X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 5.0.7) with ESMTP id 964332 for flyrotary@lancaironline.net; Wed, 01 Feb 2006 20:49:56 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-025-165.carolina.res.rr.com [24.74.25.165]) by ms-smtp-01-eri0.southeast.rr.com (8.13.4/8.13.4) with SMTP id k121n8gg009877 for ; Wed, 1 Feb 2006 20:49:10 -0500 (EST) Message-ID: <003b01c6279a$e0253720$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Suitability of NPG for Rotary Engine use Date: Wed, 1 Feb 2006 20:49:15 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0038_01C62770.F6F48C00" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0038_01C62770.F6F48C00 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks, Bill Just thought it might be useful to some who might be considering it why = NPG just might not be well suited to the stock rotary coolant system. Yes, I noticed that the chart did not measure the viscosity of the NPG = at the same temps as they did the 50/50 mixture. Might be a legitimate = reason for that but escapes me. I suspect the viscosity goes much = higher at lower temps. No problem with a running engine, but starting a = really cold block might offer some problems as you suggest. Especially = given the small diameters of some of the GM cores channels. Could be = that Dave simply was not getting any significant cooling due to minimal = flow. I recall him saying the temps went up all of a sudden and wonder = if the coolant "trapped" in the block might not have reached very high = temps before managing to "burst" lose and send the temp sensor soaring. Ed ----- Original Message -----=20 From: William=20 To: Rotary motors in aircraft=20 Sent: Wednesday, February 01, 2006 6:40 PM Subject: [FlyRotary] Re: Suitability of NPG for Rotary Engine use Excellent write-up Ed, I would be particularly leery of NPG in a = severely cold climate with small channels in the heat exchanger. High = viscosity and small channels can lead to high pressure drop -- low flow. = This then becomes unstable, if the flow becomes low, the fluid in the = radiator can become colder, leading to higher viscosity, lower flow, = higher pressure drop, all the while the engine portion can be = overheating. Note that the viscosity for NPG+ is >10 times that of 50-50 EG/water = at 50*F, a really interesting number would be the viscosity at 0*F = (Where Dave was flying). It could be that the pump cannot generate = enough pressure drop to force the fluid through the radiator if it gets = cold. On plain (room temperature) water, the Mazda pump can generate ~20 = psi at zero flow at 5500 rpm. Bill Schertz KIS Cruiser # 4045 ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Wednesday, February 01, 2006 9:31 AM Subject: [FlyRotary] Suitability of NPG for Rotary Engine use Things have been a little dull on the list, since Dave reported on = his "adventure".=20 Also, I recently received a phone call from a rotary enthusiast = (not on the list) about the use of Evans NPG (Propylene Glycol) in = rotary engines. I did a bit of research and my conclusion was the = rotary engine was not well suited to benefit from the properties of NPG = in its stock coolant system configuration. =20 That the use of 100% glycol would require increased coolant flow = rates by 10-15% and more coolant pump power would be required (hard to = quantify this one but it appears in the range of 15-25% more). Also the = hazard of fire due to a leak on hot exhaust would be increased (this = would apply to a 100% mixture of either Ethylene or Propylene glycol). = There are benefits to using NPG, however, in my opinion the effort = needed to change the rotary cooling configuration to safely use it = makes the cost effectiveness of the conversion questionable. The apparent success of Evans NPG in reciprocating engines is not in = conflict with my assessment about its suitability for the rotary engine. Attached is some supporting (I believe) facts to support this = opinion (and that is all it is). Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com -------------------------------------------------------------------------= --- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_0038_01C62770.F6F48C00 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks, Bill
 
Just thought it might be useful to some who = might be=20 considering it why NPG just might not be well suited to the stock rotary = coolant=20 system.
 
Yes, I noticed that the chart did not measure = the=20 viscosity of the NPG at the same temps as they did the 50/50 = mixture. =20 Might be a legitimate reason for that but escapes me.  I suspect = the=20 viscosity goes much higher at lower temps.  No problem with a = running=20 engine, but starting a really cold block might offer some problems as = you=20 suggest.  Especially given the small diameters of some of the GM = cores=20 channels.  Could be that Dave simply was not getting any = significant=20 cooling due to minimal flow.  I recall him saying the temps went up = all of=20 a sudden and wonder if the coolant "trapped" in the block might not have = reached=20 very high temps before managing to "burst" lose and send the temp sensor = soaring.
 
 
Ed
----- Original Message -----
From:=20 William=20
Sent: Wednesday, February 01, = 2006 6:40=20 PM
Subject: [FlyRotary] Re: = Suitability of=20 NPG for Rotary Engine use

Excellent write-up Ed, I would be = particularly=20 leery of NPG in a severely cold climate with small channels in the = heat=20 exchanger. High viscosity and small channels can lead to high pressure = drop --=20 low flow. This then becomes unstable, if the flow becomes low, the = fluid in=20 the radiator can become colder, leading to higher viscosity, lower = flow,=20 higher pressure drop, all the while the engine portion can be=20 overheating.
 
Note that the viscosity for NPG+ is = >10 times=20 that of 50-50 EG/water at 50*F, a really interesting number would be = the=20 viscosity at 0*F (Where Dave was flying). It could be that the pump = cannot=20 generate enough pressure drop to force the fluid through the radiator = if it=20 gets cold. On plain (room temperature) water, the Mazda pump can = generate ~20=20 psi at zero flow at 5500 rpm.
 
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Wednesday, February 01, = 2006 9:31=20 AM
Subject: [FlyRotary] = Suitability of NPG=20 for Rotary Engine use

Things have been a little dull on the list, = since Dave=20 reported on his "adventure". 
 
 Also, I recently received a phone call = from a=20 rotary enthusiast (not on the list) about the use of Evans NPG = (Propylene=20 Glycol) in rotary engines.  I did a bit of research and my = conclusion=20 was the rotary engine was not well suited to benefit from the=20 properties of NPG in its stock coolant system=20 configuration.  
 
 That the use of 100% glycol would =  require=20 increased coolant flow rates by 10-15% and more coolant pump = power=20 would be required (hard to quantify this one but it appears in the = range of=20 15-25% more).  Also the hazard of fire due to a leak on hot = exhaust=20 would be increased (this would apply to a 100% mixture of either = Ethylene or=20 Propylene glycol).  There are benefits to using NPG, however, = in my=20 opinion the effort needed to change  the rotary cooling=20 configuration to safely use it makes the cost effectiveness of the=20 conversion questionable.
 
The apparent success of Evans NPG in = reciprocating=20 engines is not in conflict with my assessment about its suitability = for the=20 rotary engine.
 
Attached is some supporting (I believe) = facts to=20 support this opinion (and that is all it is).
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.com

--
Homepage:  http://www.flyrotary.com/
Archive = and=20 UnSub:  =20 http://mail.lancaironline.net/lists/flyrotary/

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Homepage:  http://www.flyrotary.com/
Archive and=20 UnSub:  =20 http://mail.lancaironline.net/lists/flyrotary/
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