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91UL / UL91 / 96UL / UL96 / UL98 etc (merged thread)

9.5 to 1 i didn't realise it was as high as that thus it may get approval for way more engines than i originally thought.

peter in the part of the world im based i don't know of a single airfield bar Leeds humberdide etc which prevents mogas via jerry cans. in fact at a couple of strips its your only option.

yes all the micolight and jodel are running on the stuff but also are the majority of privately owned spamcams.

im sure 10% ethanol stc involves more than changing a few seals but technically im certain its possible. the big problem no doubt is the regulations

One thing which I'd like to know about is how people actually manage with mogas.

I understand the UK limit for carriage FOR YOUR OWN USE is 200 litres under the Carriage of Dangerous Goods regulations. I have 3 x 20l metal jerrycans, which I fill - usually at Tesco. I have a sackbarrow which takes the three cans + Flightbag + headset. I wheel this about 200m to Security, then about 250m to the hangar. The Airport has provided Flamable Liquid Cabinets for storing the cans - usually we top up after the flight. I have a wood structure to hold the cans in the car - 13 years left not a mark on the Escort estate. It now fits in the Astra hatch with one rear seat flat. The oldest can will be 23 in late December. PS I test the petrol. Rarely has it shown alcohol. If it came from the Inverness depot, which is supplied by sea tankers, it'll be free. If it came by road tanker from the south, it'll have alcohol. Tesco and Gleaner get mainly from Inverness.

Maoraigh
EGPE, United Kingdom

There was talk of ethanol. We modified a 150 years back to run on pure ethanol - it worked fine. Four of us flew flew a few hundred hours. The modifications were larger fuel lines, a rejetted carburettor, a small gasoline tank for starting the engine, and long range tanks. It ran just great, but it was weird to fly an O-200 powered 150, and see a fuel flow of 11GPH on takeoff. The range was proportionately poor, so if you wanted to go a long way, you did it with full tanks and no passenger.

The challenge to approval was not how well it worked, but how to document it, and provide operating instructions. We could have approved it on pure ethanol, but doing so was pointless, because you could not fuel it anywhere else.

It ran fine on mixtures of ethanol and Mogas (or Avgas), however, the energy content of the mixed fuel was difficult to determine in advance, thus the fuel flow for proper operation had to be determined and set on the roll - literally - during takeoff.... If one had a mixture with much gas, or were on pure gas, it would run super rich, and quit. It was necessary to have the mixture about halfway out when running on pure gasoline, or the engine would quit for over rich.

A fellow named Max Shauk did a lot of research on ethanol powered aircraft, and was very successful. I think it was mostly the unavailability of the fuel for regular aviation use the reason it was a non starter, as well as the aforementioned mixture setting challenges.

It was ultimately these odd, and indescribable operating instructions which made it impossible to approve.

Up to 10% ethanol seems to run within the margins of most engines, though it is not approved within the scope of a Mogas approval. This may be associated with material compatibility more than how the engine actually runs on it. When mixed with water, gasoline containing ethanol can become corrosive to fuel system components in a minor way.

I check every shipment for ethanol coming into my tank, and have never had a problem, though I expect that one day Mogas operation might be a problem - I'll deal with that when I have to!

Home runway, in central Ontario, Canada, Canada

UL91 - situation around Europe?

It's been a bit of a "topic" in the UK, where TOTAL have been giving away bowsers to airfields to encourage them to sell the stuff.

Yet the price differential, initially some 20p in favour of UL91, seems to be slowly disappearing.

There is no obvious reason why TOTAL are now increasing the price.

Some suggest that TOTAL's strategy is to generate demand for UL91 at the expense of 100LL and thus push airfields into no longer offering 100LL. Of course that would ground most of the turbocharged and "high compression" community but a fuel supplier does not have to care for the long term welfare of GA as a whole.

Yet this doesn't make business sense because these high-end 100LL burners also buy most fuel, and with an airfield making something like 30p (or €0.30, approx) per litre gross profit, fuel sales are very important to the airfield, so unless an airfield is such that it cannot cater for the 100LL-only customers (say, 500m grass) it will be placed in a very hard position and will probably resist doing anything that reduces 100LL sales to a point where carrying it might be put at risk. But even the "500m grass" case doesn't make universal sense because all the aerobatic types operate from that perfectly and most of the competitive ones cannot burn UL91.

TOTAL is a French company and France doesn't have a great touring pilot community. So maybe TOTAL sees Robins and more Robins (etc) and simply doesn't know where avgas is going?

Maybe it is just stupidity or arrogance... both are common in business

But I wonder what is the situation elsewhere in Europe.

Taking my favourite corner of it - Greece - very few places there sell 100LL but the number has not reduced since I first flew there in 2004. Well, except a couple of places where specific factors killed it off. Thessaloniki LGTS dropped it because the aeroclub there discovered they could buy it cheaper in drums, so the AIR BP outlet stopped carrying it...... Mikonos LGMK stopped carrying it for some other reason which I believe is fairly specific.

Everywhere, price is slowly going up, but availability appears generally constant.

Are TOTAL pushing UL91 elsewhere and, if so, with what sort of pricing?

How is the UL96 in Sweden working? It isn't pure unleaded avgas like UL91 so in theory there is a fuel system risk (and a need for testing and approvals).

Administrator
Shoreham EGKA, United Kingdom

EDKB: 100LL at 2.55 EUR, 91UL at 2.45 EUR.

LKBU (near Prague), Czech Republic

"Yet this doesn't make business sense because these high-end 100LL burners also buy most fuel,"

Actually at the four airfields that I frequent the flying schools are by far the biggest uses of AVGAS

Actually at the four airfields that I frequent the flying schools are by far the biggest uses of AVGAS

Normally I would expect that, but they could also burn 91UL.

Of the privately owned types, the non-91UL-approved engines tend to be the biggest fuel customers.

Administrator
Shoreham EGKA, United Kingdom

Of the privately owned types, the non-91UL-approved engines tend to be the biggest fuel customers.

Unless somebody has a Lear 24 :-)

A guy I know built hangar complex in Arizona with on-site fuel between the hangars, supplied by him. As one could imagine, his favorite hangar tenants were people with old, relatively low value Learjets.

What I've heard from the USA is that about 70% of 100LL sold there is burnt by about 30% of the fleet.

And that a big chunk of that 30% cannot (presently, or likely future) switch to 91UL.

This would imply that flying schools are not the biggest avgas burners there - unlike here in Europe where that probably is the case. Well, at least at airfields where training takes place and where there is little or no private hangarage. It does seem to be the case that hangarage availability is largely what drives the establishment of a locally based "touring" community. I've long lost count of the owners of "nice" hardware who said they would not base at Shoreham (my base) because there is virtually no hangarage there. But many are based at e.g. Lydd (which almost needs a helicopter to get to ) or Southend.

Administrator
Shoreham EGKA, United Kingdom

I was chatting with the MD of a major GA airfield who was unaware of the existence of UL91 by name, though recognised it when I described it.

That airfield deals with Air BP and they have not mentioned UL91 to them.

The biggest problem for this particular airfield (which is a major supplier of 100LL) would be the cost of storage. They would need a new tank and the substantial cost would have to be justified in terms of sales. Unless the profit margin on UL91 were greater than on 100LL, it would be hard to do that.

I did suggest a bowser, but that would mean employing someone to vend the fuel, adding to the costs. The airfield already offers a discount for using the self-serve pumps.

EGKB Biggin Hill
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