X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Received: from fed1rmmtao103.cox.net ([68.230.241.43] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2063020 for flyrotary@lancaironline.net; Wed, 23 May 2007 10:06:31 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.43; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao103.cox.net (InterMail vM.7.05.02.00 201-2174-114-20060621) with ESMTP id <20070523140551.URNG19731.fed1rmmtao103.cox.net@fed1rmimpo01.cox.net> for ; Wed, 23 May 2007 10:05:51 -0400 Received: from BigAl ([72.192.132.90]) by fed1rmimpo01.cox.net with bizsmtp id 2e5r1X0011xAn3c0000000; Wed, 23 May 2007 10:05:51 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Gear box oil temps Date: Wed, 23 May 2007 07:06:24 -0800 Message-ID: <000001c79d4b$ee3f6ab0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C79D08.E01C2AB0" 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 V6.00.2900.3028 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C79D08.E01C2AB0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 Al can you mount a separate small rad for the PSRU? George ( down under) =20 You mean an additional small cooler to further cool the oil before it = goes to the drive? My conclusion was that it is not necessary. There was a = typo in my reply below - it was supposed to read "I'll proceed on without worrying about that outlet temp." I'll keep an eye on that temp, but I'm = not that concerned as long as it is less than 250F. =20 I do expect to pursue further measures for making my oil cooler more effective to reduce oil temps. =20 Al =20 =20 Figures I found on the web indicates 3% is a fairly standard figure used = for a planetary gearbox efficiency. So 3% of 160 HP =3D 4.8 HP which is mostly converted to heat. =20 Tf =3D 180F + (203/((7.3 *.5) *0.4) =3D 180F + 69F =3D 249F =20 So using this example and assuming I haven't screwed up, I would expect = the oil temps coming out of the gear box to be around 249F. =20 =20 Ed; I really appreciate when you take the time and effort to do the math = that I'm to lazy to do. I think at the time I noted the re-drive temp out it was 243F, shortly = after leveling off from a climb, and the oil temp (after cooler, into drive) = was still about 210F. I'm gonna guess the power at that point was about 140 = hp. So it seems that the efficiency and/or the flow rate is a bit higher. = In any case; I'll proceed on with worrying about that outlet temp. =20 Thanks. =20 BTW; I think that monitoring the redrive outlet is important. It can = give you a heads up on problems with the redrive. It is nice to be able to = set a limit in the EM to alert you of a potential problem. =20 Al=20 ------=_NextPart_000_0001_01C79D08.E01C2AB0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

 Al can you mount a = separate small rad for the PSRU?

George ( down = under)

 

You mean an additional small = cooler to further cool the oil before it goes to the drive? My conclusion was that = it is not necessary.  There was a typo in my reply below – it was = supposed to read “I’ll proceed on without worrying about that outlet temp.” I’ll keep an = eye on that temp, but I’m not that concerned as long as it is less than = 250F.

 

I do expect to pursue further = measures for making my oil cooler more effective to reduce oil = temps.

 

Al

 

 

=

Figures I found on the web = indicates 3% is a fairly standard figure used for a planetary gearbox = efficiency.

So 3% of 160 HP =3D 4.8 = HP  which is mostly converted to heat.

 

Tf =3D 180F + (203/((7.3 *.5) *0.4) =3D 180F + 69F       = =3D 249F

 

So using this example and = assuming I haven't screwed up,  I would expect the oil temps coming out of the = gear box to be around 249F. 

 

Ed;

I really appreciate when you take the time and effort to do the math that I’m to lazy to do.

I think at the time I noted the re-drive temp out it was 243F, shortly = after leveling off from a climb, and the oil temp (after cooler, into drive) = was still about 210F. I’m gonna guess the power at that point was = about 140 hp.  So it seems that the efficiency and/or the flow rate is a bit higher.  In any case; I’ll proceed on with worrying about = that outlet temp.

 

Thanks.<= /font>

 

BTW; I think that monitoring the redrive outlet is important.  It can = give you a heads up on problems with the redrive.  It is nice to be able to = set a limit in the EM to alert you of a potential problem.

 

Al =

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