lml@lancaironline.net Mailing List Archive

Posted for "Shannon Knoepflein" <kycshann@kyol.net>: I have to comment on this. First of all, you have to be careful of what you read and how you interpret it. The biggest deal I see here is the reference value. People see the word "lean" and they automatically associate that with LOP. This is NOT the case. A person can be running 100 ROP and "lean" it out a bit, to say 25 ROP (the worst area to run BTW IMHO), but they are still running rich....rich of stoichmetric. So, when the ASTB said "lean", it is not clear if they were talking about LOP, or just "lean" of ROP, closer to stoich. From what I read, they meant "lean" of ROP, closer to stoich, not LOP. Also, I'm an engineer, and I've NEVER even heard of lead oxy-bromide or whatever they are talking about. None of my peers have either. Here is another take on the article: http://www.avweb.com/articles/pelperch/pelp0057.html There are several good articles on LOP operation in the articles here: http://www.avweb.com/articles/pelperch/ Also, check out http://www.gami.com Basically, my point is you have to understand and qualify what you are talking about. Just saying "lean" is useless. Lean of what? When I dropped our C182RG off at AirPlains in Wellington, KS (KEGT) last week, I got to see the C172 that Unisys and Lycoming are working on, developing the EPIC system. A discussion with both their engineers lead to exactly this discussion. They agreed that you have to qualify what you say, that 75-100+ ROP is safe, that 25-50 ROP is the worst area to run, and that 50 LOP to stoich is the best place to run. Their EPIC system (unlike the FADEC system which will continue the silliness of 50 ROP) will run AT stoich, or at peak if you will, or just a little lean of it. The ONLY reason they don't run it slightly more LOP is the power dropoff that they can't get back on NA engines. It seems people are finally starting to come around to the way things used to be done, with the old radials. Radials that had 3000-4000 hour TBO's were always run LOP. --- Shannon Knoepflein <---> kycshann@kyol.net