Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3139664 for flyrotary@lancaironline.net; Wed, 31 Mar 2004 23:00:49 -0500 Received: from edward (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-02-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i3140lkG014794 for ; Wed, 31 Mar 2004 23:00:48 -0500 (EST) Message-ID: <001101c4179d$eb1717c0$2402a8c0@edward> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Requesting more thoughts on cooling Date: Wed, 31 Mar 2004 23:00:49 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000E_01C41774.02058D60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_000E_01C41774.02058D60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageJohn, your heating does not seem that unsuall to me. While it, = of course, varies from installation to installation, if I run WOT from = more than 2-3 minutes my coolant temp will be pushing 200F. Now, my = radiator ducts are removable and on the ground that helps my cooling a = great deal. So if I plan on doing a lot to high power run ups I pull = the hinge pins and remove the ducts for more low speed air flow across = the radiators. I think a 15 minute 4000 rpm run up would cause my = engine to overheat on the ground depending on OAT. =20 Now if I restrict my rpm to 3000 or less then it will stablize around = 180F, again depending on OAT. I ended up putting louvers in my Cowl as the heat buildup even after = engine shut down would be enough to make the top of the cowl too hot to = place your arm on. I figure the hot air need somplace to get out from = under the cowl than the bottom. I tried putting thermostats in my engine on two occassion and ended up = overheating the engines until the metal pinged on cool down (ugly = sound). Fortunately no damage even though it went to 250F on one = occassion. So I decided just to leave the thermostat out. Other folks = apparently use them with apparently great success. My cruise oil and = coolant temp varies between 160-190F depending on OAT but normally it = stabilizes at 180F. =20 I generally taxi out and do a run up to around 3500-4000 while taxing to = check both ignitions are functioning with Controller B, then switch back = to controller A and reducing throttle to a fast taxi around 2500-2700. = At the end of the ruwnway, I then swing into the wind and do a WOT = engine check at 5200rpm+ for fuel, and oil pressure, fuel flow rate and = air/fuel ratio indication. If all meet my critieria then I release = brakes and launch. I think I would taxi to the end of the run way, run as high an rpm as = you brakes will hold and wait until the coolant temps reaches 170F and = then accelerate until you need to shut down to keep from becoming = airborne (or go off the end of the runway) then check your coolant temp. = =20 It is not uncommon for the engine to put out more waste heat than the = cooling system can handle on take off an initial climb out. So you are = running a cooling deficit until you get sufficient airspeed to reject = the waste heat. For the RV thats approx 120MPH TAS, Should be somewhere = near that for a canard or perhaps a bit higher if you ducting is a bit = less than optiumum FWIW Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: John Slade=20 To: Rotary motors in aircraft=20 Sent: Wednesday, March 31, 2004 8:34 PM Subject: [FlyRotary] Requesting more thoughts on cooling Guys, I'm signed off and ready to fly, but I'm a little concerned about = cooling issues. I don't want to melt anything in the first go around the = pattern. I'm finding that the engine gets REALLY hot after about 10 - 15 = minutes ground running, and I'm wondering if that's to be expected, or = if I have a cooling problem. Maybe I should just taxi gently to the = runway and launch to get airflow as soon as possible. For example, today I ran it up and down the taxiway for a few minutes = at fairly low speeds and around 2500 - 3000rpm. Then I did some static = runups (maybe 3800 - 4000 rpm - all the brakes will hold) and some EC2 = tuning. Then I did some mode 1 programing at various rpm. During this = run I watched the water temp gradually go up until it was over 200 and I = shut her down. The oil was still down around 140 - 160. I took the cowl = off and found that everything in the engine compartment was HOT. = Radiator, oil coolers, hoses, intake, the cowl itself. Apart from giving = my cowl a REAL GOOD post cure I dont think I've done any damage, but = this doesnt give me a lot of confidence about whether I'll make it = around the pattern. The thermostat is now in place, and I get the feeling that I'd be much = better without it. Once the engine gets a little hot the water temps = seem to "run away" if I'm producing any kind of power. So... to remove = the thermostat [3rd gen rew engine] I have to remove the water pump and = have the by-pass hole welded shut - right? Do you 13B drivers tend to just taxi out at low rpm then launch? Would = your engine overheat if you did a 15 minute medium power runup? I'd = appreciate any general thoughts, or comments on how much ground running = I should expect to get away with before the temps get too high. Anything = else I should check? Regards, John Slade ------=_NextPart_000_000E_01C41774.02058D60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
John, your heating does not seem that = unsuall to=20 me.  While it, of course, varies from installation to installation, = if I=20 run WOT from more than 2-3 minutes my coolant temp will=20 be pushing 200F.  Now, my radiator ducts are removable and on = the=20 ground that helps my cooling a great deal.  So if I plan on doing a = lot to=20 high power run ups I pull the hinge pins and remove the ducts for more = low speed=20 air flow across the radiators.  I think a 15 minute 4000 rpm run up = would=20 cause my engine to overheat on the ground depending on OAT.  =
 
Now if I restrict my rpm to 3000 or = less then it=20 will stablize around 180F, again  depending on OAT.
 
I ended up putting  louvers in my = Cowl as the=20 heat buildup even after engine shut down would be enough to make the top = of the=20 cowl too hot to place your arm on.  I figure the hot air need = somplace to=20 get out from under the cowl than the bottom.
 
I tried putting thermostats in my = engine on=20 two occassion and ended up overheating the engines  until the = metal=20 pinged on cool down (ugly sound).  Fortunately no damage even = though it=20 went to 250F on one occassion.  So I decided just to leave the = thermostat out.  Other folks apparently use them with = apparently great=20 success.  My cruise oil and coolant temp varies between 160-190F = depending=20 on OAT but normally it stabilizes at 180F.  
 
I generally taxi out and do a run up to = around=20 3500-4000 while taxing to check both ignitions are functioning with = Controller B, then switch back to controller A and reducing throttle to = a fast=20 taxi around 2500-2700.  At the end of the ruwnway, I then swing = into the=20 wind and do a WOT engine check at 5200rpm+ for fuel, and oil = pressure, fuel=20 flow rate and air/fuel ratio indication.  If all meet my critieria = then I=20 release brakes and launch.
 
I think I would taxi to the end of the = run way, run=20 as high an rpm as you brakes will hold and wait until the coolant temps = reaches=20 170F and then accelerate until you need to shut down to keep from = becoming=20 airborne (or go off the end of the runway) then check your coolant = temp. =20
 
It is not uncommon for the engine to = put out more=20 waste heat than the cooling system can handle on take off an initial = climb=20 out.  So you are running a cooling deficit until you get sufficient = airspeed to reject the waste heat.  For the RV thats approx 120MPH = TAS,=20 Should be somewhere near that for a canard or perhaps a bit higher if = you=20 ducting is a bit less than optiumum
 
FWIW
 
Ed
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 John=20 Slade
Sent: Wednesday, March 31, 2004 = 8:34=20 PM
Subject: [FlyRotary] Requesting = more=20 thoughts on cooling

Guys,
I'm signed off and ready to fly, = but I'm a=20 little concerned about cooling issues. I don't want to melt anything = in the=20 first go around the pattern.
 
I'm finding that the engine gets = REALLY hot=20 after about 10 - 15 minutes ground running, and I'm wondering if = that's to be=20 expected, or if I have a cooling problem.  Maybe I should just = taxi=20 gently to the runway and launch to get airflow as soon as=20 possible.
 
For example, today I ran it up = and down the=20 taxiway for a few minutes at fairly low speeds and around 2500 - = 3000rpm. Then=20 I did some static runups (maybe 3800 - 4000 rpm - all the brakes will = hold)=20 and some EC2 tuning. Then I did some mode 1 programing at various = rpm.=20 During this run I watched the water temp gradually = go up until=20 it was over 200 and I shut her down. The oil was still down around 140 = - 160.=20 I took the cowl off and found that everything in the engine = compartment was=20 HOT. Radiator, oil coolers, hoses, intake, the cowl itself. Apart from = giving=20 my cowl a REAL GOOD post cure I dont think I've done any damage, but = this=20 doesnt give me a lot of confidence about whether I'll make it around = the=20 pattern.
 
The thermostat is now in place, = and I get the=20 feeling that I'd be much better without it. Once the engine gets a = little hot=20 the water temps seem to "run away" if I'm producing any kind of power. = So...=20 to remove the thermostat [3rd gen rew engine] I have to remove the = water pump=20 and have the by-pass hole welded shut - = right?
 
Do you 13B drivers tend to just = taxi out at=20 low rpm then launch? Would your engine overheat if you did a 15 minute = medium=20 power runup? I'd appreciate=20 any general thoughts, or comments on how much ground running I should = expect=20 to get away with before the temps get too high. Anything else I should = check?
 
Regards,
John = Slade
 
 
 
 
 
 
 
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