X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mx2.magma.ca ([206.191.0.250] verified) by logan.com (CommuniGate Pro SMTP 4.3.5) with ESMTPS id 1025986 for flyrotary@lancaironline.net; Wed, 29 Jun 2005 12:05:35 -0400 Received-SPF: none receiver=logan.com; client-ip=206.191.0.250; envelope-from=ianddsl@magma.ca Received: from mail3.magma.ca (mail3.magma.ca [206.191.0.221]) by mx2.magma.ca (8.13.0/8.13.0) with ESMTP id j5TG4nT5019972 for ; Wed, 29 Jun 2005 12:04:50 -0400 Received: from binky (ottawa-hs-64-26-156-111.s-ip.magma.ca [64.26.156.111]) by mail3.magma.ca (8.13.0/8.13.0) with SMTP id j5TG4kbH016695 for ; Wed, 29 Jun 2005 12:04:48 -0400 Reply-To: From: "Ian Dewhirst" To: "Rotary motors in aircraft" Subject: RE: [FlyRotary] Re: NPG + use in aircraft?? Date: Wed, 29 Jun 2005 12:04:39 -0400 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0096_01C57CA2.B9A5BC80" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.6604 (9.0.2911.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 In-Reply-To: Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_0096_01C57CA2.B9A5BC80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit I could be wrong.. I am pretty sure that PG was chosen by automakers to comply with enviromental legislation they could see on the looming on the horizon. Same reason they switched to R104 from R12 it does not work any better but it is less of a hazard to the ozone layer. PG has been used by the food industry to cool machinery for decades so the concept is not new. -- Ian -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Echo Lake Fishing Resort (Georges Boucher) Sent: Wednesday, June 29, 2005 10:58 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: NPG + use in aircraft?? Bill The reason that PG is use in automotive cooling system is to reduce "film" boiling. Georges B. -------Original Message------- From: Rotary motors in aircraft Date: 06/28/05 08:39:14 To: Rotary motors in aircraft Subject: [FlyRotary] Re: NPG + use in aircraft?? At 11:58 PM 6/27/2005, you wrote: > Al >What I meant was due to the high boiling point of PG it would protect >against"film" boiling which causes pre-ignition. I don't think so. The higher boiling point would raise the temperature of the hot spot. This is not likely to impede film boiling. It takes a fairly stout heat source (and a big temperature difference) to get film boiling in plain water. Raising the boiling point would only make a difference if you were very close to the transition and everything else stayed the same. The higher viscosity of NPG would tend to impede convective cooling (as well as forced convection) which would promote localized film boiling. The lower specific heat and heat of vaporization for NPG would make it much more prone to film boiling as well. Looking at the numbers, it seems to me that if you have film boiling problem using water, you are going to be much worse off using NPG. Bill Dube' >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html . ------=_NextPart_000_0096_01C57CA2.B9A5BC80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

I could be wrong.. I am = pretty sure=20 that PG was chosen by automakers to comply with = enviromental legislation=20 they could see on the looming on the horizon. Same reason they = switched to=20 R104 from R12 it does not work any better but it is less of a = hazard=20 to the ozone layer. PG = has been used=20 by the food industry to cool machinery for decades so the concept = is not=20 new. -- Ian

-----Original = Message-----
From:=20 Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On = Behalf Of=20 Echo Lake Fishing Resort (Georges Boucher)
Sent: = Wednesday, June=20 29, 2005 10:58 AM
To: Rotary motors in = aircraft
Subject:=20 [FlyRotary] Re: NPG + use in aircraft??

Bill

The reason that PG is use in automotive cooling = system is=20 to reduce "film" boiling.

Georges B.

-------Original=20 Message-------

From: Rotary motors in=20 aircraft

Date: = 06/28/05=20 08:39:14

To: Rotary motors in=20 aircraft

Subject: = [FlyRotary]=20 Re: NPG + use in aircraft??

At 11:58 PM 6/27/2005, you wrote:

>  Al

>What I meant was due to the high boiling point of PG it = would=20 protect

>against"film" boiling which causes pre-ignition.

         I don't = think=20 so.

         The higher = boiling=20 point would raise the temperature of the hot

spot. This is not likely to impede film boiling. It takes a = fairly=20 stout

heat source (and a big temperature difference) to get film = boiling=20 in plain

water. Raising the boiling point would only make a = difference if=20 you were

very close to the transition and everything else stayed the = same.

         The higher = viscosity of NPG would tend to impede convective

cooling (as well as forced convection) which would promote=20 localized film

boiling. The lower specific heat and heat of vaporization = for NPG=20 would

make it much more prone to film boiling as well.

         Looking at = the=20 numbers, it seems to me that if you have film

boiling problem using water, you are going to be much worse = off=20 using NPG.

         Bill = Dube'

>>  Homepage:  http://www.flyrotary.com/

>>  Archive:   http://lancai= ronline.net/lists/flyrotary/List.html

.

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