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USMCmech · September 22nd, 2004, 09:15

This is a copy of a question Roundout sent me as a PM.

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hey there mr. Mech,

i have a quick question regarding octane ratings. my girlfriend (commecial applicant) called me regarding her systems homework. she was talking about 100 octane avgas being the leanest performance and 130 being the richest performance. first thing that struck me is "wtf is she talking about?" i had her read it to me straight out of the book, and sure enough, the book made some reference to lean and rich performance based on the octane rating of the gas you're burning. now i'm thinking "what is this book talking about?"

i consider myself decent at systems, but this flew completely over my head. i can get you a direct quote out of the book if you'd like it.

TIA for the help, if you have any idea what this book is trying to say, or if i'm blatantly missing something.

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No fair, you made me look stuff up! [img]/ubbthreads/images/graemlins/cool.gif[/img]

Currently only 100LL is being produced, so it's really a dead issue. If anybody asks your GF about any other type, tell her to say "I don't care, since they aren't in production anyway."

There were two other grades for aircraft, but they have gone out of production.

80-87 octane (colored red). Mainly used in very old airplanes, WW1 era.

100-130 octane (colored green) This was basicly an expirment that didn't take off. It was an aromatic blend that had diffrent levels of additives (mainly Benzol) which would boost the "octane" rating.

100/130 is a diffrent way of describing the "octane" rating where there isn't any isooctane in the fuel. These are called the performance numbers

100 is lean best power, and 130 is rich best power.

100/130 avgas was very damaging to any rubber parts it contacted. It would eat away at rubber fuel baldders, and hoses. This is probably why it disapeared.

I think I will add this to the "Tech Trivia" thread with your permision. I think it will be informative to others.

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September 22nd, 2004, 09:15	#27
USMCmech Old Skool Join Date: May 2004 Location: Dallas TX Posts: 1,717	Re: Today\'s Tech Trivia #4 This is a copy of a question Roundout sent me as a PM. [ QUOTE ] hey there mr. Mech, i have a quick question regarding octane ratings. my girlfriend (commecial applicant) called me regarding her systems homework. she was talking about 100 octane avgas being the leanest performance and 130 being the richest performance. first thing that struck me is "wtf is she talking about?" i had her read it to me straight out of the book, and sure enough, the book made some reference to lean and rich performance based on the octane rating of the gas you're burning. now i'm thinking "what is this book talking about?" i consider myself decent at systems, but this flew completely over my head. i can get you a direct quote out of the book if you'd like it. TIA for the help, if you have any idea what this book is trying to say, or if i'm blatantly missing something. [ QUOTE ] No fair, you made me look stuff up! [img]/ubbthreads/images/graemlins/cool.gif[/img] Currently only 100LL is being produced, so it's really a dead issue. If anybody asks your GF about any other type, tell her to say "I don't care, since they aren't in production anyway." There were two other grades for aircraft, but they have gone out of production. 80-87 octane (colored red). Mainly used in very old airplanes, WW1 era. 100-130 octane (colored green) This was basicly an expirment that didn't take off. It was an aromatic blend that had diffrent levels of additives (mainly Benzol) which would boost the "octane" rating. 100/130 is a diffrent way of describing the "octane" rating where there isn't any isooctane in the fuel. These are called the performance numbers 100 is lean best power, and 130 is rich best power. 100/130 avgas was very damaging to any rubber parts it contacted. It would eat away at rubber fuel baldders, and hoses. This is probably why it disapeared. I think I will add this to the "Tech Trivia" thread with your permision. I think it will be informative to others. [/ QUOTE ] [/ QUOTE ]