One of the few good things about getting old is that in many instances, you’ve seen it all before. All of the arguments against unleaded fuel just being impossible for certain engines were used back in the early seventies 70s when it was first proposed that tetraethyl lead be eliminated from automobile fuel. Amazingly, despite all of the cries of “it just can’t be done”, here we are with millions of cars running on unleaded fuel including those few remaining with air cooled engines. Where there’s a will, there’s a way.
English is not my mother tongue - but I refer in defintions to US law
18 U.S.C. § 2311. Anyone can Google.
Petersen Aviation has an STC issued by the US FAA for water methanol injection in aircraft. I trust the Petersen STC in the same way I trust the GAMI fuel STC .
Yes there will be a cost for such an installation but if the end might be a fuel several dollars cheaper per gallon with world wide availability than another fuel an aircraft owner will have to make a calculation during the life time of the engine and/or the aircraft. The PA-30 Piper Twin Comanche I referred to had the anti-icing tank and equipment on propellers installed as an STC several years after the aircraft was built. When I researched to install a water methanol injection some 12 years ago for my then PA-31 Piper Navajo - the cost was about USD 10.000 per engine. The pay off time for me at that time was about the half life of an engine between overhaul or about 3 years. All subsequent years after I would have saved a lot of money. However I did not make the investment - because my new UL100 fuel combined with an intercooler (FAA STC) would have given me the same capability.
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At the end - this article was about the ASTM. I trust them because they have made Sweden to run on ASTM approved unleaded AVGAS for 43 years. It was so easy to get Civil Aviation Authorities, engine manufacters etc to go along when I as a producer of unleaded AVGAS was inside the ASTM standard D910 which by the way is the same standard where the AVGAS 100 LL resides.
Lars,
You are citing a federal criminal statute (18 U.S.C. 2311).
That federal criminal statue is unrelated to the civil regulations in place in California.
The regulations in California will be interpreted by the California State Courts.
The California Courts are not going to go to federal criminal statutes for definitions.
Based on some direct professional experience with similar “statutory construction” issues, it is nearly certain that the California Court would just rely upon a simple dictionary definition, such as the one I quoted in the earlier message.
And, again, there is no cruise power setting for a Navajo TIO-540J2B or J2BD engine that can operate free of detonation on autogas. In fact, my direct testing of 96.5 MON unleaded avgas on that specific engine demonstrates that it detonates at those power settings on that fuel.
Therefore, in order to operate free of detonation at typical cruise power settings, the methanol-water injection would have to operate continuously.
Not intermittently.
That would require a rather large storage tank and room to put it. That would then compromise the useable load of the aircraft and/or the range of the aircraft.
Everyone can have a different opinion - - but my judgment, based on hard data from actually testing that engine on unleaded fuels is that any solution other than high octane avgas is not visible within the know and deployable technology.
Even a highly sophisticated electronic ignition will not be sufficient.
Mr. Braly, first, thank you for your comments on this editorial. It is always beneficial to hear from people who are well versed in such topics to present clear and concise data about how things actually work. I do have a question for you. I have visited your facilities in Oklahoma and you were good enough to demonstrate the operation of your engine test cell for those of us present. I also know that you have conducted operational testing on various fuel formulations to determine their suitability for aircraft use. Have you ever had the opportunity to test the 100 octane unleaded fuel that is sold in Sweeden as a substitute for 100LL? I am curious whether that fuel would actually be a viable substitute for 100LL in high performance engines like the TIO-540J2 you referenced, or whether it would be similar to fuels such as the Swift R100 that is limited to certain lower powered engines. I agree that requiring any of the US GA fleet to make modifications to their engines or airframes, such as water/methanol injection is totally outside the scope of the PAFI/EAGLE mandates. Their charter is to identify a DROP-IN replacement for 100LL that does not require any modifications of the fleet. At this point, it appears that yours is the only unleaded fuel to satisfy that critical requirement. Thank you.
We DO have some of these systems in our aircraft. This 40-year A&P/IA has run EIS in my certified aircraft for thousands of hours. Its high time to change the hardware, But Lycoming and Continental are dragging their feet, and the airframers are not demanding it like they should. If Lycon would make the changes, we wouldn’t even need the 100 octane. The automotive industry has proven that over 5 decades. There is nothing about altitude that requires high octane, and the other needs for it can be eliminated by compression ratio reduction and/or ‘those systems’ that you reference.
I agree on your Chieftain engine analysis. So compression ratio reduction COMBINED with smart EIS/intercooler/prop-efficiency-improvement/new Piper performance charts/etc. is an answer that will work even for the Chieftain, which I have more than a few hours in. Its not fair for you to have to do all the work to solve a problem and Piper & Lycoming to do nothing.
The drop-in concept is flawed. The automotive manufacturers had to make the changes 50 years ago. It would have been crazy then to expect the petro industry to make all the changes while the auto manufacturers did nothing in the overall effort to eliminate lead in the fuel.
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It has been years since I have looked at the fuels sold in Sweeden.
However, there are lots of ways to claim a fuel is “100” octane.
If you use the RON number (ASTM D2699) , that is not hard to do. If you use the correct MON (ASTM D2700) then that has never been deployed any where except through the ongoing of G100UL Avgas. -
None of the proposed unleaded fuels - - other than G100UL Avgas - - can operate safely on a TIO-540J2x.
The Chieftain engine (Lyc. TIO-540J2B or J2BD ) ALREADY HAS A VERY LOW COMPRESSION RATIO! ~ 7.3:1.
You cannot lower the CR any further - - nor can you retard the 20 dBTDC timing any further and then still be able to operate the engine at normal power settings. (With or without “smart” EIS and/or with intercoolers.)
Why not ?
See if you or others can identify the specific operational reason why that cannot (does not) work ?
No, the “drop-in” concept is OK. You just have to define it correctly.
From the 1980s through about 2005, ASTM - - INSISTED on defining a “Drop In” replacement as a fuel that met all of the test parameters listed in the Hallowed “TABLE I” properties in the existing ASTM D910-100LL specification - - with one and ONLY one exception. No lead.
That was done deliberately to postpone any change to any other fuel. People in ASTM even cautioned others in ASTM to “… do not object or propose anything that does not meet that requirement.”
The appropriate definition for a “drop-in” fuel for 100LL is a fuel:
- That has detonation characteristics the same or better than 100LL;
- That is fully fungible with 100LL;
- That can be produced in traditional refinery type production facilities without having to build new refineries;
- That has a cost basis that is not prohibitive;
- That does not materially affect the range or payload of the aircraft;
- That does not require any physical modifications to the aircraft or engine other than “paperwork” and placards.
Those were the “Design Criteria” that we developed in January of 2010, at the beginning of the G100UL Avgas program.
In 2016, Phillips Petroleum met with Tim and I in their Houston Headquarters - - and I showed them a short power point with that set of design requirements. The senior P66 fuels engineer agreed that those were the correct design criteria.
GAMI’s approach to the problem:
- Design and test a fuel that works (see above) ; and,
- THEN - - write a specification around the “fuel that works” so that it can be commercially produced with appropriate quality controls.
Ok so I really think the G100UL is the best solution in the near term.
So what is the next airport to get it? Cant wait to try it and get the lead out.
I give to the readers to interpret if an aircraft is vehicle.
Regarding the Swedish unleaded 100 aviation octane AVGAS developed year 2006 it meets the ASTM D910 table 1 (for 100 LL) at that time in all aspects except for slightly lower energy content. The Cessna documentation states a slightly lower energy content will not be a problem, fuel consumption will be about the same.
However under certain circumstances even unleaded 100 octane avitation rating (not RON) is not sufficient for engines having a type certificate to operate on 100 LL. Leaded and unleaded octane numbers sometimes do not correspond pending fuel formula. In such a case for example an intecooler may add extra margin. Also water-methanol injection used together with such an 100 aviation rating unleaded AVGAS will give the extra octane needed to be on the safe side when needed. The injection of water-methanol will thus not be needed to use all the time - just under certain conditions.
The aviation consumer will at the end chose the UL100 product they will use.
Yes, there is “something” about “altitude” that does require “high octane.”
The compressor discharge temperature of a Lycoming TIO-540J2DB at 20,000 feet on an FAA hot day is about 330 degrees F.
Shove that hot air into your very low (7.3:1) compression Navajo engine operating at 30" of MAP / 2400 RPM and operating on anything less than 100MON /130PN rated gasoline and it will begin to detonate. But only for a short while .
Lars,
What is the chemical composition of that Swedish unleaded 100 aviation octane AVGAS that was developed in 2006 ?
Is it currently being produced ?
This must be the FAA’s response to Russ’ Op-Ed… Read this link and tell us here what the purpose of EAGLE and PAFI is.
https://www.faasafety.gov/spans/noticeView.aspx?nid=14142
The FAA has gotten into the Word-Salad business. They should have used AI to write this it would have had a little more substance.
https://flyeagle.org/eagles-four-pillars/
Has the experts checked-off a single one of the items in their “Four Pillars”?
I guess they do have the ESG requirement checked -off.
The Swedish unleaded aviation octane AVGAS developed year 2006 was with European made components. All the data were repeated and verified by US reputable AVGAS laboratory in 2013 and then with components made in America.
There are valid world-wide patents on the fuel inclusive the US, Canada etc. so there is no need for me to reveal any chemical composition.
As for Sweden today about 80 % in volume of all AVGAS consumed already is unleaded with Hjelmco AVGAS 91/96 UL ® (UL94 and competitors UL91) the communities seem to be satisfied with the work already producing reduced levels of lead in the air so 100LL does not seem to be a acute problem. Remember Sweden has uninterupted production and use nationwide of unleaded AVGAS now for 43 years! Also lead is the cheapest way to obtain high octane levels - and the market seems to prefer having the lowest price possible on 100 octane AVGAS and appreciate that the Hjelmco unleaded AVGAS during all these 43 years inclusive today has carried a price about 15 % lower than that for 100 LL.
Also with our unleaded AVGAS in Sweden traditional aircraft engines made by US companies tend to go about 3000 hours before their major overhaul.
As said before 2032 seems to be the target to replace 100 LL.
Unleaded is however not the issue today. That train has already left the station. Today the issue is to make bio-AVGAS meeting ASTM standards and at the possible lowest cost.
Work is actively ongoing on that subject in the ASTM right now and with participation of US companies.
I am glad we have the ASTM and other standardization organizations because it will secure the Aviation Consumer worldwide in the not so far future to have a 100 aviation octane bio AVGAS meeting an ASTM standard and made in competition among component producers and fuel producers/blenders. An ASTM standard or its European equivalent standard is the Defence Standard (DEF/STAN) issued by the Ministry of Defence in England.
I copy from the DEF/STAN AVGAS standard and the authority it has:
The Technical Authority is the Defence Strategic Fuels Authority, Larch 3B #2317, MOD Abbey
Wood, Bristol, BS34 8JH. This standard has been produced on behalf of the Ministry of Defence
(MoD) by the Aviation Fuels Committee (AFC) under the governance of the DSFA and Military
Aviation Authority (MAA) Fuels, Lubricants and Gases Airworthiness Advisory Group (FLAAG).
English is not my mother tongue - but I refer in defintions to US law 18 U.S.C. § 2311.
I assume you’re referring to these sections:
As used in this chapter:
“Aircraft” means any contrivance now known or hereafter invented, used, or designed for navigation of or for flight in the air;
[…]
“Motor vehicle” includes an automobile, automobile truck, automobile wagon, motorcycle, or any other self-propelled vehicle designed for running on land but not on rails;
[…]
“Vessel” means any watercraft or other contrivance used or designed for transportation or navigation on, under, or immediately above, water.
An important distinction: the simple term “vehicle” is never defined. What is defined is “motor vehicle” (emphasis mine).
In common U.S. usage, a “motor vehicle” is invariably ground borne transportation; “vehicle” alone has no such restriction - we have plenty of UAVs flying around.
In addition, the U.S.C. consistently uses the full term when referring to self-propelled, ground based vehicles in other sections of the code.
Lars,
Is there any data which documents the extended intervals (out to 3,000 hours) before major overhaul when using unleaded aviation gasoline in Sweden ?
George
Thank you, Russ for your usual great reporting and analysis.
Why not file a suit against d’Acosta et al. for self dealing? Does anyone know their way around the legal system well enough to get the Justice department, the SEC, and/or the OMB to look into Eagle etc.?
In Sweden you operate an engine to the TBO if having it in commercial operations. However if you have an aero-club and alike they are not considered commercial and thus you may extend the TBO by 50 %. This is also valid for private operations.
I hear from our customers that many 100 % fully working engines have to be sent in for TBO at 3000 hours - because of the time limit. For statistics I assume engine manufacturers have reliable data. I assume the extention in hours between oil change by engine manufacturers is a result from such statistics. However such an extension for oil changes might not be done everywhere as it is regulated in the service manual from the air-frame producer. Oil changes thus typically take place in Sweden every 50 hours with a modern oil-filtration system.