X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 64 [XX] (50%) RECEIVED: IP not found on home country list (50%) BODY: contains "rx" Return-Path: Received: from mail11.syd.optusnet.com.au ([211.29.132.192] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTPS id 2057271 for flyrotary@lancaironline.net; Mon, 21 May 2007 17:51:03 -0400 Received-SPF: none receiver=logan.com; client-ip=211.29.132.192; envelope-from=lendich@optusnet.com.au Received: from george (d211-31-197-148.dsl.nsw.optusnet.com.au [211.31.197.148]) by mail11.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id l4LLoI0A004333 for ; Tue, 22 May 2007 07:50:20 +1000 Message-ID: <004501c79bf2$08f91140$94c51fd3@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] marginal cooling Date: Tue, 22 May 2007 07:50:22 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0042_01C79C45.D99ED4D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Antivirus: avast! (VPS 0657-0, 12/12/2006), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0042_01C79C45.D99ED4D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Perry, I'm not entering the debate, however your 3 cu inch to each Hp is very = similar to others suggestions - which is on the safe side of the lower = end of the scale. I would suggest from figures previously given, this range goes from 3 to = 3.5, which 3.5 being on the other far end of the scale. The 3.5 would = cool very well but you might suffer some extra unnecessary drag. George ( down under) I'm not going to get into the argument about test methods to determine = sufficient cooling. This is just a statement of what I have that works and works very = well. See my recent article in Contact Magazine. What works for me was = determined by the physical constraints of the Long-EZ firewall, and = trial and error. Without looking at the archives, I don't even remember = how this thread got started! Originally I had probably the smallest installed rad volume of anyone = flying a rotary. I was running the stock porting '86 NA 146HP engine to = about 5400RPM cruise, less in climb, probably only developing about = 120HP. I have a 1 x 3 x 9 (27 cubic inches) cabin heater core plumbed to = the engine heater port that bypasses the thermostat. My main rad during = the low power period had overall dimensions of 2 x 13W x 17L, with 2" = being the thickness of the tanks. The actual core was more like 1.25" = thick. So the core itself was 13 x 13 x 1.25 or 211 cubic inches. I = donot have a coolant temp readout in degrees. I have the actual = instrument panel gauges from the 1986 RX-7 installed in my airplane. In = the 2nd gen RX-7 the normal coolant temperature is about 1/4 to 1/3 up = from the bottom of the "normal range". Because of the thermostat it = never varies from this in the car unless there is something wrong, like = a coolant leak and resulting loss of coolant. With my original small = rad, I did see elevated temperatures on hot days during extended climbs, = the gauge would indicate about 2/3 the way up in the "normal" range. It = would not run away or go above this level. I've never bothered to find = out what the upper and lower limits of the RX-7 gauge are in real = Fahrenheit temperatures, but that data can probably be easily obtained = from the maintenance manual, other sources, or testing the stock = sensor/gauge against a thermometer. After converting to PSRU/prop December 2004, I could now rev the = engine to 5400 RPM in climb and 6400 in cruise with my fixed pitch prop. = Anticipating more heat with the additional power, before summer arrived = I installed a new double-pass rad that doubled the core volume of the = original. Two 2" tanks at the front, one 4" tank at the rear, and two 13 = x 13 x 1.25 cores in between. Now, on the hottest days I can climb full = power with no limit on duration, and the temperature indication never = budges from the 1/3 point on the gauge. Just like in the car! So about 450 cubic inches of radiator core will be more than = sufficient to cool your 146HP rotary. Scale accordingly for more = installed power? ------=_NextPart_000_0042_01C79C45.D99ED4D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Perry,
I'm not entering the debate, however = your 3 cu inch=20 to each Hp is very similar to others suggestions - which is on the safe = side of=20 the lower end of the scale.
I would suggest from figures previously = given, this range goes from 3 to 3.5, which 3.5 being on the other = far end=20 of the scale. The 3.5 would cool very well but you might suffer = some extra=20 unnecessary drag.
George ( down under)
I'm not going to get into the argument about test methods to = determine=20 sufficient cooling.
This is just a statement of what I have that = works and=20 works very well. See my recent article in Contact Magazine. What works = for me=20 was determined by the physical constraints of the Long-EZ firewall, = and trial=20 and error. Without looking at the archives, I don't even remember how = this=20 thread got started!
Originally I had probably the smallest installed rad volume of = anyone=20 flying a rotary. I was running the stock porting '86 NA 146HP engine = to about=20 5400RPM cruise, less in climb, probably only developing about 120HP. I = have a=20 1 x 3 x 9 (27 cubic inches) cabin heater core plumbed to the engine = heater=20 port that bypasses the thermostat. My main rad during the low power = period had=20 overall dimensions of 2 x 13W x 17L, with 2" being the thickness of = the tanks.=20 The actual core was more like 1.25" thick. So the core itself was 13 x = 13 x=20 1.25 or 211 cubic inches. I donot have a coolant temp readout in = degrees. I=20 have the actual instrument panel gauges from the 1986 RX-7 installed = in my=20 airplane. In the 2nd gen RX-7 the normal coolant temperature is about = 1/4 to=20 1/3 up from the bottom of the "normal range". Because of the = thermostat it=20 never varies from this in the car unless there is something wrong, = like a=20 coolant leak and resulting loss of coolant. With my original small = rad, I did=20 see elevated temperatures on hot days during extended climbs, the = gauge would=20 indicate about 2/3 the way up in the "normal" range. It would not run = away or=20 go above this level. I've never bothered to find out what the upper = and lower=20 limits of the RX-7 gauge are in real Fahrenheit temperatures, but that = data=20 can probably be easily obtained from the maintenance manual, other = sources, or=20 testing the stock sensor/gauge against a thermometer.
After converting to PSRU/prop December 2004, I could now rev the = engine=20 to 5400 RPM in climb and 6400 in cruise with my fixed pitch prop. = Anticipating=20 more heat with the additional power, before summer arrived I installed = a new=20 double-pass rad that doubled the core volume of the original. Two 2" = tanks at=20 the front, one 4" tank at the rear, and two 13 x 13 x 1.25 cores in = between.=20 Now, on the hottest days I can climb full power with no limit on = duration, and=20 the temperature indication never budges from the 1/3 point on the = gauge. Just=20 like in the car!
So about 450 cubic inches of radiator core will be more than = sufficient=20 to cool your 146HP rotary. Scale accordingly for more installed=20 power?
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