GAMI's unleaded avgas moves forward

PaulMillner

PaulMillner

Line Up and Wait
Joined
Jan 14, 2011
Messages
948
Location
Berkeley, CA
Display Name
Display name:
Paul Millner
In Tuesday's EAGLE working group call, Vitol announced that they have begun their initial large-batch blend of G100UL... 1 million gallons... at their facility in Baton Rouge. They didn't share distribution details, but I expect we'll see some of that here in California fairly soon...

In a follow-up message, they're taking some time with this first batch, and plan to certify it later this month...

Paul
 
Last edited:
Neato.

How many gallons in a load? How many gallons does a typical airport sell in a day? I imagine tanks will need to be converted. I wonder how many are already prepared to receive G100UL?
 
asicer said:
Neato.

How many gallons in a load? How many gallons does a typical airport sell in a day? I imagine tanks will need to be converted. I wonder how many are already prepared to receive G100UL?
Click to expand...
Gami gas is fungible without octane degradation when mixed in any quantity. Apparently that was a big hurdle. I think most tanks are in the 8000-15000 gallon capacity range.
 
Racerx said:
Gami gas is fungible without octane degradation when mixed in any quantity.
Click to expand...
So you can go back and forth between G100UL and 100LL without emptying the system? That's good.

Has anyone summarized the performance differences between 100LL and G100UL? Stoich ratio, energy content, etc.?
 
PaulMillner said:
...In a follow-up message, they're taking some time with this first batch, and plan to certify it later this month...
Click to expand...
What does it mean to "certify?" G100UL has not met ASTM standards.
 
Domenick said:
What does it mean to "certify?" G100UL has not met ASTM standards.
Click to expand...
As they teach in law school, the purpose of any specification is to simplify commercial transactions... if buyer and seller can reference a specification, it greatly simplifies the commercial transaction. As allowed by Federal law, GAMI chose to use a proprietary specification for their fuel rather than a consensus organization generated specification. But, GAMI's specification references about 40 ASTM consensus-organization specifications for the various properties of the fuel.

ASTM has no standard for 100 octane unleaded avgas as yet... so there's no option to meet an ASTM standard for 100UL unleaded avgas. That may come in time... GAMI had a number of good business reasons to use a proprietary specification for now, but that's an entire other discussion.

In order to sell a product, one generally has to certify that the product meets the specification. Interestingly, GAMI took a much more rigorous approach to certification of their fuel against their specification than has historically (since 1937) been used for avgas. The historic model is that each producer of avgas self-certifies that his fuel meets the specification. Instead, GAMI's fuel certification introduces FAA oversight into the batch certification process. The process is accomplished by GAMI, but under the terms of their STC, and the normal FAA supervision of any material produced to be used with an STC... PMA, parts manufacturing authority, if you will. AFAIK, no other fuel producer has that level of FAA quality process. I think it's something GAMI is entitled to be proud of, as a quality control step in production of the new fuel. But of course, the devil is in the details, and only time will tell the actual impact.

As you know, self-certified avgas has failed in commercial practice... Chevron and Mobil, at least, have had somewhat spectacular quality control failures in delivered avgas. Whether GAMI's FAA-approved process will be superior in practice remains to be seen... but it's a worthy effort I think.

Paul
 
Last edited:
PaulMillner said:
ASTM has no standard for unleaded avgas as yet
Click to expand...
Did you mean to say "no standard for unleaded 100LL replacement"? I thought UL91 (and by extension UL94) met ASTM D7547?
 
asicer said:
Did you mean to say "no standard for unleaded 100LL replacement"? I thought UL91 (and by extension UL94) met ASTM D7547?
Click to expand...
Yes, I've edited my note... no standard for 100 octane unleaded avgas. They've only been working on it 33 years... so patience, grasshopper! :)

FWIW, Phillips 20W50 multi-vis aviation oil was introduced in the 1980's without an ASTM spec also... and nominally required an STC to use in the engine (not many people bothered filling out the paperwork). Eventually ASTM got around to including multi-weight motor oils in the aviation oil specification, and the STC became irrelevant.

Paul
 
Last edited:
StraightnLevel said:
Has anyone summarized the performance differences between 100LL and G100UL? Stoich ratio, energy content, etc.?
Click to expand...
I think that's on the GAMI website... the weight of 100LL varies a bit, from 5.8 to 6.1 pounds per gallon. GAMI's fuel will be about 6.3 pounds per gallon, so roughly 5% heavier. But it contains 3% more BTUs per gallon, which mitigates some of the extra weight. If you read the AOPA or Aviation Consumer write-ups on flying the AOPA Baron with the left engine burning G100UL and the right engine burning 100LL, you'll see that they lean the unleaded engine about an extra 0.8 GPH to maintain constant power... or, they run at the same fuel-flow setting, and fly 2 knots faster. Switching an engine from one fuel to the other and back causes the EGT to vary by a couple of degrees... nothing a pilot would notice unless specifically looking for it.

Paul
 
asicer said:
I think the part in parenthesis could hold some truth.
Click to expand...

I think you're right. GAMI can't expect FBOs and IAs to be their STC police, and I doubt the FAA will have much interest in enforcing it anyway.
 
Clip4 said:
T

They are certifying their end product meets the ASTM standard.
Click to expand...
Which ASTM standard? As PaulMillner pointed out above, there is no 100UL ASTM standard.
 
Domenick said:
Which ASTM standard? As PaulMillner pointed out above, there is no 100UL ASTM standard.
Click to expand...
The producer of G100UL will provide the purchaser a Certificate of Analysis that demonstrates that the batch of fuel meets the specification... in this case, GAMI's proprietary G100UL specification. That spec, like the D910 spec for 100LL, dictates properties as measured by about 40 ASTM standard tests. What's different is that GAMI's licensed producers include a chromatographic fingerprint test as well, according to an ASTM standard, that is not a part of current D910 testing of 100LL. And that before the fuel can be sold, GAMI reviews the fingerprint to assure, according to their FAA-approved QC scheme, that the fuel really is good stuff. It's one of those redundancy things we like in aviation! And better than today's 100LL practices.

Paul
 
You must log in or register to reply here.
Back
Top