Primarily for general aviation discussion, but other aviation topics are also welcome.
From the British Historic Vehicle Clubs website:

"Filling stations that stock 2 grades of petrol and supply at least one million litres of fuel in total each year will need to ensure one product is the Super E5 protection grade. While not all filling stations meet these criteria, almost all towns across the UK will have a filling station that supplies the ‘Super’ grade and currently one major retailer, a national supermarket group, has committed to offer the product. The main exception to this is in certain parts of the Highlands, north and west coast of Scotland, which will be covered by an exemption process and allowed to continue to market the 95-octane E5 grade.

The Federation therefore recommends that all vehicles produced before 2000 and some vehicles from the early 2000s that are considered non-compatible with E10 - should use the Super E5 Protection grade where the Ethanol content is limited to a maximum of 5%. To check compatibility of vehicles produced since 2000, we recommend using the new online E10 compatibility checker: .

It should be noted that some Super E5 Protection grade products do not contain Ethanol as the E5 designation is for fuels containing up to 5% Ethanol. Similarly E10 petrol can contain between 5.5% and 10% ethanol by volume. Product availability varies by manufacturer and geographical location and enthusiasts should check the situation in their location."
Volare wrote:Considering that 100LL is 100 octane rating, I wonder what difference the 1 octane would make in real life operations in Lycarus type aircraft engines.

Different octane ratings.

Super plus 99 is 99 RON.
100LL is 100 MON.

99 RON UK petrol is about 87 MON, so there's a 13 MON difference between that and 100LL.
MikeB liked this
Miscellaneous wrote:That's exactly what I did with the kit, absolutely no problem dipping a cotton bud in the newly purchased fuel. :D

Indeed, but as I should well know (having spent the last 20 odd years in various laboratories around the world witnessing fuel analysis then sorting out any problem), the faff is not the testing, its dealing with the fuel should it fail, and sourcing an alternate .
Miscellaneous liked this
Forfoxake wrote:Please let me know the results of your research. It obviously a different country up there!

Not conclusive just yet, but promising.

I generally use a little of the aeroplane fuel for the lawnmower, strimmer etc leaving a little in a jerry can which I transfer to a 5ltr container when I get home. What's in the 5 ltr container at present is a little from last summer and some from fuel I bought in March. So not conclusive on account of it not being a single fresh 'batch'. Does ethanol evaporate, or somehow disappear over winter?

Anyway a quick look around and all I could come up with was a bottle from the kitchen. Measured quantities, mixed, agitated, allowed to settle and surprise, surprise, no indication of any ethanol. Repeated the shaking and agitating a couple of times and left for 3 hours before a final check. Still nothing. :thumright: I last flew on Saturday and have 20ltrs in the hangar which was purchased then, which I will check.

Initial check after fill.
3hrs later.
Forfoxake wrote:I think I can save you the trouble. In my experience, all unleaded petrol in Scotland contains alcohol-it all comes from Grangemouth I believe.

Fortunately, it all appears to be E5 at the moment. It will be more of a problem if/when it switches to E10 but the test cotton buds will presumably not detect the difference- you will need to use the test tube method for that.

When E5 was introduced in Scotland, some super unleaded (super plus in the Rotax SI) remained alcohol free for a while eg at Esso Stations.

Up till recently in the central belt (well, west coast) the BP super unleaded was ethanol free.

A recent test on BP super has revealed that this now contains ethanol too :(

Might try Esso Super next time, but as their marketing bumf suggests, this probably contains ethanol too....

@Forfoxake fresh fuel (purchased Saturday) at the hangar checked and no sign of any ethanol. So it appears it may well be coming from Immingham via Inverness. The explanation circulating for a while was that the finished product did not have ethanol due to being transported by sea. Whatever the reason it demonstrates it's still available.

Are there any sea fed terminals left in the central belt? Is there any supply from Bowling, for example? Or Ayrshire?