X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from m12.lax.untd.com ([64.136.30.75] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with SMTP id 970525 for flyrotary@lancaironline.net; Sat, 04 Feb 2006 21:34:59 -0500 Received-SPF: none receiver=logan.com; client-ip=64.136.30.75; envelope-from=alwick@juno.com Received: from m12.lax.untd.com (localhost [127.0.0.1]) by m12.lax.untd.com with SMTP id AABB8L3APAQ4K4P2 for (sender ); Sat, 4 Feb 2006 18:33:49 -0800 (PST) Received: (from alwick@juno.com) by m12.lax.untd.com (jqueuemail) id LGEPYB5T; Sat, 04 Feb 2006 18:33:26 PST To: flyrotary@lancaironline.net Date: Sat, 4 Feb 2006 18:32:19 -0800 Subject: Re: [FlyRotary] NPG Coolant Temperature vs 50/50 Message-ID: <20060204.183230.2280.1.alwick@juno.com> X-Mailer: Juno 5.0.33 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary=--__JNP_000_6cf1.0819.7b77 X-Juno-Line-Breaks: 8-6,9,11,13-14,17-21,23-25,27-28,33-34,38-39,47-48,52-53,62-63,68-79,80-32767 From: al p wick X-ContentStamp: 30:15:1549247114 X-MAIL-INFO:43212155c47d195d303934551134b5591d54d43431a951b1c431d454310131ed40bd94b4213555f4556dc489b52985895d7d71bda4fd413919c185346005a1a16504794dd5f5bd4dd950109551059510 X-UNTD-OriginStamp: L941HVjjYzDhN3itp//mkJOSSJwpoozy3Jk7MQLoAJVx20asBXQusQ== X-UNTD-Peer-Info: 127.0.0.1|localhost|m12.lax.untd.com|alwick@juno.com This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ----__JNP_000_6cf1.0819.7b77 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit The Egg guys no longer operate at the normal 200F when they install NPG. I don't recall the exact number, but they operate around 215F (cruise). Which explains most of your theoretical differences. They gain a significant safety bonus in the boil over temp. That safety margin is what it's all about. At least from the risk perspective. So by operating at a higher Delta T, they compensate for the reduced efficiency of the fluid. I've heard you guys describe the importance of operating coolant around 185F or so? Are you sure of that limit? Is that just a recommended thing, or hard and fast limit. I'm always skeptical of stuff like that. -al wick On Sat, 4 Feb 2006 20:56:49 -0500 "Ed Anderson" writes: Hi Al, Appreciate your (anybody else welcome also) views on one other thing that is still bothering me about the use of NPG. Given that NPG+ has a specific heat of 0.66 at 212F or 20% less than the 0.82 for the 50/50 mixture and given that NPG+ is approx 7% more dense than the 50/50 - then that for the same flowrate for both it would seem that NPG still has a 13% lesser overall capacity for heat transfer (at the same temps 212F and flow rates). Also assume that the engine is produce the same heat load (Q),lets take alook at what temperature we might see with NPG+ compared to the 50/50 solution. We have from the oldie but goody Q = c*M*DeltaT the ability to solve for the temperature increase, DeltaT. Delta T = Q/cM, now if the combined effects of c and m provide 13% less heat transfer capability than the 50/50 mixture that would indicated that to carry away the same Q at the same flow rate, the delta T of NPG+ would need to increase by 13%. So if I were getting 180F with the 50/50 for the same Q load (and flow rate) then with NPG+, I would expect 180 *1.13 = 203F. Yet, if I understood correct we have reports that lesser temperatures results noted by users of NPG - this leaves me a bit puzzled. If my assumption is correct thus far, then I am at a loss to understand the reports of lesser cooling temps when using NPG+, it would seem just the opposite would happen, that is - the coolant temperature would increase. Now, If the coolant temp with NPG+ actually does remain the same (or decreased) for the same Q and flow rate, then it could indicate the engine heat load is not being carried away as well as with the 50/50. IF the reports of lesser cooling temps occurs when switching to NPG+ are correct, then it would appear to me that the engine must then be operating under a higher heat load (i.e heat not being transfer to the radiators as effectively) . This doesn't even take into consideration the possibly lesser flow rate of NPG+ for the same pump speed as the 50/50 due to its higher 3 times higher viscosity (at 212F). Yes, I have no problem understanding that boil-over has been eliminated - but, is NPG actually cooling as well as coolant temps may lead one to believe? I mean with NPG, I could have a excessive block temperature and still not have boil-over - but my rotary engine would likely have suffered damage. What am I missing? Inquiring minds (even old ones) want to know {:>) Ed A -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ----__JNP_000_6cf1.0819.7b77 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: quoted-printable
The Egg guys no longer operate at the normal 200F when they install = NPG. I=20 don't recall the exact number, but they operate around 215F (cruise). Which= =20 explains most of your theoretical differences.
They gain a significant safety bonus in the boil over temp. That = safety=20 margin is what it's all about. At least from the risk perspective.
So by operating at a higher Delta T, they compensate for the reduced=20 efficiency of the fluid.
 
I've heard you guys describe the importance of operating coolant = around=20 185F or so? Are you sure of that limit? Is that just a recommended thing,=20 or hard and fast limit. I'm always skeptical of stuff like that.
 
-al wick
 
 
On Sat, 4 Feb 2006 20:56:49 -0500 "Ed Anderson" <eanderson@carolina.rr.com>= =20 writes:
Hi Al,
 
Appreciate your (anybody else welcome = also) views=20 on one other thing that is still bothering me about the use of NPG.&= nbsp;=20
 
Given that NPG+ has a specific heat of 0= .66 at=20 212F or  20% less than  the 0.82 for the 50/50 mixture and= =20 given that NPG+ is  approx 7% more dense than the 50/50=20 - then that for the same flowrate for both it would seem that = NPG=20 still has a 13% lesser overall capacity for heat transfer  (at the = same=20 temps 212F and flow rates).
 
Also assume that the engine is produce = the same=20 heat load (Q),lets take alook at what temperature we might see with NPG+= =20 compared to the 50/50 solution.  We have from the oldie but goody Q = =3D=20 c*M*DeltaT the ability to solve for the temperature increase,=20 DeltaT.
 
Delta T =3D Q/cM, now if the combined = effects of c=20 and m  provide 13% less heat transfer capability than the 50/50 = mixture=20 that would indicated that to carry away the same Q at the same flow rate,= the=20 delta T of NPG+ would need to increase by 13%.  So if I were getting= 180F=20 with the 50/50 for the same Q load (and flow rate) then with NPG+,  = I=20 would expect 180 *1.13 =3D 203F.  Yet, if I understood correct we=20 have reports  that lesser temperatures results noted by users = of NPG=20 - this leaves me a bit puzzled.
 
If my assumption is correct thus far, = then I am=20 at a loss to understand the reports of lesser cooling temps when using = NPG+,=20 it would seem just the opposite would happen, that is - the = coolant=20  temperature would increase. 
 
Now,  If the coolant temp with NPG+= actually=20 does  remain  the same (or decreased) for the same Q and flow = rate,=20  then it could indicate the engine heat load is not being carried = away as=20 well as with the 50/50.  IF the reports of lesser cooling=20 temps occurs when switching to NPG+  are correct, then it would= =20 appear to me that the engine must then be operating under a higher heat = load=20 (i.e heat not being transfer to the radiators as effectively) .  = This=20 doesn't even take into consideration the possibly lesser flow rate of NPG= + for=20 the same pump speed as the 50/50 due to its higher 3 times higher = viscosity=20 (at 212F). 
 
 Yes, I have no problem = understanding that=20 boil-over has been eliminated - but, is NPG actually cooling as well as=20 coolant temps may lead one to believe? I mean with NPG, I could have= a=20 excessive block temperature and still not have boil-over - but my rotary= =20 engine would likely have suffered damage.
 
 What am I missing? Inquiring minds= (even=20 old ones) want to know {:>)
 
Ed A
 
 

-al wick
Artificial intelligence in= =20 cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on=20 engine/airframe from Portland, Oregon
Prop construct, Subaru install, = Risk=20 assessment, Glass panel design=20 info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
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