UL 94 is simply 100LL without the lead. Swift fuel is different. I followed this topic closely initially but am now in the wait and see what develops mode. One concern has been having a “drop in” replacement for 100LL so that the fuel will be compatible with the delivery system including trucks, tanks, pumps and hoses as well as the end user airplane.

I recall the Swift fuel having higher energy content than 100 LL. More BTU’s per gallon.

UL94 was/is a stepping stone fuel for the eventual replacement by Swifts 100R. Both fuels evolved simultaneously but Swift needed additional testing for the 100R. Burt Rutan has been involved in the tests and used the UL94 for over 5 years without any issues. The 100R has passed all tests to date with identical octane as 100LL, and is very clean burning. Engine testing with turbo charged manifold pressures resulted in no detonation/pre ignition in-all conditions without lead deposits in the combustion chamber and on spark plug electrodes. Oil contamination from combustion by products is non existent. Swift claims double the oil change interval subject to manufacturer’s approval.

So the reason they put your request off is they are ready to phase in 100R and discontinue UL94.

The above can be sourced from the FAA webinar achieves from the Swift fuel presidents address on the current state of fuel 100LL replacement.(August 2023)

Interesting. UL94 is Swift Fuel out of Purdue right? I have been having a running conversation with the marketing / sales guy at Swift Fuel. I have asked to purchase around 500 gallons of UL94 in drums or preferably a tote. They don't really want to sell it to me. They want me to buy 8000 preferably 10,000 gallons. I've told them I'll come to them or to the place of their choosing to pick it up and truck it back to Oklahoma myself. I've asked for wholesale pricing in exchange for sharing my findings with them but the price isn't so important for running the tests I want to run. Again, they don't seem to be interested in helping me. I have no doubt that UL94 will run fine in an E-series engine. I want to run many tanks full alternating with 100LL here in Oklahoma in my controlled environment to see what sort of "second order issues" crop up. I hope that there are none.

When I was forced to give up 80 octane I discovered a number of issues that took me about ten years to get fully resolved. Today, I enjoy being able to operate on 100LL consistently well but only if I treat every gallon of fuel that I run. For years all I heard was there was something wrong with me and that it couldn't possibly be the fuel. That was just wrong. Of concern to me today is this AOPA notion that there can only be one fuel for all piston engines. It may be true, I don't know but I view an absolute like the one fuel concept to be politically motivated. However, if anyone out there thinks that the "new" fuel whatever it turns out to be is going to be even remotely affordable, you are dreaming.

Not that anyone cares, but here is what I want: I want every fuel farm at every GA airport to be a store of the "no-lead" version of 100LL with self service pumping available. This is aviation alkylate at an octane rating of between 94 and 96 depending on the exact refined products used to make it. Now before you guys go apoplectic on me, I suggest that the 100 octane people need be achieved at the fuel truck level; meaning, the FBO guys can dump in the TEL cocktail in the truck and top it off with the stock aviation alkylate. This would give you exactly the same 100LL formulation that you currently use. The concept allows the other solutions namely the Phillips solution, the ADA solution or an ether solution to be evaluated in the free market place by the users. In addition, everyone with a need for higher octane could make their own determination as to how much extra octane they need or want to pay for. I can go on and on about this but you get the idea.

The bottom line is that if you want reasonably priced fuel going forward, we have to let free market capitalism figure it out, not the EPA and certainly not the FAA. I am not advocating for TEL. In fact I don't like lead, have never wanted to be forced to use it, and am amazed that I have had to use it for 4500 hours over 40 years. I know people think that TEL is going to go away. I think it should. However, TEL is made in Russia, China, India and probably others. There is a market for TEL and as such, you will likely always be able to get it. Just because the Octel facility in the UK may stop making it, doesn't automatically mean you won't be able to get it.

As Eric likes to say...."just the view from my hangar"

Andy

Coming in April , UL94 to Santa Monica