Return-Path: Received: from seraph2.grc.nasa.gov ([128.156.10.11] verified) by logan.com (CommuniGate Pro SMTP 4.2.2) with ESMTP id 422182 for flyrotary@lancaironline.net; Mon, 20 Sep 2004 08:07:03 -0400 Received-SPF: pass receiver=logan.com; client-ip=128.156.10.11; envelope-from=Joseph.M.Berki@grc.nasa.gov Received: from lombok-fi.grc.nasa.gov (lombok-fi.grc.nasa.gov [139.88.112.33]) by seraph2.grc.nasa.gov (Postfix) with ESMTP id 967C768994 for ; Mon, 20 Sep 2004 08:06:32 -0400 (EDT) Received: from manihi.grc.nasa.gov (manihi.grc.nasa.gov [139.88.112.36]) by lombok-fi.grc.nasa.gov (NASA GRC TCPD 8.12.10/8.12.10) with ESMTP id i8KC6WV2009892 for ; Mon, 20 Sep 2004 08:06:32 -0400 (EDT) Received: from GR7700013583.lerc.nasa.gov (gr7700013583.grc.nasa.gov [139.88.139.62]) by manihi.grc.nasa.gov (NASA GRC TCPD 8.12.10/8.12.10) with ESMTP id i8KC6VDh006427 for ; Mon, 20 Sep 2004 08:06:31 -0400 (EDT) X-Info: ODIN / NASA Glenn Research Center Message-Id: <5.1.1.5.2.20040920075650.0179fd50@popserve.lerc.nasa.gov> X-Sender: scberki@popserve.lerc.nasa.gov X-Mailer: QUALCOMM Windows Eudora Version 5.1.1 Date: Mon, 20 Sep 2004 08:06:26 -0400 To: "Rotary motors in aircraft" From: Joseph M Berki Subject: Re: [FlyRotary] Re: Still high temperature In-Reply-To: Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="=====================_-1866529937==.ALT" --=====================_-1866529937==.ALT Content-Type: text/plain; charset="us-ascii"; format=flowed Hi Steve, I am no expert and am far from engine start, but from what I have seen on this forum I see that John has a plenum fed by the scoop. This may allow the air to slow down and permit the heat to transfer more efficiently. It also appears you have air trapped in the system which will have to be purged. I think your oil cooler duct is close and you might have to tweak it (K & W curve on the duct sides and/or maybe increase the feed opening). It looks like you are making progress. Keep us posted. Joe Berki Limo EZ At 06:14 AM 9/20/2004 -0400, you (Steve Brooks) wrote: >Al, >I am running the cores in series, and I agree that it appears to be >insufficient cooling. Since others are running the evaporator cores with >no trouble. I assume that the issue is air flow. John Slade seems to >have no trouble with his temperatures, and has the identical plane and >scoop. Actually I've added a front end to my scoop to get outside the >boundary layer, but still have high temperatures. > >I have a P-51 style scoop that I had put on earlier with the old cooling >system. I removed it when it didn't improve the cooling, but the old set >up I think was beyond help. Maybe I should try it with the new set up. > >I was also wondering about any other factors causing excessive heat from >the engine, like timing. I haven't tried to retard the timing any, but I >know that in piston engines, if you get the timing too advanced, it can >result in allot of heat. > >Steve Brooks >-----Original Message----- >From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On >Behalf Of Al Gietzen >Sent: Sunday, September 19, 2004 3:28 PM >To: Rotary motors in aircraft >Subject: [FlyRotary] Re: Still high temperature > > > >The high temps are indicating insufficient cooling capacity ( I guess that >s obvious); which means insufficient air flow or too little heat exchange >area. If others are getting adequate cooling at the same power with the >same cores, then it is air flow. As I recall, you are no longer running >the coolers in series, but there still may be a pressure recovery issue >with your scoop, or just too small an opening; more like the first. > > >After a few runs it seems that the air should be purged. Do you have a >means of checking (confirming your temps to be sure there isn t some >boiling going on? > > >Al > > >Subject: [FlyRotary] Still high temperature > > >I would appreciate input to a problem that I have. I just overhauled the >engine, and reworked the cooling system. I'm now using the A/C evaporator >cores for radiators. The problem I'm having is, that when I take it up, I'm >seeing coolant and oil temperature of about 210 degrees. That is climbing >to pattern, leveling off, and throttling back to low power. The oil stays >pretty much where it is, and the coolant come down just a couple of degrees. > > >When throttle back to land, the coolant and oil both come down to about 180 >at touchdown. I taxi back to the hanger and shut down with oil and coolant >about 190-195, but after shut down, I get all sorts of gurgling noises from >the header tank, which is fed by the tap on the side of the thermostat >housing. The gurgling noises go on for 5-6 minutes, which would seem like >the engine is overheated, but while hot, it doesn't seem overly hot. The >other end of the header tank feeds coolant to the turbo, so maybe the hot >water is coming from it ? Maybe my header tank should be fed differently ? >Also at this time, after a short flight, there is only a couple of cups of >additional coolant in the overflow tank. > > >I assume that the higher than desired coolant temperature, and the gurgling >noise are related. I pulled the water pump off today to double check it, >and all seems OK. The pump only has about 10 hours on it. When I run it on >the ground, and feel the radiators after shutdown, they are uniformly hot. >I put a furnace blower pointed at the scoop, and I'm getting very even >airflow through the radiators. The oil cooler, on the other hand, has about >75% of the air going through the middle of the cooler, so I'm going to have >to add some deflectors in the plenum to push more air to the outside. That >seems to be a less significant issue at the present. > > >Any thoughts ? > > >Steve Brooks >Cozy MKIV >Turbo rotary > > > > > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html --=====================_-1866529937==.ALT Content-Type: text/html; charset="us-ascii" Hi Steve,
        I am no expert and am far from engine start, but from what I have seen on this forum I see that John has a plenum fed by the scoop.  This may allow the air to slow down and permit the heat to transfer more efficiently.  It also appears you have air trapped in the system which will have to be purged. I think your oil cooler duct is close and you might have to tweak it (K & W curve on the duct sides and/or maybe increase the feed opening). It looks like you are making progress.  Keep us posted.

Joe Berki
Limo EZ

At 06:14 AM 9/20/2004 -0400, you (Steve Brooks) wrote:
Al,
I am running the cores in series, and I agree that it appears to be insufficient cooling.  Since others are running the evaporator cores with no trouble.  I assume that the issue is air flow.  John Slade seems to have no trouble with his temperatures, and has the identical plane and scoop.  Actually I've added a front end to my scoop to get outside the boundary layer, but still have high temperatures.
 
I have a P-51 style scoop that I had put on earlier with the old cooling system.  I removed it when it didn't improve the cooling, but the old set up I think was beyond help.  Maybe I should try it with the new set up.
 
I was also wondering about any other factors causing excessive heat from the engine, like timing.  I haven't tried to retard the timing any, but I know that in piston engines, if you get the timing too advanced, it can result in allot of heat.
 
Steve Brooks
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Al Gietzen
Sent: Sunday, September 19, 2004 3:28 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Still high temperature
 

The high temps are indicating insufficient cooling capacity ( I guess that s obvious); which means insufficient air flow or too little heat exchange area.  If others are getting adequate cooling at the same power with the same cores, then it is air flow.  As I recall, you are no longer running the coolers in series, but there still may be a pressure recovery issue with your scoop, or just too small an opening; more like the first.
 

After a few runs it seems that the air should be purged.  Do you have a means of checking (confirming your temps to be sure there isn t some boiling going on?
 

Al
 

Subject: [FlyRotary] Still high temperature
 

I would appreciate input to a problem that I have.  I just overhauled the
engine, and reworked the cooling system.  I'm now using the A/C evaporator
cores for radiators.  The problem I'm having is, that when I take it up, I'm
seeing coolant and oil temperature of about 210 degrees.  That is climbing
to pattern, leveling off, and throttling back to low power.  The oil stays
pretty much where it is, and the coolant come down just a couple of degrees.
 

When throttle back to land, the coolant and oil both come down to about 180
at touchdown.  I taxi back to the hanger and shut down with oil and coolant
about 190-195, but after shut down, I get all sorts of gurgling noises from
the header tank, which is fed by the tap on the side of the thermostat
housing.  The gurgling noises go on for 5-6 minutes, which would seem like
the engine is overheated, but while hot, it doesn't seem overly hot. The
other end of the header tank feeds coolant to the turbo, so maybe the hot
water is coming from it ? Maybe my header tank should be fed differently ?
Also at this time, after a short flight, there is only a couple of cups of
additional coolant in the overflow tank.
 

I assume that the higher than desired coolant temperature, and the gurgling
noise are related.  I pulled the water pump off today to double check it,
and all seems OK.  The pump only has about 10 hours on it.  When I run it on
the ground, and feel the radiators after shutdown, they are uniformly hot.
I put a furnace blower pointed at the scoop, and I'm getting very even
airflow through the radiators.  The oil cooler, on the other hand, has about
75% of the air going through the middle of the cooler, so I'm going to have
to add some deflectors in the plenum to push more air to the outside.  That
seems to be a less significant issue at the present.
 

Any thoughts ?
 

Steve Brooks
Cozy MKIV
Turbo rotary
 

 

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