X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2383959 for flyrotary@lancaironline.net; Fri, 12 Oct 2007 17:14:55 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([24.74.103.61]) by cdptpa-omta04.mail.rr.com with SMTP id <20071012211417.HTSP2011.cdptpa-omta04.mail.rr.com@edward2> for ; Fri, 12 Oct 2007 21:14:17 +0000 Message-ID: <001501c80d14$eb868db0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: FW: [FlyRotary] Re: Coolant Water Pressure Date: Fri, 12 Oct 2007 17:14:47 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0012_01C80CF3.643BB540" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0012_01C80CF3.643BB540 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Al, Racing Beat's Rotary Tech catalog specifies that for 1974 and later = pumps using stock main and water pulley, that engine rpm above 6300 rpm = would cause the stock water pump to cavitate. . This is of course with = OEM size hoses. That cavitation beings gradually and becomes worst as = rpm and temperature increases and if full throttle operation is = maintained under those conditions "...the engine will not last long." Now that information is somewhat dated (my catalog is dated 1992). I = strongly suspect that, the Renesis for example would be able to handle = a higher sustained rpm. And perhaps the later 13B's as well, I just = have not seen any information more recent on the topic. =20 I fly with a main pulley sized for 20% less water pump rpm and my = alternator has a 20% reduction as well. So my top engine rpm (sustained) = around 6500 rpm hopefully keeps me out of the bubble zone. Ed =20 ----- Original Message -----=20 From: Al Wick=20 To: Rotary motors in aircraft=20 Sent: Friday, October 12, 2007 4:29 PM Subject: [FlyRotary] Re: FW: [FlyRotary] Re: Coolant Water Pressure Where does the fear of pump cavitation come from? Is that speculative = or have some guys inadvertently choked off the pump inlet with small = diam hose instead of OEM size? -al wick ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Friday, October 12, 2007 11:31 AM Subject: [FlyRotary] FW: [FlyRotary] Re: Coolant Water Pressure This was rejected because of the photo files being too large, so = I'll send one of the pics separately. Al Subject: RE: [FlyRotary] Re: Coolant Water Pressure Bill; Here is the setup I use. On the first photo, the filler neck is on = the left, and connects to the line going to the inlet side of the pump. = The two small lines (3/16") coming into the side are air bleed lines = going from the high points of my two radiators (note that the pressure = at the filler neck will be near the lowest in the system.) The = 'overflow' from the filler cap goes to the bottom of the accumulator = bottle on the right (made from a discarded fire extinguisher). The accumulator bottle overflow goes over board, but coolant only = goes out here once on first heatup. When cold, there is only about 3 - = 4" coolant in the bottom of that bottle, so there is air in there that = compresses as things heat up. Coolant forced out of the filler neck on = heat up is draw back in on cooldown. The idea is that whenever the engine is running, there is positive = pressure on the system - at the pump inlet; reducing the chance of pump = cavitation at high RPM. And positive pressure is maintained at altitude = even when throttling back and the coolant temp is decreasing. Originally I had a 23# cap on the filler neck, and 15# on the = accumulator bottle. I later reversed the two to lower system pressure = on initial heatup (as soon as the engine heats up at all the pressure = goes to filler cap pressure), but it still gives me the sum of the two = caps under any extreme condition to protect against boiling. Keep in = mind that the caps are 'differential pressure' so at altitude the max = absolute pressure in the accumulator bottle is reduced by the reduction = in the ambient. Al -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Bill Bradburry Sent: Thursday, October 11, 2007 8:49 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Coolant Water Pressure Lynn, I don't know what we would do without you. I have several questions. =20 Where can I get a good accumulator tank? =20 I was thinking of making one out of a used fire extinguisher and = was also looking at one from Moroso that looks like a flat canteen. The = one from Moroso has an inlet on the bottom and one on the top side as = well as one for the pop off of the radiator cap. Due to space = constraints, I will probably try and make one. I need something about 3" = diameter and maybe 12" or so long. Will I need the inlet on the top = side? If so, where does it plumb to? I suppose I will still need an overflow tank from the pop off of the = radiator cap? After talking with Tracy yesterday, I tried to see if the engine = would stabilize temp somewhere below 230* at 2600 rpm. No joy! I = suspect that I will need to increase air flow to get this to happen. I = will try an leaf blower on the cowl today. My pressure stabilized at 22 lbs (cap in constant blow off relief) = but the temp would not hold. If I had this same condition with the = system you described, what would prevent the air from blowing off and = then water from the accumulator? It seems to me that no matter what system you have, the pressure has = to stabilize below the pressure rating of the radiator cap, else you = will be losing first air, then water???? Bill B -------------------------------------------------------------------------= --- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Lehanover@aol.com Sent: Wednesday, October 03, 2007 10:28 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Coolant Water Pressure In a message dated 10/3/2007 9:08:53 A.M. Eastern Daylight Time, = bbradburry@bellsouth.net writes: I think that I would see air under the radiator cap if I had a = compression gas leak? I never see any air.=20 To check a piston engine for head gasket leaks, you would put the = cylinder at TDC and pressurize the cylinder to about 150 lbs with = compressed air and check the radiator for air bubbles.How do you check a = rotary? I will check the pressure sender against a mechanical gage. =20 There is obviously a heating problem, but I think the pressure is = higher than it should be until just ready to boil. I shut the engine = off at 210*, and at 22+ lbs, the boiling point should be well above = 250*?? Thanks for the suggestions of where to look, guys. Bill B It is extremely difficult to remove all of the air from a rotary = engines cooling system. It is also extremely important. If air is under = the pressure cap in a static situation, it will remix with other coolant = when the engine is at speed. The coolant moves very quickly through the = system. The coolant volume appears to increase slightly because much of = the air is reintroduced into the water. This coolant then becomes a poor = conductor of heat. You need the anti foaming agent in Antifreeze. Just a = bit, perhaps 10%. The system with the relief cap right on the radiator = or filler point, starts to offload coolant as soon as the engine is = started. It is in hydraulic lock, and has a small volume. The actual = boiling point calculated for this coolant makes no difference at all. = The cap opens a bit when the trip pressure is attained, the pressure = drops to 22 PSI or whatever for your cap, and a bit more heating trips = the cap again. It is exactly the same as most cars. So, at first in each heat cycle, there may be no correlation between = coolant temperature, and the actual amount of coolant dumped by the cap. = This is only true closer to a constant operating temperature. And then = pressure may be alarmingly unstable with power changes. The accumulator = system makes pressure rock solid.=20 Make the pressure cap into a filler cap, sealing only the top lip of = the radiator or filling port. Connect only a bleed hose and run it to = the bottom of a recovery bottle, and put the pressure relief cap on that = bottle. Keep the bottle about 1/3 full. Note after several heat cycles, = the amount of water you need to add to keep that bottle 1/3 full is = reduced each time. Once all of the air is out of the cooling system, no = more coolant need be added to the bottle.=20 Heating and cooling of the system, makes sweeping changes in coolant = volume. The air cushion in the bottle acts as an accumulator (used in = thousands of aircraft) to maintain a constant pressure and coolant = supply. Race cars use a Rolairtrol or spin bottle in the hose from the top = of the engine to the radiator. Water enters the bottle at about half = height on a tangent and adds a spinning motion. Water leaves through a = center hole at the bottom.=20 Trapped air pops to the top of the bottle and that is plumbed to the = bottom of the accumulator as above.=20 You used to get the plans for this thing when you buy a Cosworth = race engine. Does Cosworth know something you don't?=20 Anyway, after about three heat cycles (operating temperature and = back to room temperature) the coolant system will be solid coolant with = all of the air removed. It will not be hydraulically locked against the = cap. It will have the relief cap pressure, and will hold that for as long = as the engine is hot.=20 I have a Shrader valve installed in my accumulator tank, and before = I start the engine I charge that bottle with compressed air until the = cap relieves at 22 PSI. Now I know it has pressure, and I know it has 22 = PSI. This was the stock system on all Mazda cars in the 70s. I didn't = invent it.=20 It is unlikely that you have leaking compression seals, unless there = is coolant blowing out of your makeup tank, or coolant is running out of = your exhaust system after shutdown.=20 My recovery bottle is mounted where the passenger foot well would = have been. Even with the bottom of the engine. So long as the hose ID is = less than 1/4" and the hose enters the bottle on the bottom of the = coolant supply, it matters not at all where that bottle is located. = There is a money back guarantee with this system.=20 Lynn E. Hanover=20 -------------------------------------------------------------------------= --- See what's new at AOL.com and Make AOL Your Homepage. -------------------------------------------------------------------------= --- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html -Al Wick Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam = timing.=20 Artificial intelligence in cockpit, N9032U 240+ hours from Portland, = Oregon Glass panel design, Subaru install, Prop construct, Risk assessment = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ------=_NextPart_000_0012_01C80CF3.643BB540 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Al,
 
Racing Beat's Rotary Tech catalog specifies that = for 1974=20 and later pumps using stock main and water pulley, that =  engine rpm=20 above 6300 rpm would cause the stock water pump to cavitate.  = .  This=20 is of course with OEM size hoses.  That cavitation beings gradually = and=20 becomes worst as rpm and temperature increases and if full throttle = operation is=20 maintained under those conditions "...the engine will not last=20 long."
 
Now that information is somewhat dated (my=20 catalog is dated 1992).  I strongly suspect  that, the = Renesis=20 for example would be able to handle a higher sustained rpm.  And = perhaps=20 the later 13B's as well, I just have not seen any information more = recent on the=20 topic. 
 
I fly with a main pulley sized for 20% less = water pump rpm=20 and my alternator has a 20% reduction as well. So my top engine=20 rpm (sustained) around 6500 rpm hopefully keeps me out of the = bubble=20 zone.
 
Ed 
 
 
 
----- Original Message -----
From:=20 Al Wick =
Sent: Friday, October 12, 2007 = 4:29=20 PM
Subject: [FlyRotary] Re: FW: = [FlyRotary]=20 Re: Coolant Water Pressure

Where does the fear of pump = cavitation come from?=20 Is that speculative or have some guys inadvertently choked off the = pump inlet=20 with small diam hose instead of OEM size?
 
 
 
-al wick
----- Original Message -----
From:=20 Al = Gietzen=20
To: Rotary motors in = aircraft=20
Sent: Friday, October 12, = 2007 11:31=20 AM
Subject: [FlyRotary] FW: = [FlyRotary]=20 Re: Coolant Water Pressure

This was rejected = because of=20 the photo files being too large, so I=92ll send one of the pics=20 separately.

Al

Subject: RE:=20 [FlyRotary] Re: Coolant Water Pressure

 

Bill;

 

Here is = the setup=20 I use. On the first photo, the filler neck is on the left, and = connects to=20 the line going to the inlet side of the pump.  The two small = lines=20 (3/16=94) coming into the side are air bleed lines going from the = high points=20 of my two radiators (note that the pressure at the filler neck will = be near=20 the lowest in the system.)  The =91overflow=92 from the filler = cap goes to=20 the bottom of the accumulator bottle on the right (made from a = discarded=20 fire extinguisher).

 

The = accumulator=20 bottle overflow goes over board, but coolant only goes out here once = on=20 first heatup.  When cold, there is only about 3 =96 4=94 = coolant in the=20 bottom of that bottle, so there is air in there that compresses as = things=20 heat up.  Coolant forced out of the filler neck on heat up is = draw back=20 in on cooldown.

 

The = idea is that=20 whenever the engine is running, there is positive pressure on the = system =96=20 at the pump inlet; reducing the chance of pump cavitation at high = RPM.=20  And positive pressure is maintained at altitude even when = throttling=20 back and the coolant temp is decreasing.

 

Originally I had=20 a 23# cap on the filler neck, and 15# on the accumulator = bottle.  I=20 later reversed the two to lower system pressure on initial heatup = (as soon=20 as the engine heats up at all the pressure goes to filler cap = pressure), but=20 it still gives me the sum of the two caps under any extreme = condition to=20 protect against boiling.  Keep in mind that the caps are = =91differential=20 pressure=92 so at altitude the max absolute pressure in the = accumulator bottle=20 is reduced by the reduction in the ambient.

 

Al

 

-----Original=20 Message-----
From: Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bill = Bradburry
Sent: Thursday, October=20 11, 2007 8:49=20 AM
To: Rotary motors in=20 aircraft
Subject: = [FlyRotary] Re: Coolant Water Pressure

 

Lynn, I = don=92t know what=20 we would do without you.

I have=20 several questions. 

Where=20 can I get a good accumulator tank? 

I was=20 thinking of making one out of a used fire extinguisher  and was = also=20 looking at one from Moroso that looks like a flat canteen.  The = one=20 from Moroso has an inlet on the bottom and one on the top side as = well as=20 one for the pop off of the radiator cap.  Due to space = constraints, I=20 will probably try and make one. I need something about 3=94 diameter = and maybe=20 12=94 or so long.   Will I need the inlet on the top = side?  If=20 so, where does it plumb to?

I=20 suppose I will still need an overflow tank from the pop off of the = radiator=20 cap?

After=20 talking  with Tracy = yesterday, I tried=20 to see if the engine would stabilize temp somewhere below 230* at = 2600=20 rpm.  No joy!  I suspect that I will need to increase air = flow to=20 get this to happen.  I will try an leaf blower on the cowl=20 today.

My=20 pressure stabilized at 22 lbs (cap in constant blow off relief) but = the temp=20 would not hold.  If I had this same condition with the system = you=20 described, what would prevent the air from blowing off and then = water from=20 the accumulator?

It=20 seems to me that no matter what system you have, the pressure has to = stabilize below the pressure rating of the radiator cap, else you = will be=20 losing first air, then water????

 

Bill=20 B

 

From:=20 Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of=20 Lehanover@aol.com
Sent: Wednesday, October=20 03, 2007 10:28=20 AM
To: Rotary motors in=20 aircraft
Subject: = [FlyRotary] Re: Coolant Water Pressure

 

In a=20 message dated 10/3/2007=20 9:08:53=20 A.M. Eastern = Daylight=20 Time, bbradburry@bellsouth.net writes:

I=20 think that I would see air under the radiator cap if I had a = compression=20 gas leak?  I never see any air.

To=20 check a piston engine for head gasket leaks, you would put the = cylinder at=20 TDC and pressurize the cylinder to about 150 lbs with compressed = air and=20 check the radiator for air bubbles=85How do you check a=20 rotary?

I=20 will check the pressure sender against a mechanical gage. =20

There = is=20 obviously a heating problem, but I think the pressure is higher = than it=20 should be until just ready to boil.  I shut the engine off at = 210*,=20 and at 22+ lbs, the boiling point should be well above=20 250*??

 

Thanks = for the=20 suggestions of where to look, guys=85

 

Bill=20 B

It is=20 extremely difficult to remove all of the air from a rotary engines = cooling=20 system. It is also extremely important. If air is under the pressure = cap in=20 a static situation, it will remix with other coolant when the engine = is at=20 speed. The coolant moves very quickly through the system. The = coolant volume=20 appears to increase slightly because much of the air is reintroduced = into=20 the water. This coolant then becomes a poor conductor of heat. You = need the=20 anti foaming agent in Antifreeze. Just a bit, perhaps 10%. The = system with=20 the relief cap right on the radiator or filler point, starts to = offload=20 coolant as soon as the engine is started. It is in hydraulic lock, = and has a=20 small volume. The actual boiling point calculated for this coolant = makes no=20 difference at all. The cap opens a bit when the trip pressure is = attained,=20 the pressure drops to 22 PSI or whatever for your cap, and a bit = more=20 heating trips the cap again. It is exactly the same as most=20 cars.

So,=20 at first in each heat cycle, there may be no correlation between = coolant=20 temperature, and the actual amount of coolant dumped by the cap. = This is=20 only true closer to a constant operating temperature. And then = pressure may=20 be alarmingly unstable with power changes. The accumulator system = makes=20 pressure rock solid. 

 

 

Make=20 the pressure cap into a filler cap, sealing only the top lip of the = radiator=20 or filling port. Connect only a  bleed hose and run it to = the=20 bottom of a recovery bottle, and put the pressure relief cap on that = bottle.=20 Keep the bottle about 1/3 full. Note after several heat cycles, the = amount=20 of water you need to add to keep that bottle 1/3 full is reduced = each time.=20 Once all of the air is out of the cooling system, no more coolant = need be=20 added to the bottle.

 

Heating = and=20 cooling of the system, makes sweeping changes in coolant volume. The = air=20 cushion in the bottle acts as an accumulator (used in thousands of = aircraft)=20 to maintain a constant pressure and coolant = supply.

 

Race=20 cars use a Rolairtrol or spin bottle in the hose from the top of the = engine=20 to the radiator. Water enters the bottle at about half height on a = tangent=20 and adds a spinning motion. Water leaves through a center hole at = the=20 bottom.

Trapped = air pops=20 to the top of the bottle and that is plumbed to the bottom of the=20 accumulator as above.

You=20 used to get the plans for this thing when you buy a Cosworth race = engine.=20 Does Cosworth know something you = don't? 

 

Anyway, = after=20 about three heat cycles (operating temperature and back to room = temperature)=20 the coolant system will be solid coolant with all of the air = removed. It=20 will not be hydraulically locked against the = cap.

It=20 will have the relief cap pressure, and will hold that for as long as = the=20 engine is hot.

 

I=20 have a Shrader valve installed in my accumulator tank, and before I = start=20 the engine I charge that bottle with compressed air until the cap = relieves=20 at 22 PSI. Now I know it has pressure, and I know it has 22=20 PSI.

 

This=20 was the stock system on all Mazda cars in the 70s. I didn't invent = it.=20

 

It is=20 unlikely that you have leaking compression seals, unless there is = coolant=20 blowing out of your makeup tank, or coolant is running out of your = exhaust=20 system after shutdown.

 

My=20 recovery bottle is mounted where the passenger foot well would have = been.=20 Even with the bottom of the engine. So long as the hose ID is less = than 1/4"=20 and the hose enters the bottle on the bottom of the coolant supply, = it=20 matters not at all where that bottle is located. There is a money = back=20 guarantee with this system. 

 

Lynn=20 E. Hanover 

 

See=20 what's new at AOL.com and Make AOL Your = Homepage.

--
Homepage:  http://www.flyrotary.com/
Archive = and=20 UnSub:  =20 = http://mail.lancaironline.net:81/lists/flyrotary/List.html
-Al Wick
Cozy IV powered by Turbo Subaru 3.0R with variable = valve lift=20 and cam timing.
Artificial intelligence in cockpit, N9032U 240+ = hours from=20 Portland, Oregon
Glass panel design, Subaru install, Prop = construct, Risk=20 assessment info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html
------=_NextPart_000_0012_01C80CF3.643BB540--