UL91

paul330 · Post by **paul330** » Tue Aug 16, 2011 11:27 am

Glad to see the news in the last LAA mag that UL91 is becoming available. However, I was quite surprised that it was mentioned that approval is needed from Lycoming. They have an SB out approving UL91/97 produced in Sweden plus several versions of the fuel from the ex-Eastern bloc countries. If the Total product meets the spec for UL91 AVGAS, isn't that good enough?

Brian Hope · Post by **Brian Hope** » Tue Aug 16, 2011 1:23 pm

Hi Paul, from an LAA permit aircraft perspective I believe it will be a very straightforward job for Engineering to approve UL91 for use in almost all of the fleet. Rather hypothetical at the moment though because supplies are not yet available on the UK market. I understand they will be some time in September.

paul330 · Post by **paul330** » Wed Aug 17, 2011 7:03 pm

No problem there - don't think my -10 will be ready before September anyway (2013, that is - hope to get to the LAA rally then). Was rather more interested in the approval process. I can't believe every suppliers fuel has to be individually approved. If it meets the spec (as Total AVGAS 91UL obviously does) and the engine is approved to operate on UL91 (as Lycomings are) then .......

G.Dawes · Post by **G.Dawes** » Wed Aug 17, 2011 8:53 pm

If this new wonder fuel becomes the specified fuel what do you think will happen to the price of it, I predict a price of £2.20 a litre or more as the low production and scarcity of supply will make a premium product bit like Unobtainium. you want (NEED) it, the price goes up. ordinary 100LL is about £2.10 now.

Brian Hope · Post by **Brian Hope** » Thu Aug 18, 2011 7:21 am

You know Graham, every now and again it might be an idea to look at the glass as if it were half full, it really does make life much more pleasurable. We know that 100LL has a finite life, five years, maybe ten and it will be phased out. The fact that Total, and at least one other company in Scandinavia, are already working on, and now providing, replacement fuels surely has to be a good thing - none of us want to get to the point where 100LL becomes increasingly difficult to get (and thus even more expensive) and no alternative is available.
And for Rotax owners this fuel is a godsend, none of the havoc that lead plays on their engines and no worries (if they're group A) of being illegal on mogas that has ethanol in it.
My prediction is that other brands of 91UL will come on stream and 100LL will gradually be replaced by it because for the vast majority of the UK GA fleet it is a more appropriate fuel. Hopefully too 5% ethanol will be shown to be acceptable with appropriate fuel system materials compatibility and that too will become an option again.
Now, doesn't that make you feel more cuddly and warm than taking the glass half empty approach that we're all going to get ripped off?

G.Dawes · Post by **G.Dawes** » Thu Aug 18, 2011 7:52 pm

You just have to do it don't you, How much do think it will be? Most of the outlets in this country do not have Total.

Rod1 · Post by **Rod1** » Thu Aug 18, 2011 8:35 pm

It will be priced between mogas and 100LL. As close to 100LL as Total can get and still advance market share.

Rod1

paul330 · Post by **paul330** » Wed Dec 07, 2011 8:54 am

I see with (possible) dismay that the LAA approval for UL91/96 Avgas does not include the IO540. This is despite the fact that it is approved by Lycoming under SB1070Q (but not Mogas or 80/87 Avgas as required by the LAA document). Since the 540 is simply a 360 with an extra bank of cylinders, I fail to see why this should be - or have I missed something?

Nigel Hitchman · Post by **Nigel Hitchman** » Wed Dec 14, 2011 6:59 pm

Paul,
I think you missed something, as did quite a lot of others. The 96UL approved by Lycoming is the Swedish stuff, this Total 91UL is a different fuel with lower octane rating. I was hoping it might be approved for my 160hp O-320 too

Dave Hall · Post by **Dave Hall** » Wed Dec 14, 2011 10:40 pm

Thanks for confirming that, Nigel. I was getting excited too about the 91UL in an O320-B, from reading a Lycoming bulletin, but alas it doesn't seem to be the same stuff as 91/96UL, that is approved, but isn't available in the UK as far as I know.

Maybe if 91UL ends up with too small a market, they will up the octane rating so the market becomes economically large, as well as more ecological.

Brian Hope · Post by **Brian Hope** » Wed Dec 14, 2011 10:57 pm

Hi Dave, with pretty well all but the 160 and up Lycomings being able to use the fuel I don't believe it will have 'too small a market.' There are an awful lot of small Continental, Gypsy, Rotax, Jabiru, VW etc engined aircraft out there to fill the coffers of anybody selling UL91. No doubt a 100LL unleaded equivelent will be available in the UK at some point in the not too distant future.

Nigel Hitchman · Post by **Nigel Hitchman** » Fri Dec 16, 2011 9:52 am

However, Im told that work is in progress to see if the total 91UL can indeed be approved for other lycoming engines, so I guess its watch this space!

paul330 · Post by **paul330** » Sat Jan 07, 2012 4:33 pm

The fact is that there are plenty of 8.5:1 compression ratio 4 cylinder engines approved for Mogas and UL91. Lycoming never approved any of the 6-cylinder engines despite being the same compression - probably due to liability issues associated with the larger aircraft using the engine.

Perhaps I did misunderstand. I thought the Total UL91 was being marketed as a 100LL replacement but it appears to be more of a guaranteed quality Mogas. I still don't believe that any of the standard compression non-turbocharged engines would have any problem running it. In fact, many of the approved 4-cylinder engines (IO360 -B -M) are in the same block as the IO540-D in SB1070Q which states 91/96 rather than 80/87.

So, the simple question is - Why should 4-cylinder 8.5:1 compression ratio engines be approved for UL91 whilst 6-cylinder engines aren't?

Rod1 · Post by **Rod1** » Sun Jan 08, 2012 6:02 pm

List of airfields who have had deliveries of Avgas UL91 already

Barton
Compton Abbas
Dunkeswell
Henstridge
North Weald
Rochester
Turweston
Thruxton
Wellesbourne
Wolverhampton

Final stages of preparation

Popham
Gloucester - Staverton
Sleap

10 further locations WIP

It is expected that 80% of SEP’s will be cleared to run on this fuel within the next 2 years.

Rod1

mcrunden · Post by **mcrunden** » Thu Jan 12, 2012 9:34 am

I was hoping to be able to run our Lycoming 320 -d (160hp) on the new UL91 fuel but see that it's not listed as approved by the LAA.

The Lycoming Service Instruction SI1070Q list includes alternative fuel UL91/96 which I guess must be Hjelmco Avgas 91/96 UL which is not the same as the Total UL91. However when looking through the EASA SIB 2011-01R1 (table 1) the UL91 Octane ratings appear to be the same or slightly higher than the UL91/96 fuel.

Does anyone know why engines cleared for UL91/96 are not approved for the new UL91 or is it just that Lycoming haven't got around to approving it yet?

Light Aircraft Association

UL91

UL91

UL91/96 for IO540?

UL91