X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [65.54.250.90] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 970519 for flyrotary@lancaironline.net; Sat, 04 Feb 2006 21:32:47 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.54.250.90; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sat, 4 Feb 2006 18:32:01 -0800 Message-ID: Received: from 4.171.129.64 by BAY115-DAV18.phx.gbl with DAV; Sun, 05 Feb 2006 02:32:01 +0000 X-Originating-IP: [4.171.129.64] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] NPG Coolant Temperature vs 50/50 Date: Sat, 4 Feb 2006 21:31:57 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_013B_01C629D2.6D483EC0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Sat, 4 Feb 2006 21:31:57 -0500 X-OriginalArrivalTime: 05 Feb 2006 02:32:01.0827 (UTC) FILETIME=[5866D730:01C629FC] This is a multi-part message in MIME format. ------=_NextPart_000_013B_01C629D2.6D483EC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I have not heard of NPG or NPG+ lowering coolant temps. I thought Dave = Leonard reported temps somewhat higher than with EG & water (correct = Dave?). That would be consistent with Ed's calculations. No boil over = with NPG (unless leaving leftover water in system) but no improved = cooling per se'. Only if EG & water does boil will NPG result in = improved cooling. What I meant in my previous post is that if EG & = water boils, you have an unacceptable cooling system (for aircraft = applications) and NPG is a dead end as a fix. But that's just my = opinion, ICBW. Tracy=20 ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Saturday, February 04, 2006 8:56 PM Subject: [FlyRotary] NPG Coolant Temperature vs 50/50 Hi Al, Appreciate your (anybody else welcome also) views on one other thing = that is still bothering me about the use of NPG. =20 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 =3D c*M*DeltaT the = ability to solve for the temperature increase, DeltaT. Delta T =3D 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 =3D 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.=20 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).=20 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 ------=_NextPart_000_013B_01C629D2.6D483EC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I have not heard of NPG or NPG+ lowering coolant temps.  I = thought=20 Dave Leonard  reported temps somewhat higher than with EG = &=20 water (correct Dave?).  That would be consistent = with Ed's=20 calculations.  No boil over with NPG (unless leaving leftover = water in=20 system) but no improved cooling per se'.   Only if EG & = water does=20 boil will NPG result in improved cooling.  What I meant in my = previous post=20 is that if EG & water boils, you have an unacceptable cooling = system=20 (for aircraft applications) and NPG is a dead end as a fix.  But = that's=20 just my opinion, ICBW.
 
Tracy
----- Original Message -----
From: Ed Anderson
To: Rotary motors in = aircraft
Sent: Saturday, February 04, = 2006 8:56=20 PM
Subject: [FlyRotary] NPG = Coolant=20 Temperature vs 50/50

Hi Al,
 
Appreciate your (anybody else welcome = also) views=20 on one other thing that is still bothering me about the use of = NPG. =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 = 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
 
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