X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2360447 for flyrotary@lancaironline.net; Sun, 30 Sep 2007 09:27:59 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([24.74.103.61]) by cdptpa-omta02.mail.rr.com with SMTP id <20070930132719.UZPR3965.cdptpa-omta02.mail.rr.com@edward2> for ; Sun, 30 Sep 2007 13:27:19 +0000 Message-ID: <001501c80365$a1fcd220$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Oil Delta - T Date: Sun, 30 Sep 2007 09:27:22 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0012_01C80344.1ABB96A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0012_01C80344.1ABB96A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I suspect that you temp sensor location may be the problem rather than = calibration. If its outside the main flow channel, then its hard to = tell just how close or far off of the main flow temps it may be = registering. =20 On the other hand if your coolant engine outlet temp is measuring only = 161F (and assuming that is somewhere near the actual temp) then you = radiator is clearly doing its job by cooling down the coolant before it = enters the engine. When I am cruising at 5400 rpm my coolant temps = range from 155F-175F depending on OAT. This is temp out of the engine. = Since your temp is in the same ball park, it appears your radiator is = doing a good job especially given the 90F OAT. =20 Ed ----- Original Message -----=20 From: Mark Steitle=20 To: Rotary motors in aircraft=20 Sent: Saturday, September 29, 2007 10:13 PM Subject: [FlyRotary] Re: Oil Delta - T Ed,=20 OK, I'll recallibrate the sensors ONE MORE TIME! They were reading = within a degree of each other before I relocated one of them. I did = take the time to verify the EC-2 sensor was reading correctly at 212* = during the switch. But I didn't check it lower than that. I'll use = ambient temp for a low reference. =20 I suspect the problem may be where one of the sensors is located. The = first sensor is located on the WP housing at the outlet from the engine. = Since that is one of the factory locations, I don't see any problem = there. The second sensor is on the WP housing inlet, but not on the = main line, it is on the one returing from the swirl tank, but is very = close to where the main WP inlet is located. It is fed by a line that = runs through the swirl tank from the outlet side of the radiator, but at = the top instead of the bottom (to draw any air out of the radiator). = Directly across from this fitting is the "hot" inlet to the radiator. = I'm sure that some of the coolant goes straight across the core to the = swirl tank fitting. (Yes, this is confusing me too) I questioned the = wisdom of putting the sensor where I did, but did it anyway due to the = ease of installation (No draining the cooling system, no drilling, no = tapping). Anyway, this was supposed to be a "temporary" test setup. =20 So, it looks like I probably need to find a better place to locate the = second sensor. I'll check the accuracy of this sensor at around 150* = and see what it shows. If there is a significant error, I'll dive into = the EC-2 calibration system one more time (heaven help me). =20 Mark=20 =20 On 9/29/07, Ed Anderson wrote:=20 Mark, if you really had excess air flowing through your radiators = the coolant would drop more than 4 Deg F. In fact, the more air flow = the more coolant Delta T you would drop through the radiator. So if you = had something like 180F in and 120F out then I might suspect too much = air flow through the cores, but not with a drop of only 4 deg F. In = fact if that delta T is correct (which I suspect it is not), then you = would need tremendous coolant flow rates for it to carry away the engine = heat it needs to at 5200 rpm.=20 I did some back of envelope calculations.=20 IF your coolant flow was 30 GPM at 8.25 lb/gal coolant with a 0.65 = (50/50 mix) Cp, then a 4 degreeF drop in coolant temp would only be = getting rid of 644 BTU/Min.=20 At 5200 rpm and a 19:1 A/F ratio you would need to get rid of = approx 3100 BTU/Min through your radiator. I suspect that the 4 degree = drop you are measuring may be in error. I assume you are measuring temp = at radiator inlet (engine outlet) and radiator outlet (or engine inlet) = It would take something like a 20 deg coolant temp drop at 30 GPM flow = or a flow rate of 150 GPM at 4 deg drop to get rid of that much heat. =20 On the other hand if you were flowing 60 gpm of pure water and had a = 6.5F drop that would get rid of the required BTUs. I have no clue as to = the flow rate of a 20B water pump, but suspect my guess of 60 gpm might = be on the high side.=20 Since you are apparently cooling just fine with the radiators, then = : 1. My calculations are incorrect 2. Your coolant temp drop is more than 4 Fdeg 3. your flow rate is >50 gpm 4. You oil system is dumping the excess heat that your radiators = are not getting rid of. FWIW Ed ----- Original Message -----=20 From: Mark Steitle=20 To: Rotary motors in aircraft=20 Sent: Saturday, September 29, 2007 7:51 PM Subject: [FlyRotary] Re: Oil Delta - T =20 Tracy,=20 I flew again today. I'm still staying very close to the airport = and was forced to limit my altitude to 2500' due to clouds. OAT was = about 90* and oil got to 215, but came right down after leveling off and = settled in at 190*. The strange thing is the water temps in economy = cruise (5200 engine rpm, 1800 prop rpm) were in the 157* range. I'm = measuring water temp in and out. Water out was about 161*, so I'm = getting very little temp drop through the radiator. We're figuring that = this is probably due to too much air to the water radiator or too rapid = coolant flow through the radiator (I'm running the 20B pump). My main = pulley has been downsized, but I may also need to enlarge the wp pulley = a little to slow the flow. I'm considering doing a quick mod to check = this theory. If that's true, then my oil temps should drop because I = suspect airflow through the two radiators are fighting for the exit = space and the water radiator is winning. =20 Mark =20 On 9/29/07, Tracy Crook wrote:=20 Haven't had any 100+ days since installing the Renesis but = cooling is similar to the 2nd gen I had a few years ago when we had 10 = consecutive days of 100+ temps. Didn't have to wait it out but simply = limited power after initial climbout. Still had more ROC than most = certified planes at the reduced power setting. I start with around 2500 = FPM on a standard day and never had to settle for less than ~1000 fpm = due to heat issues.=20 Hope my 20B RV-8 does as well or better but I will install spray = bar for initial tests. Tracy (delayed 20B test schedule due to motorcycle distraction) =20 On 9/27/07, Mark Steitle wrote:=20 Tracy, So, what do you call a "hot" day? In Austin, it is normal = during the summer for temps to be in the upper 90's and even above 100 = on occasion. I don't want to be grounded waiting for the Texas heat to = subside. I guess I could install a spray bar for summer flying. Right = now I can keep temps in the green up into the low 90's. Living in = Texas, I would like a little more margin than that. Not everyone can = swing a summer home in Colorado. ;-)=20 Mark S. (Just happy to be flying again.) =20 On 9/26/07, Tracy Crook wrote:=20 Engine will cool at any throttle setting that enables the = plane to fly. The coolant & oil temp curve looks about like the power = required curve of the airframe, minumum at around 95 mph and rises on = either side of that speed. Only exception is WOT at Vx on hot day. = Engine will exceed redline temps if this is maintained more than a = minute or so. Fortunately there is never any real need to do that. =20 Tracy =20 On 9/26/07, Mark Steitle wrote:=20 Tracy,=20 Is there a particular speed that you must reach before = your system cools? =20 Mark =20 On 9/26/07, Tracy Crook wrote: = For another data point, the delta T on oil cooler = depends on power setting on my installation (no big surprise). It is = around 40 degrees F at higher power settings. Tracy =20 On 9/18/07, Mark Steitle wrote:=20 For those that are flying (rotaries), I'm curious as = to what delta-T you're seeing across the oil cooler. And at what speed = you attain adequate cooling. Mark S. ------=_NextPart_000_0012_01C80344.1ABB96A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I suspect that you temp sensor location may be = the problem=20 rather than calibration.  If its outside the main flow channel, = then its=20 hard to tell just how close or far off of the main flow temps it may be=20 registering.  
 
On the other hand if your coolant engine outlet = temp is=20 measuring only 161F (and assuming that is somewhere near the actual = temp) then=20 you radiator is clearly doing its job by cooling down the coolant before = it=20 enters the engine.  When I am cruising at 5400 rpm my coolant temps = range=20 from 155F-175F depending on OAT.  This is temp out of the = engine. =20 Since your temp is in the same ball park, it appears your radiator is = doing=20 a good job especially given the 90F OAT. 
 
 
 
Ed
----- Original Message -----
From:=20 Mark = Steitle=20
Sent: Saturday, September 29, = 2007 10:13=20 PM
Subject: [FlyRotary] Re: Oil = Delta -=20 T

Ed,
OK, I'll recallibrate the sensors ONE MORE TIME!  They were = reading=20 within a degree of each other before I relocated one of them.  I = did take=20 the time to verify the EC-2 sensor was reading correctly at 212* = during the=20 switch.  But I didn't check it lower than that.  I'll use = ambient=20 temp for a low reference. 
 
I suspect the problem may be where one of the sensors is=20 located.  The first sensor is located on the WP housing at the = outlet=20 from the engine.  Since that is one of the factory locations, I = don't see=20 any problem there.  The second sensor is on the WP housing inlet, = but not=20 on the main line, it is on the one returing from the swirl tank, but = is very=20 close to where the main WP inlet is located.  It is fed by a = line=20 that runs through the swirl tank from the outlet side of the = radiator,=20 but at the top instead of the bottom (to draw any air out of the=20 radiator).  Directly across from this fitting is the "hot" inlet = to the=20 radiator.  I'm sure that some of the coolant goes straight across = the=20 core to the swirl tank fitting. (Yes, this is confusing me too)  = I=20 questioned the wisdom of putting the sensor where I did, but did it = anyway due=20 to the ease of installation (No draining the cooling system, no = drilling, no=20 tapping).  Anyway, this was supposed to be a "temporary" test=20 setup. 
 
So, it looks like I probably need to find a better place to = locate the=20 second sensor.  I'll check the accuracy of this sensor at = around=20 150* and see what it shows.  If there is a significant error, = I'll dive=20 into the EC-2 calibration system one more time (heaven help=20 me).   
 
Mark 

 
On 9/29/07, Ed=20 Anderson <eanderson@carolina.rr.com&g= t;=20 wrote:=20
  Mark, if you really had excess = air flowing=20 through your radiators the coolant would drop more than 4 Deg = F.  In=20 fact, the more air flow the more coolant Delta T you would drop = through the=20 radiator.  So if you had something like 180F in and 120F out = then I=20 might suspect too much air flow through the cores, but not with a = drop of=20 only 4 deg F.   In fact if that delta T is correct (which = I=20 suspect it is not), then you would need tremendous coolant flow = rates for it=20 to carry away the engine heat it needs to at 5200 rpm.
 
 I did some back of envelope=20 calculations. 
 
 IF your coolant flow was 30 GPM at = 8.25 lb/gal=20 coolant with a 0.65 (50/50 mix) Cp, then a 4 degreeF drop in coolant = temp=20 would only be getting rid of 644 BTU/Min. 
 
 At 5200 rpm and a 19:1 A/F ratio you = would need=20 to get rid of approx 3100 BTU/Min through your radiator.  I = suspect=20 that the 4 degree  drop you are measuring may be in = error.  I=20 assume you are measuring temp at radiator inlet (engine = outlet) and=20 radiator outlet (or engine inlet)   It would take = something like a=20 20 deg coolant temp  drop at 30 GPM flow or a flow rate of 150 = GPM at 4=20 deg drop to get rid of that much heat.  
 
On the other hand if you were flowing 60 gpm = of pure=20 water and had a 6.5F drop that would get rid of the required = BTUs.  I=20 have no clue as to the flow rate of a 20B water pump, but suspect my = guess=20 of 60 gpm might be on the high side.
 
Since you are apparently cooling just fine = with the=20 radiators, then :
 
1.  My calculations are = incorrect
2.  Your coolant temp drop is more than = 4=20 Fdeg
3.  your flow rate is >50 = gpm
4.  You oil system is dumping the = excess heat=20 that your radiators are not getting rid of.
 
FWIW
 
Ed
 
 
----- Original Message ----- =
From: = Mark = Steitle
To: Rotary = motors in=20 aircraft
Sent: Saturday, September = 29, 2007=20 7:51 PM
Subject: [FlyRotary] Re: = Oil Delta -=20 T

 
Tracy,
 
I flew again today.  I'm still staying very close to the = airport=20 and was forced to limit my altitude to 2500' due to=20 clouds.  OAT was about 90* and oil got to 215, but came right = down=20 after leveling off and settled in at 190*.  The strange thing = is the=20 water temps in economy cruise (5200 engine rpm, 1800 prop rpm) = were in the=20 157* range.  I'm measuring water temp in and out.  Water = out was=20 about 161*, so I'm getting very little temp drop through the=20 radiator.  We're figuring that this is probably due to = too much=20 air to the water radiator or too rapid coolant flow = through the=20 radiator (I'm running the 20B pump).  My main pulley has been = downsized, but I may also need to enlarge the wp pulley = a little=20 to slow the flow.  I'm considering doing a quick mod to check = this=20 theory.  If that's true, then my oil temps should drop = because I=20 suspect airflow through the two radiators are fighting for the = exit space=20 and the water radiator is winning. 
 
Mark

 
On 9/29/07, Tracy=20 Crook <tracy@rotaryaviation.com > wrote:=20
Haven't had any 100+ days since installing the Renesis but = cooling=20 is similar to the 2nd gen I had a few years ago when we had = 10=20 consecutive days of 100+ temps.  Didn't have to wait it out = but=20 simply limited power after initial climbout.  Still had = more ROC=20 than most certified planes at the reduced power setting.  I = start=20 with around 2500 FPM on a standard day and never had to settle = for less=20 than ~1000 fpm due to heat issues.
 
Hope my 20B RV-8 does as well or better but I will install = spray=20 bar for initial tests.
 
Tracy (delayed 20B test schedule due to motorcycle=20 distraction)

 
On 9/27/07, Mark=20 Steitle <msteitle@gmail.com=20 > wrote:=20
Tracy,
 
So, what do you call a "hot" day?  In Austin, it is = normal=20 during the summer for temps to be in the upper 90's and even = above 100=20 on occasion.  I don't want to be grounded waiting for the = Texas=20 heat to subside.  I guess I could install a spray bar for = summer=20 flying.  Right now I can keep temps in the green up into = the low=20 90's.  Living in Texas, I would like a little more = margin=20 than that.  Not everyone can swing a summer=20 home in Colorado.   ;-)
 
Mark S.
(Just happy to be flying again.)
 


 
On 9/26/07, Tracy Crook <tracy@rotaryaviation.com > = wrote:=20
Engine will cool at any throttle setting that enables = the plane=20 to fly.  The coolant & oil temp curve looks about = like the=20 power required curve of the airframe, minumum at around 95 = mph and=20 rises on either side of that speed.  Only exception is = WOT at=20 Vx on hot day.  Engine will exceed redline = temps if=20 this is maintained more than a minute or so.   = Fortunately=20 there is never any real need to do that. 
 
Tracy

 
On 9/26/07, Mark Steitle <msteitle@gmail.com > wrote:=20
Tracy,
 
Is there a particular speed that you must reach = before your=20 system cools? 
 
Mark


 
On 9/26/07, Tracy Crook <tracy@rotaryaviation.com > = wrote:=20
For another data point, the delta T on oil cooler = depends=20 on power setting on my installation (no big = surprise).  It=20 is around 40 degrees F at higher power settings.
 
Tracy

 
On 9/18/07, Mark Steitle <msteitle@gmail.com > = wrote:=20
For those that are flying (rotaries), I'm curious = as to=20 what delta-T you're seeing across the oil = cooler.  And at=20 what speed you attain adequate cooling.
 
Mark=20 = S.


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