Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 362625 for flyrotary@lancaironline.net; Thu, 12 Aug 2004 13:54:39 -0400 Received-SPF: none receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from EDWARD (cpe-069-132-183-211.carolina.rr.com [69.132.183.211]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i7CHs4Pg004186 for ; Thu, 12 Aug 2004 13:54:06 -0400 (EDT) Message-ID: <001001c48095$5cb22e00$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: DeltaT Coolant was : [FlyRotary] Re: coolant temps Date: Thu, 12 Aug 2004 13:54:06 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01C48073.D56029A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_000D_01C48073.D56029A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Tracy my calculations shows your coolant temp drop is where it should = be: My calculations show that at 7 gph fuel burn you need to get rid of 2369 = BTU/Min through your coolant/radiators. I rounded it off to 2400 = BTU/min. Q =3D W*DeltaT*Cp Basic Heat/Mass Flow equation With water as the mass = with a weight of 8 lbs/ gallon and a specific heat of 1.0=20 Q =3D BTU/min of heat removed by coolant mass flow Assuming 30 GPM coolant flow =3D 30*8 =3D 240 lb/min mass flow. = specific heat of water Cp =3D 1.0 Solving for DeltaT =3D Q/(W*Cp) =3D 2400/(240*1) =3D 2400/240 =3D 10 = or your delta T for the parameters specified should be around 10F Assuming a 50/50 coolant mix with a Cp of 0.7 you would have approx = 2400/(240 *0.7) =3D 2400/168 =3D 14.2F so I would say you do not fly = with a 50/50 coolant mix but something closer to pure water. But in any = case, certainly in the ball park. You reported 10-12F under those conditions, so I would say condition is = 4. Normal operation Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: Tracy Crook=20 To: Rotary motors in aircraft=20 Sent: Thursday, August 12, 2004 12:59 PM Subject: [FlyRotary] Re: coolant temps I've got a question regarding coolant temps I hope some of you can = help with.=20 We've been running the Eagle540 recently, getting ready for that = impending=20 first flight. Our installed instrumentation on the coolant side is = located on=20 the higher pressure, high temp engine outlet side of the coolant = circuit...=20 the flow comes out of the top rear of the engine to the thermostat = housing.=20 Temp sensor is installed in the t-stat housing. From there it goes = through=20 the firewall and down to the radiator, then returns back through the = firewall=20 and on to the water pump. The water pump forces the coolant into = the block=20 and the circuit is complete. We are not running 50/50 = water/anti-freeze=20 because of the magnesium components... we are running straight Evans = NPG.=20 During recent runs (engine RPM about 2000RPM, the rev limiter is = set at 3800,=20 so we're just over 50%) we're seeing the high temp side over 230 = degrees. NPG=20 doesn't boil until somewhere around 400, but we obviously don't have = any=20 desire to operate at that kind of temperature. For those of you who = are=20 instrumented both before and after the radiator (evap cores, = whatever) what=20 kind of temperature spread are you seeing? I suspect I'll = eventually be=20 instrumenting the cool side of the circuit, but would like to know = what to=20 expect on the hot side. If we're seeing a 40 degree delta across = the radiator=20 (I imagine) is 250-260 considered too hot as a redline for the hot = side? (Our=20 oil temps are very well behaved, we still haven't exceeded 150 on = the oil cool=20 side and TITs are running 1350-1400 at these reduced power levels... = sounds ok=20 to me, but what do I know?) TIA for any info you're willing to = share. My before & after coolant temp delta was surprisingly low. Only got = readings at cruise power settings (6.5 - 7 GPH) where it was only 10 - = 12 Deg F. This could mean several things. 1. Rads are no good. 2. = instrumentation was no good. 3. water goes through system really fast. = =20 Or (4) it could be normal. I don't think the answer is 1 or 2. I = don't have time to do calcs to see if 4 is the case. Anybody got time = to run them? Assume GPH at 30 gpm if you do. =20 Oil temp delta was higher (expected) at 20 - 50 depending on power = setting. Tracy ------=_NextPart_000_000D_01C48073.D56029A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Tracy my calculations shows your coolant temp = drop is=20 where it should be:
 
My calculations show that at 7 gph fuel burn you = need to=20 get rid of 2369 BTU/Min through your coolant/radiators.  I rounded = it off=20 to 2400 BTU/min.
 
Q =3D W*DeltaT*Cp  Basic Heat/Mass = Flow=20 equation  With water as the mass with a weight of 8 lbs/ gallon and = a=20 specific heat of 1.0
 
Q =3D BTU/min of heat removed by coolant mass=20 flow
 
 Assuming 30 GPM coolant flow =3D 30*8 =3D = 240 lb/min=20 mass flow. specific heat of water  Cp =3D 1.0
 
 
 Solving for DeltaT =3D Q/(W*Cp) =3D = 2400/(240*1) =20 =3D  2400/240 =3D 10 or  your delta T for the parameters = specified should=20 be around 10F
 
Assuming a 50/50 coolant mix with a Cp  of = 0.7 you=20 would have approx 2400/(240 *0.7) =3D 2400/168 =3D 14.2F so I would say = you do not=20 fly with
 
 a 50/50 coolant mix but something closer = to pure=20 water.  But in any case, certainly in the ball park.
 
You reported 10-12F under those conditions, so I = would say=20 condition is 4. Normal operation
 
Ed
 
Ed Anderson
RV-6A N494BW Rotary = Powered
Matthews,=20 NC
----- Original Message -----
From:=20 Tracy = Crook
Sent: Thursday, August 12, 2004 = 12:59=20 PM
Subject: [FlyRotary] Re: = coolant=20 temps

 

I've got a question regarding coolant temps I hope some of you = can help=20 with.
 We've been running the Eagle540 recently, getting = ready for=20 that impending
first flight.  Our installed instrumentation = on the=20 coolant side is located on
the higher pressure, high temp engine = outlet=20 side of the coolant circuit...
the flow comes out of the top = rear of the=20 engine to the thermostat housing.
 Temp sensor is installed = in the=20 t-stat housing.  From there it goes through
the firewall = and down=20 to the radiator, then returns back through the firewall
and on = to the=20 water pump.  The water pump forces the coolant into the block =
and=20 the circuit is complete.  We are not running 50/50 = water/anti-freeze=20
because of the magnesium components... we are running straight = Evans=20 NPG.
 During recent runs (engine RPM about 2000RPM, the rev = limiter=20 is set at 3800,
so we're just over 50%) we're seeing the high = temp side=20 over 230 degrees.  NPG
doesn't boil until somewhere around = 400, but=20 we obviously don't have any
desire to operate at that kind of=20 temperature.  For those of you who are
instrumented both = before and=20 after the radiator (evap cores, whatever) what
kind of = temperature=20 spread are you seeing?  I suspect I'll eventually be =
instrumenting=20 the cool side of the circuit, but would like to know what to =
expect on=20 the hot side.  If we're seeing a 40 degree delta across the = radiator=20
(I imagine) is 250-260 considered too hot as a redline for the = hot=20 side?  (Our
oil temps are very well behaved, we still = haven't=20 exceeded 150 on the oil cool
side and TITs are running 1350-1400 = at=20 these reduced power levels... sounds ok
to me, but what do I=20 know?)  TIA for any info you're willing to=20 share.

     <Marv>
My before & after coolant temp delta was surprisingly=20 low.  Only got readings at cruise power settings (6.5 - 7=20 GPH) where it was only 10 - 12 Deg F.  This could = mean=20 several things.  1.  Rads are no good.  2. =20 instrumentation was no good.  3.  water goes through = system really=20 fast.  
 
Or (4) it could be normal.  I don't think the answer is 1 = or=20 2.  I don't have time to do calcs to see if 4 is the = case. =20 Anybody got time to run them?  Assume GPH at 30 gpm if you = do. =20
 
Oil temp delta was higher (expected) at 20 - 50 depending on = power=20 setting.
 
Tracy
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