Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2936722 for flyrotary@lancaironline.net; Sat, 17 Jan 2004 18:21:22 -0500 Received: from edward (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-02-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i0HNLJYs011313 for ; Sat, 17 Jan 2004 18:21:20 -0500 (EST) Message-ID: <001a01c3dd50$9e718db0$2402a8c0@edward> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Cooling Article - SportAviation Mag Date: Sat, 17 Jan 2004 18:21:21 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0017_01C3DD26.B54A7F80" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0017_01C3DD26.B54A7F80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Keep in mind, Kelvin, that the are referring to optimum type ducts. = Naturally, If you can accommondate an optimum duct then you have the = best solution. However, I have read research papers on short ducts as = well. It seems that a short duct can provided adequate cooling, in fact = better cooling than a long duct that has separation of air flow and = distruption due to eddies. You do not however, get as much pressure = recovery with a short duct. This means that you will probably have = higher air flow velocity throught your radiator. While this will = probably cool adequately your cooling drag will increase considerably. = Depending on what proportion of your total drag your cooling drag factor = is will determine how much impact it has on performance. As long as you have sufficient mass flow throught your radiator you will = cool. However, you will likely be incurring more drag than when using = an optimum duct. =20 Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: kevin lane=20 To: Rotary motors in aircraft=20 Sent: Saturday, January 17, 2004 1:52 PM Subject: [FlyRotary] Re: Cooling Article - SportAviation Mag in that article they mentioned that optimal entry duct length is 2 to = 3 times the height or width of the radiator, whatever is greater. with = my belly-mounted radiator, 8 x 22", that means I need something between = 4 and 6 feet? since I am eyeball engineering this thing and mimicking = the p-51 I have an entry duct closer to 22" in length. does this seem = reasonable? with a 6' scoop perhaps I could make water landings :-) Kevin Lane Portland, OR e-mail-> n3773@comcast.net web-> http://home.comcast.net/~n3773 (browse w/ internet explorer) ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Friday, January 16, 2004 5:18 PM Subject: [FlyRotary] Cooling Article - SportAviation Mag Excellent article in EAA Sport Aviation Mag I received today, on = liquid cooling. In reading it, much seemed familar and sure enough one = of the two references is Kuchemann and Weber. They also point out that = the Streamline Duct is a more practical alternative to the 7 Deg optimum = duct for aviation use as well as other useful information. Well worth = reading. Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ------=_NextPart_000_0017_01C3DD26.B54A7F80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Keep in mind, Kelvin, that the are = referring to=20 optimum type ducts.  Naturally, If you can accommondate an optimum = duct=20 then you have the best solution.  However, I have read research = papers on=20 short ducts as well.  It seems that a short duct can provided = adequate=20 cooling, in fact better cooling than a long duct that has separation of = air flow=20 and distruption due to eddies.  You do not however, get as much = pressure=20 recovery with a short duct.  This means that you will probably have = higher=20 air flow velocity throught your radiator.  While this will probably = cool=20 adequately your cooling drag will increase considerably.  Depending = on what=20 proportion of your total drag your cooling drag factor is will determine = how=20 much impact it has on performance.
 
As long as you have sufficient mass = flow throught=20 your radiator you will cool.  However, you will likely be incurring = more=20 drag than when using an optimum duct. 
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 kevin = lane=20
Sent: Saturday, January 17, = 2004 1:52=20 PM
Subject: [FlyRotary] Re: = Cooling Article=20 - SportAviation Mag

in that article they mentioned that = optimal=20 entry duct length is 2 to 3 times the height or width of the radiator, = whatever is greater.  with my belly-mounted radiator, 8 x 22", = that means=20 I need something between 4 and 6 feet?  since I am eyeball = engineering=20 this thing and mimicking the p-51 I have an entry duct closer to 22" = in=20 length.  does this seem reasonable?  with a 6' scoop perhaps = I could=20 make water landings :-)
Kevin Lane  Portland, OR
e-mail-> n3773@comcast.net
web-> http://home.comcast.net/~n3773
(browse=20 w/ internet explorer)
----- Original Message -----
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Friday, January 16, = 2004 5:18=20 PM
Subject: [FlyRotary] Cooling = Article -=20 SportAviation Mag

Excellent article in EAA Sport = Aviation=20 Mag I received today,  on liquid cooling. In reading it, = much=20 seemed familar and sure enough one of the two references is = Kuchemann and=20 Weber.  They also point out that the Streamline Duct is a more=20 practical alternative to the 7 Deg optimum duct for aviation use as = well as=20 other useful information.  Well worth reading.
 
 
Ed Anderson
RV-6A N494BW Rotary=20 Powered
Matthews, = NC
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