X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao06.cox.net ([68.230.241.33] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1231245 for flyrotary@lancaironline.net; Mon, 10 Jul 2006 15:04:29 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.33; envelope-from=ALVentures@cox.net Received: from BigAl ([72.192.132.90]) by fed1rmmtao06.cox.net (InterMail vM.6.01.06.01 201-2131-130-101-20060113) with ESMTP id <20060710190341.JZGK6235.fed1rmmtao06.cox.net@BigAl> for ; Mon, 10 Jul 2006 15:03:41 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Temperature control Date: Mon, 10 Jul 2006 12:03:45 -0700 Message-ID: <000001c6a453$917c2170$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C6A418.E51D4970" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C6A418.E51D4970 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 The issue: On the ground, cooling stabilizes at 180-190F deg and oil is usually 10 degrees below the cooling with an OAT of 65-70F deg. When running with higher OAT (75-85F deg) after about 0.5 hours of = moderate taxi runs (up to 4300RPM) the cooling temps reach 212Fdeg with the oil = about 200F deg. =20 The question: Can something be done to get lower operating temperatures without redesigning the system? Would switching to pure water help and if so by how much? Would removing the thermostat help and if so by how much? How much change should I expect if I were to do both? You guys down south should have a good idea of how best to enhance = cooling. What are your suggestions? Thanks, Jim Maher(Dyke Delta) Jim; =20 Going to pure water will decrease the delta T from rad in to rad out. Removing the thermostat will increase the flow rate which will also = decrease the delta T across the rad. The net effect is increased average heat rejection temperature at a given power level, and therefore, increased = heat rejection. However, without knowing your current flow rate and temp = drop through the rad, there is no way to tell how much improvement you'd get. = =20 =20 But from what you describe, I'd say don't do anything at this point. = Wait til your plane flies and see how it cools on climbout and cruise. Your ground cooling seems adequate to get you airborne. If you have a long = wait on the ground; turn your engine off, until you have to move again. =20 If you want to know the effect of pure water or thermostat removal on = your system, you'll have to make the change and see the results. =20 FWIW, =20 Al (Scheduled for first flight this weekend; forecast temps upper 90's. Yikes!) ------=_NextPart_000_0001_01C6A418.E51D4970 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

The issue:

On the ground, cooling stabilizes at 180-190F = deg and oil is usually 10 degrees below the cooling with an OAT of 65-70F = deg.

When running with higher OAT (75-85F deg) = after about 0.5 hours of moderate taxi runs (up to 4300RPM) the cooling temps reach = 212Fdeg with the oil about 200F deg.

 

The question:

Can something be done to get lower operating temperatures without redesigning the system?

Would switching to pure water help and if so = by how much?

Would removing the thermostat help and if so = by how much?

How much change should I expect if I were to = do both?

You guys down south should have a good idea = of how best to enhance cooling.

What are your suggestions?

Thanks,

Jim Maher(Dyke Delta)

Jim;

 

Going to pure water will decrease = the delta T from rad in to rad out.  Removing the thermostat will = increase the flow rate which will also decrease the delta T across the rad.  The = net effect is increased average heat rejection temperature at a given power = level, and therefore, increased heat rejection.  However, without knowing = your current flow rate and temp drop through the rad, there is no way to tell how = much improvement you’d get. 

 

But from what you describe, = I’d say don’t do anything at this point.  Wait til your plane = flies and see how it cools on climbout and cruise.  Your ground cooling seems adequate to get you airborne.  If you have a long wait on the = ground; turn your engine off, until you have to move again.

 

If you want to know the effect of = pure water or thermostat removal on your system, you’ll have to make = the change and see the results.

 

FWIW,

 

Al (Scheduled for first flight = this weekend; forecast temps upper 90’s.  = Yikes!)

------=_NextPart_000_0001_01C6A418.E51D4970--