X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ms-smtp-01.southeast.rr.com ([24.25.9.100] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2072978 for flyrotary@lancaironline.net; Tue, 29 May 2007 12:49:20 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-103-061.carolina.res.rr.com [24.74.103.61]) by ms-smtp-01.southeast.rr.com (8.13.6/8.13.6) with SMTP id l4TGmSHN016838 for ; Tue, 29 May 2007 12:48:29 -0400 (EDT) Message-ID: <000701c7a211$3385a9d0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Cooling Recommendations Date: Tue, 29 May 2007 12:48:35 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01C7A1EF.AC14ABC0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0004_01C7A1EF.AC14ABC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: Lehanover@aol.com=20 To: Rotary motors in aircraft=20 Sent: Tuesday, May 29, 2007 12:37 PM Subject: [FlyRotary] Re: Cooling Recommendations In a message dated 5/29/2007 11:21:11 A.M. Eastern Daylight Time, = eanderson@carolina.rr.com writes: On the other hand, since 99 % of what we do is at the eye-ball = engineering style - any examples is bound to be helpful. Ed What about the adjustable inlet and cowl flap interconnection being of = any help. I can buy a lot of cooling capability and fit it into a BD-4 cowl. I = could then limit flow through the cores with a variable inlet scheme. I = have had to add pancake fans to keep temps under control when a problem = occurs on the false grid after the signal to start engines. We could = just turn on the fan and keep running. Piston cars would have to shut = down and risk boiling the fuel in the carb and flooding. We beat other = cars more than once who couldn't restart after going to operating temp = and shutting down for a while.=20 Once I added the biggest radiator Griffin could make I had no such = problem again and pitched the fan. But I note that just a small fan = could cool enough to allow idle speeds all afternoon. Idle is 2,200 RPM = and never a drop in the catch tank. Lynn E. Hanover There is no question that if you want to cool that you can do it. One = approach, as you mention, Lynn is to put a large radiator in. I always = say with enough metal and airflow it WILL COOL. But, you also might = like to minimize drag while getting adequate cooling - depending a lot = on the type of airframe, flight regime, typical environment (South = Florida vs Northen Canada) and manner of operation. There is certainly more than one way to peel this grape that will = work. Cowl flaps can help provided that your inlet is doing its job = well -, but they can add also weight and complexity. Same for variable = inlets - perhaps more so. My personal feeling is that if you have a = very large range between your operating extremes then such things as = Cowl flaps become more necessary. But, for the RV and BD series I = personnally do not think they are necessary . At least one individual = installed cowl flaps and found them unsatisfactory in an RV. Just did = not provide as much benefit as they did downside. So again, a lot depends on what your priorities are and what you are = willing to give up for it. With a BD-4 you have a relative large space under the cowl which gives = options=20 Ed -------------------------------------------------------------------------= ----- See what's free at AOL.com. ------=_NextPart_000_0004_01C7A1EF.AC14ABC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 Lehanover@aol.com
Sent: Tuesday, May 29, 2007 = 12:37=20 PM
Subject: [FlyRotary] Re: = Cooling=20 Recommendations

In a message dated 5/29/2007 11:21:11 A.M. Eastern Daylight Time, = eanderson@carolina.rr.com=20 writes:
On the other hand, since 99 % of what we do is at the eye-ball=20 engineering style - any examples is bound to be helpful.
 
Ed
What about the adjustable inlet and cowl flap = interconnection being=20 of any help.
 
I can buy a lot of cooling capability and fit it into a BD-4 = cowl. I=20 could then limit flow through the cores with a variable inlet scheme. = I have=20 had to add pancake fans to keep temps under control when a problem = occurs on=20 the false grid after the signal to start engines. We could just turn = on the=20 fan and keep running. Piston cars would have to shut down and risk = boiling the=20 fuel in the carb and flooding. We beat other cars more than = once who=20 couldn't restart after going to operating temp and shutting down for a = while. 
 
Once I added the biggest radiator Griffin could make I had no = such=20 problem again and pitched the fan. But I note that just a small fan = could cool=20 enough to allow idle speeds all afternoon. Idle is 2,200 RPM and never = a drop=20 in the catch tank.
 
Lynn E. Hanover


There is no question that if you want to cool that you = can do=20 it.  One approach, as you mention, Lynn  is to put a large = radiator=20 in.  I always say with enough metal and airflow it WILL = COOL.  But,=20 you also might like to minimize drag while getting adequate cooling -=20 depending a lot on the type of airframe, flight regime, typical = environment=20 (South Florida vs Northen Canada)  and manner of operation.
 
There is certainly more than one way to peel this grape that will = work.  Cowl flaps can help provided that your = inlet is=20 doing its job well -, but they can add also weight and = complexity. =20 Same for variable inlets - perhaps more so.  My personal feeling = is that=20 if you have a very large range between your operating extremes then = such=20 things as Cowl flaps become more necessary.  But, for the RV and = BD=20 series I personnally do not think they are necessary .  At least = one=20 individual installed cowl flaps and found them unsatisfactory in an = RV. =20 Just did not provide as much benefit as they did downside.
 
So again, a lot depends on what your priorities are and what you = are=20 willing to give up for it.
 
With a BD-4 you have a relative large space under the cowl which = gives=20 options
 
Ed

 
See what's free at AOL.com.=20
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