X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 5.0.7) with ESMTP id 960550 for flyrotary@lancaironline.net; Mon, 30 Jan 2006 09:52:22 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-025-165.carolina.res.rr.com [24.74.25.165]) by ms-smtp-01-eri0.southeast.rr.com (8.13.4/8.13.4) with SMTP id k0UEpYDn005161 for ; Mon, 30 Jan 2006 09:51:36 -0500 (EST) Message-ID: <000f01c625ac$ab6dcbe0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Cooling air inlets Date: Mon, 30 Jan 2006 09:51:35 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000C_01C62582.C1A48A40" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_000C_01C62582.C1A48A40 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Bob, I fly a Rv-6A with a 13B. I started out using 24 square inch opening = for each of the radiator cores AND 24 square inch opening for the oil = cooler for a total of 3x24 =3D 72 sq inches. I have since reduced the radiator openings to 18 sq inches each - = leaving the oil cooler at 24 sq inches for a total of 60 sq inches, but = I spent a lot of research and experimenting with the ducts to get the = best pressure recovery I could. =20 I estimate (based on fuel burn) that I am producing between 170-180HP. = Naturally the more HP you make the more cooling you need. So what may = work fine for a 160 HP engine may be marginal (or worst) for a 180-200 = HP installation. =20 50 sq inches will probably cool at cruise with no problem - however, it = could be marginal or worst on a hot day with a max power climbout. A = lot depends on how well the ducting and exit of the air is done. = Ducting and associated detail is one reason why seemingly identical = installations may vary greatly in cooling ability. Its all about trade offs, given sufficient surface area and airflow - IT = WILL COOL. However, you may encounter lots of cooling drag if you have = not make an attempt to optimize your compromise. =20 Its possible that using one 50 sq inch duct (such as the James cowl) may = be adequate (I believe Tracy Crook is intending to use such with a 20 B = - so if it will cool a 20 B then there is little doubt it will cool a = 13B). I am eagerly awaiting the results of using such approaches . Ed=20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ----- Original Message -----=20 From: John Downing=20 To: Rotary motors in aircraft=20 Sent: Monday, January 30, 2006 9:22 AM Subject: [FlyRotary] Re: Cooling air inlets Bob; The 40 sq. will not cool the engine. Ed and others are using a = 2 1/2 inch x 10 inch hole under the spinner for the oil cooler, as more = than half of the engine cooling is through oil, as I understand it. I'm = working on the oil cooler opening as well as the round holes to cool the = coolant. My exit is currently 61.8 sq. inches, so it appears that I = need to add some type of cowl flaps to exit more air. JohnD from = the farm ----- Original Message -----=20 From: BMears9413@aol.com=20 To: Rotary motors in aircraft=20 Sent: Sunday, January 29, 2006 9:19 PM Subject: [FlyRotary] Re: Cooling air inlets That's good to know that you think around 40 square inches of air = inlet will cool your motor. I'm planning to run an underbelly air scoop = to the radiator that will have 51 sq. in. inlet. I had no idea if that = would be enough. but from what you guys are saying, in should be = sufficient for my 20B. Bob Mears ------=_NextPart_000_000C_01C62582.C1A48A40 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Bob,
 
I fly a Rv-6A with a 13B.  I started out using = 24 square=20 inch opening for each of the radiator cores AND 24 square inch opening = for the=20 oil cooler for a total of 3x24 =3D 72 sq inches.
 
I have since reduced the radiator openings to 18 sq = inches=20 each - leaving the oil cooler at 24 sq inches for a total of 60 sq = inches, but I=20 spent  a lot of research and experimenting with  the = ducts to get=20 the best pressure recovery I  could. 
 
I estimate (based on fuel burn) that I am producing = between=20 170-180HP.  Naturally the more HP you make the more cooling you = need. =20 So what may work fine for a 160 HP engine may be marginal (or worst) for = a=20 180-200 HP installation. 
 
50 sq inches will probably cool at cruise with no=20 problem - however, it could be marginal or worst on a hot day = with a=20 max power climbout.  A lot depends on how well the ducting and exit = of the=20 air is done.  Ducting and associated detail is one reason = why=20 seemingly identical installations may vary greatly in cooling=20 ability.
 
Its all about trade offs, given sufficient surface = area and=20 airflow - IT WILL COOL.  However, you may encounter lots of cooling = drag if=20 you have not make an attempt to optimize your compromise.  =
 
Its possible that using one 50 sq inch duct (such as = the James=20 cowl) may be adequate (I believe Tracy Crook is intending to use such = with a 20=20 B - so if it will cool a 20 B then there is little doubt it will cool a=20 13B).   I am eagerly awaiting the results of using such = approaches=20 .
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary = Powered
Matthews,=20 NC
eanderson@carolina.rr.com
 
 
----- Original Message -----
From:=20 John=20 Downing
Sent: Monday, January 30, 2006 = 9:22=20 AM
Subject: [FlyRotary] Re: = Cooling air=20 inlets

Bob;  The 40 sq. will not cool the engine.  Ed and = others are=20 using a 2 1/2 inch x 10 inch hole under the spinner for the oil = cooler, as=20 more than half of the engine cooling is through oil, as I understand = it. =20 I'm working on the oil cooler opening as well as the round holes to = cool the=20 coolant.  My exit is currently 61.8 sq. inches, so it appears = that I need=20 to add some type of cowl flaps to exit more air. =20 JohnD     from the farm
----- Original Message -----
From:=20 BMears9413@aol.com
To: Rotary motors in = aircraft=20
Sent: Sunday, January 29, = 2006 9:19=20 PM
Subject: [FlyRotary] Re: = Cooling air=20 inlets

That's good to know that you think around 40 square inches of = air inlet=20 will cool your motor. I'm planning to run an underbelly air scoop to = the=20 radiator that will have 51 sq. in. inlet. I had no idea if that = would be=20 enough. but from what you guys are saying, in should be sufficient = for my=20 20B.
 
Bob Mears
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