X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wr-out-0506.google.com ([64.233.184.238] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1110342 for flyrotary@lancaironline.net; Fri, 12 May 2006 07:07:40 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.233.184.238; envelope-from=russell.duffy@gmail.com Received: by wr-out-0506.google.com with SMTP id 69so532839wri for ; Fri, 12 May 2006 04:06:54 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:from:to:subject:date:message-id:mime-version:content-type:x-priority:x-msmail-priority:x-mailer:importance:in-reply-to:x-mimeole; b=Sd5sUrwUdi4+gxc7uav2Akyh0djTVQvDgfudwk8kYFk4vZIgYu8zYPrVt4xrDnuO+ohDXIt6lYEDoIlMMGzrCbb3IIRtb3Fm8xqIKLUXycsNZecRQK+BA6SfWjyeUNmgwu2PdBRNgHKzEqbHTOv9LgmrROhMMoTphzYl5lZ7BQQ= Received: by 10.54.94.3 with SMTP id r3mr2291764wrb; Fri, 12 May 2006 04:06:54 -0700 (PDT) Return-Path: Received: from raddell ( [209.114.234.11]) by mx.gmail.com with ESMTP id 24sm2503064wrl.2006.05.12.04.06.53; Fri, 12 May 2006 04:06:54 -0700 (PDT) From: "Russell Duffy" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] oil cooling issues Date: Fri, 12 May 2006 07:06:53 -0400 Message-ID: <000201c675b4$2e26dde0$c49412c6@raddell> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0003_01C67592.A7153DE0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_0003_01C67592.A7153DE0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Mine is taken in the oil pan, where it is the highest temperature. I have seen 260 F. many times, and I consider that normal during climb and taxi. I also use Mobil One Synthetic oil, to tolerate the heat. During cruise it will stabilize at 220F. =20 You need to get the oil above 220 F, to evaporate the moisture anyway.=20 =20 Hi George, =20 The "standard" (closest we have to one) for measuring oil temp is to = measure it as it returns to the engine, after the cooler. According to Racing = Beat, this temp should never exceed 210 F. Lot's of folks have exceeded this = for short periods, up to 240 F or so, and have had no problems, but it's not something you really want to keep doing. =20 =20 As I understand it, the issue is not the breakdown of the oil, but the melting of the rotor bearings. I've never seen this myself, but it = makes sense to me. After all, since we use oil to cool the rotors, it's easy = to see that they will overheat as the result of overheating the oil. The = oil flow through the bearings also takes away lots of heat, so the rotor bearings become the first thing to go. =20 =20 The biggest problem with measuring the oil in the pan is that it may not = be the most consistent measurement. Oil drains back from several = locations, sloshes around, etc, and you only see what's at the sensor. Still, it's probably OK to measure there, but there's no accepted spec for allowable temp. I'm sure your 220 F cruise is below 210 F going into the engine, = but I'd bet that 260 F in the pan is pushing it. =20 =20 As for desired temp, I believe Lynn has mentioned that 180 F (after the cooler) is best power for oil, and that you lose power above that temp. = =20 Cheers, Rusty (two more weeks) ------=_NextPart_000_0003_01C67592.A7153DE0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
Mine is taken in the oil pan, where it is the highest = temperature.

I=20 have seen 260 F. many times, and I consider that normal during = climb
and=20 taxi.  I also use Mobil One Synthetic oil, to tolerate the = heat.
During=20 cruise it will stabilize at 220F. 

You need to get the oil = above=20 220 F, to evaporate the moisture anyway. 
 
Hi George,
 
The=20 "standard" (closest we have to one) for measuring oil temp is to measure = it as=20 it returns to the engine, after the cooler.  According to Racing = Beat, this=20 temp should never exceed 210 F.  Lot's of folks have exceeded this = for=20 short periods, up to 240 F or so, and have had no problems, but it's not = something you really want to keep doing.  
 
As I=20 understand it, the issue is not the breakdown of the oil, but the = melting=20 of the rotor bearings.  I've never seen this myself, but it = makes=20 sense to me.  After all, since we use oil to cool the=20 rotors, it's easy to see that they will overheat as the result of=20 overheating the oil.  The oil flow through the bearings also = takes=20 away lots of heat, so the rotor bearings become the first thing to=20 go.  
 
The biggest=20 problem with measuring the oil in the pan is that it may not be the most = consistent measurement.  Oil drains back from several locations, = sloshes=20 around, etc, and you only see what's at the sensor.  Still, it's = probably=20 OK to measure there, but there's no accepted spec for allowable=20 temp.  I'm sure your 220 F cruise is below 210 F going = into the=20 engine, but I'd bet that 260 F in the pan is pushing=20 it.  
 
As for=20 desired temp, I believe Lynn has mentioned that 180 F (after the cooler) = is best=20 power for oil, and that you lose power above that temp. =20
 
Cheers,
Rusty (two=20 more weeks)
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