Frequently Asked Questions Regarding G100UL™ Avgas
Q1. Are there any potential issues with G100UL™ avgas 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 where something that is one part in 1000 has a huge impact on the octane rating. 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™ avgas long term compatible with fuel cells, gaskets, seals, etc?
We have done a lot of compatibility testing over the last year. Dozens of tests. Here is one example: We found a "new" 1950 fuel tank bladder from a popular aircraft still in service to this day. This bladder had never been put into service in an aircraft. We subjected that tank bladder to accelerated compatibility testing. The samples tested in G100UL™ avgas and 100LL for the equivalent of about nine months. The samples tested in the G100UL™ avgas were actually in better condition after being in the G100UL™ avgas than the control specimens left sitting on the shelf, or the samples placed in 100LL for the same length of time and under the same conditions. Also, keep in mind, 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™ avgas. We have had the G100UL™ avgas fuel in the fiberglass wing of the TN SR 22 Cirrus over a year, 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, 2010 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.
Short answer: Nothing is showing up as being in any way a "component compatibility" issue, much less a show stopper.
Q3. Are there any problems with vapor pressure or something similar?
Vapor pressure problems arise from vapor pressure that is too high. Car gas has much higher vapor pressure than avgas. High vapor pressure causes vapor lock. The G100UL™ fuel tends to run at the lower limit of the existing ASTM D910 vapor pressure specification. However, we can set the vapor pressure anywhere it needs to be by minor adjustments to some of the components of the fuel, without otherwise affecting its other important characteristics like detonation.
We are currently doing winter testing of G100UL™ fuel in a Cessna 150. We are not seeing any significant difference between G100UL™ fuel and 100LL in starting characteristics. They both get harder to start in cold weather below freezing and they both get easier to start in warmer weather.
Q4. Aside from different ingredients, are there any expensive processes or equipment necessary to manufacture this stuff?
No. Just like grade 100LL, G100UL™ avgas can be made in 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. With some minor alteration of some of the existing process streams, the fuel can be made to be a still better fuel. There is nothing about this that is exotic or particularly hard to do. If it was approved, and certification ready for use, we believe that any refinery could build a million or maybe even 10M gallons of at least one version and ship it in relatively short time frame.
Q5. Why is the FAA dragging their feet on this?
I asked that question. The answer I received was not something I would want to share in public, even now more than a year later. Let me say, the answer made little sense, even to this day.
A year ago, I thought those issues were rapidly being resolved. However, as this is updated in early March of 2011, the project certification effort is again waiting on the FAA to generate an issue paper they have promised to produce now for over a year. Lots of good people have helped on this, including lots of people inside the FAA. There are however some issues being raised by one particular person in the FAA that have caused enormous and unjustified delays in the project.
Some major industry "stakeholders" have taken active steps that have had the effect of impeding progress with the certification effort.
Q6. What can we do to move it along?
The effort by the Clean 100-Octane Coalition during the summer of 2010 was extremely effective.
That organization managed to get 94UL "off the table".
Unfortunately, their second goal, to get the roadblocks removed, has not been successful. All of those roadblocks that were in place in the first half of 2010 remain fully in place as of March of 2011.
Anyone who has a significant interest in this matter is encouraged to talk to any of the Congressional general aviation caucus members.
We welcome any group that wants to come to Ada and investigate the G100UL™ fuel issue. GAMIís G100UL™ fuel continues to be the only unleaded avgas in the world which is routinely flown on a high performance turbocharged high compression piston aircraft engine.
That is a fundamental fact. We set out to find a fuel that works -- and then write a specification around that fuel. We have done that. Over time, it will become harder and harder for other industry stakeholders to ignore that simple reality.