X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Thu, 07 Apr 2005 13:32:34 -0400 Message-ID: X-Original-Return-Path: Received: from rwcrmhc12.comcast.net ([216.148.227.85] verified) by logan.com (CommuniGate Pro SMTP 4.3c4) with ESMTP id 860242 for lml@lancaironline.net; Thu, 07 Apr 2005 06:54:03 -0400 Received-SPF: none receiver=logan.com; client-ip=216.148.227.85; envelope-from=mjrav@comcast.net Received: from mark1 (c-65-96-140-242.hsd1.ma.comcast.net[65.96.140.242]) by comcast.net (rwcrmhc12) with SMTP id <2005040710531301400f8flse>; Thu, 7 Apr 2005 10:53:14 +0000 X-Original-Message-ID: <004701c53b60$a9c004c0$f28c6041@mark1> From: "Mark Ravinski" X-Original-To: "Lancair Mailing List" Subject: Warming up and prop cycling. X-Original-Date: Thu, 7 Apr 2005 06:57:59 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0044_01C53B3F.22467B30" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1478 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1478 This is a multi-part message in MIME format. ------=_NextPart_000_0044_01C53B3F.22467B30 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable My opinion - for what it's worth - is that the suggested limits on prop = pitch cycling are similar to the limits for otherwise cold engines. When the prop is deep cycled it places a load on the engine. Tolerances = are not what they should be due to uneven temperatures and the oil is = not working as it does for continuous operation. Consider the fit of a = piston under this condition - The cylinder may be out of round due to = uneven heating, there is combustion on one surface and cold oil on the = other, then you load it so the RPM drops from 1800 to -what- 900? This = puts a strain on the parts and drops the oil pressure and flow too. For our (Lancair) purposes, there is little or no advantage to deep = cycling and there may be the possibility of doing harm. Mark Ravinski N360KB 1321 hrs ------=_NextPart_000_0044_01C53B3F.22467B30 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
My opinion - for what it's worth - is = that the=20 suggested limits on prop pitch cycling are similar to the limits for = otherwise=20 cold engines.
When the prop is deep cycled it places = a load on=20 the engine.  Tolerances are not what they should be due to uneven=20 temperatures and the oil is not working as it does for continuous=20 operation.  Consider the fit of a piston under this condition - The = cylinder may be out of round due to uneven heating, there is combustion = on one=20 surface and cold oil on the other, then you load it so the RPM drops = from 1800=20 to -what- 900?  This puts a strain on the parts and drops the oil = pressure=20 and flow too.
For our (Lancair) purposes, there is = little or no=20 advantage to deep cycling and there may be the possibility of doing=20 harm.
 
Mark Ravinski
N360KB 1321 = hrs
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