X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-yw0-f52.google.com ([209.85.213.52] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTPS id 5436280 for flyrotary@lancaironline.net; Sat, 10 Mar 2012 08:09:48 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.213.52; envelope-from=rwstracy@gmail.com Received: by yhpp61 with SMTP id p61so1551315yhp.25 for ; Sat, 10 Mar 2012 05:09:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:references:from:content-type:x-mailer:in-reply-to :message-id:date:to:content-transfer-encoding:mime-version; bh=sliD118dqi94UwSbCxXo7tqGCMZlfZwy1NeP0Dzzy7E=; b=jRUN6W/aibDoE783jg13B0OYhU0MKWua9h3ed+2HrgQy579LIx8z8r/+DD8KYW0KQi anD8lXL7gUdWNsMIUG3hlhNuqdr8WFD8oDVPCeaVQ51czyFWFDdKDYLbHRHT+qSWlMjU x5GQJkxhxudIZh3l/fSTuy2nclk38u2CvSvA7D7k+3vjiGzjJYgp6PYiUoVehODfREZB YwcA12WS/a1oz1+6Jqph+0PB8UKpUB9PMM3XcneS9TnzLUYgs5wlV1oq1J7WPefJE+Fu btwcMmZ5J2yPxukvdZMVhIZyHoyyJUEmHT5rACp4r1QX4QE5W2wOfPScwzWGnHS0KStI o7uw== Received: by 10.236.136.33 with SMTP id v21mr6955538yhi.17.1331384952316; Sat, 10 Mar 2012 05:09:12 -0800 (PST) Return-Path: Received: from [192.168.1.2] (156.sub-166-248-68.myvzw.com. [166.248.68.156]) by mx.google.com with ESMTPS id u9sm14572202anb.1.2012.03.10.05.09.09 (version=TLSv1/SSLv3 cipher=OTHER); Sat, 10 Mar 2012 05:09:11 -0800 (PST) Subject: Re: [FlyRotary] Re: Engine cooling References: From: Tracy Content-Type: multipart/alternative; boundary=Apple-Mail-8-890433951 X-Mailer: iPad Mail (8F191) In-Reply-To: Message-Id: <8D9E4EB5-94DF-4C14-BD07-A532003C7BB6@gmail.com> Date: Sat, 10 Mar 2012 08:09:07 -0500 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (iPad Mail 8F191) --Apple-Mail-8-890433951 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Yes, ducting is a BIG factor. The better your ducts are the more you can r= educe that 3ci / hp number. I'm closer to 2 ci / HP and it's working ok bu= t did a lot of work on ducts. 3 is ' reasonable' because it is conservativ= e without being almost impossible. Tracy Sent from my iPad On Mar 9, 2012, at 11:51 PM, William Jepson wrote: > Thomas, proper ducting can make a world of difference. > Bill Jepson >=20 > On Mar 9, 2012 8:40 PM, "Thomas Giddings" wrote: > Hmmm.....If the 3 CI per HP is accurate then i guess I need to add a trail= er to my Questair Venture project to get enough Radiator to cool the HP I wa= s planning. =20 > KIND REGARDS > Thomas Giddings > n360tg@earthlink.net > 727 858 1772 >=20 >=20 >=20 > On Mar 9, 2012, at 2:42 PM, Tracy wrote: >=20 >> Ah, I missed the detail of having 2 rads. It was the odd definition of "= radiator surface area" that got me off track. Guess that means face area.= If the designers of the P51 had used his formula, the rad core would have m= easured about 5 feet square and would not have fit in the airplane. But I d= o agree with his basic rule of thumb on rad core volume. 3 CI per HP is a r= easonable target. >>=20 >> Tracy >>=20 >> On Fri, Mar 9, 2012 at 11:10 AM, Ernest Christley wr= ote: >> Tracy wrote: >> > Sanity check: >> > >> > 1) Requirement: Radiator surface required is 1.5 sq in of surface area >> > per cubic inch of the engine. For example: LS1 V8 Chevrolet =3D 350 cu i= n >> > x 1.5 =3D 525 sq in of radiator surface area required. For this purpose= , >> > this applies only to the surface area of the radiator that the air flow= >> > first makes contact with. >> > >> > >> > 2) Requirement: Minimum of 3.0 cu in of cooling volume per HP produced.= >> > For example: We only utilize up to 300 HP of an LS1 for aircraft use. >> > Using a dual radiator configuration with two radiators measuring 15=E2=80= =9D x >> > 18=E2=80=9D x 2.25=E2=80=9D thick =3D the total cooling volume is 1215 c= u in. >> > Therefore, our cooling volume to HP ratio: 1215 cu in cooling volume =C3= =B7 >> > 300 HP =3D 4.05 cu in per HP. With this formula, we have been able to >> > maintain climb out temperatures of around 200=C2=B0F and 190=C2=B0F at c= ruise on >> > a 100=C2=B0F day. With a cooling system like this, we could taxi from H= ouston >> > to Dallas with no overheating problems. >> > >> > Is it just me or is the math here bogus? >> > >>=20 >> He's got dual radiators that add up to 540in^2 of surface and 1215in^3 of= volume. The math is right. >> What doesn't add up to me, is that he says you can get by with 3in^3/hp, b= ut then demonstrates that 4in^3/hp is just >> adequate on a reasonably hot day. I would not take issue with the math, j= ust his definition of what constitutes "minimum". >>=20 >>=20 >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/Lis= t.html >>=20 >=20 --Apple-Mail-8-890433951 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
Yes, ducting is a BIG factor.   Th= e better your ducts are the more you can reduce that 3ci / hp  number. &= nbsp;I'm closer to 2 ci / HP and it's working ok but did a lot of work on du= cts.   3 is ' reasonable' because it is conservative without being almo= st impossible.

Tracy

Sent from my iPad
=

On Mar 9, 2012, at 11:51 PM, William Jepson <wrjjrs@gmail.com> wrote:

Thomas, proper ducting can make a world of di= fference.
Bill Jepson

On Mar 9, 2012 8:40 PM, "Thomas Giddings" <= n360tg@earthlink.net> wrote:
Hmmm.....If the 3 CI per HP is accurate t= hen i guess I need to add a trailer to my Questair Venture project to get en= ough Radiator to cool the HP I was planning.  
KIND REGARDS
Thomas Giddings



On Mar 9, 2012, at 2:42 PM, Tracy wrote:

Ah,  I missed the detail of having 2 rads.  It was th= e odd definition of "radiator surface area"  that got me off track.&nbs= p;  Guess that means face area.  If the designers of the P51 had u= sed his formula, the rad core would have measured about 5 feet square and wo= uld not have fit in the airplane.   But I do agree with his basic r= ule of thumb on rad core volume.  3 CI per HP is a reasonable target.
Tracy

On Fri, Mar 9, 2012 at 11:10 AM,= Ernest Christley <echristley@att.net= > wrote:
Tracy wrote:
> Sanity check:
>
> 1) Requirement: Radiator surface required is 1.5 sq in of surface area<= br> > per cubic inch of the engine. For example: LS1 V8 Chevrolet =3D 350 cu i= n
> x 1.5 =3D 525 sq in of radiator surface area required. For this purpose= ,
> this applies only to the surface area of the radiator that the air flow=
> first makes contact with.
>
>
> 2) Requirement: Minimum of 3.0 cu in of cooling volume per HP produced.=
> For example: We only utilize up to 300 HP of an LS1 for aircraft use. > Using a dual radiator configuration with two radiators measuring 15=E2=80= =9D x
> 18=E2=80=9D x 2.25=E2=80=9D thick =3D the total cooling volume is 1215 c= u in.
> Therefore, our cooling volume to HP ratio: 1215 cu in cooling volume =C3= =B7
> 300 HP =3D 4.05 cu in per HP. With this formula, we have been able to > maintain climb out temperatures of around 200=C2=B0F and 190=C2=B0F at c= ruise on
> a 100=C2=B0F day. With a cooling system like this, we could taxi from H= ouston
> to Dallas with no overheating problems.
>
> Is it just me or is the math here bogus?
>

He's got dual radiators that add up to 540in^2 of surface and 1215in^3 of vo= lume.  The math is right.
What doesn't add up to me, is that he says you can get by with 3in^3/hp, but= then demonstrates that 4in^3/hp is just
adequate on a reasonably hot day.  I would not take issue with the math= , just his definition of what constitutes "minimum".


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Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http://mail.lancaironline.net:81/lists/fly= rotary/List.html


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