X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop-Diagnostic: (direct reply)\eX-PolluStop-Score: 0.00\eX-PolluStop: Scanned with Niversoft PolluStop 2.1 RC1, http://www.niversoft.com/pollustop Return-Path: Received: from frontend2.cwpanama.net ([201.225.225.168] verified) by logan.com (CommuniGate Pro SMTP 4.3c4) with ESMTP id 861249 for flyrotary@lancaironline.net; Thu, 07 Apr 2005 22:40:15 -0400 Received-SPF: none receiver=logan.com; client-ip=201.225.225.168; envelope-from=rijakits@cwpanama.net Received: from [201.224.93.110] (HELO usuarioq3efog0) by frontend2.cwpanama.net (CommuniGate Pro SMTP 4.2.1) with SMTP id 38551208 for flyrotary@lancaironline.net; Thu, 07 Apr 2005 21:45:05 -0500 Message-ID: <00c701c53be4$2e838280$6e5de0c9@usuarioq3efog0> From: "rijakits" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: rule of thumb and RV-3 sizes- was Cooling Inlet Date: Thu, 7 Apr 2005 21:39:26 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00C3_01C53BBA.4563A040" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_00C3_01C53BBA.4563A040 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Considering the material Schmidtbauer and Anders were studying, most of that research was probably based on liquidcooled systems (how much streamline optimizing can you do on a aircooled cylinder head compared to optimizing duct work and even radiators...). They just applied to their Lycomings as best as they could. If you look at the WW II powerhouses like Mustang/Thunderbolt/Spitfire/Me109/FW190/etc. you will always see more sofisticated ducting on the liquid cooled ones than on the aircooled ones (these basically having only the oil coolers to be placed in a location of choice to acomodate perfect ducting...) With the rotary we are obviously dealing with a lot of ductwork - radiator inlet/exit - oilcooler inlet/exit - combustion air intake/cooling air exit augmentation - , so optimizing it will be a drag reduction priority, .....for me. I also will closely look into fishmouth exhaust ends and possibly try to connect this system with exhaust augmentation for the cooling exit ducts. Thomas J. From: echristley This is completely logical if you consider the extremely small surface area available to transfer heat on the cylinderhead fins compared to the surface area on even a small radiator. I agree. To take this even further, an *optimized* water cooled installation will use fewer CFM to cool a given number of BTUs (and have less drag) than an aircooled engine. The P-51 would probably not been able to escort bombers all the way to Germany and back if it had an air cooled engine (all other factors remaining the same). Tracy ------=_NextPart_000_00C3_01C53BBA.4563A040 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Considering the material Schmidtbauer and Anders were studying, = most of=20 that research was probably based on liquidcooled systems (how much = streamline=20 optimizing can you do on a aircooled cylinder head compared to = optimizing duct=20 work and even radiators...). They just applied to their Lycomings as = best as=20 they could.

If you look at the WW II powerhouses like=20 Mustang/Thunderbolt/Spitfire/Me109/FW190/etc.

you will always see more sofisticated ducting on the liquid = cooled=20 ones than on the aircooled ones (these basically having only the oil = coolers to=20 be placed in a location of choice to acomodate perfect=20 ducting...)

With the rotary we are obviously dealing with a lot of = ductwork -=20 radiator inlet/exit - oilcooler inlet/exit - combustion air = intake/cooling air=20 exit augmentation - , so optimizing it will be a drag reduction = priority,=20 .....for me. I also will closely look into fishmouth exhaust ends and = possibly=20 try to connect this system with exhaust augmentation for the cooling = exit=20 ducts.

Thomas J.

From: echristley

This is completely logical if you consider the extremely = small=20 surface area
available to transfer heat on the cylinderhead fins = compared=20 to the surface
area on even a small radiator.

I = agree. =20 To take this even further, an *optimized* water cooled installation = will use=20 fewer CFM to cool a given number of BTUs (and have less drag) than = an=20 aircooled engine. The P-51 would probably not been able to = escort=20 bombers all the way to Germany and back if it had an air cooled = engine (all=20 other factors remaining the same).

Tracy

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