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 5.2.14) with ESMTP id 3740874 for flyrotary@lancaironline.net; Tue, 30 Jun 2009 21:08:29 -0400 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 (sv1-1.per.aanet.com.au [203.24.100.68]) by poplet2.per.eftel.com (Postfix) with ESMTP id 787A11738CD for ; Wed, 1 Jul 2009 09:07:53 +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 98C08BEC01E for ; Wed, 1 Jul 2009 09:07:47 +0800 (WST) Message-ID: <810A0BA3DC6F4803A6723B879916306E@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Round Radiators Date: Wed, 1 Jul 2009 11:07:54 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0005_01C9FA3C.2E8464A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 090630-0, 06/30/2009), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0005_01C9FA3C.2E8464A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed, Thanks mate I found my notes and you are indeed right 3cu" per hp and 55 = deg from Vertical. My notes say 20 to 30 deg will increase cooling and increase drag. Over 30 deg things improve and at 55 deg, cooling effectiveness is 30 = deg greater than non-inclined and drag is less than at 20 deg inclined.- = my notes say 30 degrees so I assume that degree F.=20 I must also correlate those figures on size to BTU's before I go ahead. I have included my notes on the subject for youeself or anyone = interested OK. George (down under) Ambitious undertaking for certain, George. =20 I think the rule of thumb you are looking for is 3 cubic inches of = core volume for each HP. So 180 HP rotary would require 180 * 3 =3D 540 = cubic inches of core. My two GM cores are 10x9 x 3.5 *2 =3D 630 cubic = inches and they are designed for Freon rather than water. So a "real" = water radiator would undoubtedly do better and 540 does not seem = unreasonable. =20 Regarding the incident angle, I would say it's the angle relative to = the incoming airflow. So if you stood the core vertically, then 55 deg = would be the most you would want from the vertical - but, I must say = that unless you are also designing and understand the effects of "angle = of attack" on the small air channels and can shape them to give you the = characteristic you want, I would hesitate to vary much from 70 - 90 deg. =20 Some folks have quoted studies where cooling improved by inclining the = radiator, but when I read the report, it was clear the reason the = cooling improved is that with a slanted radiator orientation - you could = place a larger core which resulted in better cooling until around 22 deg = from vertical - after than it seems the air had a harder timing making = the turn to flow into the air channels and no further improvement even = with increased size was found. At least that was my interpretation of = the data. =20 This is an area I admit to only a very limited understanding - and = certainly not enough feel comfortable designing a radiator - however, if = you have an acquaintance who has some experience in that field, go for = it!!!! =20 Good luck. =20 Ed =20 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 George Lendich Sent: Tuesday, June 30, 2009 6:48 PM To: Rotary motors in aircraft Subject: [FlyRotary] Round Radiators =20 Ed, Bernie's comments on weird have prompted me to start my investigation = on a round radiator, PWR locally has an engineer who is interested in my = ideas and we may move to develop a prototype. It seems the easiest way to manufacture this type of radiator is along = the lines of the stacker radiator, used mostly for water to oil and are = very efficient for this purpose. I've seen where people are using them = for radiators in racing. To optimize the suitability for my application = the air flow channels would be modified for reasons of maximum surface = area, turbulence etc. =20 Naturally a round radiator need to be thinner rather than thicker ( = unlike the round intercoolers). In my design the air flows from the = centre outwardly and taken back toward a butterfly to control the exit = air flow. =20 The inlet would need to be shaped to maximize pressure as would the = internals. I can't easily explain everything but I would appreciate some = help with sizing fore hp etc. I do have notes on the subject and will = have to find them again but I think a rule of thumb is either 3 sq" per = hp or 3 cu" per hp and radiator incidence in excess of 55 deg and if the = angle is taken from the vertical or horizontal. Any help is appreciated! George (down under) =20 __________ 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_0005_01C9FA3C.2E8464A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ed,
Thanks mate I found my notes and you = are indeed=20 right 3cu" per hp and 55 deg from Vertical.
My notes say 20 to 30 deg will increase = cooling and=20 increase drag.
Over 30 deg things improve and at 55 = deg, cooling=20 effectiveness is 30 deg greater than non-inclined and drag is less than = at 20=20 deg inclined.- my notes say 30 degrees so I assume that degree=20 F. 
 
I must also correlate those figures on = size to=20 BTU's before I go ahead.
I have included my notes on the subject = for=20 youeself or anyone interested OK.
George (down under)

Ambitious = undertaking=20 for certain, George.

 

I think the = rule of=20 thumb you are looking for is 3 cubic inches of core volume for each = HP. =20 So 180 HP rotary would require 180 * 3 =3D 540 cubic inches of = core.  My=20 two GM cores are 10x9 x 3.5 *2 =3D 630 cubic inches and they are = designed for=20 Freon rather than water.  So a =93real=94 water radiator would = undoubtedly do=20 better and 540 does not seem = unreasonable.

 

Regarding = the=20 incident angle, I would say it=92s the angle relative to the incoming=20 airflow.  So if you stood the core vertically, then 55 deg would = be the=20 most you would want from the vertical =96 but, I must say that unless = you are=20 also designing and understand the effects of =93angle of attack=94 on = the small=20 air channels and can shape them to give you the characteristic you = want, I=20 would hesitate to vary much from 70 - 90 = deg.

 

Some folks = have=20 quoted studies where cooling improved by inclining the radiator, but = when I=20 read the report, it was clear the reason the cooling improved is that = with a=20 slanted radiator orientation =96 you could place a larger core which = resulted in=20 better cooling until around 22 deg from vertical =96 after than it = seems the air=20 had a harder timing making the turn to flow into the air channels and = no=20 further improvement even with increased size was found. At least that = was my=20 interpretation of the data.

 

This is an = area I=20 admit to only a very limited understanding =96 and certainly not = enough feel=20 comfortable designing a radiator =96 however, if you have an = acquaintance who=20 has some experience in that field, go for = it!!!!

 

Good=20 luck.

 

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 George Lendich
Sent: Tuesday, June 30, 2009 = 6:48=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Round=20 Radiators

 


Ed,

Bernie's comments on = weird have=20 prompted me to start my investigation on a round radiator, PWR locally = has an=20 engineer who is interested in my ideas and we may move to develop a=20 prototype.

It seems the easiest way = to=20 manufacture this type of radiator is along the lines of the = stacker=20 radiator, used mostly for water to oil  and are very efficient = for this=20 purpose. I've seen where people are using them for radiators in = racing. To=20 optimize the suitability for my application the air flow channels = would be=20 modified for reasons of maximum surface area, turbulence=20 etc.

 

Naturally a round = radiator need to=20 be thinner rather than thicker ( unlike the round intercoolers). In my = design=20 the air flows from the centre outwardly and taken back toward a = butterfly to=20 control the exit air flow.

 

The inlet would need to = be=20 shaped  to maximize pressure as would the internals. I can't = easily=20 explain everything but I would appreciate some help with sizing fore = hp etc. I=20 do have notes on the subject and will have to find them again but I = think a=20 rule of thumb is either 3 sq" per hp or 3 cu" per hp and radiator = incidence in=20 excess of 55 deg and if the angle is taken from the vertical or=20 horizontal.

Any help is=20 appreciated!

George (down=20 under)

 



__________ 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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