X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-qy0-f176.google.com ([209.85.221.176] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTP id 4085564 for flyrotary@lancaironline.net; Sun, 17 Jan 2010 08:59:09 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.221.176; envelope-from=rwstracy@gmail.com Received: by qyk6 with SMTP id 6so1308088qyk.3 for ; Sun, 17 Jan 2010 05:58:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:message-id:subject:from:to :content-type; bh=rAIBYwsjIPZa68c95Bw1i4VkxE0aAeG7atmQJaREavE=; b=MQZHXxScLaNfigSxyqsxH3GXy7eQceHINdBZdcO6pHi5cy4EX+/kxdjwkReX9pzQ4P LRQc7HnEd86WOZh5jrx6MJdmNSEMATrn7EZWEUxkuhdm1IecrexT40hJE4wXPLZTwECk F7Kn6NwBUSJolktE+vDfGKhcRuejJbNlt5G0Q= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; b=Ez5OsPlsJlMrQcamxTnrlzKuGWh6JPRtnK2aafNxsAyitNwsshR+mb8DoRfkZHdAEe tkyYe9FUnD/TS+iMXv+a+d/TFSYawELluB/r7kofXgFcYVut8pv4sYXrPMEFYOHLD3bP p5+UejYwVdYxnHTVEt1llXgDOpfvFBYbeUNAI= MIME-Version: 1.0 Sender: rwstracy@gmail.com Received: by 10.224.72.96 with SMTP id l32mr3731821qaj.127.1263736712988; Sun, 17 Jan 2010 05:58:32 -0800 (PST) In-Reply-To: References: Date: Sun, 17 Jan 2010 08:58:32 -0500 X-Google-Sender-Auth: fe30805f3a65a6fb Message-ID: <1b4b137c1001170558v54e9b0bbn6af52f62ee212259@mail.gmail.com> Subject: Re: [FlyRotary] Re: Inclined Radiators was : [FlyRotary] Re: Scoops From: Tracy Crook To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=00c09f88d27ade0ae9047d5ca1cb --00c09f88d27ade0ae9047d5ca1cb Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Two points, Air does not care which tilt axis we are talking about so that is not a factor. Mine was tilted on the horizontal axis if it helps envision it. A 'wedge' duct does not preclude a 'bell shaped' duct. The bell shape DOES become distorted to the point of not being recognizable but it still functions as one. I spent several days sculpting mine. Wouldn't have spen= t that time if a simple wedge would be as good. Tracy On Sat, Jan 16, 2010 at 10:56 PM, George Lendich wrot= e: > 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 th= e Y > axis or vertical. So 35 degrees inclined vertical isn't too bad - in a b= ell > shaped duct. However I could be wrong and the original reference could ha= ve > been 55 degrees inclined from vertical, which also sounds plausible, seei= ng > 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 shap= ed > 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 th= e > placement of rad i.e. under engine or side of cowl with appropriate depth= of > the inlet opening. > Comments please. > George ( down under) > > 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 inclini= ng > 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 o= il > cooler. It was the "30 row oil cooler" from CXracing if anyone is curiou= s. > > Tracy > > On Sat, Jan 16, 2010 at 4:18 PM, George Lendich wro= te: > >> Ed, >> 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. >> >> >> >> Basically the figures that George mentioned were quoted in the source. >> However (big however) what may not have been clearly pointed out was tha= t >> 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 coolin= g >> 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 zer= o >> degree inclination. If you incline the radiator by 30 deg and then incr= ease >> its height to again fill the duct,. you can get an approx 15% increase i= n >> the frontal size of the radiator (in the same 24x12 duct). At 60 deg yo= u >> 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 r= id >> 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 offs= et >> its benefit (this was all addressing their use in race cars). >> >> >> >> The source indicated that up to 30Deg the drag increases and heat transf= er >> goes down due to uneven air flow distribution and disturbances =96 appar= ently >> above that angle this adverse effect decreases and of course you have th= e >> 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 >> >> 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 ta= ken >> 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 >> >> > --00c09f88d27ade0ae9047d5ca1cb Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Two points,
=A0 Air does not care which tilt axis we are talking about = so that is not a factor.=A0 Mine was tilted on the horizontal axis if it he= lps envision it.

A 'wedge' duct does not=A0 preclude a '= bell shaped' duct.=A0=A0 The bell shape DOES become distorted to the po= int of not being recognizable but it still functions as one.=A0 I spent sev= eral days sculpting mine.=A0 Wouldn't have spent that time if a simple = wedge would be as good.

Tracy

On Sat, Jan 16, 2010 at 10:56 PM, George Len= dich <lendich@aanet.com.au> wrote:
Tracy, Ed &Al,
I don't know if we are all talking= about the same=20 thing so to clarify in my own mind,=A0 I would like to say my opinion on=20 these notes I have, suggest to me that the 55 degrees, is from the directio= n 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=A0 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 sou= nds=20 plausible, seeing their talking inclined, one might think inclined from=20 vertical.=A0 Al what's your thoughts on this.
=A0
However I believe Tracy, you are sayin= g 80 degrees=20 from vertical and=A0 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 th= at degree=20 to the duct walls.
=A0
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 du= ct 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=A0the placement of=A0rad i.e. under engine or side of cowl=20 with appropriate depth of the inlet opening.
Comments please.
George ( down under)=A0=A0

Well=20 the basic idea has validity because I carried it to an extream.=A0 My rad= =20 is inclined about 80 degrees to the 5" duct so flow axis is almost= =20 perpendicular to the duct.=A0 A 5" rad would never cool that 20B so= =20 inclining it radically was the only answer in my configuration.=A0 Water= =20 cooling has never been my problem.=A0 Oil cooling is working pretty good= =20 with the new oil cooler.=A0 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 Lendic= h <lendich@aanet.com.au>=20 wrote:
Ed,
I would like to see that again, as= I believe=20 would others, =A0like 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

<= /font>=A0

Basicall= y the=20 figures that George mentioned were quoted in the source.=A0 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) incre= ased=20 was that inclining the heat exchanger permitted you to install ever l= arger=20 area cores in the same size duct.=A0 So the increase in cooling=20 effectiveness by inclination was in large part due to the larger size= =20 radiator permitted by inclined placement in the duct.

<= /font>=A0

For exam= ple take=20 a duct that is 24=94 wide (X) and 12=94 high (Y) at zero degree=20 inclination.=A0 If you incline the radiator by 30 deg and then increa= se=20 its height to again fill the duct,. you can get an approx 15% increas= e in=20 the frontal size of the radiator (in the same 24x12 duct).=A0 At 60 d= eg=20 you could gain approx 100% increase in frontal size by again increasi= ng=20 the height of the core to fill the duct.=A0 . Naturally that aids in= =20 getting rid of the heat.=A0 They also point out the larger core adds= =20 weight until you reach a point where the adverse effect of the heavie= r=20 radiator core offset its benefit (this was all addressing their use i= n=20 race cars).

<= /font>=A0

The sour= ce=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 a= bove=20 that angle this adverse effect decreases and of course you have the m= uch=20 larger frontal area..

<= /font>=A0

At least= that is=20 what I recall.=A0 If anyone is interested I=92ll see if I can find th= e=20 article in my files

<= /font>=A0

Ed

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: Rotar= y motors in=20 aircraft
Subject:=20 [FlyRotary] Re: Scoops

=A0

= =A0

= 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%.

= =A0

George; do you=20 have the source for that info? It may be a good idea to verify this= =20 information. =A0I don=92t recall the specifics; but what I do recall = is=20 that the conclusion was configuration dependant, and should not be ta= ken=20 as generally applicable.=A0 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.=A0 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.

h= ttp://www.eset.com



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