Return-Path: Received: from fed1rmmtao07.cox.net ([68.230.241.32] verified) by logan.com (CommuniGate Pro SMTP 4.2.2) with ESMTP id 422825 for flyrotary@lancaironline.net; Mon, 20 Sep 2004 13:59:17 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.32; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao07.cox.net (InterMail vM.6.01.03.04 201-2131-111-106-20040729) with ESMTP id <20040920175847.DHFH29837.fed1rmmtao07.cox.net@BigAl> for ; Mon, 20 Sep 2004 13:58:47 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Still high temperature Date: Mon, 20 Sep 2004 10:59:18 -0700 Message-ID: <000001c49f3b$8cccdee0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C49F00.E07077E0" 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_01C49F00.E07077E0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Steve: =20 I am running the cores in series, =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 Some things to consider about the air flow: The typical optimum = thickness from an airside pressure drop and drag standpoint, for a typical = radiator core is about 2.3 to 3"; and that is with a scoop area increase of about = 4:1 entrance to core. You can go thicker on the core with about that ratio, = but you are starting to press your luck especially if the air has to make a significant turn. The two cores in series makes for an equivalent = thickness greater than the actual combined thickness because exit and entrance = losses. So for cores in series, you have to slow the air significantly to get it = all to go through both cores rather than spill at the scoop entrance, plus = you need sufficient flow so can take the heat load from both with a temp increase of maybe about 50F or less. =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. =20 Are you able to get a timing light on the mark? Set up the timing = according to Tracy's specs. =20 Al =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_01C49F00.E07077E0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Steve:

 

I am running the cores in = series,

 

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?  

 

Some things to consider about the air flow: The = typical optimum thickness from an airside pressure drop and drag standpoint, for = a typical radiator core is about 2.3 to 3”; and that is with a scoop area = increase of about 4:1 entrance to core.  You can go thicker on the core with = about that ratio, but you are starting to press your luck especially if the = air has to make a significant turn.  The two cores in series makes for an equivalent thickness greater than the actual combined thickness because = exit and entrance losses.  So for cores in series, you have to slow the = air significantly to get it all to go through both cores rather than spill = at the scoop entrance, plus you need sufficient flow so can take the heat load = from both with a temp increase of maybe about 50F or less.

 

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.

 

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

 

Al

 

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

------=_NextPart_000_0001_01C49F00.E07077E0--