Return-Path: Received: from ms-smtp-03.southeast.rr.com ([24.93.67.84] verified) by logan.com (CommuniGate Pro SMTP 4.1.5) with ESMTP id 2625776 for flyrotary@lancaironline.net; Mon, 06 Oct 2003 07:05:12 -0400 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-03.southeast.rr.com (8.12.10/8.12.2) with SMTP id h96B2fW0004064 for ; Mon, 6 Oct 2003 07:02:43 -0400 (EDT) Message-ID: <002601c38bf9$4ce68840$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Thick Vs Thin Radiators - NASCAR Date: Mon, 6 Oct 2003 07:02:14 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0023_01C38BD7.C5ABB560" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_0023_01C38BD7.C5ABB560 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ok, Jim Got your point. I agree, my experience indicates that attention to = details in and around the inlet/plenum pays high benefits. I suspect = that if I reduced the second inlet by the same amount that cooling might = be compromised - but, don't know as haven't tried it. I believe that my = second unmodified duct is picking up some of the load. However, its = clear that regardless of what area I end up with when all is said and = done, it will be smaller with less cooling drag than if I had not = smoothed the ramp. I also agree that 7 Deg has aways struck me as pretty low. Actually = when I plotted the curves to help me contour the shape of the foam, = there was no way 7 deg would work with the length of my duct. So I = decided that I would plot a curve that diverged no more than 7 deg/inch = - which would give me a approx 21 Deg divergence over the 3 or so inches = from inlet to radiator. I must be getting some flow separation, = however, it appears that (as you would imagine) that it is not as bad = with my previous (sharply divergent) inlet. So, nice to realize we are in "violent agreement" {:>) Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ----- Original Message -----=20 From: Jim Sower=20 To: Rotary motors in aircraft=20 Sent: Monday, October 06, 2003 12:12 AM Subject: [FlyRotary] Re: Thick Vs Thin Radiators - NASCAR Ed,=20 <... Did this help or did I just make it more confusing ...>=20 Once again we find ourselves in "violent agreement" ... :o)=20 In your crude "box" plenum, (or any design with too sharp corners) = when the air couldn't negotiate the turn, it separated, became a = turbulent eddy and stopped going anywhere or doing anything useful. = Smoothing out your ramps reduced inlet from 24 square inches to 8-9. = That's 2/3!! A HUGE savings in cooling drag. That is what I was = trying to get across. Merely delivering air to the radiator face is not = enough. We have to deliver it in a sufficiently organized manner to = enable it to work as efficiently as it can. I know 7 deg is hard to = achieve in our limited space, but my objective is to have everyone = giving it their very best shot at 7 deg, and accepting what they end up = with as the best package they can make, rather than just hanging = radiators out in the sky.=20 I was surprised that it was only 7 deg. I expected more like 20 .... = Jim S.=20 =20 =20 =20 ------=_NextPart_000_0023_01C38BD7.C5ABB560 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ok, Jim
 
    Got your = point.  I agree,=20 my experience indicates that attention to details in and around the = inlet/plenum=20 pays high benefits.  I suspect that if I reduced the second inlet = by the=20 same amount that cooling might be compromised - but, don't know as = haven't tried=20 it.  I believe that my second unmodified duct is picking up some of = the=20 load.  However, its clear that regardless of what area I end up = with when=20 all is said and done, it will be smaller with less cooling drag than if = I had=20 not smoothed the ramp.
 
    I also agree that 7 = Deg has=20 aways struck me as pretty low.  Actually when I plotted the curves = to help=20 me contour the shape of the foam, there was no way 7 deg would work with = the=20 length of my duct.  So I decided that I would plot a curve that = diverged no=20 more than 7 deg/inch - which would give me a approx 21 Deg divergence = over the 3=20 or so inches from inlet to radiator.  I must be getting some flow=20 separation, however, it appears that (as you would imagine) that it is = not as=20 bad with my previous (sharply divergent) inlet.
 
So, nice to realize we are in "violent = agreement"=20 {:>)
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
----- Original Message -----
From:=20 Jim=20 Sower
Sent: Monday, October 06, 2003 = 12:12=20 AM
Subject: [FlyRotary] Re: Thick = Vs Thin=20 Radiators - NASCAR

Ed,
<... Did this help or did I just make it = more=20 confusing ...>
Once again we find ourselves in "violent = agreement" ...=20 :o)
In your crude "box" plenum, (or any design with too sharp = corners)=20 when the air couldn't negotiate the turn, it separated, became a = turbulent=20 eddy and stopped going anywhere or doing anything useful.  = Smoothing out=20 your ramps reduced inlet from 24 = square inches=20 to 8-9.  That's  2/3!!  A HUGE savings in = cooling=20 drag.  That is what I was trying to get across.  Merely = delivering=20 air to the radiator face is not enough.  We have to deliver it in = a=20 sufficiently organized manner to enable it to work as efficiently as = it=20 can.  I know 7 deg is hard to achieve in our limited space, but = my=20 objective is to have everyone giving it their very best shot at 7 deg, = and=20 accepting what they end up with as the best package they can make, = rather than=20 just hanging radiators out in the sky.=20

I was surprised that it was only 7 deg.  I expected more like = 20 ....=20 Jim S.
 
 
  =

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