X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: <13brv3@bellsouth.net> Received: from imf23aec.mail.bellsouth.net ([205.152.59.71] verified) by logan.com (CommuniGate Pro SMTP 4.3.4) with ESMTP id 1004123 for flyrotary@lancaironline.net; Thu, 16 Jun 2005 12:23:40 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.71; envelope-from=13brv3@bellsouth.net Received: from ibm66aec.bellsouth.net ([65.6.194.9]) by imf23aec.mail.bellsouth.net with ESMTP id <20050616162248.NXCE8541.imf23aec.mail.bellsouth.net@ibm66aec.bellsouth.net> for ; Thu, 16 Jun 2005 12:22:48 -0400 Received: from rd ([65.6.194.9]) by ibm66aec.bellsouth.net with ESMTP id <20050616162247.XLWS5308.ibm66aec.bellsouth.net@rd> for ; Thu, 16 Jun 2005 12:22:47 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: turbo oil drain Date: Thu, 16 Jun 2005 11:22:47 -0500 Message-ID: <000001c5728f$a1fdc5e0$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C57265.B927BDE0" 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 V6.00.2900.2527 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C57265.B927BDE0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Rusty, there is no rule that states that you have to use engine oil, since you already have a pump to scavenge and you really don't need much = oil pressure for a turbo, add a small sump and a little cooler perhaps, and = your worries of an engine oil leak are over. The added advantage is that you = can lubricate before start and cool after shutdown. For the record I know = there is not much under cowl room, but you seem like a fellow bent on = adventure ;-) -- Ian=20 =20 Interesting thought, but as you know, there isn't room for all that. However... it does bring up another possibility. =20 =20 (danger, unconventional thinking below) =20 The way these (non)seals are made on the turbo, does it hurt to have = suction on the drain side of the seal? And, would it leak if you had a 12" head = of gravity fed oil on the bearings when the engine is shut down? =20 What I'm wondering is if I could add a fitting about midway up the oil = pan, and use it as the oil feed to the turbo. It would be gravity assisted, = but the scavenging pump would be on the oil outlet of the turbo sucking it through, and returning it to the pan. The inlet restriction would = probably have to be eliminated to keep the suction from being too great on the bearings. In fact, it might need to be restricted on the outlet side instead, which would be quite Abby normal.=20 =20 If that could work, then the turbo would only have access to a limited amount of the engine oil, so it couldn't rob the engine of oil in the = event of a leak. On the other hand, there couldn't realistically be a leak, = since there's no real pressure on the bearings, so it might not matter whether = you put the oil supply line at the middle or bottom (drain bolt) of the pan. The oil supply would be a bit hotter, but my oil temps are way down = there, so it shouldn't be an issue. =20 =20 If the pump stops running, the oil flow would stop, and I suppose the = shaft oil would vaporize. Perhaps, the vapor would bubble up, and liquid oil would take it's place to some extent until it formed a sludgy goo that slowed the shaft to a stop. I presume the shaft would eventually = seize, but hopefully, this wouldn't be a catastrophic problem for anything but = the turbo itself.=20 =20 Is this loony, or could it work? =20 Cheers, Rusty (betting I know the answer) =20 =20 =20 =20 ------=_NextPart_000_0001_01C57265.B927BDE0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
Hi Rusty, there is no rule that = states that=20 you have to use engine oil, since you already have a pump to scavenge = and you=20 really don't need much oil pressure for a turbo, add a small sump and a = little=20 cooler perhaps, and your worries of an engine oil leak are over.  = The added=20 advantage is that you can lubricate before start and cool=20 after shutdown.  For the record I know there is not much under = cowl=20 room, but you seem like a fellow bent on adventure ;-) -- Ian 
 
Interesting thought, but as you know, there = isn't room for=20 all that.  However... it does bring up another possibility. =20
 
(danger, unconventional thinking=20 below)
 
The way these (non)seals are made on the turbo, = does it=20 hurt to have suction on the drain side of the seal?  And, = would it=20 leak if you had a 12" head of gravity fed oil on the bearings when the = engine is=20 shut down?
 
What I'm wondering is if I could add a fitting = about midway=20 up the oil pan, and use it as the oil feed to the turbo.  It would = be=20 gravity assisted, but the scavenging pump would be on the oil = outlet of the=20 turbo sucking it through, and returning it to the pan.  The = inlet=20 restriction would probably have to be eliminated to keep the suction = from being=20 too great on the bearings.  In fact, it might need to be restricted = on the=20 outlet side instead, which would be quite Abby=20 normal. 
 
If that could work, then the turbo would only = have access=20 to a limited amount of the engine oil, so it couldn't rob the engine of = oil in=20 the event of a leak.  On the other hand, there=20 couldn't realistically be a leak, since there's no real pressure on = the=20 bearings, so it might not matter whether you put the oil supply = line at the=20 middle or bottom (drain bolt) of the pan.  The oil supply would be = a bit=20 hotter, but my oil temps are way down there, so it shouldn't be an=20 issue. 
 
If the pump stops running, the oil flow = would stop,=20 and I suppose the shaft oil would vaporize.  = Perhaps, the=20 vapor would bubble up, and liquid oil would take it's place to some = extent until=20 it formed a sludgy goo that slowed the shaft to a stop.  =  I=20 presume the shaft would eventually seize, but hopefully, this wouldn't = be=20 a catastrophic problem for anything but the turbo=20 itself. 
 
Is this loony, or could it = work?
 
Cheers,
Rusty (betting I know the=20 answer)  
 
 
 
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