Return-Path: Received: from [65.33.160.181] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 4.3c2) with HTTP id 763669 for lml@lancaironline.net; Mon, 28 Feb 2005 18:17:44 -0500 From: "Marvin Kaye" Subject: Re: [LML] Re: FADEC Rough idle explanation To: lml X-Mailer: CommuniGate Pro WebUser Interface v.4.3c2 Date: Mon, 28 Feb 2005 18:17:44 -0500 Message-ID: In-Reply-To: <45fd8f2c19b858511b88f34ed896331c@advancedpilot.com> References: <45fd8f2c19b858511b88f34ed896331c@advancedpilot.com> MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Transfer-Encoding: 8bit Posted for W Atkinson : Matt: No need for a flame suit! About twenty years or so TCM had a fuel system like you are describing. It worked exactly as they wanted it to work. It was complex. It worked. At the rpms, powers, and FFs we are running, it became so close to a constant flow system that TCM decided that it wasn't worth the added complexity for such a minimal gain. I think TCM had it right 20+ years ago. I, like you, use my airplane for serious travel. Dispatchability is a big issue with me. That's one reason I like to think that the best and most elegant solution will be the simplest. Since the gains from adjusting the spark are very large and the gains from further fine-tuning the fuel injection are at best, marginal, that is the approach that I think is most likely to yield the most gain for the most reliability and best dispatchability--and cost. It is an important concept to appreciate that oftentimes the enemy of good is an attempt at better! Now, all of that said, the pilot public seems to be all wrapped up in making airplanes like cars--to what end, I'm not sure. That may SELL a system that is actually inferior. As an example, the engine monitor manufacturers know that the DIF function on the monitors is frequently misunderstood and not very helpful. Pilot's think it's a big deal and it's a selling point, so they keep it---all-the-while knowing that it's non-contributory to anything useful in injected engines and is a source of confusion. IMO, so goes sequential fuel injection in aircraft engines. It doesn't help in any meaningful way, but , by gum, if the pilots think it's a big deal, we'll make it -- even at the expense of reliability, weight, cost, maintenance, and common sense. Ain't Amureca great? Walter