X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from blu0-omc2-s26.blu0.hotmail.com ([65.55.111.101] verified) by logan.com (CommuniGate Pro SMTP 5.2.10) with ESMTP id 3342720 for flyrotary@lancaironline.net; Mon, 08 Dec 2008 16:47:16 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.55.111.101; envelope-from=neilak@sympatico.ca Received: from BLU0-SMTP21 ([65.55.111.71]) by blu0-omc2-s26.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.3959); Mon, 8 Dec 2008 13:46:40 -0800 X-Originating-IP: [69.158.11.75] X-Originating-Email: [neilak@sympatico.ca] Message-ID: Return-Path: neilak@sympatico.ca Received: from NeilPC ([69.158.11.75]) by BLU0-SMTP21.blu0.hotmail.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.2668); Mon, 8 Dec 2008 13:46:38 -0800 From: To: "'Rotary motors in aircraft'" In-Reply-To: Subject: RE: [FlyRotary] Re: Update ... Three more flights, water ok, oil too cool Date: Mon, 8 Dec 2008 16:46:25 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0037_01C95954.835B1840" X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 Thread-Index: AclZQu+kAJZUqfShTYmEgDr5xdKWAgAMixzw X-OriginalArrivalTime: 08 Dec 2008 21:46:39.0197 (UTC) FILETIME=[734D58D0:01C9597E] This is a multi-part message in MIME format. ------=_NextPart_000_0037_01C95954.835B1840 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Jeff, Congrats on a successful flight. I went back a few posts to have a look at your radiator setup again and it seems to me that you are going to be short on your water cooling requirements when the warm weather returns. (I'm northwest of Toronto and have property near Kirland Lake so I know winters). Although the cubic area of your radiator seems sufficient (575cu-in) it's shape (read thickness) is likely your problem. Many moons ago I tried to make a 6" thick radiator work but I soon discovered the air flow resistance impossible to overcome. Air would simply go around the inlet duct rather than through it because of the high air flow resistance of the core. The P-51 had a very thick radiator but it was made up of 1000s of tubes (kind of like soda straws) and you could actually see through the 12" thick rad. Your rad appears to be standard automotive tube and fin construction, as was mine. A tube/fin radiator 20" x 20" by 1" thick is far more efficient than one 10" x 10" x 5" thick for 2 reasons. Resistance to airflow (which I mentioned) and, by the time air gets to the back row of tubes/fins of the rad, it has already been heated up by the tube/fin rows in front of it. Simply put, the delta T between water and air gets smaller as you progress from front to back. If you go through historical posts, this list seems to have found a practical maximum radiator thickness of around 2.5". Again assuming a standard tube/fin automotive style rad (including evaporator cores). It is imperative that you measure your oil temps and water temps in the same place as everyone else, otherwise, comparisons go out the window. Are you measuring water temps from the back of the water pump? Are you measuring oil temps at the bypass block? Your oil cooler placement is getting lots of air, the core is not too thick and it is 90 degrees to the oncoming airflow. It's going to work well. I hate to suggest it but you may need a different shape radiator to get the water temps down. Go back though old posts and look at Eds cooling arrangement and radiator dimensions. It is functional and can be adapted to your cowl. (You have a nice big cowl to work with so I'm sure you will get this sorted out.) NeilK _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Jeff Whaley Sent: Monday, December 08, 2008 9:40 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Update ... Three more flights, water ok, oil too cool Mark, I'm not sure what the cruise temps are as we have been flying short, tight circuits only. I think cruise temperatures need to be determined before doing too much else, though re-installing the thermostat may happen. What is the relationship between the water and oil temp? I guess you have stock Mazda thermostat 195F? Most of the rotary world has cheek radiators up front, with the oil cooler going in whatever space is left. My oil cooler is up front on top of the PSRU with inlets/outlets on both ends and the water radiator (19x5.5x5.5) is below/behind the oil pan . two independent systems one working too well the other not well enough . see attached photo. Jeff ------=_NextPart_000_0037_01C95954.835B1840 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Jeff,

 

      =       Congrats on a successful flight.  

 

      =       I went back a few posts to have a look at your radiator setup again and it = seems to me that you are going to be short on your water cooling requirements = when the warm weather returns.  (I’m northwest of Toronto and have property near Kirland Lake so I know = winters).

 

      =       Although the cubic area of your radiator seems sufficient (575cu-in) it’s = shape (read thickness) is likely your problem.  Many moons ago I tried to = make a 6” thick radiator work but I soon discovered the air flow = resistance impossible to overcome.  Air would simply go around the inlet duct rather than through it because of the high air flow resistance of the core. =  The P-51 had a very thick radiator but it was made up of 1000s of tubes (kind of = like soda straws) and you could actually see through the 12” thick rad. =  Your rad appears to be standard automotive tube and fin construction, as was = mine.

 

      =       A tube/fin radiator 20” x 20” by 1” thick is far more = efficient than one 10” x 10” x 5” thick for 2 reasons. =  Resistance to airflow (which I mentioned) and, by the time air gets to the back row = of tubes/fins of the rad, it has already been heated up by the tube/fin = rows in front of it.  Simply put, the delta T between water and air gets smaller = as you progress from front to back.   

 

If you go = through historical posts, this list seems to have found a practical maximum = radiator thickness of around 2.5”.  Again assuming a standard tube/fin = automotive style rad (including evaporator cores).

 =

It is imperative = that you measure your oil temps and water temps in the same place as everyone = else, otherwise, comparisons go out the window.  Are you measuring water = temps from the back of the water pump?  Are you measuring oil temps at = the bypass block?

 =

Your oil cooler = placement is getting lots of air, the core is not too thick and it is 90 degrees = to the oncoming airflow.  It’s going to work well.  I hate to suggest it = but you may need a different shape radiator to get the water temps down. =  Go back though old posts and look at Eds cooling arrangement and radiator = dimensions.  It is functional and can be adapted to your cowl.  (You have = a nice big cowl to work with so I’m sure you will get this sorted = out.)

 =

NeilK

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Jeff Whaley
Sent: Monday, December = 08, 2008 9:40 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Update ... Three more flights, water ok, oil too = cool

 

Mark,

I’m = not sure what the cruise temps are as we have been flying short, tight circuits = only. I think cruise temperatures need to be determined before doing too much = else, though re-installing the thermostat may = happen.

What is the relationship between the water and oil temp? I guess you have stock = Mazda thermostat 195F?

Most of the = rotary world has cheek radiators up front, with the oil cooler going in = whatever space is left. My oil cooler is up front on top of the PSRU with = inlets/outlets on both ends and the water radiator (19x5.5x5.5) is below/behind the oil = pan … two independent systems one working too well the other not well enough = … see attached photo.

Jeff

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