X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 30 May 2006 07:12:45 -0400 Message-ID: X-Original-Return-Path: Received: from gateway1.stoel.com ([198.36.178.141] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1132327 for lml@lancaironline.net; Mon, 29 May 2006 20:54:36 -0400 Received-SPF: pass receiver=logan.com; client-ip=198.36.178.141; envelope-from=JJHALLE@stoel.com Received: from PDX-SMTP.stoel.com (unknown [172.16.103.137]) by gateway1.stoel.com (Firewall Mailer Daemon) with ESMTP id 7DE16EB384 for ; Mon, 29 May 2006 17:53:01 -0700 (PDT) Received: from PDX-MX6.stoel.com ([172.16.103.64]) by PDX-SMTP.stoel.com with Microsoft SMTPSVC(5.0.2195.6713); Mon, 29 May 2006 17:53:48 -0700 X-MimeOLE: Produced By Microsoft Exchange V6.0.6249.0 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Subject: Lean of Peak question X-Original-Date: Mon, 29 May 2006 17:53:48 -0700 X-Original-Message-ID: <17E9FE5945A57A41B4D8C07737DB6072037256C8@PDX-MX6.stoel.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: lml Digest #1616 Thread-Index: AcaDBsKv7LGhemtlTOG2jXGjGTkv+AAelh4Q From: "Halle, John" X-Original-To: "Lancair Mailing List" X-OriginalArrivalTime: 30 May 2006 00:53:48.0503 (UTC) FILETIME=[82CC7670:01C68383] Since starting to build my Legacy more than five years ago, I have been = reading all kinds of stuff about lean of peak. The sum and substance of = it seems to be that both traditional wisdom and non-uniform cylinder = peak mixtures dictated rich of peak operation. Then came Gamijectors = and a huge split of opinion as to whether lean of peak operation (now = feasible) was advisable. The debate continues with tradition (it seems) = on one side and the numbers on the other. All this was interesting to me in an academic sort of way until I = started thinking back on my early training (back in the late 60s.) At = that time, there was (I think) a single engine temp guage (pretty sure = it was egt from one randomly selected cylinder) on the Cherokee 140s on = which I trained, but there may have been no engine temperature guage. = Without regard to any guage that might have been installed, I was taught = to lean for cruise by slowly leaning the mixture until the engine ran = rough and then enrichening it enough so that it smoothed out again. Thinking back on this, it seems that there are two possibilities for = what this produced. The first is that the cylinders were peaking at = widely different mixtures. As a result, the procedure I was taught = would produce one cylinder running lean of peak and all of the others = running richer in relation to its peak than the leanest one (God knows = how much.) The second is that the cylinders had a relatively uniform = peak mixture and I was running all four cylinders lean of peak. = Presumably, it varied from aircraft to aircraft. I believe my training in this regard was the standard training given to = new pilots. If so, most of us over a certain age routinely operated = lean of peak on one or more cylinders whenever we followed the training = we were given. Am I missing something?