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PAFI. What killed Swift Fuel candidate

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Freemasm

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Rather than creating thread drift in another lead/AVGAS forum, I'd like to start here. Many know the seemingly quiet death of PAFI. Swift fuel seemed very promising and I have friends who buy it in bulk/are very happy with it. It appears Swift is only pursuing the STC route now.

Real info is hard to find. Anyone have any knowledge they can share regarding Swift's "exit" from the PAFI initiative/death of PAFI. Ex: lots of talk the big producers campaigned Swift's PAFI demise? Anything would be appreciated. Thanks.
 
Current unleaded

If the current unleaded fuel becomes available in California, Nevada, Arizona, I am all in, even if it is slightly more expensive,
 
The airport manager at Reid Hillview and San Martin Airports is investigating using Swift; they are hiring consultants, so it must still be alive.
 
The airport manager at Reid Hillview and San Martin Airports is investigating using Swift; they are hiring consultants, so it must still be alive.

Poorly worded on my part. It is available though pretty limited. It was the leading candidate to replace 100LL in most people's view. Then somewhat suddenly, the efforts associated with PAFI seemed to stop. As mentioned, the STC efforts seem to be alive and well.
 
This popped up on Swift's website a few months ago as far as I know:


"Swift 100R is a 100-Motor-Octane aviation gasoline designed to fully replace 100LL Leaded Avgas across the entire global piston fleet

FAA Certification testing and ASTM fuel specifications are currently in-progress

Sign-up if you would like to collaborate with Swift Fuels as we strive to fully replace 100LL, click here.

If you want to financially support our efforts, buy a $100 FOREVER Avgas STC from Swift Fuels for your aircraft, click here.

Contact Us to Order Swift 100R"

This is different from the UL94 they have been selling nation wide for a number of years.

It's not clear if 100R will be FAA approved without an STC or not though.

I believe GAMI also dropped out of PAFI with their G100UL fuel and nothing has been updated since 2017 that I've seen so hard to know what's going on with them: https://gami.com/g100ul/news.php
 
I looked into the cost of fuel from Swift, it only works out on large scale and volume in order to keep costs low. I would love to run it, my engine was made for 80/87 which does not like the higher lead in 100LL

I am not surprised that a government project isn’t moving along or getting results. IMO Gov’t couldn’t find their way out of a wet paper bag.
 
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How much compression can you run with the 94UL? (no turbos)

Depends on ignition timing. With programmable EIs, some folks are running up to 9 to 1 on on mogas which is lower octane than this. You just limit timing a bit at high MAP and have full advance in cruise where MAP is lower.

You take a small HP hit at TO power and sea level. Cruise performance at altitude is unaffected from what we see.
 
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I find this comment rather disingenuous. My experience is that federal employees in science-based branches of federal agencies are highly motivated and conscientious at fulfilling their agency mission.

Thanks Steve. As a retired senior Air Force civilian, I couldn’t agree more.

Dave
 
Case in point

If the current unleaded fuel becomes available in California, Nevada, Arizona, I am all in, even if it is slightly more expensive,

Just so you know. My friend buys Swift 94UL at 700 gallons US bulk from a distributer here in FL. He paid ~$5.50/gallon, delivered to his property with his last purchase. You can find 100LL cheaper down here but also way more expensive. Obviously doesn't mean too much out where you are but here it's do-able. Storing it legally is probably the biggest problem. Of course, anything that could affect fuel farm sales isn't going to be welcomed at any airport as well.
 
Thanks for that link Cannon. Good stuff.

There are at least 2 other unleaded avgas producers in Europe. Been doing it for years for non-cert aircraft.

There is another big player in the US UL avgas race based in TX, not mentioned. They contacted me in the Fall of 2019 and had been carrying out dyno testing for some time with FAA involvement, not under PAFI however.

Their fuel matched the specific gravity range of the current 100LL, which none of the others did apparently and that was the PAFI deal breaker according to them. All flight manuals would have to be re-written and the FAA wouldn't accept that. The other brands were not drop in replacements for 100LL on that basis alone.

These TX folks are big enough to refine and distribute their product in the US which I don't think Swift or GAMI are without partners.

I'll try to nudge my contact there and see if he can say any more on their progress or lack of it now.
 
Thanks for that link Cannon. Good stuff.

There are at least 2 other unleaded avgas producers in Europe. Been doing it for years for non-cert aircraft.

There is another big player in the US UL avgas race based in TX, not mentioned. They contacted me in the Fall of 2019 and had been carrying out dyno testing for some time with FAA involvement, not under PAFI however.

Their fuel matched the specific gravity range of the current 100LL, which none of the others did apparently and that was the PAFI deal breaker according to them. All flight manuals would have to be re-written and the FAA wouldn't accept that. The other brands were not drop in replacements for 100LL on that basis alone.

These TX folks are big enough to refine and distribute their product in the US which I don't think Swift or GAMI are without partners.

I'll try to nudge my contact there and see if he can say any more on their progress or lack of it now.

It seems like a real bummer that something like a modest difference in density (specific gravity) would be a show-stopper.

On the other hand, the task of doing the engineering to determine whether the increase in TOGW with full tanks would be ok, or else appropriate changes to the POH to adjust W&B allowables, range tables, etc., for every single aircraft type, would be a daunting task
 
It seems like a real bummer that something like a modest difference in density (specific gravity) would be a show-stopper.

On the other hand, the task of doing the engineering to determine whether the increase in TOGW with full tanks would be ok, or else appropriate changes to the POH to adjust W&B allowables, range tables, etc., for every single aircraft type, would be a daunting task

Exactly the FAA's point. If I recall, some of the candidate fuels weighed as much as 9% more than 100LL, so it wasn't unsubstantial. This was a result of most formulations submitted using a high load of Aromatics which are pretty dense.

Drop in, had to be just that, no changes in allowed power settings or weight/ weight and balance for operators.
 
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Unicorn

Exactly the FAA's point. If I recall, some of the candidate fuels weighed as much as 9% more than 100LL, so it wasn't unsubstantial. This was a result of most formulations submitted using a high load of Aromatics which are pretty dense.

Drop in, had to be just that, no changes in allowed power settings or weight/ weight and balance for operators.

I guess the faa is trying to find unicorn pee. I think even a mogas substitute will have the same problem.
If the fuel is the equal to or less expensive than 100LL, a one time cost to paste some stickers in a poh cant be that bad. Come on Man. Give every plane $1000 to paste stickers in their manual. With the amount of certified 100LL operators still left flying, thats gotta be, what, like no more than $1 million?


Just like the fiberglass revolution, the glass cockpit revolution, lean of peak operation and ballistic chutes, this is another area experimental aviation will need to lead the way. ( pun intended)
 
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Not sure where this fits in PAFI or 100LL vs Mogas or is E10 ok threads.

The same folks that really hate lead also hate all aromatics in all fuels- benzene, toluene, and xylene.

Benzene is already capped, but the others act like benzene after combustion.

I post this because even if/when 100LL and its lead go away "it" would not be over.
 
It’s not going to be over until we are 100% carbon neutral, which is unfortunately going to be some time out. Getting the lead out would be a step in the right direction and would show that we actually give a rats about the impact on others. It blows my mind that for the sake of spending a few minutes writing a spreadsheet and hitting the print button to make a new loading chart we as an industry are too **** inflexible/lazy to be bothered. It’s exactly the reason the media make us out to be a bunch of over privileged sods. When we make moves like not being bothered to do a paperwork exercise to save spewing lead over everyone as we fly, we play into the media’s hands.
Tom
RV-7, that drinks lead free liquified dinosaurs until a dinosaur free variant can be found.
 
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Too Much

Ok too much non aviation stuff getting in here.
As a last word, i want unleaded fuel to be able to use fully synthetic oil ( no wear) and extend oil changes to a few hundred hours, or whatever.
 
The weight of a gallon of 100LL varies with temp.

Since we buy by volume, not weight; the weight of the replacement fuel per gallon shouldn't matter if it's close (although 9% is pushing it)
 
The weight of a gallon of 100LL varies with temp.

Since we buy by volume, not weight; the weight of the replacement fuel per gallon shouldn't matter if it's close (although 9% is pushing it)

On something like a Navajo, the 9% would mean about 100 extra pounds when filling the tanks. It wouldn't be that hard to create a new page for the POH to reflect this. Lots of times, you can't legally fill the tanks anyway.

Of more concern may be that the aromatics are pretty high on the solvent scale and may not be compatible with existing fuel system materials plus they are fairly nasty to humans both combusted and in in their natural liquid state. Maybe you're eliminating the lead in exchange for other demons here.

Xylene and Toulene are restricted in California. Both are on the Proposition 65 list as well so these may not fly with the FAA or EPA as major ingredients in UL avgas. But they are maybe nonstarters anyway due to their specific gravity.

Swift, Gevo and others can take light gas stocks and alcohols and convert to olefins and then to specific hydocarbons for use in fuels.

It's not as easy as it looks to meet all the requirements and health safety concerns at an affordable price for consumers in the end. It will be interesting to see what chemistry is finally approved by the FAA.

In the meantime, Swift UL94 is available in many places for our RVs at least in the US : https://www.google.com/maps/d/u/0/v...&ll=40.805955463244274,-94.37862123125001&z=5
 
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On something like a Navajo, the 9% would mean about 100 extra pounds when filling the tanks. It wouldn't be that hard to create a new page for the POH to reflect this. Lots of times, you can't legally fill the tanks anyway.

Of more concern may be that the aromatics are pretty high on the solvent scale and may not be compatible with existing fuel system materials plus they are fairly nasty to humans both combusted and in in their natural liquid state. Maybe you're eliminating the lead in exchange for other demons here.

Xylene and Toulene are restricted in California. Both are on the Proposition 65 list as well so these may not fly with the FAA or EPA as major ingredients in UL avgas. But they are maybe nonstarters anyway due to their specific gravity.

Swift, Gevo and others can take light gas stocks and alcohols and convert to olefins and then to specific hydocarbons for use in fuels.

It's not as easy as it looks to meet all the requirements and health safety concerns at an affordable price for consumers in the end. It will be interesting to see what chemistry is finally approved by the FAA.

In the meantime, Swift UL94 is available in many places for our RVs at least in the US : https://www.google.com/maps/d/u/0/v...&ll=40.805955463244274,-94.37862123125001&z=5

@Mr. Farnham
Did it meet heating value? If so, the density misses are at least quite manageable. (Do Canadians think/talk in Joules when not speaking to people in the states?)
 
@Mr. Farnham
Did it meet heating value? If so, the density misses are at least quite manageable. (Do Canadians think/talk in Joules when not speaking to people in the states?)

From what I have seen, (and there is not much technical released by the players) the heating value was slightly higher compared to typical 100LL on one of the formulations.

We are caught in the middle of SI, Imperial and US units in Canada so usually conversant in all. Engineers have been trained in SI for some time in Canada. Many grey hairs are more comfortable working in Imperial units and converting to SI.

Most of us use knots, US gallons and deg F in our airplanes. On the ground, in cars, km/hr., liters and deg C.

Us Canadians spend a lot of time using online unit converters for the ones we don't have in our heads already. :D
 
What's the relationship between the lead and the octane increase?

Linear, exponential, log something else?

What happens if you just decrease the lead in 100LL?
 
I've heard somewhere, but can't find the reference. 100LL without the lead is mind 90s for octane rating. Good enough for most of us, which is the problem. Not good enough for everybody. I wish it was as easy as two different flavours of avgas. It would be great if they could offer 94UL (or other comparable variant) for most folks and 100LL for those that need it. However, that means two fuel trucks, when they already struggle to sell enough avgas to justify the one truck.

We are caught in the middle of SI, Imperial and US units in Canada so usually conversant in all. Engineers have been trained in SI for some time in Canada. Many grey hairs are more comfortable working in Imperial units and converting to SI.

Most of us use knots, US gallons and deg F in our airplanes. On the ground, in cars, km/hr., liters and deg C.

Us Canadians spend a lot of time using online unit converters for the ones we don't have in our heads already. :D

Ross, your being simplistic. :p Go walk down a floatplane dock. The 185 is in US gallons, the Beaver is in Canadian gallons, the pump is in liters, the paperwork is in pounds. That's 4 different fuel units between 2 planes parked on the same dock. Regarding temperature, I've seen deg F and deg C on different gauges in the same plane!
 
What's the relationship between the lead and the octane increase?

Linear, exponential, log something else?

What happens if you just decrease the lead in 100LL?

There is a very steep increase with the first small amount of TEL. From Liston.
 

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Of more concern may be that the aromatics are pretty high on the solvent scale and may not be compatible with existing fuel system materials plus they are fairly nasty to humans both combusted and in in their natural liquid state. Maybe you're eliminating the lead in exchange for other demons here.

I seem to recall that one of the failed PAFI candidates (the Shell one?) seemed to run okay in the engines, but was found to also function extremely well as a paint stripper.

Which immediately took it out of contention.

- mark
 
I got a reply to an email I sent to Swift. Their 100R fuel program is still underway with the FAA though it seemed that the agency wasn't exactly expediting progress on this. I guess we knew this last part already since it was 2018 when PAFI didn't result in any UL avgas. It will involve an STC just like the the GAMI effort as I understand it. The FAA sounds like it might be lukewarm to the STC idea, still looking for the perfect UL avgas which meets the current ASTM spec that 100LL does instead. I hope the FAA allows a slightly revised spec to get this fuel to market sooner rather than later.

And the latest form the FAA showing PAFI itself isn't dead but about to be revived (if any of the fuel companies still want to play inside it): https://www.faa.gov/about/initiatives/avgas/

I get the impression that the fuel companies are all a bit fed up with the foot dragging and intransience on the part of the FAA.

https://www.avweb.com/insider/going-to-the-moon-was-easy-compared-to-100ul/
 
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I received a reply form GAMI today on their G100UL fuel today. They reported that they are very close to having their STC approved and that specific gravity is only very slightly higher than 100LL and that the heating value of their fuel is slightly higher as well.

Good news, depending on what "very close" means with the FAA.

I wish these guys well. Next hurdles will be production and distribution of the product on a large scale.
 
There is a very steep increase with the first small amount of TEL. From Liston.

Can you get me smarter in how to read this? Knock limited power, increase per cent (sic? Percent?)? I would thought it would be referenced to CR. I guess I’ll oh could extrapolate if you assumed each engine minimized any detonation margin. What are they saying that I’m missing?

I’ll state again if the heating values meet/exceed that of 100LL, the SG increase is very manageable; even advantageous. STCs would be OK but I don’t know if any of the potential providers will lay it on the table regarding “mixability” issues with other offerings. This would hurt us. A single source provider for the approved 100LL replacement will probably take advantage of that market position. If the STC’d providers will allow the aforementioned mixing, the completion can only help us users.
 
A lot of testing in the '50s and even indeed today use single cylinder CFR engines to explore detonation limits with different fuels. The CR can be easily changed on these or in the case of aviation fuel testing, supercharged versions can be used to establish the knock limits of various fuels by raising MAP until knock occurs.

The graph shows that with the addition of 3.6 ml of TEL, the knock hp threshold was raised by 48% over the base 100 octane fuel with no lead.

It looks to me from reviewing various comments that both Swift and GAMI will be using STCs to get their fuel to market for certified aircraft.

Per cent was an older form of percent, more often used in Britain and the colonies. Liston's book came out in the '40s and is one of the best texts every published on aviation power plants. A little history on Liston:

"Professor Joseph Liston (BSME '30, MSME '35) joined Purdue from the faculty of the University of Oklahoma Mechanical Engineering Department. He was a former naval aviator, and pioneered landings on aircraft carriers. Professor Liston's primary interest was in aircraft propulsion, and he developed several outstanding power plant design courses and test facilities during the 1940s. Professor Liston remained on the Purdue staff until retiring in 1972."
 
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A lot of testing in the '50s and even indeed today use single CFR engines to explore detonation limits with different fuels. The CR can be easily changed on these or in the case of aviation fuel testing, supercharged versions can be used to establish the knock limits of various fuels by raising MAP until knock occurs.

The graph shows that with the addition of 3.6 ml of TEL, the knock hp threshold was raised by 48% over the base 100 octane fuel with no lead.

It looks to me from reviewing various comments that both Swift and GAMI will be using STCs to get their fuel to market for certified aircraft.

I hope they dont go after the same market. If there are three suppliers (normal avgas, GAMI and Swift, a fractured market may mean nobody survives, that's my fear). Maybe Swift and GAMI can join forces???
 
I don't see Swift and GAMI joining forces as they are competitors. I see possibly both meeting a slightly revised ASTM spec and having approval to be mixed if both make it to market, much like you mix different brands of 100LL right now.

My take, and I could be wrong, is that the FAA initially thought and wanted the new UL avgas to meet the current ASTM spec for 100LL exactly, so drop in, no STCs. Years down the road with many dollars spent, that looks unlikely as both visible players (not sure where Shell and the Texas guys are at) are working on STC approvals.

I see normal 100LL quickly going away once UL production and distribution meet demand.

This is a huge market for either GAMI or Swift which are pretty small companies in this context and certainly will need refining and distribution partners.
Shell could drop into the market at any time too and change the whole landscape.
 
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Depends on ignition timing. With programmable EIs, some folks are running up to 9 to 1 on on mogas which is lower octane than this. You just limit timing a bit at high MAP and have full advance in cruise where MAP is lower.

You take a small HP hit at TO power and sea level. Cruise performance at altitude is unaffected from what we see.


Rotax runs water cooled heads on their engines, and run just fine on 91 octane Mogas with up to 10% ethanol. Compression ratio, I believe, is 10.8 : 1 on a
Rotax 912 ULS.
 
We need a fuel that keeps the TIO-540 happy at 49inHg, the 10:1 compression performance engines as well as the not so crazy engines that can burn mogas. Currently 100LL is that fuel. It has high vapour pressure to handle the poorly laid out fuel system in most airplanes (sucking it all the way to engine driven pump) and not too expensive.

When the one article above mentioned modifying a race fuel, I got scared of price. Race fuel can be astronomically expensive, $10/gallon + is normal.
 
Thank goodness for the experimental world!

I am burning both 100LL and 93UL. E0 and E10. As we have the MoTeC ECU (the Gold-Standard per resident forum expert Ross Farnham), I can easily burn either fuel.

Certainly many here can do the same. So why get our panties in a wad over the FAA dragging it's feet on this?

I have had friends literally pass away, waiting on the new fuel that will never happen.
 
It is an extremely high bar for entry, to be able to have a drop-in fuel that checks all the boxes for all engines. I for one do not expect to live long enough to see that happen.

What I expect WILL happen is that new fuels will come to the market, outside of PAFI, and engines will be designed/built/purchased that will eat that fuel happily and will begin to gain market share. The others can continue to run 100LL for as long as it's available. Eventually they will be orphaned, and there will be much wailing and gnashing of the teeth and people running about with sackcloth and ashes, but that will be the end of it.

There is no simple or easy way to make the transition. It requires not only a new fuel, but new engine design to burn it. The "turbonormalized" versus turbocharged example given above is a perfect example. One will work fine, the other may not. Some airplanes will have to be re-engined if 100LL finally goes away, there's no choice.
 
Clostermann, good points you make here.

When 115/145 was phased out, operators of mainly ex military radials had to switch to 100/130 and they often had to reduce MAP to do that safely. HP was reduced somewhat. Ditto when 100LL replaced 100/130.

It could be done with the new unleaded avgas if it can't meet similar detonation margins as 100LL but would require POH re-writes again. This seems like not where the FAA wants to head and STCs may happen first before a full, fleet wide drop in fuel is a reality (if it ever happens at all). Some of the candidates have already said as much.

In the Experimental world we see a fair number of people using programmable ignition systems which allow automatic ignition retard with high MAP and re-advancing timing as MAP is reduced. This maintains detonation margins as a slight expense in TO power at sea level.

BTW, The Big Show is my favorite book of all time.
 
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MY Fear

My fear is that what ever unleaded fuel comes out with the STC for the most planes it will still be an uphill battle. The big twins burn lots of gas and that income will be hard to sunset. And I don’t see airports having two avgas fuels available like in the old days.

I really want an unleaded fuel to succeed but my piddly little 36 gals won’t generate the profit margin for most FBOs.
 
An interesting tidbit published in late 2019:

"Swift Fuel’s Unleaded UL94 Avgas is sold nationwide - priced competitively with 100LL and is expected to remain low subject to oil market volatility. Over 110,000 aircraft are already FAA-authorized to use the UL94 Avgas as a “drop-in ready” fuel. Swift UL94 is compliant with all ASTM D7547 avgas specifications and D4814 auto gasoline specifications, making it a highly versatile premium gasoline product in the global marketplace. Note that UL94 avgas is not a full replacement for 100LL for higher compression engines, therefore, only those aircraft with engine requiring 94 motor-octane avgas or lower are compatible – which still represents 65% of the US piston fleet. For more information about UL94, FAA certifications, and the latest listing of airports with Swift Fuels UL94 available, please visit: www.swiftfuels.com"

Searching around a bit, I found several mentions that the Swift avgas was priced well below 100LL.

Also, I was never aware of the German connection with Swift in the USA: https://swiftfuel.eu/who-we-are/

Note the recent news here and the RV connection: https://swiftfuel.eu/news
 
So exactly how much is this renewable 100R fuel going to cost? The same as 100LL fuel?

And how many years will it take for the FAA (lethargic at best) to certify this fuel?

We all know the answers, and this is why 93UL is a good and viable solution. Distribution is not a problem either, as it's available at every corner gas station.

Just ensure you purchase "Top Tier" grade fuel.

Yes, I have a collection of 5 gallon gas cans and a portable fuel pump.

Just like when I owned a C-172, and burned auto fuel in it. Best decision I ever made.

Now, top off those tanks and fly safe!
 
I suspect the final answer will be along the lines of Swift 94UL. While I can burn 93 ethanol free pump gas I find vapor issues a problem. Swift 94UL is nothing more than 100LL without the lead, so such issues are not present.

Considering the recent comments from the regulatory czars, engines will need to change. Direct injection on my Chevrolet truck standard engine (11.5 to 1 pistons) lets me burns 87 octane pump gas. Why can’t Lycoming do the same?

Carl
 
Automotive engines are liquid cooled, therefore much tighter temperature control. Fuel and ignition is also closed loop computer controlled; knock sensors, the whole works. Those engines will destroy themselves if temperature, fuel mixture and tignition timing go places that airplane engines do.
 
I suspect the final answer will be along the lines of Swift 94UL. While I can burn 93 ethanol free pump gas I find vapor issues a problem. Swift 94UL is nothing more than 100LL without the lead, so such issues are not present.

Considering the recent comments from the regulatory czars, engines will need to change. Direct injection on my Chevrolet truck standard engine (11.5 to 1 pistons) lets me burns 87 octane pump gas. Why can’t Lycoming do the same?

Carl

Liability?
 
Liability?

Here is example of how our elected officials (read agency political appointees) can drive evolutionarily change. In addition to regulating out lead from 100LL, they should provide statutory liability relief, creating incentive for Lycoming and anyone else to create such engines. In other words provide solutions in addition to barriers.

We can always dream…..
Carl
 
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