X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-yx0-f180.google.com ([209.85.213.180] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTPS id 5436044 for flyrotary@lancaironline.net; Fri, 09 Mar 2012 23:51:46 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.213.180; envelope-from=wrjjrs@gmail.com Received: by yenl4 with SMTP id l4so1444870yen.25 for ; Fri, 09 Mar 2012 20:51:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=R7VPve732GHcKv/nybPbdFF6zLVvv92e9grIUX/sASQ=; b=EncRMsj5PljkgwJYec/GhrzhU4jtbu/BK9QQDZhU9ctkHSkFNNcvCUIB/Gf/92SOva b0+cI3+cICL7PysqusCPmOrfRMjMDUBJfGcpdrMMq30YDrBXfqvM379BB4NVlQjLXAys Wn6FBcdH55Zz8rmyvefPSXT/OQs+CsL7BftTM8DYbmT/aJJP7gIJpnHuonBNEt+eV2v/ sBWHkOqD8UBhp1n59NAYj4E/ooTEuApuxLxjj6HV2IAZFSA/Eaa1DQE7/0HRISL+GfEC 3fIhi1tIFY7iSsHlJ6KpATwxudd8N8Q2JEI6sR1rai0XEmCJoZnKxgpK7MbDYL8VLRcV ZQeg== MIME-Version: 1.0 Received: by 10.224.100.197 with SMTP id z5mr1426468qan.61.1331355070973; Fri, 09 Mar 2012 20:51:10 -0800 (PST) Received: by 10.229.100.73 with HTTP; Fri, 9 Mar 2012 20:51:10 -0800 (PST) Received: by 10.229.100.73 with HTTP; Fri, 9 Mar 2012 20:51:10 -0800 (PST) In-Reply-To: References: Date: Fri, 9 Mar 2012 20:51:10 -0800 Message-ID: Subject: Re: [FlyRotary] Re: Engine cooling From: William Jepson To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=20cf306f744613463604badc4244 --20cf306f744613463604badc4244 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Thomas, proper ducting can make a world of difference. Bill Jepson 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 > trailer to my Questair Venture project to get enough Radiator to cool the > HP I was planning. > 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 wou= ld > 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 wro= te: > >> 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 purpos= e, >> > this applies only to the surface area of the radiator that the air flo= w >> > 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 cruis= e on >> > a 100=B0F day. With a cooling system like this, we could taxi from Hou= ston >> > 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 o= f >> 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". >> >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> > > > --20cf306f744613463604badc4244 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable

Thomas, proper ducting can make a world of difference.
Bill Jepson

On Mar 9, 2012 8:40 PM, "Thomas Giddings&qu= ot; <n360tg@earthlink.net>= ; wrote:
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. =A0
KIND REGARDS
Thomas Giddings



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

Ah,=A0 I missed the detail of having 2 rads.=A0 It was the o= dd definition of "radiator surface area"=A0 that got me off track= .=A0=A0 Guess that means face area.=A0 If the designers of the P51 had used= his formula, the rad core would have measured about 5 feet square and woul= d not have fit in the airplane.=A0=A0 But I do agree with his basic rule of= thumb on rad core volume.=A0 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 purpos= e,
> this applies only to the surface area of the radiator that the air flo= w
> 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.<= br> > 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<= br> > maintain climb out temperatures of around 200=B0F and 190=B0F at cruis= e on
> a 100=B0F day. With a cooling system like this, we could taxi from Hou= ston
> 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. =A0The 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. =A0I would not take issue with the math, = just his definition of what constitutes "minimum".


--
Homepage: =A0http:/= /www.flyrotary.com/
Archive and UnSub: =A0 http://mail.lancaironline.net:81/lists= /flyrotary/List.html


--20cf306f744613463604badc4244--