Frans wrote:
Our mechanics received a service bulletin from Rotax, where UL91 was banned for use with our Rotax 914 engine. It might not be banned for other engines, but it was a clear statement.
Does the ban also apply to Hjelmco 91/96UL?
According SI-916 i-001R2 / SI-915 i-001R3
SI-912 i-001R8 / SI-912-016R13
SI-914-019R13 (out today 30 September) UL91 and UL94 can be used (also in Rotax 914). Minimum RON (Research Octane Number) is 95 but 98 for Rotax 916 iSc. Hjelmco should be okay as it matches the appropriate requirements, although not explicity mentioned.
@Frans could you link the SB which bans UL91 usage for Rotax 914?
FAA approves lots of engines for GAMI 100UL
This thing seems to be moving forward.
I can’t wait for unleaded fuel to be widely available to the market. I’ve had 3 stuck exhausts valves so far this year and I would like to think this will be reduced if we had the option to run on unleaded fuels.
Do you lean aggressively (also on the ground)?
Peter wrote:
This thing seems to be moving forward.
Perhaps, but it’s a bizarre twist to be honest, and too little, too late. No one cares about the tiny amount of lead used in piston aircraft anymore. The average politician today have no clue what this is all about in any case. Lead in gasoline was removed decades ago as far as they are concerned. CO2 on the other hand is very much on the agenda, the carbon footprint. (not that the average politician has much clue on this either, but it is firmly on the agenda, and that’s the only thing that matters)
Since 1985 the Team Vanguard has been flying on shows promoting 100% ethanol. This is on RV-3s with IO-320.
Ethanol is taking flight as America’s premiere renewable fuel. The Vanguard Squadron flies a dazzling four ship formation aerobatic airshow powered by ethanol. The Vanguard Squadron has been ethanol powered since the team began flying together in 1993. Ethanol adds power and performance to the Squadron’s aircraft without any major engine modifications. The team has over 3,000 flight hours using 100% ethanol. The Squadron shares their love for flying and raising ethanol awareness by flying airshows across the country. The Vanguards are available for fly-bys for events such as ethanol plant openings, parades and ground breaking ceremonies. The Squadron flies 10-15 airshow events each year. Flying across the country promoting ethanol as the fuel for the future has introduced the Squadron to many people interested in aviation and alternative fuel solutions.
The writing on the wall is pretty clear IMO. It’s either electric or at least zero carbon footprint. Ethanol works just fine with loads of “octane” and power for even the most demanding tasks (Indy car for instance). The entire fleet of piston GA could use ethanol with only minor tweaks, or at least E85.
The entire fleet of piston GA could use ethanol with only minor tweaks
I don’t think so; check out common fuel tank sealants (PR…) and their alcohol tolerance. It’s only a few %.
This thing seems to be moving forward.
No turbocharged engines in that list. Maybe next year ? 🤞🏼
Peter wrote:
check out common fuel tank sealants
Requiring a minor tweak to work 
Which really pinpoints the main problem. This 100UL is a fuel for yesterday technology. Here yesterday means 50+ years ago. But, as this Team Vanguard has shown since 1985 (which already is 36 years ago), ethanol works just fine on ancient technology, and is much more future proof than any fossil fuel.
According to the internet, the production of ethanol (as fuel from bio material) is about 25 billion gallons per year. The production of 100LL is about 150 million. That’s more than two orders of magnitude difference. The production of fossil gasoline must be 10-20 times the production of ethanol, more than 3 orders of magnitude. For each liter of gasoline produced, there are produced 50-100 ml of ethanol and less than 1 ml of 100LL.
What it boils down to is how much impact does 100LL do on the global environment. It’s minuscule, less than 0.1 percent of gasoline. Then add diesel, fuel oil (for ships) and jet fuel. Haven’t looked it up, but in total it must be somewhere between 0.01 and 0.05 percent, or 100 to 500 ppm. Clearly this is no big fish by any stretch of the imagination, and who knows what kind of other nasty stuff burning this 100UL creates? The problem with lead was pollution in cities with high traffic as I remember, it was not a global concern of the environment. Although it certainly could be if this was allowed to continue.
With such small values, it all becomes 100% symbolism IMO. Meaning it feels better to tell people my hobby doesn’t pollute, even though it makes no real impact on the environment either way. How would I like the future to be? pay more for this symbolism? or would I rather pay considerably less for something that is infinitely better for the environment (and the engines), like E85, 100% ethanol or the best option: battery electric power.
I will definitely chose the latter. For those who cannot (read: will not) change to cleaner fuel, I think using true and trusted 100LL or 100UL makes no measurable difference on anything other than the cost of fuel. 100UL is more expensive.
Maybe because Ethanol has only around 60 percent the energy density of gasoline?
Years ago the UK AAIB published a report on a guy who ran his Cessna on paint thinners. I can’t find it now – maybe someone has a link? Poor guy had the misfortune to hit a post or something, causing a leak which someone noticed.
They were gung ho to show how reckless this was, setting up a test engine to prove it. Unfortunately, the engine ran just fine. So they had to resort to all the familiar ‘seal damage’ etc..
What goes around …
