Return-Path: Sender: (Marvin Kaye) To: lml Date: Fri, 15 Nov 2002 09:14:33 -0500 Message-ID: X-Original-Return-Path: Received: from scaup.mail.pas.earthlink.net ([207.217.120.49] verified) by logan.com (CommuniGate Pro SMTP 4.0.1) with ESMTP id 1871600 for lml@lancaironline.net; Fri, 15 Nov 2002 07:53:18 -0500 Received: from user242.net005.fl.sprint-hsd.net ([205.245.15.242] helo=Peter) by scaup.mail.pas.earthlink.net with esmtp (Exim 3.33 #1) id 18CfyH-000141-00 for lml@lancaironline.net; Fri, 15 Nov 2002 04:53:18 -0800 From: "Peter Van Arsdale" X-Original-To: "'Lancair Mailing List'" Subject: Prop driving a crankshaft X-Original-Date: Fri, 15 Nov 2002 07:52:55 -0500 X-Original-Message-ID: <007301c28ca5$ee536350$6402a8c0@Peter> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0074_01C28C7C.057D5B50" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.3416 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_0074_01C28C7C.057D5B50 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit One of the absolute no-no's when flying a DC-3 was to never reduce the power below "square" ( M.P. x 100 never less than RPM) other than at the flare upon landing. Doing so would create an abnormal wear on a main bearing, causing metal to clog a lubricating hole and subsequent failure within a very short period of time. When ATC wanted a rapid descent. we would reduce RPM to as low as 1500 to us 15" MP and would tell them that was the best we could do. This was a design flaw that was worked out in later large radial engines, but application and removal of power was always done in an extremely delicate and judicial manner. Running a fleet of TSIO 520 Continental engines on 402 Cessnas, we were taught to never reduce power below 15" MP at 2300 RPM also being delicate with power changes. Don't know if that made any difference, but those engines consistently ran to 2600 hrs between overhauls. I would think that the rapid cooling associated with reverse loading a light aircraft engine would be a more serious issue than forces caused by the prop driving the engine, but the only analysis I've come across is anecdotal. Peter Van Arsdale Naples Fl ------=_NextPart_000_0074_01C28C7C.057D5B50 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
One of = the absolute=20 no-no's when flying a DC-3 was to never reduce the power below=20 "square" ( M.P. x 100  never less than RPM) other=20 than at the flare upon landing.  Doing so = would create=20 an abnormal wear on a main bearing, causing metal to clog a = lubricating=20 hole and subsequent failure within a very short period of=20 time.  When ATC wanted a rapid descent. we would reduce RPM to = as low=20 as 1500 to us 15" MP and would tell them that was the best we could = do. =20 This was a design flaw that was worked out in later large radial = engines, but=20 application and removal of power was always done in an extremely = delicate and=20 judicial manner.
 
Running a fleet of=20 TSIO 520 Continental engines on 402 Cessnas, we were taught to never = reduce=20 power below 15" MP at 2300 RPM also being delicate with=20 power changes.  Don't know if that made any difference, but = those=20 engines consistently ran to 2600 hrs between = overhauls.
 
I = would think that=20 the rapid cooling associated with reverse loading a light aircraft = engine would=20 be a more serious issue than forces caused by the prop driving the = engine, but=20 the only analysis I've come across is = anecdotal.
 
Peter = Van=20 Arsdale
Naples = Fl
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