Fuel options

mandm

mandm

En-Route
PoA Supporter
Joined
Feb 7, 2020
Messages
2,944
Location
Chicago
Display Name
Display name:
Michael
Alrighty, my airplane uses 100LL, and I’m fine with that. I’ve seen UL and MOGAS popping up on Foreflight. Wondering what that’s all about. I read that there are STCs that allow you the legal right to use UL or MOGAS.

So how does that work? Is an STC for fuel basically a piece of paper that says you can use UL or MOGAS (with no changes) or is it a part/upgrade that is purchased and installed?

When someone switches over to UL or MOGAS, is that your new forever, or can you interchange fuels? UL and MOGAS are still not widely available so that’s why I ask.
 
You can mix and match fuels. On some airplane/engine combinations it is just a paperwork exercise. On others there might be some modifications required.
 
What airplane/engine?

Some 100LL airplanes don't really need 100. But in most cases, 100 only airplanes will not be able to use MOGAS or the currently available 94UL.

All pistons engines will eligible to use the upcoming G100UL.

In ALL cases, you need an STC to use the alternative fuel. They vary in price. Swift fuels has a "lifetime" STC available right now. It covers 94UL for those aircraft/engines that can run on it, and will include their 100 UL fuel whenever it comes out.

As was said, in some cases it is just matter of some paper work and some decals for the filler ports. In other cases, you may have to add or change a fuel pump.
 
Pinecone said:
As was said, in some cases it is just matter of some paper work and some decals for the filler ports. In other cases, you may have to add or change a fuel pump.
Click to expand...
Petersen also required an engine placard in the form of a special Adel clamp on one of the foremost engine pushrod tubes.

When the engine is changed (such as an exchange engine instead of an overhaul of the existing engine) the STC has to be updated. The STCs are serial-number specific, and include the airframe and engine serials.
 
Dan Thomas said:
Petersen also required an engine placard in the form of a special Adel clamp on one of the foremost engine pushrod tubes.

When the engine is changed (such as an exchange engine instead of an overhaul of the existing engine) the STC has to be updated. The STCs are serial-number specific, and include the airframe and engine serials.
Click to expand...
Both the airframe and the engine need to be approved. If you're on an airframe that has multiple engine options swapping the engine for a different model may invalidate the ability to use the STC.
I questioned Petersen about Navion availability and all they could say is "they tested it and it failed." They couldn't even tell me which of the Navion configurations they tried it on. Navions came from the factor with E-185, E-225, IO-470C, IO-470H, GO-435, etc... Even within the E-series, there were a couple of different carbs used (MA-4/5 and PS5C at least).
 
I use Mogas in My Debonair (IO470K).
Petersen STC is just a paperwork exercise in my airframe, no modifications. I switch back and forth and intermix mogas with 100ll all the time. No worries.

https://www.autofuelstc.com/
 
OP -Are you looking for input for your particular type aircraft?
 
I love how my c85 was NEVER designed gor 100LL and I need no STC for it, but I do to dump mogas in it. Neither are the fuel that engine was designed for.

I look forward to the day I can get no lead fuel easy, the little continentals don’t love the Hobbs of lead in 100LL
 
Huckster79 said:
I love how my c85 was NEVER designed gor 100LL and I need no STC for it, but I do to dump mogas in it. Neither are the fuel that engine was designed for.

I look forward to the day I can get no lead fuel easy, the little continentals don’t love the Hobbs of lead in 100LL
Click to expand...

Welcome to FAA Land.
Soon enough you'll need another STC for G100UL which is completely miscible and virtually identical performance wise to the 100ll you use now.
Bureaucracy is fun.
 
Justin Brady said:
Welcome to FAA Land.
Soon enough you'll need another STC for G100UL which is completely miscible and virtually identical performance wise to the 100ll you use now.
Bureaucracy is fun.
Click to expand...

Right, but I’ll gladly buy it though if I can get unleaded fuel at some point easily.
 
Justin Brady said:
Welcome to FAA ICAO/Treaty-Land.
Click to expand...
FTFY. The STC/approval requirements are global. The FAA could decide not to require an STC but then they would have to restrict those aircraft/components/parts to the US only with no export possibilities.
 
Bell206 said:
FTFY. The STC/approval requirements are global. The FAA could decide not to require an STC but then they would have to restrict those aircraft/components/parts to the US only with no export possibilities.
Click to expand...
For a drop in fuel replacement? I think not.
I'm not saying the whole STC process is bad (it is and isn't depending on case IMO) but for a drop in fuel replacement I don't agree that it's a necessary thing to do.
Every piston engine out there can use G100L the same 100LL.
There's no reason to make the public pay for (not to mention all that paperwork) an STC for something that requires no testing or modification.
It's akin to making me buy an STC to swap from Aeroshell to Phillips oil, they are for all intents and purposes the same and both meet all the same requirements.

Essentially where we're going to be in a few years is in a world where 100LL is illegal and you can't legally use it's replacement without paying for an STC, which is ridiculous IMO.
 
Justin Brady said:
For a drop in fuel replacement? I think not.
Click to expand...
Afriad so. The fuel and oil are part of the aircraft/engine certification process. G100L is a major alteration to that certification and requires the necessary documentation just like any other modification.
Justin Brady said:
There's no reason to make the public pay for (not to mention all that paperwork) an STC for something that requires no testing or modification.
Click to expand...
You do understand G100L was developed and approved by private individuals at their own substantial expense. So you don't think they should charge for G100L and recoup their investment plus ROI?
Justin Brady said:
It's akin to making me buy an STC to swap from Aeroshell to Phillips oil,
Click to expand...
FYI: when the 1st Phillips multi-weight oil was released it did require an STC to use. ;)
 
I have a Piper Arrow PA28R180 with a Lycoming IO360B1E.

Doesn’t the rest of the world use mostly JetA for GA ASE? Once switching over to UL or MOGAS, might be even more difficult for international travel?
 
Bell206 said:
Afriad so. The fuel and oil are part of the aircraft/engine certification process. G100L is a major alteration to that certification and requires the necessary documentation just like any other modification.

You do understand G100L was developed and approved by private individuals at their own substantial expense. So you don't think they should charge for G100L and recoup their investment plus ROI?

FYI: when the 1st Phillips multi-weight oil was released it did require an STC to use. ;)
Click to expand...

I'm well aware. Not looking to rehash this argument it's been beaten to death, apologies for bringing it up :D. (Cliff notes on my stance: recoup costs and profit from licensing to producters, not the STC. They are doing both.)

I've read the story of the Phillips XCII. So what changed between then and now that we no longer need an STC for multi viscosity?
 
I don't believe any injected lycomings are approved for mogas. My o-360 Cherokee is eligible...but requires a $3500 boost pump.
 
Justin Brady said:
They are doing both.
Click to expand...
Not yet. The approval is only at the STC level. The approved ASTM or SAE standard would have to include G100L before the producers could be licensed/charged at that level.
Justin Brady said:
So what changed between then and now that we no longer need an STC for multi viscosity?
Click to expand...
As I recall, the SAE standard was revised to include multi-weight oils so it became approved at the standard level vs the STC level. Engine OEMs also approved its use via bulletins but I don't remember if that was concurrent with the SAE change or not.

mandm said:
Once switching over to UL or MOGAS, might be even more difficult for international travel?
Click to expand...
Not that I recall. If the aircraft is legal to use mogas its good to go. However, I believe some countries limited what type of ops could be performed if burning mogas. The main issue, especially in the EU from what I've been told, is finding ethanol free-mogas.
 
Justin Brady said:
For a drop in fuel replacement? I think not.
I'm not saying the whole STC process is bad (it is and isn't depending on case IMO) but for a drop in fuel replacement I don't agree that it's a necessary thing to do
Every piston engine out there can use G100L the same 100LL.
There's no reason to make the public pay for (not to mention all that paperwork) an STC for something that requires no testing or modification.
It's akin to making me buy an STC to swap from Aeroshell to Phillips oil, they are for all intents and purposes the same and both meet all the same requirements.

Essentially where we're going to be in a few years is in a world where 100LL is illegal and you can't legally use it's replacement without paying for an STC, which is ridiculous IMO.
Click to expand...

Gami has been testing the fuel since 2010. First with engines. Then they have to test it on airframes. And also test it for being intermingled with 100LL. The latter was the big hangup. Octane degradation when mixing g100ul and 100ll. Mogas on some models requires no alterations. Mogas on others requires significant alterations. The stc will be based on horsepower and if I remember it'd be like $1.25 per hp. Your dollars would go to GAMI for all their hard earned work. Sure they'll get something for licensing the fuel. But that's a long payoff.

The GAMI fuel isn't technically a drop in replacement because of the process GAMI took to get here. While the fuel is a drop in replacement, they somewhat circumvented the government's process because they were never in PAFI.

Now could the government just cut GAMI a check? Honestly thats what I'd hope for. Instead of funding another acronym in EAGLE. With all the money the FAA and EPA has spent studying fuels, studying lead impacts, and government bureaucracy in general already. Just cut them a check for however many millions and be done with it.
 
Last edited:
Justin Brady said:
I've read the story of the Phillips XCII. So what changed between then and now that we no longer need an STC for multi viscosity?
Click to expand...

Neither XCII or the similar Amsoil version met SAE J1899 thus requiring an STC.
 
Racerx said:
Gami has been testing the fuel since 2010. First with engines. Then they have to test it on airframes. And also test it for being intermingled with 100LL. The latter was the big hangup. Octane degradation when mixing g100ul and 100ll. Mogas on some models requires no alterations. Mogas on others requires significant alterations. The stc will be based on horsepower and if I remember it'd be like $1.25 per hp. Your dollars would go to GAMI for all their hard earned work. Sure they'll get something for licensing the fuel. But that's a long payoff.

The GAMI fuel isn't technically a drop in replacement because of the process GAMI took to get here. While the fuel is a drop in replacement, they somewhat circumvented the government's process because they were never in PAFI.

Now could the government just cut GAMI a check? Honestly thats what I'd hope for. Instead of funding another acronym in EAGLE. With all the money the FAA and EPA has spent studying fuels, studying lead impacts, and government bureaucracy in general already. Just cut them a check for however many millions and be done with it.
Click to expand...

I suppose It's just a difference of opinion on the correct business move to make. I'm well aware of all the testing and money spent on G100UL.
My point in pointing that out is that Peterson has no product to sell, just the STC so that's what they use to offset their cost. Gami has a product to sell so IMO the proper move is to profit off their product, not for the legal right to use it as well. I see it as double dipping and I'm reasonably sure that a few years after everyone pays for the STC the FAA will find a way to make it legal for everyone and we'll all be holding hundreds of dollars worth of paper while gami pockets many millions off the stc and then continues to make many millions every year off the fuel itself.
For the record I feel the same way about requiring customers to pay for the STC to install a used product, you already made your money once, why should I pay thousands of dollars for another signature?


At the end of the day I'm happy it's here (or almost here) I just don't like the double dipping. It leaves a sour taste in my mouth that's all.
They could make just as much or more money just setting up a website to give the STC away and make their money on the fuel.
They knew it was a long investment when they started, I'm not sure why we're expected to give them a congratulatory payday now and then pay royalties in perpetuity to use the fuel.

It's like free shipping. Most people would rather pay $24 shipped than pay 8.99+14.99 shipping. You'll make more sales, make an extra 2c/transaction and your customers will be happier.
At the end of the day it doesn't matter what I think anyway but it's a fun discussion :).
 
The main question will be ,do you need a different stc for each fuel providers product. I have an stc for ul 94. Will I need an stc for gami fuel?
 
Justin Brady said:
For the record I feel the same way about requiring customers to pay for the STC to install a used product, you already made your money once, why should I pay thousands of dollars for another signature?
Click to expand...
You can blame your congressman for this and the subsequent FAR. There's no IP protection for aviation mods. People were buying STCs then duplicating them for their profit and not the STC holders profit. However, there are STC holders that allow anyone to download a permission letter free of charge regardless where the item came from. Then again there's nothing preventing you from getting your own STC and giving it away free to everyone.;)
 
Bell206 said:
You can blame your congressman for this and the subsequent FAR. There's no IP protection for aviation mods. People were buying STCs then duplicating them for their profit and not the STC holders profit. However, there are STC holders that allow anyone to download a permission letter free of charge regardless where the item came from. Then again there's nothing preventing you from getting your own STC and giving it away free to everyone.;)
Click to expand...

An aviation mod can be patented can it not?
 
Justin Brady said:
An aviation mod can be patented can it not?
Click to expand...
It depends. To be patented, an invention must be new, useful, and non-obvious. For example, the first person to invent a useful aircraft modification (for example, vortex generators) could patent the invention and nobody else could use them without licensing the patent. Once the patent is expired, somebody else install VGs on a particular model aircraft, do the testing, and get the STC, but they couldn't patent it because the basic concept is no longer patentable and the installation on a new aircraft model is obvious.

However, the owner of a STC has [presumably] put significant time and money into the approval process; licensing the STC for a fee is a reasonable way to recoup those expenses. Anybody else is free to go through the same process and get their own STC. I'm pretty sure there are several different STC'd VGs for many popular aircraft.

Chemicals are patentable, so presumably GAMI's fuel blend is patentable, and the STC is required before anybody can use it. However, that wouldn't stop somebody else (e.g. Swiftfuel) from developing their own [different] blend and patenting and getting a STC for that.

Unlike Peterson, whose mogas STC is the only thing they have to sell, GAMI could provide the STC for free and make all their money on fuel sales, but it's going to be a long slow implementation period, during which they have little income and they've already spent lots of money. I have no idea what their business plan looks like, but charging for the STC allows them to recoup some of that investment sooner, and may even have allowed them to set a lower per gallon price.
 
Justin Brady said:
I suppose It's just a difference of opinion on the correct business move to make. I'm well aware of all the testing and money spent on G100UL.
My point in pointing that out is that Peterson has no product to sell, just the STC so that's what they use to offset their cost. Gami has a product to sell so IMO the proper move is to profit off their product, not for the legal right to use it as well. I see it as double dipping and I'm reasonably sure that a few years after everyone pays for the STC the FAA will find a way to make it legal for everyone and we'll all be holding hundreds of dollars worth of paper while gami pockets many millions off the stc and then continues to make many millions every year off the fuel itself.
For the record I feel the same way about requiring customers to pay for the STC to install a used product, you already made your money once, why should I pay thousands of dollars for another signature?


At the end of the day I'm happy it's here (or almost here) I just don't like the double dipping. It leaves a sour taste in my mouth that's all.
They could make just as much or more money just setting up a website to give the STC away and make their money on the fuel.
They knew it was a long investment when they started, I'm not sure why we're expected to give them a congratulatory payday now and then pay royalties in perpetuity to use the fuel.

It's like free shipping. Most people would rather pay $24 shipped than pay 8.99+14.99 shipping. You'll make more sales, make an extra 2c/transaction and your customers will be happier.
At the end of the day it doesn't matter what I think anyway but it's a fun discussion :).
Click to expand...

Because they went the stc route there is some paperwork the stc holder has to have on have on file for each aircraft that holds the stc. So think of it as a paperwork fee.
 
Racerx said:
They have several, covering quite a few formulations.
Click to expand...
That makes sense; a well written patent application describes a "preferred embodiment" of the invention and as many alternates as possible, to avoid the patent being "invented around".
 
Justin Brady said:
For a drop in fuel replacement? I think not.
I'm not saying the whole STC process is bad (it is and isn't depending on case IMO) but for a drop in fuel replacement I don't agree that it's a necessary thing to do.
Every piston engine out there can use G100L the same 100LL.
There's no reason to make the public pay for (not to mention all that paperwork) an STC for something that requires no testing or modification.
It's akin to making me buy an STC to swap from Aeroshell to Phillips oil, they are for all intents and purposes the same and both meet all the same requirements.

Essentially where we're going to be in a few years is in a world where 100LL is illegal and you can't legally use it's replacement without paying for an STC, which is ridiculous IMO.
Click to expand...

The reason an STC is required is because the fuel is approved under an STC. It does not meet the ASTM requirements for aviation fuel.

Long term, ASTM may change the standard to it is included, and then an STC would not be required.
 
So fuel injected aircraft are not capable of MOGAS (which is basically same fuel at the gas station for cars?), but potentially a newer fuel UL94 which seems to be popping up more and more? So lead is not required? But it can or cannot be used in the system?
 
mandm said:
So fuel injected aircraft are not capable of MOGAS (which is basically same fuel at the gas station for cars?), but potentially a newer fuel UL94 which seems to be popping up more and more? So lead is not required? But it can or cannot be used in the system?
Click to expand...

That is not absolutely true. There are a few injected engines which are approved on the auto fuel STCs. The injection system design is part of the contributing factor as to why it may or may not have gotten approved.

Lead was added to the fuel to prevent knock. There are some other benefits that manufacturers enjoyed from the use of leaded fuel but most of the engines you will find in service today will run fine on unleaded as long as the octane requirements are met. The new aviation fuels will either need to meet current fuel requirements or if they can’t, an STC for their use will be required. Just like the aforementioned oil that required an STC to use since it didn’t meet (and I think it still wouldn’t) SAE J1899.

FWIW, Lycoming has approved many of their engines to run on some of the currently available unleaded fuels. Continental may have done the same but I don’t know that for sure. Even with the engine manufacturers approval it still isn’t acceptable to run the various fuels in your aircraft without some sort of airframe approval.
 
mandm said:
So fuel injected aircraft are not capable of MOGAS (which is basically same fuel at the gas station for cars?), but potentially a newer fuel UL94 which seems to be popping up more and more? So lead is not required? But it can or cannot be used in the system?
Click to expand...
If you have a type certificated aircraft, part of the "can or can not" depends, at least in part, on the state of paperwork. If no one has done the paperwork for your airplane/engine, you are SOL - even if the fuel would actually work.
One reason for not working may be that the 94UL or MOGAS (gas station premium, but without ethanol) may not have enough knock resistance (octane rating) for your engine.
Another reason that MOGAS may be a problem would be issues with vapor lock - your fuel lines get to hot for whatever pressure is in them. Less likely to be an issue with a gravity fed carburetor engines, more likely to be a problem with a low wing fuel injected engine with the pumps in front of the firewall (sucking on the tank).
On the other hand, GAMI 100 octane no lead will work just fine in your ride once it is available. And if you buy the STC it will even be legal.
 
Bell206 said:
You can blame your congressman for this and the subsequent FAR. There's no IP protection for aviation mods. People were buying STCs then duplicating them for their profit and not the STC holders profit. However, there are STC holders that allow anyone to download a permission letter free of charge regardless where the item came from. Then again there's nothing preventing you from getting your own STC and giving it away free to everyone.;)
Click to expand...
Fuel is not IP nor an aviation mod.

They can (and I’m sure will) make money licensing the formula (now that is IP) to fuel producers. An stc for this is moronic.
 
Salty said:
An stc for this is moronic.
Click to expand...
How so? The STC has nothing to do with the IP side. The permission letter to use the STC was mandated to give some property protection for the STC holder for its use.
 
Salty said:
They can (and I’m sure will) make money licensing the formula (now that is IP) to fuel producers. An stc for this is moronic.
Click to expand...
If the fuel doesn't meet the existing ASTM specification for avgas, then the STC is required to legally use it in a standard certificated aircraft.

If the specification is rewritten to include the new fuel in the definition of "avgas", then the STC will be irrelevant and unnecessary. I suspect that will happen eventually.
 
You must log in or register to reply here.
Back
Top