X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTP id 4085165 for flyrotary@lancaironline.net; Sat, 16 Jan 2010 16:18:49 -0500 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id 5B501173823 for ; Sun, 17 Jan 2010 05:18:13 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 62981BEC004 for ; Sun, 17 Jan 2010 05:18:11 +0800 (WST) Message-ID: <51BBFACF79104007954ABC0D9C777297@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Inclined Radiators was : [FlyRotary] Re: Scoops Date: Sun, 17 Jan 2010 07:18:14 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0012_01CA9745.3B8F11D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100116-0, 01/16/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0012_01CA9745.3B8F11D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed,=20 I would like to see that again, as I believe would others, like Al and = Thomas. I'm hoping someone tries it in an aircraft to test the theory. TIA George ( down under) I recall an article on some experiments done on inclined radiators in = race cars.=20 =20 Basically the figures that George mentioned were quoted in the source. = However (big however) what may not have been clearly pointed out was = that the major part of the reason cooling effectiveness (not efficiency) = increased was that inclining the heat exchanger permitted you to install = ever larger area cores in the same size duct. So the increase in = cooling effectiveness by inclination was in large part due to the larger = size radiator permitted by inclined placement in the duct. =20 For example take a duct that is 24" wide (X) and 12" high (Y) at zero = degree inclination. If you incline the radiator by 30 deg and then = increase its height to again fill the duct,. you can get an approx 15% = increase in the frontal size of the radiator (in the same 24x12 duct). = At 60 deg you could gain approx 100% increase in frontal size by again = increasing the height of the core to fill the duct. . Naturally that = aids in getting rid of the heat. They also point out the larger core = adds weight until you reach a point where the adverse effect of the = heavier radiator core offset its benefit (this was all addressing their = use in race cars). =20 The source indicated that up to 30Deg the drag increases and heat = transfer goes down due to uneven air flow distribution and disturbances = - apparently above that angle this adverse effect decreases and of = course you have the much larger frontal area.. =20 At least that is what I recall. If anyone is interested I'll see if I = can find the article in my files =20 Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Al Gietzen Sent: Friday, January 15, 2010 1:13 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Scoops =20 =20 Thomas, Nice research. I found my notes on inclined radiators, they state 1. 0-20/30* will decrease cooling and increase drag. 2. Over 30* things improve. 3. At approx 55* cooling effectiveness is 30% greater than = non-inclined rads=20 and drag is less by 20%. =20 George; do you have the source for that info? It may be a good idea to = verify this information. I don't recall the specifics; but what I do = recall is that the conclusion was configuration dependant, and should = not be taken as generally applicable. Sorry, but I don't remember what = the factors were; maybe something about the configuration of the core. Or maybe my memory just isn't right. Worth checking. All __________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ------=_NextPart_000_0012_01CA9745.3B8F11D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ed,
I would like to see that again, as I = believe would=20 others,  like Al and Thomas. I'm hoping someone tries it in an = aircraft to=20 test the theory.
TIA
George ( down under)

I recall an = article=20 on some experiments done on inclined radiators in race cars.=20

 

Basically = the figures=20 that George mentioned were quoted in the source.  However (big = however)=20 what may not have been clearly pointed out was that the major part of = the=20 reason cooling effectiveness (not efficiency) increased was that = inclining the=20 heat exchanger permitted you to install ever larger area cores in the = same=20 size duct.  So the increase in cooling effectiveness by = inclination was=20 in large part due to the larger size radiator permitted by inclined = placement=20 in the duct.

 

For example = take a=20 duct that is 24=94 wide (X) and 12=94 high (Y) at zero degree = inclination. =20 If you incline the radiator by 30 deg and then increase its height to = again=20 fill the duct,. you can get an approx 15% increase in the frontal size = of the=20 radiator (in the same 24x12 duct).  At 60 deg you could gain = approx 100%=20 increase in frontal size by again increasing the height of the core to = fill=20 the duct.  . Naturally that aids in getting rid of the = heat.  They=20 also point out the larger core adds weight until you reach a point = where the=20 adverse effect of the heavier radiator core offset its benefit (this = was all=20 addressing their use in race cars).

 

The source = indicated=20 that up to 30Deg the drag increases and heat transfer goes down due to = uneven=20 air flow distribution and disturbances =96 apparently above that angle = this=20 adverse effect decreases and of course you have the much larger = frontal=20 area..

 

At least = that is what=20 I recall.  If anyone is interested I=92ll see if I can find the = article in=20 my files

 

Ed

Ed=20 Anderson

Rv-6A = N494BW Rotary=20 Powered

Matthews,=20 NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.r= otaryaviation.com/Rotorhead%20Truth.htm

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Al Gietzen
Sent: Friday, January 15, 2010 = 1:13=20 AM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re:=20 Scoops

 

 

Thomas,

Nice research.

I=20 found my notes on inclined radiators, they = state

1. 0-20/30* will decrease cooling and = increase=20 drag.

2. Over 30* things=20 improve.

3. At approx 55* cooling effectiveness is = 30% greater=20 than non-inclined rads

and drag is less by = 20%.

 

George; = do you=20 have the source for that info? It may be a good idea to verify this=20 information.  I don=92t recall the specifics; but what I do = recall is that=20 the conclusion was configuration dependant, and should not be taken as = generally applicable.  Sorry, but I don=92t remember what the = factors were;=20 maybe something about the configuration of the=20 core.

Or maybe = my memory=20 just isn=92t right.  Worth checking.

All



__________ Information from ESET = NOD32=20 Antivirus, version of virus signature database 3267 (20080714)=20 __________

The message was checked by ESET NOD32 = Antivirus.

http://www.eset.com

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