X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from elasmtp-dupuy.atl.sa.earthlink.net ([209.86.89.62] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTP id 5436034 for flyrotary@lancaironline.net; Fri, 09 Mar 2012 23:40:39 -0500 Received-SPF: none receiver=logan.com; client-ip=209.86.89.62; envelope-from=n360tg@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=VkJfW4KEoVarhvOvaQWrgkcQtOF1cgGKEF5E8avI4pJhirHPfGULqwjcEz1keCB1; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [184.0.224.156] (helo=[192.168.1.69]) by elasmtp-dupuy.atl.sa.earthlink.net with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.67) (envelope-from ) id 1S6E69-0005rT-7F for flyrotary@lancaironline.net; Fri, 09 Mar 2012 23:40:05 -0500 From: Thomas Giddings Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-20-859886199 Subject: Re: [FlyRotary] Re: Engine cooling Date: Fri, 9 Mar 2012 23:40:04 -0500 In-Reply-To: To: "Rotary motors in aircraft" References: Message-Id: <5109B4F2-235A-4828-850E-E67B5DFA8174@earthlink.net> X-Mailer: Apple Mail (2.1084) X-ELNK-Trace: 77b0437ff618fec294f5150ab1c16ac07c540ca440b21de7e34a1a7695f579de15281a724b783e02350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 184.0.224.156 --Apple-Mail-20-859886199 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Hmmm.....If the 3 CI per HP is accurate then i guess I need to add a = trailer to my Questair Venture project to get enough Radiator to cool = the HP I was planning. =20 KIND REGARDS Thomas Giddings n360tg@earthlink.net 727 858 1772 On Mar 9, 2012, at 2:42 PM, Tracy wrote: > 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 measured about 5 feet square and would not have fit in = the airplane. But I do agree with his basic rule of thumb on rad core = volume. 3 CI per HP is a reasonable target. >=20 > Tracy >=20 > On Fri, Mar 9, 2012 at 11:10 AM, Ernest Christley = wrote: > 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 in > > 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=94= x > > 18=94 x 2.25=94 thick =3D the total cooling volume is 1215 cu in. > > Therefore, our cooling volume to HP ratio: 1215 cu in cooling volume = =F7 > > 300 HP =3D 4.05 cu in per HP. With this formula, we have been able = to > > maintain climb out temperatures of around 200=B0F and 190=B0F at = cruise on > > a 100=B0F day. With a cooling system like this, we could taxi from = Houston > > 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, 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". >=20 >=20 > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html >=20 --Apple-Mail-20-859886199 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252
KIND = REGARDS
Thomas Giddings
72= 7 858 1772



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

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 measured about 5 feet square and would = not have fit in the airplane.   But I do agree with his basic = rule 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
> per cubic inch of the engine. For example: LS1 V8 Chevrolet =3D 350 = cu in
> 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=94 x
> 18=94 x 2.25=94 thick =3D the total cooling volume is 1215 cu = in.
> Therefore, our cooling volume to HP ratio: 1215 cu in cooling = volume =F7
> 300 HP =3D 4.05 cu in per HP. With this formula, we have been able = to
> maintain climb out temperatures of around 200=B0F and 190=B0F at = cruise on
> a 100=B0F day. With a cooling system like this, we could taxi from = Houston
> 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 volume.  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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