G100UL in the news
Fuller talks engine technology, avgas outlook with TCM head - August 19, 2010
Jack Pelton looks at GAMI's G100UL - August 18, 2010
Industry Leaders: Don't Panic On Avgas - July 27, 2010
Showing off G100UL - July 22, 2010
G100UL: The future of fuels - February 28, 2010
AVweb's G100UL Flight Test
Frequently Asked Questions Regarding G100UL
Q1. Are there any potential issues with G100UL that will pose problems with the EPA? For instance, any known carcinogens or other health hazards?
Nothing identified. The stuff in the fuel is already in aviation gasoline, to some extent. These are just pretty ho-hum hydrocarbons. There is no magic pixie dust like TEL. This is compositional. There was just something fundamental that was over looked for years. If this fuel is an emissions issue, then other fuels are worse!
Q2. Is G100UL long term compatible with fuel cells, gaskets, seals, etc?
That is a Bill Clinton question. Depends on what the meaning of long term is! Currently, Avgas in many parts of the country has as much as 20% toluene in the Avgas. Toluene is more aggressive as a solvent than any of the major components of G100UL. We have had the G100UL fuel in the fiberglass wing of the TN SR 22 Cirrus for nearly six months, now. There is no evidence of any issues.
We have done extensive component testing of all of the rubber parts from the TCM fuel systems. That includes accelerated testing by immersion in fuel that was maintained at elevated temperatures (55°C, rather than room temperature) for extended periods in order to take advantage of the 10°C => doubles the reaction rate concept in chemistry. Those components were then washed off in 100LL and taken to the FAA at the Engine Propeller Directorate on March 31, and placed on the table next to a set of new parts that had been soaked overnight in 100LL. Nobody in the room could tell which was which.
We would already be doing long term formal component testing - but the FAA has ordered the Ft Worth Aircraft Certification Office to do nothing until the whole matter is reviewed in Washington. That has been ongoing since early April. So we can't even formally start the testing!
Short answer: Nothing is showing up as being in any way a "component compatibility" issue, much less a show stopper. We do need to do some more work with older airplanes and carbureted engines. That is ongoing.
Q3. Are there any problems with vapor pressure or something similar?
Good question. Vapor pressure problems arise from VP that is too high. That causes vapor lock. This fuel tends to run at the lower limit of the existing ASTM D910 vapor pressure spec, and even slightly outside on the lower side. Until the 1960s, there was no lower limit on avgas vapor pressure. The Chinese avgas lower vapor pressure limit is below the spec for G100UL. This does not appear to be an issue. If it is, we can raise the vapor pressure. It would increase the cost of the fuel by a few pennies.
Q4. Aside from different ingredients, are there any expensive processes or equipment necessary to manufacture this stuff?
Just like grade 100LL, G100UL can be made in dozens and dozens of different ways. At least one way to make a conforming version of the G100UL fuel can be done with the chemicals and infrastructure that now exists inside any large refinery. It is not the best way to make the best fuel. But it can be done. With some capital investment, the fuel can be made to be a still better fuel. Not exotic or particularly hard to do. If it was approved, and certification ready for use, any refinery could build a million or 10M gallons of at least one version and ship it in relatively short time frame. Something like 90-120 days.
Q5. Why is the FAA dragging their feet on this?
I asked that question. The answer I received was not something I want to share in public. Let me say, it made no sense at all to me. But I think those issues are rapidly being resolved. The matter is sitting on the desk at 800 Independence Ave, waiting on a signature. Lots of good people have helped on this. Including lots of people inside the FAA.
Q6. What can we do to move it along?
Show up on Thursday at OSH. At 11:30 am. At the "Meet the Administrator" session. Support the Clean 100-Octane Coalition. They have two fundamental goals: 1) Get 94UL "off the table"; and, 2) Get the FAA to remove the road blocks to anyone that has a credible approach to a fuel STC that runs on a full scale aircraft engine at a performance and detonation level that exceeds the existing minimum specification grade 100LL.