Help me understand: UL94 fuel approval vs. compression ratio vs other aspects?

[A64Pilot]

54 minutes ago, ArtVandelay said:

Can’t a electronic ignition system solve the same problem simply by changing the timing, based on cylinder temperatures and MP just like the water injection system?

Yes, but they could do so more efficiently with a knock sensor. If you simply retarded timing based on MP or cyl head temp to a known safe advance, you would be unnecessarily reducing power, because you would have to reduce to a known safe timing for worse case, and of course lose a significant amount of power.

Toyota developed the knock sensor in 1980 I believe, it’s a pretty simple device really, it “listens” for detonation and as soon as it hears it, it retards timing until it goes away. I believe pretty much all cars since the early 90’s have it, I know my LT and LS engines do.

https://www.jstor.org/stable/44470940 Max power and also efficiency is produced right at the edge of detonation in a  normal engine.

This of course reduces power, and with aircraft, how do you develop charts etc when power is unknown?

Thing with water injection is you prevent detonation, without a loss of power. It most often used in fact in applications to increase power beyond the point you could without it. Water injection doesn’t change timing, just simply sprays a water mist into the suck side of the engine.

Everything comes with problems, like if the water injection and or knock sensor or reduction in timing didn’t happen for whatever reason, you would then be restricted in MP and I’m sure would need enunciation of failure.

Simplest answer is of course leave things where they are

Edited February 14, 2022 by A64Pilot

[RobertGary1]

11 hours ago, philip_g said:

I used to run windshield washer fluid. It's 30% methanol 

But yet again something illegal in California. We can only buy the non freezing stuff up in the mountains. Which is odd since you’d already be in the mountains before you can buy it. This stuff has its own env problems. 

[A64Pilot]

Way back in 1934 Buick was first with vacuum advance, as we know at high power if you have too much advance, you detonate, and detonation destroys engines, so with high MP you can’t tolerate as much advance.

But at low power output you can run much more advance and achiever greater fuel milage, so along came vacuum advance so that the timing was advanced based on MP and of course MP is tied to power, so an engine ran higher timing and got better milage at lower power output.

Then we have mechanical advance as well. the flame front moves across the combustion chamber at a set speed, so if you increase RPM you need to increase timing to keep the peak cyl pressure occurring at the same degree of rotation of the crankshaft, so we have mechanical advance in old auto distributors too, basically just fly weights with springs so thet the faster they are spun they fling out and rotate the plate the points are on and increase timing, same as vacuum advance but for a different reason. I don’t know how long they have been around, but assume they predate vacuum advance.

Airplane magnetos have none of this as they induce complications and remember our Magnetos are I’d guess at least 75 yr old designs if not older? Plus aircraft engines run at a very narrow power and RPM range, yes of course with variable advance there can be gains in efficiency at part throttle, but changing timing can also change the vibrations of the engine. and that can cause issues with props, so I think timing wise airplane are stuck in the early 20th Centrury.

I say at least 75 hrs old because my 1946 C85’s Mags are just like new ones.

Edited February 14, 2022 by A64Pilot

[A64Pilot]

14 minutes ago, RobertGary1 said:

But yet again something illegal in California. We can only buy the non freezing stuff up in the mountains. Which is odd since you’d already be in the mountains before you can buy it. This stuff has its own env problems. 

Really? It’s just Methanol and water?

OK, so how about Ethanol and water?

[N201MKTurbo]

1 hour ago, ArtVandelay said:

Can’t a electronic ignition system solve the same problem simply by changing the timing, based on cylinder temperatures and MP just like the water injection system?

There is no electronic magic that will fix this problem. All the electronic system would do is retard the timing so the engine doesn't detonate. This will reduce the power the engine makes. We would still need to re do all the performance charts.

The one thing the electronic systems can do is restore the performance at reduced power settings.

It is impossible to get the same power on a lower octane fuel. The water injection reduces the detonation margins by cooling the combustion charge by the latent heat of vaporization of the fluid, essentially razing the octane of the fuel. 

[John Schreiber]

A&P IA CMEL here:

RE: the angle valve engine octane requirements vs parallel with just slightly higher CR.

Angle valve engines have greater volumetric efficiency than Lycoming parallel valve engines. They actually bring in just over 10% more air, so even if the CR were the same, detonation margin would be reduced. You could think of it this way: It would be similar to a parallel valve engine with 9.5:1 CR. This is one reason ideal ignition timing on the Lycoming angle valve engines is 20 degrees. There is no practical way to reduce ignition timing below 20 or so, to allow a lower octane fuel without negatively affecting performance.

RE: UL94

This is a great fuel, for engines designed to run 91/96 or lower octane fuels. It should be required at all airports, on a ramp with reasonable transient parking, and easy access to ground transportation. The FAA should create this plan, and allow a single low bidder to implement it at all GA airports that signed up for FAA funds. As far as the land lease, I suggest that the FEDS just condemn the necessary area, and TAKE it. NO local airport authority 10 Mil liability coverage BS. This would cost under 40K per airport to implement. Let the FBOs fight over the 100 octane stuff. (it should immediately be required to meet 100VLL spec.) The big thing is that high volume flight training could stop dumping lead very quickly. It will be better for everyone. No students in 172s maneuvering among the G5s at KPMB. In the late 80s, I had aircraft in flight schools and used autogas. Ethanol was not common added back then. FBO's and local governments, + ethanol mandates have colluded to make it difficult for any method other than the one suggested here, to get the lead out now. Just in case you do not know, the lead issue approaches that of FLINT. https://www.nbcbayarea.com/news/local/children-near-reid-hillview-airport-experience-lead-poisoning-new-study-reveals/2623245/

RE: Water/Methanol injection

There is very serious research on this, done by airlines after world war 2. Here is one source. https://www.sae.org/publications/technical-papers/content/460192/  basically this remedy is worth 12 points of octane! It actually is the answer, combined with UL94 or Hjelmco's 91/96 https://www.avweb.com/features/the-return-of-anti-detonation-water-injection-adi/  NOTE: UL94 is made to a new ASTM standard D7547; that allows all lead to be removed, where Hjelmco has a tiny bit of lead to meet ASTM D910. https://www.hjelmco.com/pages.asp?r_id=13963  Search FAA SAIB: HQ-16-05R1.

The airlines were using Grade 80 with water methanol on supercharged engines. Total liquid consumed was equivalent, with water displacing AVGAS. More power can be obtained using water methanol injection with 87 octane, than 100 octane with enrichment only, so it is possible to get the same power on a lower octane fuel, and MORE power on supercharged engines. 

The actual cost to manufacture a Water Methanol system similar to https://www.flyinpulse.com/ should not be more than $900.00. WATER alone is better than Water Ethanol, but Water Methanol produces more total power than water alone. How much water??  wwiiaircraftperformance.org › p-47 › P-47_Water-Injection_3feb44.pdf 2.1 gal per minute @ 2500HP.

Thanks for listening.

John Schreiber

Edited February 24, 2022 by John Schreiber
additional research sources

[A64Pilot]

I don’t know how to attach an email, so I took this screenshot.

Seems the FAA is in my opinion for once getting ahead of the game and has put a time limit of eight years on the issue, hopefully preempting any kind of immediate ban. Or that’s my take on what this says

 

[RobertGary1]

1 hour ago, John Schreiber said:

A&P IA CMEL here:

RE: the angle valve engine octane requirements vs parallel with just slightly higher CR.

Angle valve engines have greater volumetric efficiency than Lycoming parallel valve engines. They actually bring in just over 10% more air, so even if the CR were the same, detonation margin would be reduced. You could think of it this way: It would be similar to a parallel valve engine with 9.5:1 CR. This is one reason ideal ignition timing on the Lycoming angle valve engines is 20 degrees. There is no practical way to reduce ignition timing below 20 or so, to allow a lower octane fuel without negatively affecting performance.

RE: UL94

This is a great fuel, for engines designed to run 91/96 or lower octane fuels. It should be required at all airports, on a ramp with reasonable transient parking, and easy access to ground transportation. The FAA should create this plan, and allow a single low bidder to implement it at all GA airports that signed up for FAA funds. As far as the land lease, I suggest that the FEDS just condemn the necessary area, and TAKE it. NO local airport authority 10 Mil liability coverage BS. This would cost under 40K per airport to implement. Let the FBOs fight over the 100 octane stuff. (it should immediately be required to meet 100VLL spec.) The big thing is that high volume flight training could stop dumping lead very quickly. It will be better for everyone. No students in 172s maneuvering among the G5s at KPMB. In the late 80s, I had aircraft in flight schools and used autogas. Ethanol was not common added back then. FBO's and local governments, + ethanol mandates have colluded to make it difficult for any method other than the one suggested here, to get the lead out now. Just in case you do not know, the lead issue approaches that of FLINT. https://www.nbcbayarea.com/news/local/children-near-reid-hillview-airport-experience-lead-poisoning-new-study-reveals/2623245/

RE: Water/Methanol injection

There is very serious research on this, done by airlines after world war 2. Here is one source. https://www.sae.org/publications/technical-papers/content/460192/  basically this remedy is worth 12 points of octane! It actually is the answer, combined with UL94 or Hjelmco's 91/96 https://www.avweb.com/features/the-return-of-anti-detonation-water-injection-adi/  NOTE: UL94 is made to a new ASTM standard D7547; that allows all lead to be removed, where Hjelmco has a tiny bit of lead to meet ASTM D910. https://www.hjelmco.com/pages.asp?r_id=13963  Search FAA SAIB: HQ-16-05R1.

The airlines were using Grade 80 with water methanol on supercharged engines. Total liquid consumed was equivalent, with water displacing AVGAS. More power can be obtained using water methanol injection with 87 octane, than 100 octane with enrichment only, so it is possible to get the same power on a lower octane fuel, and MORE power on supercharged engines. 

The actual cost to manufacture a Water Methanol system similar to https://www.flyinpulse.com/ should not be more than $900.00. WATER alone is better than Water Ethanol, but Water Methanol produces more total power than water alone. How much water??  wwiiaircraftperformance.org › p-47 › P-47_Water-Injection_3feb44.pdf 2.1 gal per minute @ 2500HP.

Thanks for listening.

John Schreiber

I’m still not seeing why the faa would mandate or even encourage the incomplete 94 UL solution? GAMI is close with G100UL and that is a replacement for 100ll. 

[A64Pilot]

I for one am uncomfortable with a single source of supply for anything. GAMI should be allowed to play of course, but free enterprise thrives on competition, if GAMI’s fuel is the best and at the best price it will dominate, if not, well?

I like the idea of water and Mogas,  It’s not hard to get ethanol free fuel, not even close to the difficulty in transporting 100LL.

94UL is the answer for the majority of the fleet, water injection could cover the rest, and if you don’t want water for whatever reason, well then GAMI’s fuel may be an option for you, but I suspect without a monopoly it may not fare well. just my suspicion.

Edited February 24, 2022 by A64Pilot

[RobertGary1]

10 hours ago, A64Pilot said:

I for one am uncomfortable with a single source of supply for anything. GAMI should be allowed to play of course, but free enterprise thrives on competition, if GAMI’s fuel is the best and at the best price it will dominate, if not, well?

I like the idea of water and Mogas,  It’s not hard to get ethanol free fuel, not even close to the difficulty in transporting 100LL.

94UL is the answer for the majority of the fleet, water injection could cover the rest, and if you don’t want water for whatever reason, well then GAMI’s fuel may be an option for you, but I suspect without a monopoly it may not fare well. just my suspicion.

The problem is fbos aren’t going to invest in two blends. And one of those only works for some planes. 

[A64Pilot]

They will invest in whatever sells, but I agree most will as much as possible carry only one gasoline fuel, and Jet of course

But with water injection 94UL covers everything 100LL does, and if my understanding is correct, 94UL is literally 100LL without the lead, which makes me feel sure that over time it won’t dissolve fuel tank sealer or O-rings or whatever, or degrade or break down in storage, leave some kind of deposits or whatever.

Before you say but the Gami fuel will be tested for that I’ll remind you the the Mobil 1 synthetic oil, was tested and FAA approved to.

Personally as I have a 280 gl tank in my hangar and have fuel delivered, I’d just have them deliver the much less expensive alcohol free Mogas and pay car gas prices and get 94UL when I travel, I’m looking forward to water injection, you think LOP keeps plugs clean? Water injection literally steam cleans combustion chambers.

We would probably not touch plugs until overhaul, especially fine wires.

[carusoam]

Welcome aboard JS!

Great detailed first post!

What brings you here?

Best regards,

-a-

[1980Mooney]

On 2/24/2022 at 7:07 AM, A64Pilot said:

I for one am uncomfortable with a single source of supply for anything. GAMI should be allowed to play of course, but free enterprise thrives on competition, if GAMI’s fuel is the best and at the best price it will dominate, if not, well?....

94UL is the answer for the majority of the fleet, water injection could cover the rest, and if you don’t want water for whatever reason, well then GAMI’s fuel may be an option for you, but I suspect without a monopoly it may not fare well. just my suspicion.

 

16 hours ago, RobertGary1 said:

The problem is fbos aren’t going to invest in two blends. And one of those only works for some planes. 

This is why there aren't a whole lot of companies clamoring to get into this market....and why FBO's don't want to make multiple investments in dual infrastructure that will sell less fuel in total combined.

[RobertGary1]

It’s too bad they can’t just deliver automotive fuel and add an additive at the fbo. In the jet we order with or without prist and it’s a switch on the truck that blends it. But if it were that simple they’d have done it. 

[Pinecone]

On 2/12/2022 at 1:31 PM, A64Pilot said:

Octane does not increase power, it does however allow higher compressions and greater spark advance  which does increase power

Your car for instance, if it will run fine on 87 octane regular gas, putting premium in it won’t increase its power or decrease its fuel consumption, Octane in excess of min required does no good, except of course adds cushion to prevent detonation, and we have a rather large cushion with 100 Octane fuel.

Exactly.

 

And sort of.

With modern, computer controlled engines, premium may provide better performance in certain situations.  In that, even though 87 is fine for most operation, there are times (hot, full throttle), where the computer is retarding timing, going richer or changing cam timing to reduce detonation and thus reducing power.

And some cars do get better performance with higher than rated octane (actually in the US AKI for auto gas).  My 2002 BMW M3 is documented in several publications to get better performance up to about 96 AKI (a 50/50 mix of 93 pump premium and 98 unleaded race gas).

[Pinecone]

On 2/13/2022 at 3:05 PM, A64Pilot said:

If you think about it IF 94UL is just 100LL without the lead, couldn’t lead be blended in in a similar manner as Prist is to jet fuel to make 100LL from 94UL?

This is solvable, only question is there enough profit to be made doing so?

Handling high concentration TEL is NOT a good thing to do.  If you splash some Prist on your pants, it is not a huge deal.  Splash 90% TEL on your pants and you are looking at a significant lead exposure from skin absorption.

Before you panic, the level in fuel is pretty low.  Do not take a bath in 100LL.

But, there could be a mixing of say 94UL and something high lead fuel.  Just like at the auto pump, if you select 89, you are getting a mixture of 87 and 91/93, there is a not a tank for 89.   So the FBO would have a BIG tank of 94UL and a smaller tank of "AvPrem" and either a mixing pump, or a separate pump/lines/nozzle that dispensed 100LL.

[Pinecone]

On 2/14/2022 at 5:35 PM, A64Pilot said:

OK, so how about Ethanol and water?

 

That's for after flying.

 

Actually, it would work fine also.

[Pinecone]

On 2/24/2022 at 2:07 PM, A64Pilot said:

I for one am uncomfortable with a single source of supply for anything. GAMI should be allowed to play of course, but free enterprise thrives on competition, if GAMI’s fuel is the best and at the best price it will dominate, if not, well?

GAMI is not a source of fuel.  They will license oil companies to make G100UL.

[A64Pilot]

45 minutes ago, Pinecone said:

Exactly.

 

And sort of.

With modern, computer controlled engines, premium may provide better performance in certain situations.  In that, even though 87 is fine for most operation, there are times (hot, full throttle), where the computer is retarding timing, going richer or changing cam timing to reduce detonation and thus reducing power.

And some cars do get better performance with higher than rated octane (actually in the US AKI for auto gas).  My 2002 BMW M3 is documented in several publications to get better performance up to about 96 AKI (a 50/50 mix of 93 pump premium and 98 unleaded race gas).

Those are outliers though, both my ICE cars work better on Premiun, one is an LS6 motor from the Corvette and the other is turbocharged for performance, but a turbo doesn’t necessarily require higher octane. Mine are also outliers in that they are performance automobiles.

Actually using premium fuel in a car that doesn’t require it may actually reduce performance due to premiums slower rate of burn which amounts to being similar to reduced timing.

But the bottom line is that the aircraft issue has been solved and without going to what I expect will be a quite expensive replacement. A problem with Autogas is it’s all over the map meaning it varies a lot in its composition by State and time of year etc. That is what I think will be it’s biggest hurdle for being approved with alcohol injection.

I went down a road of trying to get approval for burning Bio-Diesel in a turbine, the problem became that there is no standard, Bio Diesel is actually a family if you will of several different fuels with vastly different chemical compositions.

But who knows what the future will bring, I believe nothing has been done due to 100LL being sold in such low quantity it’s not really much of a problem and doing nothing is easier than doing something. 

It really depends in my opinion if the people against it get Political traction, if they do then we are in trouble, because there has been a lot of talk about what could be done, but nothing has because of course 100LL is available.

Personally if an alcohol water injection system were STC’d, I’d buy it. Who knows maybe lead free auto gas will bring some benefits besides low price.

How many years ago did Lycoming certify an engine to run on pure Ethanol? So they know what isn’t ETH compatible and solved it.

But it may be the airframe and not the engine that’s the show stopper, what does ETH due to bladders, fuel tank sealant, hoses etc? I don’t know myself, but I’ve seen it eat up boat fiberglass fuel tanks and that really surprised me.

Edited May 12, 2022 by A64Pilot

[A64Pilot]

55 minutes ago, Pinecone said:

GAMI is not a source of fuel.  They will license oil companies to make G100UL.

That’s my belief too, but I’ve read different.

It just doesn’t pass the common sense test for Gami to become a fuel manufacturer, but then I would have told you that no start up car company could possibly compete against Toyota and GM either, so who knows.

However depending on how hard it will be to incentive those oil companies, it could get real expensive, if there isn’t real money in it, they won’t bother.

I assume 100LL is being blended or manufactured whatever because all the equipment etc was already existing, if it hadn’t been 100LL could cost a lot more than it does, but maybe the equipment and infrastructure could just switch over to the Gami fuel?

Lot of questions I don’t have answers to, just put me down as being suspicious of the $1 a gallon claim. No claims ever actually pan out in the light of day

Whether Gami manufactures it or not, if 100LL goes away and the Gami fuel is the only substitute, then Gami is sole source.

I met a guy in the late 70’s. He was the sole source of the Super Heterodyne chips used in high end Radar detectors or claimed he was anyway, I don’t think he manufactured them, but if you were a Radar detector manufacturer and wanted them you weren’t getting them from anywhere else.  He actually delivered them in a briefcase. They were his intellectual property as is I’m sure the Gami fuel.

Or maybe he was lying through his teeth and was stringing me along

On edit, I’d be more comfortable if there was more than one solution, anytime there is only one source often things get real expensive, why do you think so many aircraft parts cost so much? One source and minimum quantities.

Edited May 12, 2022 by A64Pilot

[Pinecone]

19 hours ago, A64Pilot said:

Those are outliers though, both my ICE cars work better on Premiun, one is an LS6 motor from the Corvette and the other is turbocharged for performance, but a turbo doesn’t necessarily require higher octane. Mine are also outliers in that they are performance automobiles.

Actually using premium fuel in a car that doesn’t require it may actually reduce performance due to premiums slower rate of burn which amounts to being similar to reduced timing.

 

The idea that premium burns slower is a OWT.  All that octane (or AKI) measures is the resistance to detonation.  Which has nothing to do with burn rate.  What happens is the heat and pressure precede the flame front, and cause additional ignition events.  One petroleum engineer (Corvette guy), states that the heat and pressure actually create a mini reactor and rearranges the molecules making them prone to such ignition.

And even if it did burn slower, modern cars would advance the timing.

Edited May 13, 2022 by Pinecone

[M20F]

I run my Executive on Gin Martini’s.  

[A64Pilot]

These guys haven’t heard it’s an OWT, quiet a few haven’t.

https://www.motortrend.com/how-to/combustion-basics-how-does-fuel-make-a-difference/

But what your saying about the engine bumping timing for higher octane fuel is logical, if the system is allowed to increase timing by enough

Back right after Hurricane Katrina only 87 Octane fuel was available, the LS6 ran off of it, but fuel milage and HP decreased by quite a bit, it turned down the timing as it detected knock of course and the reduced timing was the reason fuel milage and HP decreased, HP was of course just a feeling, but milage is tracked of course, it’s calculated, not measured.

Edited May 13, 2022 by A64Pilot

[Pinecone]

I would listen to a petroleum engineer that is a car guy over a magazine any day.  ESPECIALLY Motor Trend.

Yeap, modern high performance cars can run in non-premium fuel, at lower performance.  And you are banking on the system responding quickly enough that nothing bad happens before the ignition and cam timings are retarded.

[A64Pilot]

11 minutes ago, Pinecone said:

I would listen to a petroleum engineer that is a car guy over a magazine any day.  ESPECIALLY Motor Trend.

Yeap, modern high performance cars can run in non-premium fuel, at lower performance.  And you are banking on the system responding quickly enough that nothing bad happens before the ignition and cam timings are retarded.

Yes but if you have to like we did right after Katrina, you can do so safely IF you keep your foot out of it, and just accept your no longer driving a performance car until you can get good gas again