Return-Path: Received: from fed1rmmtao04.cox.net ([68.230.241.35] verified) by logan.com (CommuniGate Pro SMTP 4.2.3) with ESMTP id 432501 for flyrotary@lancaironline.net; Sat, 25 Sep 2004 21:03:26 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.35; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao04.cox.net (InterMail vM.6.01.03.04 201-2131-111-106-20040729) with ESMTP id <20040926010253.DFGQ11627.fed1rmmtao04.cox.net@BigAl> for ; Sat, 25 Sep 2004 21:02:53 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Still high temperature Date: Sat, 25 Sep 2004 18:03:04 -0700 Message-ID: <000001c4a364$93dbd010$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C4A329.E77CF810" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C4A329.E77CF810 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 What is the area at the opening of the scoop? What is the area at the = face of the cooler? Does the area of the duct increase at all points after = the entrance? =20 =20 The opening of the scoop is 14.5" by 4.25" or 61.625 SQ. IN. The duct = does open up to the cores, although it is only about 12" from the opening to = the junction of the 2 cores, which are in a shallow "V".=20 =20 Steve; =20 My analysis of air flow required for 200 hp climb at 120 kts on a 95F = day, and a very effective scoop is 65 sq.in. inlet area - just for the = coolant rads. Another 25 sq. in. inlet for the oil cooler. This is more than typically needed for cruise, but it's a tradeoff. =20 Another idea is to remove the oil cooler altogether from the main = scoop, and add an additional scoop for the oil cooler. This would leave more = air for the radiators, but be higher drag. At this point, I guess I could settle for cool and slower. =20 The pressure recovery of your scoop/core configuration is difficult to predict, but may be OK for the coolant cores. It seems an additional = scoop for the oil cooler is the way to go if you can find a way to configure = it. Better a little more drag than not being able to take off without overheating. =20 FWIW, =20 Al =20 =20 =20 It does seem very likely that you are going to have some trapped air if = you don't have a bleed at the highest point. You may need to add a threaded bung and a petcock valve; or as I refer, a small o-ring plug that is = drilled with a small port into the bottom and then out the side at the top of threads and just below the o-ring. Just loosen the plug about a turn = while you are filling until all the air is out. I agree. I've ordered an AN-16 elbow to redo the turn out of the = thermostat housing. I'm going to drill a hole and tap it, in the side of the = fitting for a plug.=20 =20 Are you able to get a timing light on the mark? Set up the timing = according to Tracy's specs. I did set it with a timing light, but it was pretty close to the static setting. I couldn't really adjust it with the RPM's above 3000, so I subtracted the 4 degree from it, and set the timing for 1500 RPM's at 21 degrees BTDC. I hope that this is right. =20 Steve =20 Subject: [FlyRotary] Re: Still high temperature =20 Al, 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. =20 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. =20 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. =20 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 =20 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. =20 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? =20 Al=20 =20 Subject: [FlyRotary] Still high temperature =20 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. =20 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. =20 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. =20 Any thoughts ? =20 Steve Brooks Cozy MKIV Turbo rotary =20 =20 >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0001_01C4A329.E77CF810 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

What is the area at the = opening of the scoop?  What is the area at the face of the cooler?  Does = the area of the duct increase at all points after the = entrance?  

 

The opening of the scoop is 14.5" by 4.25" or 61.625 SQ. IN.  The duct does open up = to the cores, although it is only about 12" from the opening to the = junction of the 2 cores, which are in a shallow "V". 

 <= /font>

Steve;<= /font>

 <= /font>

My analysis = of air flow required for 200 hp climb at 120 kts on a 95F day, and a very = effective scoop is 65 sq.in. inlet area – just for the coolant rads. =  Another 25 sq. in. inlet for the oil cooler.  This is more than typically = needed for cruise, but it’s a tradeoff.

 <= /font>

  Another idea is to remove the oil cooler altogether from the main scoop, = and add an additional scoop for the oil cooler.  This would leave more = air for the radiators, but be higher drag.  At this point, I guess I could = settle for cool and slower.

 

The pressure = recovery of your scoop/core configuration is difficult to predict, but may be OK = for the coolant cores.  It seems an additional scoop for the oil cooler is = the way to go if you can find a way to configure it.  Better a little more = drag than not being able to take off without overheating.

 <= /font>

FWIW,

 <= /font>

Al

 

 

 

It does seem very likely = that you are going to have some trapped air if you don’t have a bleed at = the highest point.  You may need to add a threaded bung and a petcock = valve; or as I refer, a small o-ring plug that is drilled with a small port = into the bottom and then out the side at the top of threads and just below the = o-ring.  Just loosen the plug about a turn while you are filling until all = the air is out.

I agree.  = I've ordered an AN-16 elbow to redo the turn out of the thermostat = housing.  I'm going to drill a hole and tap it, in the side of the fitting for a = plug. 

 

Are you able to get a = timing light on the mark?  Set up the timing according to Tracy’s specs.

I did = set it with a timing light, but it was pretty close to the static setting.  =  I = couldn't really adjust it with the RPM's above 3000, so I subtracted the 4 degree = from it, and set the timing for 1500 RPM's at 21 degrees BTDC.  I hope = that this is right.

 

Steve

 

Subject: [FlyRotary] Re: Still high temperature

 

Al,=

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

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