X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao106.cox.net ([68.230.241.40] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4451233 for flyrotary@lancaironline.net; Tue, 31 Aug 2010 18:35:31 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.40; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao106.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20100831223457.HKM3042.fed1rmmtao106.cox.net@fed1rmimpo01.cox.net> for ; Tue, 31 Aug 2010 18:34:57 -0400 Received: from BigAl ([72.199.216.236]) by fed1rmimpo01.cox.net with bizsmtp id 1Aaw1f00c56cS2o03Aawls; Tue, 31 Aug 2010 18:34:56 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.1 cv=PyPhBskYoaHflNqPyNkGzxEHMB/j16Lz16eTzQWlCdI= c=1 sm=1 a=-yno0YABMgYA:10 a=lN8H/RjlhkCyIsyuOn2r7w==:17 a=-MoOJUqEAPBIkKp-_IAA:9 a=7qjEjnZ3179P8dvmCVkA:7 a=qWeQ4mCA35ZzL75aNLgsgSB1Ue8A:4 a=wPNLvfGTeEIA:10 a=yMhMjlubAAAA:8 a=llXi6Q8-DBCIsN6pSyQA:9 a=SCHrnJhh19wlxJN3snsA:7 a=6bq4-FJCoY3pWXKVx0BDXcOLms8A:4 a=lN8H/RjlhkCyIsyuOn2r7w==:117 X-CM-Score: 0.00 Authentication-Results: cox.net; none From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] First FLight! Date: Tue, 31 Aug 2010 15:35:33 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000B_01CB4922.268CF9C0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6863 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5931 Thread-index: ActIkM6rW0NdlX6yScCDBVpWA70NrAAzOCog In-reply-to: Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_000B_01CB4922.268CF9C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable =20 I have the small (facial area) thick radiator from Ed Klepeis (see the = pic below). Is anyone else using this one? How have your temps been? I = would like info and pictures on your setup to see if there is some tweaking I = can do to mine. Chris; =20 There is a lot more to the cooling capacity of a radiator than the = thickness of the core. But in general, when the core gets more than about 3=94 = thick, and a relatively high fin density, the pressure drop gets high and it becomes a more difficult issue to achieve sufficient airflow. For a = given DT of the air, the amount of air flow for a given heat load is the same. Generally for thicker cores you design for a higher DT; but that of = course is limited to the difference between the OAT and the max coolant temp of around 200F. The smaller the x-section of the core for a given flow = results the greater velocity. Now you have both the velocity and thickness as factors increasing the pressure drop. You have a fixed dynamic pressure available based on your flight speed; s-o-o-o . . you can see where this = is heading. =20 Optimization studies of cooling capacity, drag, rad weight, etc; suggest core thickness of about 2 =BD=94. Obviously you can go above and below = that based on other factors, but it=92s a good guide. =20 What are the dimensions of your core? What is the size of your inlet = scoop? What is your climb speed? =20 Al G =20 ------=_NextPart_000_000B_01CB4922.268CF9C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

 

I have the small (facial area) thick radiator = from Ed Klepeis (see the pic below).  Is anyone else using this one?  = How have your temps been?  I would like info and pictures on your setup = to see if there is some tweaking I can do to mine.

Chris;

 

There is a lot more to the = cooling capacity of a radiator than the thickness of the core. =A0But in = general, when the core gets more than about 3” thick, and a relatively high fin = density, the pressure drop gets high and it becomes a more difficult issue to = achieve sufficient airflow.=A0 For a given DT of the = air, the amount of air flow for a given heat load is the same.=A0 =A0Generally for thicker cores you design for a higher DT; but that of course is limited to the difference between the = OAT and the max coolant temp of around 200F. =A0The smaller the x-section of the = core for a given flow results the greater velocity.=A0 Now you have both the = velocity and thickness as factors increasing the pressure drop.=A0 You have a fixed = dynamic pressure available based on your flight speed; s-o-o-o . . you can see = where this is heading.

 

Optimization studies of cooling capacity, drag, rad weight, etc; suggest core thickness of about 2 = =BD”.=A0 Obviously you can go above and below that based on other factors, but it’s a = good guide.

 

What are the dimensions of your = core? What is the size of your inlet scoop?=A0 What is your climb = speed?

 

Al G

 

------=_NextPart_000_000B_01CB4922.268CF9C0--