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 4085361 for flyrotary@lancaironline.net; Sat, 16 Jan 2010 22:56:56 -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 A45E31734B4 for ; Sun, 17 Jan 2010 11:56:19 +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 BA49EBEC017 for ; Sun, 17 Jan 2010 11:56:17 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Inclined Radiators was : [FlyRotary] Re: Scoops Date: Sun, 17 Jan 2010 13:56:20 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000B_01CA977C.D8F03440" 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 100116-1, 01/16/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_000B_01CA977C.D8F03440 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Tracy, Ed &Al, I don't know if we are all talking about the same thing so to clarify in = my own mind, I would like to say my opinion on these notes I have, = suggest to me that the 55 degrees, is from the direction of the air flow = i.e. 55 degrees from the horizon or X axis. That would be only 35 = degrees from the Y axis or vertical. So 35 degrees inclined vertical = isn't too bad - in a bell shaped duct. However I could be wrong and the = original reference could have been 55 degrees inclined from vertical, = which also sounds plausible, seeing their talking inclined, one might = think inclined from vertical. Al what's your thoughts on this. However I believe Tracy, you are saying 80 degrees from vertical and I = believe he must be referring to a wedge shaped duct, as I don't think = you could fabricate a bell shaped duct to cope with that degree to the = duct walls. This brings me to the question on what angle is desirable in a wedge = shaped duct, if your unable to fit in a bell shaped duct or should I = merely be considering the size of the inlet opening. I believe I = remember in wedge shaped ducts they should be as high or as wide as the = Rad, considering the placement of rad i.e. under engine or side of cowl = with appropriate depth of the inlet opening. Comments please. George ( down under) =20 Well the basic idea has validity because I carried it to an extream. = My rad is inclined about 80 degrees to the 5" duct so flow axis is = almost perpendicular to the duct. A 5" rad would never cool that 20B so = inclining it radically was the only answer in my configuration. Water = cooling has never been my problem. Oil cooling is working pretty good = with the new oil cooler. It was the "30 row oil cooler" from CXracing = if anyone is curious. Tracy On Sat, Jan 16, 2010 at 4:18 PM, George Lendich = wrote: 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 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=94 wide (X) and 12=94 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 = =96 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=92ll = 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=20 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=92t 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=92t = remember what the factors were; maybe something about the configuration = of the core. Or maybe my memory just isn=92t 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_000B_01CA977C.D8F03440 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
Tracy, Ed &Al,
I don't know if we are all talking = about the same=20 thing so to clarify in my own mind,  I would like to say my opinion = on=20 these notes I have, suggest to me that the 55 degrees, is from the = direction of=20 the air flow i.e. 55 degrees from the horizon or X axis. That would be = only 35=20 degrees from the Y axis or  vertical. So 35 degrees inclined = vertical isn't=20 too bad - in a bell shaped duct. However I could be wrong and the = original=20 reference could have been 55 degrees inclined from vertical, which also = sounds=20 plausible, seeing their talking inclined, one might think inclined from=20 vertical.  Al what's your thoughts on this.
 
However I believe Tracy, you are saying = 80 degrees=20 from vertical and  I believe he must be referring to a wedge shaped = duct,=20 as I don't think you could fabricate a bell shaped duct to cope with = that degree=20 to the duct walls.
 
This brings me to the question on what = angle is=20 desirable in a wedge shaped duct, if your unable to fit in a bell shaped = duct or=20 should I merely be considering the size of the inlet opening. I believe = I=20 remember in wedge shaped ducts they should be as high or as wide as the = Rad,=20 considering the placement of rad i.e. under engine or side of = cowl=20 with appropriate depth of the inlet opening.
Comments please.
George ( down = under)  

Well=20 the basic idea has validity because I carried it to an extream.  = My rad=20 is inclined about 80 degrees to the 5" duct so flow axis is almost=20 perpendicular to the duct.  A 5" rad would never cool that 20B so = inclining it radically was the only answer in my configuration.  = Water=20 cooling has never been my problem.  Oil cooling is working pretty = good=20 with the new oil cooler.  It was the "30 row oil cooler" from = CXracing if=20 anyone is curious.

Tracy

On Sat, Jan 16, 2010 at 4:18 PM, George = Lendich <lendich@aanet.com.au> = wrote:
Ed,
I would like to see that again, as = I believe=20 would others,  like Al and Thomas. I'm hoping someone tries it = in an=20 aircraft to test the theory.
TIA
George ( down under)

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

 

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

 

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

 

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

 

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

 

Ed

Ed=20 Anderson

Rv-6A = N494BW=20 Rotary Powered

Matthews,=20 NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html<= /P>

http://www.flyrotary.com/

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

http://www.rotaryaviation.com/Rotorhead%20Truth.htm

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

 

 

Thomas,

Nice=20 research.

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

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

2. = Over 30*=20 things improve.

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

and drag is less=20 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=20 that the conclusion was configuration dependant, and should not be = taken=20 as generally applicable.  Sorry, but I don=92t remember what = the=20 factors were; maybe something about the configuration of the=20 core.

Or = maybe my=20 memory 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=20 Antivirus.

http://www.eset.com


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