I'm flying a Cherokee 140 that does not have EGT but does have a CHT. The gauge has a a star sy mbol on it but I dont reallly know what it means. One day while I was leaning the CHT went above the star so I richened the mixture back below it. Is CHT an effective instrument for leaning? There are no colored markings on the CHT.
Jack Cooper ----- Original Message ----- From: "Mark Langford" <n5...@hiwaay.net> To: "KRnet" <kr...@mylist.net> Sent: Tuesday, August 25, 2009 7:47:13 AM GMT -05:00 US/Canada Eastern Subject: Re: KR> Was Flying again, now EGTs Jeff Scott wrote: > EGT temps really aren't important unless you are worrying about melting > down your exhaust pipes. They vary depending on altitude, mixture, RPM, > and engine. The actual number isn't important, but is typically used > only to measure the current EGT reading vs Peak EGT reading. Yep, I was planning on going into more detail when I started writing that reply, but ended up hitting the "send" button before shutting the computer off, not realizing I really hadn't finished it yet. I'd have hoped that Dan (and others on the list) have figured out what their peak EGTs are under different throttle conditions, in order to get a feel for what's normal and what's way too rich (much lower EGTs). Just to make sure the carb is set up properly and has a full mixture range, it'd be prudent to make sure you could find a peak value and have enough mixture control to make the mixture leaner on either side of peak temperature, by both going richer and leaner than peak EGT. Some people are probably flying way too rich and don't even know it, which can lead to heavy carbon deposits and shorter cylinder wear due to "washdown" from excess fuel. Flying without an EGT meter is a recipe for that kind of problem, because you'd really have no idea what your mixture is, although I suppose you could adjust it by finding max speed at a given throttle setting, come to think of it, again assuming you get less power at both the lean and rich sides of max speed. Of course some folks are flying without a mixture control at all, so maybe I'm just getting all worked up over nothing, but I'd think judicious leaning would save enough fuel to make a real difference over the life of the airplane to justify a "proper" aircraft carb. Well that's another can of worms better left tighly closed... Mark Langford, Huntsville, AL mail: N56ML "at" hiwaay.net website: www.N56ML.com _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
