher compression than that can run 87. Even automotive engines pushing 11:1 ratios can run on 91 octane. I know it's not a total apples to apples comparison but what gives? Is it a different octane scale, vastly different timing curves, the continual operation at high power?

Or are there likely a lot of these engines that only "require" 100 octane because that's all that was around when they were certified?
 
@cowman The biggest difference is the electronic ignition and fuel injection that can adjust timing and fuel real time. Lead prevents using an oxygen sensor and the vibration limits the use of knock sensors in airplane engines. Go to older cars that have carbs and point/condenser ignition and you'll see similar limitations on octane.
 
cowman said:
So I'm wondering something about octane... my IO-540-k15d has a compression ratio of 8.7:1 according to what I'm able to look up.

I know automotive engines with higher compression than that can run 87. Even automotive engines pushing 11:1 ratios can run on 91 octane. I know it's not a total apples to apples comparison but what gives? Is it a different octane scale, vastly different timing curves, the continual operation at high power?

Or are there likely a lot of these engines that only "require" 100 octane because that's all that was around when they were certified?
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Different methods are used to rate knock resistance in avgas and automotive gas. 93 auto gas is basically the same as 100LL, and 100LL would be 105 or more on the automotive scale.
 
cowman said:
I know automotive engines with higher compression than that can run 87. Even automotive engines pushing 11:1 ratios can run on 91 octane. I know it's not a total apples to apples comparison but what gives? Is it a different octane scale, vastly different timing curves, the continual operation at high power?
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The biggest difference applicable to use in a near-fixed RPM aircraft engine application is the large cylinder bore, combined to a smaller extent with the less compact 2V/cylinder combustion chamber design. The larger variety of current US aircraft engines are (in automotive terms) 9 liter engines with only 6 cylinders. This allows them to make power at low RPM (negating the need for propeller gearing) and be relatively light (due to the lack of propeller gearing and smaller number of cylinders) but those benefits in terms of weight, simplicity and maintainability are made possible by high octane fuel.

A slightly higher RPM geared aircraft engine with many more, smaller cylinders like the 9 cylinder, 2950 RPM, 360-400 HP Russian engines can use lower octane fuel, and those particular engines were designed around the assumption of poor quality fuel in the USSR. But they have their own problems. Rotaxes can do the same thing with a small number of cylinders by limiting their size and therefore the engine’s total power output.
 
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the simplicity/reliability dichotomy is overstated. People act like we're asking these gearing step down units to dry-engage the propeller of an Ohio-class SSBN. :rofl:

Given the failure mode I've personally experienced on direct drive engines, I'm not offended by the spectre of PRSU failure; especially if they're cheap enough to be treated as consumables and thus replaced on conservative intervals. Long way to go to hit even crappily-reworked Lyco $ these days.
 
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