X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-lpp01m010-f52.google.com ([209.85.215.52] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTPS id 5435077 for flyrotary@lancaironline.net; Fri, 09 Mar 2012 10:31:41 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.215.52; envelope-from=rwstracy@gmail.com Received: by lahi5 with SMTP id i5so1632486lah.25 for ; Fri, 09 Mar 2012 07:31:03 -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=YciOLqTcFR5DVE66EdxnGdEqiF0wWO5Vs0ROmIjaSvo=; b=0CuL0QCPgo8/ZVvYkuSelKKYS4VunXBnwxHgRdwsUS9IuzCdd+noJqezy31nh+1EHp +9A8ot9qTVQOTSIxBCuPP+1mPTk+7UWYVYJIwdrGECpawBkiWNnl7BdI+BpcolgUFXL7 JH95qQ/fV/dkytsExIU4DZ1htPT7Dkt+IL/Ih93Kt5iFIAGMo9VqfxyMlQPp0yveM2LK 96TwrOffdRDin/mFwA+Tuax+MgMD5v8euitIfc2WQvYVIUug0VkNCheqIuePqoLzrpic F18R6aVjEUBLhGy86FGAnjKH6TScHfv7yMtqo7AiMol/PKNM6+9McyDiO5IWcCZynjli yjIw== MIME-Version: 1.0 Received: by 10.152.135.198 with SMTP id pu6mr1915356lab.46.1331307063603; Fri, 09 Mar 2012 07:31:03 -0800 (PST) Received: by 10.112.94.179 with HTTP; Fri, 9 Mar 2012 07:31:03 -0800 (PST) In-Reply-To: References: Date: Fri, 9 Mar 2012 10:31:03 -0500 Message-ID: Subject: Re: [FlyRotary] Re: Engine cooling From: Tracy To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=f46d04426e169cf16504bad114d3 --f46d04426e169cf16504bad114d3 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable 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 30= 0 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? Tracy On Fri, Mar 9, 2012 at 9:20 AM, Jeff Whaley wrote: > I think the approach makes sense for the worse-case hot weather > environment but from a northern perspective you have to do something when > it gets cold. If you design a system to cool at 100F OAT, your engine it = is > going to be too cold at 0F OAT; in fact it will be exactly 100F less, > typically 80F. > Right now I'm using grills that block off approximately 50% of inlet air > flow; at 0F I add tape to reduce to 25% air flow. This is of course only > ground adjustable but adequate for typical winter flying. Running > synthetic oil a bit too cool is less significant than running the glycol > too cool. My long-term approach will be to install an in-flight adjustab= le > flap to restrict the outlet air of my radiator, which does not provide > airflow over the engine, only my oil coolers do that. > Jeff > > -----Original Message----- > From: Ernest Christley [mailto:echristley@att.net] > Sent: Thursday, March 08, 2012 3:38 PM > Subject: Re: [FlyRotary] Engine cooling > > Chris Barber wrote: > > > > Just some data points for discussion. PLEASE if you know some stuff > > that is rotary specific, or just wrong, CHIME IN!! > > > > > > > > Chris > > > > Houston > > > > > > > > Cooling Guidelines for V8 Engines in Aircraft by Bud Warren and > > Phyllis Ridings > > > > After much thought, Bud decided to install a thermostat in the LS1 > > engine of the Ravin 500 to do some test flying. During cold weather > > the resulting engine temps have remained stable at 190=B0F at cruise, > > and near 200=B0F during climb out; just about what we see during the > > warm months of the year. This has corrected the check engine light > > coming on due to the engine remaining in warm up mode. > > This approach makes me nervous. It doesn't hit us much here in the > southern US, but things get colder as we move north. > When it is freezing on the ground, it's very easy to get REALLY cold > temps at altitude. If it is 0*F on the ground, > then the rule of thumb says that it will be -40* at altitude. > > The problem described is that the engine isn't able to produce enough hea= t > to warm the water with the amount of -40*F air that is rushing through. > The prescription given is to force the water to stay in the engine longe= r. > This necessarily means that the water will stay in the radiator longer. > Now the thermostat opens even less, because what it pulls from the radiat= or > is ice water. At some point, the water gets really hard in the radiator > and stops flowing altogether. The there is no flow from the engine to me= lt > it. The engine water keep recirculating and it eventually overheats. > > The Mack truck I bought in the late 80's had a shutter arrangement in > front that would close when it got to cold and block airflow through the > radiator. I think a thin aluminum panel, possibly controlled by a > push-pull cable from the cockpit, that slid in to partially block the > radiator would be a much safer solution. It would also alleviate the > concern over broken thermostats. The panel would require minimal support= , > as it could simply lay flat against the radiator face. > > This message, and the documents attached hereto, is intended only for the > addressee and may contain privileged or confidential information. Any > unauthorized disclosure is strictly prohibited. If you have received this > message in error, please notify us immediately so that we may correct our > internal records. Please then delete the original message. Thank you. > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > --f46d04426e169cf16504bad114d3 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Sanity check:

1) Requirement: Radiator surface required is 1.5 sq in= of surface area per cubic inch of the engine. For example:=A0LS1=A0V8 Chev= rolet =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.=A0<= /span>


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=A0LS1 for aircraft=20 use. Using a dual radiator configuration with two radiators measuring=20 15=94 x 18=94 x 2.25=94 thick =3D the total cooling volume is 1215 cu in.=A0
Therefore, our cooling volume to HP ratio: 1215 cu in cooling volume =F7=20 300 HP =3D 4.05 cu in per HP. With this formula, we have been able to=20 maintain climb out temperatures of around=A0200=B0F and=A0190=B0F at cruise= on a=A0100=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?

T= racy


On Fri, Mar 9, 2012 at 9:= 20 AM, Jeff Whaley <jwhaley@datacast.com> wrote:
I think the approach makes sense for the wor= se-case hot weather environment but from a northern perspective you have to= do something when it gets cold. If you design a system to cool at 100F OAT= , your engine it is going to be too cold at 0F OAT; in fact it will be exac= tly 100F less, typically 80F.
Right now I'm using grills that block off approximately 50% of inlet ai= r flow; at 0F I add tape to reduce to 25% air flow. =A0This is of course on= ly ground adjustable but adequate for typical winter flying. =A0Running syn= thetic oil a bit too cool is less significant than running the glycol too c= ool. =A0My long-term approach will be to install an in-flight adjustable fl= ap to restrict the outlet air of my radiator, which does not provide airflo= w over the engine, only my oil coolers do that.
Jeff

-----Original Message-----
From: Ernest Christley [mailto:echris= tley@att.net]
Sent: Thursday, March 08, 2012 3:38 PM
Subject: Re: [FlyRotary] Engine cooling

Chris Barber wrote:
>
> Just some data points for discussion. PLEASE if you know some stuff > that is rotary specific, or just wrong, CHIME IN!!
>
>
>
> Chris
>
> Houston
>
>
>
> Cooling Guidelines for V8 Engines in Aircraft by Bud Warren and
> Phyllis Ridings
>
> After much thought, Bud decided to install a thermostat in the LS1
> engine of the Ravin 500 to do some test flying. During cold weather > the resulting engine temps have remained stable at 190=B0F at cruise,<= br> > and near 200=B0F during climb out; just about what we see during the > warm months of the year. This has corrected the check engine light
> coming on due to the engine remaining in warm up mode.

This approach makes me nervous. =A0It doesn't hit us much here in the s= outhern US, but things get colder as we move north.
=A0When it is freezing on the ground, it's very easy to get REALLY cold= temps at altitude. =A0 If it is 0*F on the ground,
then the rule of thumb says that it will be -40* at altitude.

The problem described is that the engine isn't able to produce enough h= eat to warm the water with the amount of -40*F air that is rushing through.= =A0The prescription given is to force the water to stay in the engine long= er. =A0This necessarily means that the water will stay in the radiator long= er. Now the thermostat opens even less, because what it pulls from the radi= ator is ice water. =A0At some point, the water gets really hard in the radi= ator and stops flowing altogether. =A0The there is no flow from the engine = to melt it. =A0The engine water keep recirculating and it eventually overhe= ats.

The Mack truck I bought in the late 80's had a shutter arrangement in f= ront that would close when it got to cold and block airflow through the rad= iator. =A0I think a thin aluminum panel, possibly controlled by a push-pull= cable from the cockpit, that slid in to partially block the radiator would= be a much safer solution. =A0It would also alleviate the concern over brok= en thermostats. =A0The panel would require minimal support, as it could sim= ply lay flat against the radiator face.

This message, and the documents attached hereto, is intended only for the a= ddressee and may contain privileged or confidential information. Any unauth= orized disclosure is strictly prohibited. If you have received this message= in error, please notify us immediately so that we may correct our internal= records. Please then delete the original message. Thank you.

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

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