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 2751750 for flyrotary@lancaironline.net; Wed, 19 Nov 2003 13:36:36 -0500 Received: from o7y6b5 (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 hAJIaXNX018821 for ; Wed, 19 Nov 2003 13:36:35 -0500 (EST) Message-ID: <000a01c3aecb$97579780$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Core vs Radistor was Re: [FlyRotary] radiator Date: Wed, 19 Nov 2003 13:33:13 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0007_01C3AEA1.AE4F34E0" 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_0007_01C3AEA1.AE4F34E0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Paul, The two cores I use each have a fin volume area of 9*10.5*3.6 =3D = 340 in^3 (does not include side tanks). So two give a core volume of = 2*340=3D 680 in^3. Your radiator would give approx (discounting 2" total for tanks) = 15*7.25*3 =3D 337 in^3 even with 8" and disregarding the side tanks = would only give 17*8*3 =3D 408 in^3. =20 So if we assume that the two cores represented a minimum adequate fin = core are then your radiator would have to be 60% more efficient = (408*1.6 =3D 652 in^3) to come close to the two cores. My primitive cooling model indicates that with only 337 in^3, you would = probably need airflow near 223 mph to provide adequate cooling at power = =3D 160HP. Now at a more nominal cruise say 75% =3D .75*160 =3D 120Hp, = you could probably get by with airflow at 170 MPH. =20 What this could mean is similar to folks using the two cores - in that = low airspeeds and high power settings exceed their cooling capacity - = however, we are generally able to get up to adequate speeds and/or pull = back the power sufficiently to come back within our cooling capacity = before overtemps get serious. So while we may overheat during take off = and initial climb, once we get up airspeed cooling appears to be = adequate with the two cores. =20 So assuming you could get to around 170 mph before the overcoming the = cooling inertia of your coolant mass, then by throttling back to 120HP = you might be achieve adequate cooling. However, if it took too long to = reach 170MPH then I would expect to see over heating. Now I admit this is little better than back of the envelope cooling = model, but two cores should keep 160Hp cool at around 115 - 120MPH and = that is about what people seem to be experiencing with two cores. So, Paul, my best opinion is that you will likely find the 17*8*3 inch = radiator inadequate for aircraft use at the power settings we see. It = might be even worst for a canard installation. However, if anyone on the list has experience to the contrary regarding = equivalent radiator size, please jump in.=20 Rusty, what was the size of your radiator and the final determination = about its adequacy? Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ----- Original Message -----=20 From: sqpilot@earthlink=20 To: Rotary motors in aircraft=20 Sent: Wednesday, November 19, 2003 11:55 AM Subject: [FlyRotary] radiator Hi, fellow rotary enthusiasts.....I'm getting ready to order a = radiator for my 13b powered SQ2000 canard pusher. I talked to Al Wick, = and he has a 160 hp Subaru powered Cozy and is cooling it very well with = a radiator that is 17" x 7.25" x 3" deep. Any idea if that size might = also cool a rotary? How does that seem to compare with two GM = evaporator cores? I was told that if I can increase the height to 8 = inches instead of 7.25, they can put two fans on it, as well as the = built-in Meziere EWP. I can work with the additional height of 8 inches. = Just don't want to spend $1100.00 for too small a radiator. If 17x8x3 = equates to approximately the same size as two evaporator cores like Ed = Anderson is using, I should be OK. If anyone can compare the square = inches of the two, I would sure appreciate it. Thanks in advance for = any and all efforts and recommendations. Paul Conner ------=_NextPart_000_0007_01C3AEA1.AE4F34E0 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
Paul,
 
    The two cores I use = each have a=20 fin volume area of 9*10.5*3.6 =3D 340 in^3 (does not include side = tanks).  So=20 two give a core volume of 2*340=3D 680 in^3.
 
Your radiator would give approx = (discounting 2"=20 total for  tanks) 15*7.25*3 =3D 337 in^3  even with 8" and = disregarding=20 the side tanks would only give 17*8*3 =3D 408 in^3. 
 
So if we assume that the two cores = represented a=20 minimum adequate fin core are then your  radiator would have = to be 60%=20 more efficient (408*1.6 =3D 652 in^3) to come close to the two = cores.
 
My primitive cooling model indicates = that with only=20 337 in^3, you would probably need airflow near 223 mph to provide = adequate=20 cooling at  power =3D 160HP.  Now at a more nominal cruise say = 75% =3D=20 .75*160 =3D 120Hp, you could probably get by with airflow at 170=20 MPH.  
 
What this could mean is similar to = folks using the=20 two cores - in that low airspeeds and high power settings exceed their = cooling=20 capacity - however, we are generally able to get up to adequate speeds = and/or=20 pull back the power sufficiently to come back within our cooling = capacity before=20 overtemps get serious.  So while we may overheat during take off = and=20 initial climb, once we get up airspeed cooling appears to be adequate = with the=20 two cores.  
 
So assuming you could get to around 170 = mph before=20 the overcoming the cooling inertia of your coolant mass, then by = throttling back=20 to 120HP you might be achieve adequate cooling.  However, if it = took too=20 long to reach 170MPH then I would expect to see over = heating.
 
 Now I admit this is little better = than back=20 of the envelope cooling model, but two cores should keep 160Hp cool at = around=20 115 - 120MPH and that is about what people seem to be experiencing with = two=20 cores.
 
So, Paul, my best opinion is that you = will likely=20 find the 17*8*3 inch radiator inadequate for aircraft use at the power = settings=20 we see.  It might be even worst for a canard = installation.
 
However, if anyone on the list has = experience to=20 the contrary regarding equivalent radiator size, please jump=20 in. 
 
 Rusty, what was the size of your = radiator and=20 the final determination about its adequacy?
 
Ed
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
----- Original Message -----
From:=20 sqpilot@earthlink
Sent: Wednesday, November 19, = 2003 11:55=20 AM
Subject: [FlyRotary] = radiator

Hi, fellow rotary enthusiasts.....I'm = getting=20 ready to order a radiator for my 13b powered SQ2000 canard = pusher.  I=20 talked to Al Wick, and he has a 160 hp Subaru powered Cozy and is = cooling it=20 very well with a radiator that is 17" x 7.25" x 3" deep.  Any = idea if=20 that size might also cool a rotary?  How does that seem to = compare with=20 two GM evaporator cores?  I was told that if I can increase the = height to=20 8 inches instead of 7.25, they can put two fans on it, as well as the = built-in=20 Meziere EWP. I can work with the additional height of 8 inches.  = Just=20 don't want to spend $1100.00 for too small a radiator. If 17x8x3 = equates to=20 approximately the same size as two evaporator cores like Ed Anderson = is using,=20 I should be OK. If anyone can compare the square inches of the two, I = would=20 sure appreciate it.  Thanks in advance for any and all efforts = and=20 recommendations.  Paul = Conner
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