X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.123] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTP id 4083770 for flyrotary@lancaironline.net; Fri, 15 Jan 2010 09:05:29 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.123; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.0 c=1 a=6yxuJnDx-MYA:10 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=ekHE3smAAAAA:20 a=UretUmmEAAAA:8 a=Ia-xEzejAAAA:8 a=nUuTZ29dAAAA:8 a=USCwz3RLSduxDIq8v78A:9 a=EkpJbHvpsHy6bT9rZwkA:7 a=PyNC0UF3pptQCg8tsni9oO8wzLoA:4 a=1vhyWl4Y8LcA:10 a=EzXvWhQp4_cA:10 a=i10X5FndG7RJKgCX:21 a=p7Mwcjt9cEtJ_ylh:21 a=SSmOFEACAAAA:8 a=VnSGEEpEx1Z1hYe3Lp0A:9 a=c1KLqqLBD5yaHVSSUA8A:7 a=pJXOLjWxs2uRwSB1adQh9hlz-04A:4 a=4Dt-ia5S8M5Upx1J:21 a=yjTc8_mQZwMiHFgQ:21 X-Cloudmark-Score: 0 X-Originating-IP: 75.191.186.236 Received: from [75.191.186.236] ([75.191.186.236:1379] helo=computername) by cdptpa-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id 8F/42-19578-406705B4; Fri, 15 Jan 2010 14:04:53 +0000 From: "Ed Anderson" Message-ID: <8F.42.19578.406705B4@cdptpa-omtalb.mail.rr.com> To: "'Rotary motors in aircraft'" Subject: Inclined Radiators was : [FlyRotary] Re: Scoops Date: Fri, 15 Jan 2010 09:05:06 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0021_01CA95C1.D4F20CE0" X-Mailer: Microsoft Office Outlook, Build 11.0.5510 Thread-Index: AcqVqbhycDVQUuRaSVG1WukMwV7NVgAPABQA In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0021_01CA95C1.D4F20CE0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit I recall an article on some experiments done on inclined radiators in race cars. 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. 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). 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.. At least that is what I recall. If anyone is interested I'll see if I can find the article in my files 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 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 and drag is less by 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_0021_01CA95C1.D4F20CE0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

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

 

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.

 

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).

 

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..

 

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

 

Ed

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

 

 

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

and drag is less by 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

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