gallois wrote:
an aviation fuel called AKI93 no ethanol and no lead
Now, that was interesting. I have never heard about it, but apparently they are already selling it. Essentially “aircraft grade” MOGAS 98. This is exactly what we want: Mogas 98 with no ethanol, aircraft spec vapor pressure and (close to) “aircraft grade” storage specs.
Comparing the octane levels with Warter’s own UL 91. Warter call it LOB and LOM (Polish), but obviously LOB = RON and LOM = MON
UL91 : MON = 91, RON = 95
AKI93 : MON = 89, RON = 97
OK, so not quite 98 RON, but more than enough to work fine on Rotax and Lycoming (according to Warter).
But, what does it cost? If it’s 100LL price, forget it. If it’s close to Mogas 98, then this is just perfect.
“aircraft grade” MOGAS 98
that’s what it is, unfortunately the price is also “aircraft grade”
RV14 wrote:
that’s what it is, unfortunately the price is also “aircraft grade”
Yes, that’s what I would realistically expect. The words aircraft grade and cheap are incompatible 
But, nonetheless, this AKI93 looks much more suitable than UL91 on the face of it. Funny, UL91 is also AKI 93
The words aircraft grade and cheap are incompatible
The local prices here are €1.27 per liter for 100LL and €1.13 for premium (ish) 91 AKI auto fuel with 10% alcohol. For a while 100LL was cheaper. Both prices are very much a function of taxes regardless but I’m not convinced the increased cost of production for Avgas is dramatically high in relation to the retail price. I think what makes the price of aircraft grade fuel higher, when it is higher, is mainly the lack of a competitive local market.
LeSving wrote:
this AKI93 looks much more suitable than UL91 on the face of it.
Why is AKI93 better than UL91? Storage of AKI93 shows to be 6 months, with 24 months for UL91. The specifications for the two fuels look different, but no idea of the relevance of these two “standards”.
UL91: Aviation gasoline UL 91 meets the requirements of ASTM D 7547 and DEF STAN 91-90.
AKI93: Meets the requirements of WT-23/OBRPR/PD/151
Does anyone know if there is a testing agency that goes around Europe testing fuels randomly, and assessing massive fines on operators that provide substandard fuel?
When we had our 100LL pump one of the club members had to regularly check things like specific gravity etc. But I don’t know if they were checking to any specific standard. Total also did some checks when delivering the fuel. What those checks were, I have no idea.
Why is AKI93 better than UL91
In short, the RON number makes all the difference. The service letter from Rotax: SL-912-016R2_914-014R2_Essentual… gives a clue.
LeSving wrote:
In short, the RON number makes all the difference. The service letter from Rotax: SL-912-016R2_914-014R2_Essentual… gives a clue.
Interestingly, while UL91 and Hjelmco 91/96UL both have a MON of 91, UL91 has a RON of 95, while 91/96UL has a RON of 98.
AKA AKI94.5
One has to wonder what the RON of 1O0LL actually is. Aviation rich is not the same as RON.
It’s a jungle.
