There are some materials which can tolerate no more than 1% alcohol. For example the TB20 fuel system limit is 1 or 2% alcohol.
Water is not a problem until you get some and then it is 
I don’t think it is BS. It is the same old “GA problem” in that the vast majority of pilots never fly further than say 100nm and never above say 3000ft and never in the winter, etc, etc, so the internet fills up with people saying There is no problem with X when actually they don’t have a problem because they never exercise the holes in the cheese. Like my elevator trim freezing solid at 14k, at -14C, due to the maint co. using a motorcycle spray lube whose temp range is nowhere specified and whose mfg told me “we have never had any complaints”
Anyway, regardless of whether ethanol does it, we are stuck with it (well most of us are) if we are to use forecourt petrol
Oh and this is before one gets onto the topic of these
being totally useless except for this
unless you have one of these
and this is your wife
An easier route (legally) is to buy a bowser and organise with a fuel delivery company to fill it up somewhere. A lot of people around Europe do this, with 100LL too, some posted about the regulatory mess around it all, but the proper solution – a fixed pump at the airfield/strip – is going to kill off activity quite well where it doesn’t currently exist, because most people in GA are not interested in sticking their hands in their pocket and want somebody else to pay for stuff
We need a straight 100LL replacement and we can all carry on. Those on forecourt petrol (I won’t use “mogas” because of the ambiguity) have presumably already made their own arrangements, or have adjusted their flying patterns where the stuff exists.
I don’t think cars get water in their tanks. Planes have tank vents, dodgy filler cap seals, etc. Bad seals there is just a hole in the cheese, but at least if you drain your tanks you will see the water there, but if it absorbed then you won’t see it.
Yes I think Viton is a solution, but it’s not an option for fuel tank bladders, or the/some sealants in wet tanks.
Here is an entire master’s thesis (70 pages) on aluminium alloy corrosion in alcohol-blended fuels and the contribution of dissolved water to such corrosion. Here is a somewhat shorter research paper on the same topic, and here is a position paper of the National Marine Manufacturers Association regarding both aluminium and fiberglass tanks filled with such fuels. More publications can easily be found on the web.
Another challenge with “mogas” is can you be sure it does not have ethanol? I used a lot of mogas in my RV-8 from BP in which the CH website says that it does not contain any ethanol. Can I really trust them? I used to say, sure, no problem, since my entire fuel system consisted only of components I confirmed were happy with ethanol in the fuel, so if they do change their blend, not a problem.
Then, my boost pump manufacturer, Andair, comes out with an SB (https://www.andair.co.uk/about/service-alerts/) that says, “Well, heck, darn. We were wrong. It seems our pumps are affected by mogas with ethanol. Ooops. Our bad!” So, I’m back to UL91 (thankfully available on my airfield) and 100LL when traveling, since UL91 seems really hard to get, for some reason.
I sincerely hope we ban leaded fuel across the whole planet, and let companies like GAMI sell theirs. There will be other competitors. I just hope that the chemicals that they put into the unleaded G100UL are not worse for our health, the environment, or our engines than 100LL. Unintended consequences?
Darkfixer wrote:
According to German AOPA at least 3 manufacturers has applied for approval for 100LL after 2025.
My guess is BP and Shell, and most likley Hjelmco oil has applied and Warter as Peter wrote…
On the same webpage it says that in next coming months that EU will get back on the topic.100LL will be replaced in future for example Gami 100UL, question is when.
If I understand it correctly there are 1 approved 100UL and 2 other on the way.
I also know that Hjelmco has 100UL since 10-15 years back, but it’s not certified due to costs.If 100LL would be banned 2025 in Europe, then it would be devastating to the GA community.
Update:
Hjelmco has not applied for ban exemption.
They buy their 100LL from some producer in Europe.
At least fibre glass tanks on motorbikes have been known to start leaking maybe 20 years before any alcohol was introduced in gasoline.
The alcohol now in gasoline melts the polyester resin that was once used successfully to manufacture motorcycle and small boat fuel tanks (in say the late 60s and 70s). They have to be lined now or you have problems in short order. This stuff works pretty well. This is one reason why boats and docks in the US are supplied with dedicated boating gasoline that has no alcohol.
Later, in the late 90s, when the European motorcycle manufacturers (actually meaning Acerbis, their fuel tank supplier) introduced plastic fuel tanks that had no problems in Europe (where fuel didn’t yet have alcohol) to the US market, there were major problems, for example tanks expanding to the point where they couldn’t be reinstalled when removed. There were also bubbles under the paint resulting from fuel leaching through the tank but this may occur with any fuel. Tanks were often replaced under warranty twice, before the warranty ran out, but no long term solution was implemented for the benefit of existing owners. The US owners of the affected 90s bikes found that if you had two tanks, drying one out and storing it a while would result in it shrinking back to the point where it could be reinstalled. So every time you remove the fuel tank, you reinstall the other one, and you run them in sequence. They can also be lined, as you would a polyester resin fiberglass tank. The ultimate solution for the manufacturers was a different design approach that uses alcohol resistant plastics that unfortunately cannot be painted, underneath painted plastic panels installed for cosmetics. I prefer steel or aluminum tanks.
The vast majority of ULMs here in France have been using unleaded 95 or occasionally unleaded 98 from the local supermarket, over at least the last decade.
The supermarket unleaded 95 is either E5 or E10.
We have around 30-40 ULMs based here now and we have had 2 fuel related problems, both at the carb. Both resulted in a strange noise and vibration at around 2500RPM. The carbs were adjusted and no further problems ensued. Whether this had anything to do with alcohol no one commented on it being the likely cause.
There are pilots here who carry out the same sort of missions at the same sort of altitudes as @Peter. They do not of course fly in IMC or at night, but many do fly through and over mountains.
We used to have many aircraft based here which used 100LL but their numbers have dwindled. Those who must have 100LL now number 1 or 2.
We used to have AVGAS 100LL on the field but now there is no real demand and when the reservoir sprung a leak, no one was prepared to stump up the money to repair it. It’s not a big problem as we have at least 3 airfields within a 15min flight including integration in the circuit with 100LL.
As Peter says the bigger problem of using mogas/ sp95/sp98/ul91 etc is its availability on airfields. Especially as the increase in ULMs has led to the use of much smaller airfields where there is unlikely to ever be a fuel supply.
One has to assume that as Rotax engined aircraft filling more of the usual GA market, including twins that sooner or later more of the airfields, currently having fuel pumps, will either add mogas (generic term) pumps or replace 100LL pumps with the more in demand mogas pumps.
If a replacement for 100LL is going to be coming, it needs to be soon, otherwise at many airfields it will no longer be economically viable to switch to it.
