X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Thu, 21 Sep 2006 11:27:02 -0400 Message-ID: X-Original-Return-Path: Received: from secure5.liveoakhosting.com ([64.49.254.21] verified) by logan.com (CommuniGate Pro SMTP 5.1c.4) with ESMTPS id 1413346 for lml@lancaironline.net; Thu, 21 Sep 2006 10:37:17 -0400 Received-SPF: none receiver=logan.com; client-ip=64.49.254.21; envelope-from=walter@advancedpilot.com Received: (qmail 440 invoked from network); 21 Sep 2006 09:36:35 -0500 Received: from 216-107-97-170.wan.networktel.net (HELO ?10.0.1.3?) (216.107.97.170) by rs5.liveoakhosting.com with SMTP; 21 Sep 2006 09:36:35 -0500 Mime-Version: 1.0 (Apple Message framework v752.2) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-1-153636799 X-Original-Message-Id: From: Walter Atkinson Subject: Re: [LML] Backfires LOP X-Original-Date: Thu, 21 Sep 2006 09:37:43 -0500 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.752.2) --Apple-Mail-1-153636799 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Jim: **I believe that the ROP has excess fuel which should cool the burn and just maybe leave MORE lead on the valve stem than while LOP.** 1) The excess fuel really does not cool the burn. What happens is that the excess fuel delays the burn RATE, which delays the peak pressure, which lowers the pressure against the thermal boundary layer and decreases the number of BTUs that are transferred into the metal. 2) I garner from your statement that you think lead in the fuel helps lubricate the valves. This is another OWT. Lead as it exists during and after the combustion event is a salt of bromide. (Bromide is added to the fuel to scavenge the lead so it leaves the combustion chamber, rather than leave deposits. Since the temp of combustion is around 3800 dF and the lead salt melts at 1308dF, it leaves the combustion chamber as a gas.) In any case, salts are abrasive. Abrasives make really poor lubricants. Lead does nothing to lubricate the valves. Nothing. Walter --Apple-Mail-1-153636799 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1
Jim:

**I believe that the ROP has excess fuel = which should cool the burn and just maybe leave MORE lead on the valve = stem than while LOP.**

1) The excess fuel really does not cool the burn.=A0 What = happens is that the excess fuel delays the burn RATE, which delays the = peak pressure, which lowers the pressure against the thermal boundary = layer and decreases the number of BTUs that are transferred into the = metal.

2) I garner from your statement that you think lead in the fuel = helps lubricate the valves.=A0 This is another OWT.=A0 Lead as it exists = during and after the combustion event is a salt of bromide.=A0 (Bromide = is added to the fuel to scavenge the lead so it leaves the combustion = chamber, rather than leave deposits.=A0 Since the temp of combustion is = around 3800 dF and the lead salt melts at 1308dF, it leaves the = combustion chamber as a gas.)=A0 In any case, salts are abrasive.=A0 = Abrasives make really poor lubricants.=A0 Lead does nothing to lubricate = the valves.=A0 Nothing.

Walter

= --Apple-Mail-1-153636799--