X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.122] verified) by logan.com (CommuniGate Pro SMTP 5.4c2) with ESMTP id 4921496 for flyrotary@lancaironline.net; Fri, 25 Mar 2011 08:28:06 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.122; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=Nm3SJc7L3wlcojC9snsyzORkYWw1JOu3BeZkTeIwPUk= c=1 sm=0 a=7k9kUfyZK_AA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:17 a=Ia-xEzejAAAA:8 a=pedpZTtsAAAA:8 a=pttEB18CiZOqt3iXdZ0A:9 a=b7ZJf2IjLA0KQUdigioA:7 a=pBxBceeaVZz4Dl498ndgXjP9BZcA:4 a=wPNLvfGTeEIA:10 a=EzXvWhQp4_cA:10 a=eJojReuL3h0A:10 a=g_gC5TQEuOvn0do8:21 a=IrtLvs39GL2AL7Cv:21 a=eywV0Svk_UOjquRxsk0A:9 a=DgBIidPzhtrf1xO4p2YA:7 a=-A7iOT63emLmI80UM5dBm5YcvmYA:4 a=ShnoHrQU2bQp6CkD:21 a=KPvEF4cvVwr4p8EH:21 a=rPkcCx1H5rrOSfN0dPC7kw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.167.5 Received: from [174.110.167.5] ([174.110.167.5:65412] helo=EdPC) by cdptpa-oedge02.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 9A/38-11439-13A8C8D4; Fri, 25 Mar 2011 12:27:30 +0000 Message-ID: <896393C305524643AAE55D4CF9C6D53C@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Radiator Caps [FlyRotary] Re: On the subject of installations...Coolant Pressure Date: Fri, 25 Mar 2011 08:27:15 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004D_01CBEAC6.72A41050" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_004D_01CBEAC6.72A41050 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable One thing to keep in mind about the pressure rating of the radiator cap = you are using. All are rated relative to a standard sea level ambinent = pressure. This means that he air pressure itself is contributing 14.7 = psi at sea level. =20 So at sea level when your differential pressure coolant gauge is reading = 10 psi - the absolute pressure in your coolant system is then 14.7 + 10 = =3D 24.7 psi. Now if you are flying at 8000 MSL your ambient pressure = is approx 1/2 at sea level. So your 14.7 psi CAP now has the lesser = capacity of 7.3 + 10 =3D 17.3 psi absolute pressure capacity - somewhat = less than the 24.7 psi absolute it had at sea level. When you increase in altitude this component naturally decreases. So = while a 14.7 psi CAP may work fine at sea level, more than one person = found that at altitude that rating was insufficient and some coolant = was lost. I personally would not fly with less than a 21 psi cap and currently fly = with a 24 psi radiator cap. There is another factor that occurred to me. Once a hot coolant system = blows the relief valve on the cap, that lowers the pressure inside the = system, superheated (>212F) coolant can quickly flash to steam and = further cause lost of coolant. So a Higher PSI cap can lessen the = chance of that happening. =20 FWIW Ed From: Bill Bradburry=20 Sent: Thursday, March 24, 2011 5:30 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: On the subject of installations...Coolant = Pressure Lynn, =20 You have hit my quandary squarely on the head. Assuming that the = pressure was zero at room temp and rose to say 6-7 pounds at 200 = degrees, and assume that the flow restriction in the system caused a = pressure rise of about 2 pounds at 2000 rpm and a pressure rise of, say, = 6-7 pounds at 6000 rpm. Under that scenario, you would have a pressure = that ran at between 7-9 pounds at 2000 and rose to 12-14 pounds at 6000. = Those pressures would be easily contained with the stock cap of 14 = pounds. And the pressure would be constantly changing with rpm and = possibly temp of the system as you were under power or not. =20 I have a 21 pound cap. My system climbs smartly to the top and stays = there. No fluctuation with rpm, no real fluctuation at temp because it = has already hit the 21 pounds before the engine is actually hot. = (around 190) =20 Something is wrong and I don't understand what it is. =20 Bobby =20 I am going to insert answers to your questions in your msg below. =20 Bill B =20 -------------------------------------------------------------------------= ------- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On = Behalf Of Bobby J. Hughes Sent: Thursday, March 24, 2011 1:57 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: On the subject of installations...Coolant = Pressure =20 Bill, =20 This is all I can think of at the moment.=20 =20 Are you running a thermostat or did you plug the hole between the inlets = and outlets of the water pump?=20 =20 No thermostat. The Renesis has a thermostat tower which is too tall to = fit under my cowl, so I removed it and fabricated a flat plate with two = 1.25 aluminum tubes for the inlet and outlet of the water pump. That = hole you are referencing exists in the tower, but not in my plate. =20 If plugged did you drill a small hole in the plug to allow air a place = to escape? I used a #30 drill.=20 =20 Any air in my system would have to be carried to the highest point, = (radiator cap) then be forced by pressure to the bottom of the swirl = tank where it would be trapped. This seems to be working because I have = found that after I open the system for some reason, the level in the = swirl tank will go down and there is never any air at the top of the = radiator. =20 After an engine run is the radiator the same temperature at the inlet / = outlet / bottom and top? If I have trapped air only part of my radiator = gets hot to the touch. Dual pass barrier leaking? =20 Seems to be. I have mistakenly laid my arm on the top of the radiator = after a run.usually I manage to get off pretty fast! :>) I can not see = into the radiator tank on the barrier side. It is possible it could be = leaking. I suppose if there was a rag in the thing it could be trapped = here also. I have no way to see in there even if the hose was removed. = I would need some kind of flexible camera or something like that. =20 Use an extra CHT channel and clamp it to the inlet of your radiator to = measure Delta T. =20 Good idea. I will have to rig one up. I don't have an extra now. =20 My water pressure does not vary that much in operation. But it does hold = a little pressure for a few days after shutdown. 1-2 psi.=20 =20 What is your pressure during operation? What is the pressure cap = rating? Does it vary at all with temp and/or rpm? Mine is maxed = out..always! =20 What size hoses? I'm running 1in.=20 =20 The RX-8 uses 1.25 hoses. I stuck with that size as well. =20 Where are you measuring water pressure? =20 =20 The hose that comes off the top of the rear iron goes to the top of the = radiator, just below the cap. A tee in this line has the water pressure = sender in it. The radiator cap is just a cap, not a pressure cap. The = outlet in the radiator neck goes to the bottom of the swirl tank. =20 Is your pressure cap on the bleed / swirl tank? =20 Yes. =20 Any pictures of the plumbing? =20 Not of the current setup. =20 Bobby -------------------------------------------------------------------------= ------- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On = Behalf Of Bill Bradburry Sent: Thursday, March 24, 2011 10:23 AM To: Rotary motors in aircraft Subject: [FlyRotary] On the subject of installations...Coolant Pressure =20 I need some help with figuring out my cooling problems. =20 Just so it doesn't get lost in the following BS, I need to state that I = think the problem is related to the coolant pressure. It seems to me to = be way too high. I am beginning to think that the coolant is somehow = partially blocked. =20 Now the rest of the story.. =20 After I did the flight described in the attached email, I installed an = opening in the bottom of the cowl that would work something like a cowl = flap that is permanently open. The new opening is 9 inches by 5 inches = or 54 sq in.. There is a flare in front of the opening that is at an = angle of 45 degrees and extends down into the airstream about 4 inches. = (it is 6 inches long.) This opening is in addition to two 6 X 6 = openings, one of which has a 3 inch diameter exhaust pipe in it. =20 This helped a little, but nothing like I expected it would. The = pressure inside the radiator inlet dropped from 10 inches of water to 8 = inches of water. (by the way, Steve was right about it being inches of = water and not inches of Hg.) The pressure after the radiator and inside the cowl dropped to 8 inches = as well. The temperature of the water dropped to 208 and the oil a = couple of degrees. Neither of these had the result that I expected. =20 My water pressure cap is rated at 21 lbs. I have not calibrated the = sender that came with my EM-2 and it shows 3 lbs when the engine is = cold. I assume that this is zero. When in flight the pressure climbs = to 24 lbs and stays there. I assume that at this point, the cap is at = 21 lbs and is bleeding off air. There is about a pint to a quart of air = above the coolant in the bleed tank. =20 This morning I ran the engine on the ground for about 10-15 minutes at = an rpm of 3000 to 3200. The OAT was 75 degrees. =20 I read the temps and pressures every minute or two during the run. I = hope this doesn't get jumbled during transmission.=20 =20 Oil temp - 80 103 130 139 = 144 155 162 165 Air temp after cooler - 97 109 = 122 129 133 134 =20 Water temp - 86 126 161 173 = 178 190 198 199 Air temp after rad - 109 133 = 157 169 179 183 =20 Water pressure - 2 11 17 20 = 21 24 =20 =20 I noticed that the water pressure could be brought from 2 lbs to 9 lbs = by changing the rpm while the engine was still relatively cool =20 What should I expect for water pressure at lower temps and how could I = go about making a determination that the water passages are clear? =20 I am beginning to think that a rag has been left either in the engine or = the radiator. I have never torn the engine down and I sent the radiator = out to have a leak repair a couple of years ago. It is a double pass = radiator. I can look into the end that has both sides connected thru = the radiator cap neck, but not into the inlet and outlet end.=20 =20 Suggestions??? =20 Thanks, =20 Bill B =20 -------------------------------------------------------------------------= ------- From: Bill Bradburry [mailto:bbradburry@bellsouth.net]=20 Sent: Sunday, March 20, 2011 5:29 PM To: 'Rotary motors in aircraft' Subject: On the subject of installations... =20 My water temp has been running between 199 and 217, depending on the = OAT. The oil is pretty steady at around 175. Today I finally got to = fly with pressure probes inside the cowling. I was all set to try and = enlarge the inlet to the radiator to solve the problem. It turns out = that "in" is not the problem, it is "out" that is the problem! =20 I have 10 inches of Hg pressure in the radiator inlet and 10 inches of = Hg on the outlet side as well as the same pressure everywhere I measured = inside the cowl. I need to open up the cowl some so more air can get = out. I had considered a cowl flap but that would not work in this = instance because the problem is at cruise. I need a permanent opening. = I am considering louvers and I am looking for a source. I know some of = you are using them. Where did you get them and how are they installed = so that they look ok? =20 I am also considering some kind of flare around the exit area to create = a low pressure area to help suck air out. Do any of you have those and = do they seem to work? =20 While I look into this, I also need to do something about my = muffler.Thank you, Bobby! =20 I wonder about that spiral muffler some of you are trying?? =20 Bill B 9 hours and counting. =20 By the way, I was considering putting a 1 or 2 inch wide piece of = cardboard across the bottom of the oil cooler to partially block it in = the hopes that more air would then flow through the radiator. Sort of = like truckers do with the radiator in cold weather. What opinions do = you have about that idea? I realize it would make more sense if the oil = was really cool, but I think the oil might not get much hotter if an = inch or so was blocked. What do you think??? ------=_NextPart_000_004D_01CBEAC6.72A41050 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
One thing to keep in mind about the pressure = rating of the=20 radiator cap you are using.  All are rated relative to a standard = sea level=20 ambinent pressure.  This means that he air pressure itself is = contributing=20 14.7 psi at sea level. 
 
So at sea level when your differential pressure = coolant=20 gauge is reading 10 psi - the absolute pressure in your coolant system = is then=20  14.7 + 10 =3D 24.7 psi.  Now if you are flying at 8000 MSL = your ambient=20 pressure is approx 1/2 at sea level.  So your 14.7 psi CAP now has = the=20 lesser capacity of 7.3 + 10 =3D 17.3 psi absolute pressure capacity - = somewhat=20 less than the 24.7 psi absolute it had at sea level.
 
When you increase in altitude this component = naturally=20 decreases.  So while a 14.7 psi CAP may work fine at sea level, = more than=20 one person found that at altitude  that rating was  = insufficient=20 and some coolant was lost.
 
I personally would not fly with less than a 21 = psi cap and=20 currently fly with a 24 psi radiator cap.
 
There is another factor that occurred to = me.  Once=20 a hot coolant system blows the relief valve on the cap, that lowers = the=20 pressure inside the system, superheated (>212F) coolant can quickly = flash to=20 steam and further cause lost of coolant.  So a Higher PSI cap can = lessen=20 the chance of that happening. 
 
FWIW
 
Ed

Sent: Thursday, March 24, 2011 5:30 PM
Subject: [FlyRotary] Re: On the subject of = installations...Coolant=20 Pressure

Lynn,

 

You have hit = my=20 quandary squarely on the head.  Assuming that the pressure was zero = at room=20 temp and rose to say 6-7 pounds at 200 degrees, and assume that the flow = restriction in the system caused a pressure rise of about 2 pounds at = 2000 rpm=20 and a pressure rise of, say, 6-7 pounds at 6000 rpm.  Under that = scenario,=20 you would have a pressure that ran at between 7-9 pounds at 2000 and = rose to=20 12-14 pounds at 6000.  Those pressures would be easily contained = with the=20 stock cap of 14 pounds.  And the pressure would be constantly = changing with=20 rpm and possibly temp of the system as you were under power or=20 not.

 

I have a 21 = pound=20 cap.  My system climbs smartly to the top and stays there.  No = fluctuation with rpm, no real fluctuation at temp because it has already = hit the=20 21 pounds before the engine is actually hot.  (around=20 190)

 

Something is = wrong and=20 I don=92t understand what it is.

 

Bobby

 

I am going to = insert=20 answers to your questions in your msg = below.

 

Bill=20 B

 

From: Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. = Hughes
Sent: Thursday, March 24, 2011 = 1:57=20 PM
To: Rotary motors = in=20 aircraft
Subject: = [FlyRotary]=20 Re: On the subject of installations...Coolant=20 Pressure

 

Bill,

 

This is all I = can think=20 of at the moment.

 

Are you = running a=20 thermostat or did you plug the hole between the inlets and outlets of = the water=20 pump?

 

No = thermostat.  The=20 Renesis has a thermostat tower which is too tall to fit under my cowl, = so I=20 removed it and fabricated a flat plate with two 1.25 aluminum tubes for = the=20 inlet and outlet of the water pump.  That hole you are referencing = exists=20 in the tower, but not in my plate.

 

If plugged = did you=20 drill a small hole in the plug to allow air a place to escape? I used a = #30=20 drill.

 

Any air in my = system=20 would have to be carried to the highest point, (radiator cap) then be = forced by=20 pressure to the bottom of the swirl tank where it would be = trapped.  This=20 seems to be working because I have found that after I open the system = for some=20 reason, the level in the swirl tank will go down and there is never any = air at=20 the top of the radiator.

 

After an = engine run is=20 the radiator the same temperature at the inlet / outlet / bottom and = top? If I=20 have trapped air only part of my radiator gets hot to the touch. Dual = pass=20 barrier leaking?

 

Seems to = be.  I=20 have mistakenly laid my arm on the top of the radiator after a = run=85usually I=20 manage to get off pretty fast!  :>)  I can not see into the = radiator tank on the barrier side.  It is possible it could be=20 leaking.  I suppose if there was a rag in the thing it could be = trapped=20 here also.  I have no way to see in there even if the hose was=20 removed.  I would need some kind of flexible camera or something = like=20 that.

 

Use an extra = CHT=20 channel and clamp it to the inlet of your radiator to measure Delta=20 T.

 

Good = idea.  I will=20 have to rig one up.  I don=92t have an extra=20 now.

 

My water = pressure does=20 not vary that much in operation. But it does hold a little pressure for = a few=20 days after shutdown.  1-2 psi.

 

What is your = pressure=20 during operation?  What is the pressure cap rating?  Does it = vary at=20 all with temp and/or rpm?  Mine is maxed=20 out..always!

 

What size = hoses? I=92m=20 running 1in.

 

The RX-8 uses = 1.25=20 hoses.  I stuck with that size as = well.

 

Where are you = measuring=20 water pressure?  

 

The hose that = comes off=20 the top of the rear iron goes to the top of the radiator, just below the = cap. A=20 tee in this line has the water pressure sender in it.  The radiator = cap is=20 just a cap, not a pressure cap.  The outlet in the radiator neck = goes to=20 the bottom of the swirl tank.

 

Is your = pressure cap on=20 the bleed / swirl tank?

 

Yes.

 

Any pictures = of the=20 plumbing?

 

Not of the = current=20 setup.

 

Bobby

From: Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bill = Bradburry
Sent: Thursday, March 24, 2011 = 10:23=20 AM
To: Rotary motors = in=20 aircraft
Subject: = [FlyRotary]=20 On the subject of installations...Coolant=20 Pressure

 

I need some = help with=20 figuring out my cooling problems.

 

Just so it = doesn=92t get=20 lost in the following BS, I need to state that I think the problem is = related to=20 the coolant pressure.  It seems to me to be way too high.  I = am=20 beginning to think that the coolant is somehow partially=20 blocked.

 

Now the rest = of the=20 story=85.

 

After I did = the flight=20 described in the attached email, I installed an opening in the bottom of = the=20 cowl that would work something like a cowl flap that is permanently = open. =20 The new opening is 9 inches by 5 inches or 54 sq in..  There is a = flare in=20 front of the opening that is at an angle of 45 degrees and extends down = into the=20 airstream about 4 inches.  (it is 6 inches long.)  This = opening is in=20 addition to two 6 X 6 openings, one of which has a 3 inch diameter = exhaust pipe=20 in it.

 

This helped a = little,=20 but nothing like I expected it would.  The pressure inside the = radiator=20 inlet dropped from 10 inches of water to 8 inches of water.  (by = the way,=20 Steve was right about it being inches of water and not inches of=20 Hg.)

The pressure = after the=20 radiator and inside the cowl dropped to 8 inches as well.  The = temperature=20 of the water dropped to 208 and the oil a couple of degrees.  = Neither of=20 these had the result that I expected.

 

My water = pressure cap=20 is rated at 21 lbs.  I have not calibrated the sender that came = with my=20 EM-2 and it shows 3 lbs when the engine is cold.  I assume that = this is=20 zero.  When in flight the pressure climbs to 24 lbs and stays = there. =20 I assume that at this point, the cap is at 21 lbs and is bleeding off = air. =20 There is about a pint to a quart of air above the coolant in the bleed=20 tank.

 

This morning = I ran the=20 engine on the ground for about 10-15 minutes at an rpm of 3000 to = 3200. =20 The OAT was 75 degrees.

 

I read the = temps and=20 pressures every minute or two during the run.  I hope this = doesn=92t get=20 jumbled during transmission.

 

Oil temp =96=20             &= nbsp;        80=20      103     =20 130           &nbs= p; =20 139           &nbs= p;=20 144          =20 155         =20 162        =20 165

Air temp = after cooler -=20             &= nbsp; 97      =20 109           &nbs= p;            = ;       =20 122           =20 129         =20 133        =20 134

 

Water temp=20 -            =      =20 86       126      = 161           &nbs= p; =20 173           &nbs= p;=20 178          =20 190         =20 198         =20 199

Air temp = after rad=20 -            =        =20 109     =20 133           &nbs= p;            = ;       =20 157          =20 169         =20 179          =20 183

 

Water = pressure=20 -            = =20 2         =20 11       =20 17       =20        20     = ;         =20 21            = ;            =    =20 24     

 

I noticed = that the=20 water pressure could be brought from 2 lbs to 9 lbs by changing the rpm = while=20 the engine was still relatively cool

 

What should I = expect=20 for water pressure at lower temps and how could I go about making a=20 determination that the water passages are = clear?

 

I am = beginning to think=20 that a rag has been left either in the engine or the radiator.  I = have=20 never torn the engine down and I sent the radiator out to have a leak = repair a=20 couple of years ago.  It is a double pass radiator.  I can = look into=20 the end that has both sides connected thru the radiator cap neck, but = not into=20 the inlet and outlet end.

 

Suggestions???

 

Thanks,

 

Bill=20 B

 

From: Bill=20 Bradburry [mailto:bbradburry@bellsouth.net]
Sent: Sunday, March 20, 2011 5:29 = PM
To: = 'Rotary motors in=20 aircraft'
Subject: On the subject of=20 installations...

 

My water temp = has been=20 running between 199 and 217, depending on the OAT.  The oil is = pretty=20 steady at around 175.  Today I finally got to fly with pressure = probes=20 inside the cowling.  I was all set to try and enlarge the inlet to = the=20 radiator to solve the problem.  It turns out that =93in=94 is not = the problem,=20 it is =93out=94 that is the problem!

 

I have 10 = inches of Hg=20 pressure in the radiator inlet and 10 inches of Hg on the outlet side as = well as=20 the same pressure everywhere I measured inside the cowl.  I need to = open up=20 the cowl some so more air can get out.  I had considered a cowl = flap but=20 that would not work in this instance because the problem is at = cruise.  I=20 need a permanent opening.  I am considering louvers and I am = looking for a=20 source.  I know some of you are using them.  Where did you get = them=20 and how are they installed so that they look = ok?

 

I am also = considering=20 some kind of flare around the exit area to create a low pressure area to = help=20 suck air out.  Do any of you have those and do they seem to=20 work?

 

While I look = into this,=20 I also need to do something about my muffler=85Thank you,=20 Bobby!

 

I wonder = about that=20 spiral muffler some of you are trying??

 

Bill B  = 9 hours=20 and counting=85

 

By the way, I = was=20 considering putting a 1 or 2 inch wide piece of cardboard across the = bottom of=20 the oil cooler to partially block it in the hopes that more air would = then flow=20 through the radiator.  Sort of like truckers do with the radiator = in cold=20 weather.  What opinions do you have about that idea?  I = realize it=20 would make more sense if the oil was really cool, but I think the oil = might not=20 get much hotter if an inch or so was blocked.  What do you=20 think???

=
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