X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-ma04.mx.aol.com ([64.12.206.42] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTP id 5067171 for flyrotary@lancaironline.net; Thu, 28 Jul 2011 23:06:55 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.206.42; envelope-from=Lehanover@aol.com Received: from mtaomg-da03.r1000.mx.aol.com (mtaomg-da03.r1000.mx.aol.com [172.29.51.139]) by imr-ma04.mx.aol.com (8.14.1/8.14.1) with ESMTP id p6T368sC023541 for ; Thu, 28 Jul 2011 23:06:08 -0400 Received: from core-moe001c.r1000.mail.aol.com (core-moe001.r1000.mail.aol.com [172.29.188.65]) by mtaomg-da03.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id D635BE00008D for ; Thu, 28 Jul 2011 23:06:07 -0400 (EDT) From: Lehanover@aol.com Message-ID: <294ca.3a3ff54c.3b637d9f@aol.com> Date: Thu, 28 Jul 2011 23:06:07 -0400 (EDT) Subject: Re: [FlyRotary] Re: Coolant Restrictor Plate To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_294ca.3a3ff54c.3b637d9f_boundary" X-Mailer: AOL 9.6 sub 5004 X-AOL-IP: 173.88.24.45 X-Originating-IP: [173.88.24.45] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:400454176:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d338b4e32239f0482 --part1_294ca.3a3ff54c.3b637d9f_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en There is a wide gulf between the calculated heat rejection of any =20 particular system and the actual performance of that system in real life. Just ask Mistral. Or anyone else who tried to cool a rotary. As in any car,= =20 the water pump is sufficient to cool the car in Death Valley on the=20 hottest day of the year, at idle. So, when we spin up the engine to 5,500 = RPM and=20 the pump is spinning 7,000 RPM we can pump a good sized stream of water=20 over a two story building. Good to know, but how about a radiator. Not qui= te=20 as good an outcome. The radiator sharp edged tubes stick up into the=20 manifold and defy fluid flow through them. Some racing radiators are fille= d with=20 epoxy right to the tips of the tubes to provide a very smooth transition= =20 into the tubes and flow is profoundly improved.=20 =20 So the formula says in part that more flow means more (Better) cooling,= =20 and this is accurate. But when you see that the radiator is the biggest =20 restriction in the coolant loop you might guess that a low pressure area co= uld =20 develop between the inside of the radiator and the water pump. And in every= =20 case it dose. So now you notice that all lower (suction side) radiator=20 hoses have a big spring inside to prevent the hose from collapsing. So, th= e=20 suction side of the pump can pull quite a low pressure on that hose, corre= ct?=20 Even with a 22 pound pressure cap and a really big free flowing radiator.= =20 There is never more than 14.7 pounds available to crush that hose, so the= =20 pressure inside the hose must be lower than that by a good margin. And if = the=20 pressure inside the hose is that low, what is the pressure inside the cool= =20 side radiator manifold? Notice in the olden days that the radiator died=20 from the bottom tube ends (up and down radiators) seem to rot away and lea= ks=20 at the bottom killed the radiator.=20 =20 No, it was cavitation.=20 =20 Also cavitation can kill a pump quickly. It eats away the pump vanes like = =20 acid. Notice that the top hoses are smaller than the bottom hoses? =20 Could drag increasing at the square of velocity be performing the function = =20 of a..........dare I say restrictor? If the top hose is long enough it has= =20 that effect. Now in the lab and in the drawings all of that fluid is =20 incompressible. And the surface of the tubes is uniformly exposed to the fl= uid, =20 so we predict that at thus and so, a flow rate we expect rejection value X.= =20 But we seem to not achieve value X in actual practice. Because, while the= =20 fluid is very nearly incompressible the air bubbles in the fluid are easil= y=20 compressed, and thus allow for volume changes, and then for both high and= =20 low pressure to exist in the same closed system. =20 Removing the radiator as the biggest restriction in the circuit just about = =20 eliminates suction side cavitation. So I installed a restrictor in the=20 water outlet of 5/8" diameter. It is welded in place. It never changes. Be= en=20 doing it since 1980. Have yet to overheat a rotary. Have never lost a wate= r=20 pump or radiator.=20 =20 I would not use that small a restrictor for 5,500 RPM. Probably way too =20 small. My engines were used between 7,500 and 9,600 RPM. This with the smal= l =20 crank drive pulley and the stock water pump pulley.=20 =20 What I have deduced from this may be completely wrong. But, it does work = =20 for me. Or, perhaps my system is so overly large it is just tolerating my = =20 folly.=20 =20 Lynn E. Hanover =20 =20 =20 =20 In a message dated 7/28/2011 10:51:23 A.M. Paraguay Standard Time, =20 eanderson@carolina.rr.com writes: I saw Lynn=E2=80=99s coolant diagram with a restrictor plate in it =E2=80= =A6 you guys=20 with evaporator cores and 1=E2=80=9D coolant hoses have a 1=E2=80=9D restr= iction, this=20 based on Mazda=E2=80=99s design of 1.5=E2=80=9D inlet/outlet on the stock = water pump and the=20 stock design includes a thermostat. With all of that as a background (nev= er=20 had a thermostat), I decided to try a restrictor plate in my coolant=20 system, using a 0.75=E2=80=9D hole in a plate at the water pump outlet int= o my 1.5=E2=80=9D=20 radiator hoses. I can say that it doesn't do any harm and may have actual= ly=20 provided about 5% improvement =E2=80=A6 more testing to follow. --part1_294ca.3a3ff54c.3b637d9f_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
There is a wide gulf between the calculated heat rejection of any=20 particular system and the actual performance of that system in real life.
Just ask Mistral. Or anyone else who tried to cool a rotary. As in any= car,=20 the water pump is sufficient to cool the car in Death Valley on the hottest= day=20 of the year, at idle. So, when we spin up the engine to 5,500 RPM and the p= ump=20 is spinning 7,000 RPM we can pump a good sized stream of water over a two s= tory=20 building. Good to know, but how about a radiator. Not quite as good an outc= ome.=20 The radiator sharp edged tubes stick up into the manifold and defy fluid fl= ow=20 through them. Some racing radiators are filled with epoxy right to the tips= of=20 the tubes to provide a very smooth transition into the tubes and flow is=20 profoundly improved.
 
So the formula says in part that more flow means more (Better) = =20 cooling, and this is accurate. But when you see that the radiator is the bi= ggest=20 restriction in the coolant loop you might guess that a low pressure area co= uld=20 develop between the inside of the radiator and the water pump. And in every= case=20 it dose. So now you notice that all lower (suction side) radiator hoses hav= e a=20 big spring inside to prevent the hose from collapsing. So, the suction side= of=20 the pump can pull quite a low pressure on that hose, correct? Even with a 2= 2=20 pound pressure cap and a really big free flowing radiator. There is never m= ore=20 than 14.7 pounds available to crush that hose, so the pressure inside the h= ose=20 must be lower than that by a good margin. And if the pressure inside the ho= se is=20 that low, what is the pressure inside the cool side radiator manifold? Noti= ce in=20 the olden days that the radiator died from the bottom tube ends (up and dow= n=20 radiators) seem to rot away and leaks at the bottom killed the radiator.
 
No, it was cavitation.
 
Also cavitation can kill a pump quickly. It eats away the pump vanes l= ike=20 acid. Notice that the top hoses are smaller than the bottom hoses?
 
Could drag increasing at the square of velocity be performing the func= tion=20 of a..........dare I say restrictor?  If the top hose is long enough i= t has=20 that effect. Now in the lab and in the drawings all of that fluid is=20 incompressible. And the surface of the tubes is uniformly exposed to the fl= uid,=20 so we predict that at thus and so, a flow rate we expect rejection value X.= But=20 we seem to not achieve value X in actual practice. Because, while the = fluid=20 is very nearly incompressible the air bubbles in the fluid are easily=20 compressed, and thus allow for volume changes, and then for both high and l= ow=20 pressure to exist in the same closed system.
 
Removing the radiator as the biggest restriction in the circuit just a= bout=20 eliminates suction side cavitation. So I installed a restrictor in the wate= r=20 outlet of 5/8" diameter. It is welded in place. It never changes. Been doin= g it=20 since 1980. Have yet to overheat a rotary. Have never lost a water pump or= =20 radiator.
 
I would not use that small a restrictor for 5,500 RPM. Probably way to= o=20 small. My engines were used between 7,500 and 9,600 RPM. This with the smal= l=20 crank drive pulley and the stock water pump pulley.
 
What I have deduced from this may be completely wrong. But, it does wo= rk=20 for me. Or, perhaps my system is so overly large it is just tolerating my= =20 folly. 
 
Lynn E. Hanover
 
 
 
In a message dated 7/28/2011 10:51:23 A.M. Paraguay Standard Time,=20 eanderson@carolina.rr.com writes:
=

I saw Lynn=E2=80=99s coolant diagram with a restrict= or plate in=20 it  =E2=80=A6  you guys with evaporator cores and 1=E2=80=9D co= olant hoses have a 1=E2=80=9D=20 restriction, this based on Mazda=E2=80=99s design of 1.5=E2=80=9D inlet/o= utlet on the stock=20 water pump and the stock design includes a thermostat.  With all of = that=20 as a background (never had a thermostat), I decided to try a restrictor p= late=20  in my coolant system, using a 0.75=E2=80=9D hole in a plate at the = water pump=20 outlet into my 1.5=E2=80=9D radiator hoses.  I can say that it doesn= 't do any=20 harm and may have actually provided about 5% improvement =E2=80=A6 more t= esting to=20 follow.

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