Primarily for general aviation discussion, but other aviation topics are also welcome.
#1829400
MikeW wrote:
mr spog wrote:Yes, I telephoned Power Local Fuels again yesterday, and they confirmed that they are still Zero ethanol/achohol, and intend to remain so.


Unfortunately they don't do super, only normal 95, fine for a 912, not very good for a 912S.


I think you'll find that UK standard unleaded is manufactured to the same EN228 super standard that Rotax specify as the Min Mogas standard for the 912S. UK super unleaded is EN228 super plus .. and Yes it is stupidly confusing!
#1829470
The BS EN228 specification already incorporates both premium and super unleaded grades. For both grades, with regards to ethanol, the two "E" sub-specifications in fact relate to 2.7% and 3.7% max oxygen content fuels, with maximum ethanol limits of 5 and 10% respectively.

The labels on forecourt pumps form part of the spec. E5 doesn't necessarily mean 5% ethanol - it means the fuels conform to the 2.7% maximum oxygen content specification which amongst other parameters, allows for any ethanol content between 0% and 5%. E10 means 3.7% oxygen content with any ethanol content between 0 and 10%. It was deemed that E5 and E10 labels would make things easier to understand :D

The fact that super unleaded used to be largely ethanol-free but now largely isn't is not due to refineries closing - it is a shift from alternative bio components such as from ETBE to ethanol due to a "sustainability index" (SI) now incorporated in fuel mandates. ETBE generally has low SI, Ethanol can have a high SI depending on manufacturing process and feedstock source.

As for the earlier question about the affect of removing ethanol (which can indeed be done by water washing), the residual fuel will have a significantly lower octane. It will also be very likely to be somewhat corrosive (as metal deactivator additive will also be removed by water washing)
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#1829479
russp wrote:
MikeW wrote:
mr spog wrote:Yes, I telephoned Power Local Fuels again yesterday, and they confirmed that they are still Zero ethanol/achohol, and intend to remain so.


Unfortunately they don't do super, only normal 95, fine for a 912, not very good for a 912S.


I think you'll find that UK standard unleaded is manufactured to the same EN228 super standard that Rotax specify as the Min Mogas standard for the 912S. UK super unleaded is EN228 super plus .. and Yes it is stupidly confusing!


Well having spent a bit of time Googling EN228 in various incarnations my brain hurts! It seems you are right though. As far as I can make out Rotax are still using pre 2009 terms when basic 91 octane became "regular", super 95 became standard unleaded (or premium) and super plus became super - is that it?
For stupidity it's on a par with Annexe 2 becoming Annex 1.
Good to know - thank you.
#1829537
skydriller wrote:Question : if a pump does not have written E5 on it, does it still possibly have up to 5% ethanol or is it ethanol free?


Can be either.

Current UK rules are:

Mandatory to have spec (Eg BS/FR EN228) stated.

Mandatory to state if fuel has high oxygenate content (Eg "E10")

Recommended (but not mandated) to state if fuel has low oxygenate content (eg "E5")
#1829539
you can test for ethanol in MOGAS quite simply, all you need is a test tube.

Add a small amount of water to the tube, about 5% of volume.
Mark the level on the tube with a Sharpie type marker.
Fill the tube with MOGAS and fit cork.
Shake tube until the MOGAS and water mix.
Leave the tube to separate.
The water absorbs any ethanol, so if the water level after it has separated is above your Sharpie mark, you have ethanol. If it returns to the mark, you don't.

If you had a really big test tube you could strip ethanol from all your MOGAS in this way, but what are you left with? What will the MON actually be? Was there an important additive bound to the Ethanol?

The presence of Ethanol in premium unleaded is down to the supplier and which refinery it comes from. Supermarket fuel tends to contain ethanol where "proper" fuel suppliers like Esso and BP don't. But this is affected by region so you do have to check, and it is obviously subject to change.

Lots of us need better availability of UL91.

Disclaimer. I'm not a chemist, the value of this is what you paid for it.
#1829617
Sooty25 wrote:
Lots of us need better availability of UL91.

Disclaimer. I'm not a chemist, the value of this is what you paid for it.


This is the key - persuading airfield operators there is a hidden demand is the first part of the story, persuading pilots who have only ever used 100LL and think that they can't use UL91 (when the majority of GA aircraft can do so quite happily) that they can and should is the second part and the third is persuading the govt to set taxation so UL91 is financially advantageous to pilots using Avgas.

The LAA have said that there is an ongoing project in conjunction with AOPA to achieve these three aims.
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