100 Octane LL AV Gas

[L16pilot]

Originally Posted by turbo69bird

There’s a few things I don’t agree with in that article . One is it’s not formulated for low RPM that’s relative. Most lycoming engines run at WOT at 2700 ROM or less many 2100 ROMs on the take off roll. So what low RPM he’s taking about and what the High Rpm?

If it doesn’t last longer that’s news to the aviation and landscapers who use it specifically because it doesn’t gel up like regular fuels.
Also airplane engines have 7.0 to 7.9 to one compression in its most popular engines
MOR rating is only half the story as well when it comes to octane .
I’ve personally drained fuel from an airplane wing that sat for over 10 years that didn’t have a tinge of varnish smell or flakes to it.

Regarding the author's comment about 100LL not being formulated for low RPM, I think what needs to be considered is that when 100LL was created, Tetraethyl lead was the best option to increase the octane rating based on the technology available while meeting all other requirements of recip aviation engines. Your comment about typical GA aircraft engines is correct, (2700 rpm or less), but I think the other performance factors outweighed the operating RPM range during development.

Also, for me personally, Avgas provides other valuable advantages with the prime one being it does not "go bad" in engines/carburetors/fuel systems that sit for extended periods of time saving tons of time/money/effort/frustration. I for one am looking forward to mass distribution and availability of the new GAMI G100UL fuel which promises all the performance/characteristics of 100LL, but without the tetraethyl lead.