Because most of the piston fleet is already designed to run on 91 octane AvGas (leaded or not).
100UL and 91Mogas are different blends entirely. Also, you have to convince companies to specially make 100UL and 91 no-alcohol Mogas (whereas refiners would shout “alleluia” if told that they can just leave out lead out of their regular AvGas blend!).
Because most of the fleet NEVER needed (or wanted) 100 octane in the first place! Your kind of thinking is why we all are stuck with 100LL to this day. Pushing a more expensive fuel is a terrible “solution” for most of the fleet when we already have a drop in perfect solution that may even be less expensive.
You keep glossing over the fact that most of the fleet that doesn’t need 100LL also consumes the least amount of it.
Small, low-compression engines are found in many privately owned and flown aircraft. Their numbers are large, but the amount of hours flown are small, as well as the amount of fuel they consume per hour. In all, they amount to about 30% of fuel sales.
High-compression engines are found in larger/faster aircraft, typically revenue-producing or business use. While there are not as many, they have more engines (think twins), fly more hours and consume a LOT more fuel, both per hour and in total. They consume about 70% of 100LL fuel sales.
A low-octane unleaded “solution” only solves 30% of the problem.
Your solution of “screw the small planes” is not helpful and I’m frankly getting tired of it. This is a positive for GA and for reducing lead so lighten up, Francis.
That assumes that the economics of having 2 or 3 avgas grades of fuel is the same as the economics of having mutiple grades of mogas, but it’s not. It may not be economically worth it for the refiners to make two grades of specialized fuel to be available at every airport.
Yeah not just the refiners but the airports and FBOs who would have to absorb the cost of installing and maintaining new tanks and pumps - not likely to be feasible for most of them. That’s why we don’t even have 94UL or mogas at most airports in spite of lots of planes (including more and more experimentals) being able to use it (and wishing they could).
Right there with you. Can we PLEASE just have access to avgas without any of the additives - lead or otherwise - needed to get it to 100 octane?
Does this mean we will no longer need an STC to us 91UL? If yes, then does that mean the “inventors” of 91UL lose all that money they would have collected? Or is the FAA or someone going to “buy” the rights to 91UL and make it available for everyone? If no, then what does this announcement actually do? All the planes that qualify already can buy an STC and use 91UL.
IF the FAA really wanted to support UL fuel they would"buy" the rights to 100UL and 91UL and allow everyone to make, sell, and use it.
Federally mandated fuels are about maintaining an infrastructure. I’d say it’s better to support/subsidize that here than literally throw trillions of dollars overseas, IMHO.
Because divide and conquer is the goal. The piston GA community is a thorn in their sides, and they want us gone.
I’d be surprised.
And, by the way, it’s not 100% of the fleet. Helicopters (among others) are still waiting…
Will they require a new color dye for 91UL fuel so we know the refinery didn’t ship the same fuel they sell as MOGAS with ethanol in it? Or will it be up to the pilots/FBOs to test the fuel themselves?
Ethanol is added at the rack, not the refinery. Nothing has to change there, the tankers just don’t add ethanol. Simple.
The refinery is not putting out 91 octane… which is WHY they need to add ethanol later. The refinery will need to have a different blend to get 91 minimum which is silly because unleaded AvGas is already available by not adding lead. No change at the refinery is needed.
Just a reminder about Avgas and Mogas… Swift’s UL94 is pretty much 100LL minus the addition of a few drops of liquid tetraethyl lead. That is why it is ASTM certified, meets requirements for stability, vapor pressure, density, etc… And UL91 is pretty much Mogas, excluding any ethanol, which is not available in some places (California…) and doesn’t meet aviation stability specs, but works in engines designed for old mid-grade 91 Octane Avgas… The new compounds from folks like VP, Shell, GAMI and Swift have been tested in some aircraft, but have varying weights, unknown compounds and may or may not dissolve paint, rubber or plastic parts… If you can use UL91 or UL94, it works better in engines than 100LL (just ask old Cessna 152 owners about lead fouling with 100LL!) but if you need all of the 100 octane rating (measured - not calculated - to prevent detonation…) then hang on until plane makers have fully tested their products and refiners have worked out supply chain that is greater than tank truck lots…
It’s not a screw the small planes solution, it’s a keep one fuel that works solution.
Notice the choice of words to “have access”. What you guys really want is for someone else to make an investment to sell you something you don’t buy enough of for it to be profitable.
And, I suspect what a lot of people want is for the high performance fuel to actually become unobtainable so those planes will be scrapped which you guys think will make your planes more valuable. I don’t think it will really work out that way, but the mindset in piston GA is unexplainable if you assume rational actors, so I stopped doing that.
I remember fueling up my Cessna 150 with red 80/87 octane. It’s no longer available.
Why?
Because the avgas market is so small. Splitting it into two even smaller pieces didn’t make financial sense.
With 80/87 (red) and 100LL (blue), an FBO has twice the number of pumps to buy and maintain. But one pump (blue) outsells the other by over 2-to-1. Now they have a pump (red) that costs just as much as the other, but sells less than half the volume. Which means the cost per gallon will go up a bit due to the lower volume. And you can’t sell more of it because the red only works in some planes, but the blue stuff works in everything.
It didn’t take long for the industry to settle on one pump selling 100LL.
Now, 91UL is a bit different, being essentially a by-product of mogas production so it’s already widely available. But as others have pointed out, it likely only makes sense for an FBO to put in a second pump for it if there’s a large population of low-compression singles based at their airport.
Why don’t you talk to your local FBO and ask them what they would do?
Ends up that information about the valves, and the unleaded fuel is just a Myth.
UL 94 is the future. The drop in UL 100 will be way to expensive because it is synthetic blend. The aircraft that now require 100 octane fuel can be modified as they should have done years ago, instead of holding all the other aircraft hostage.