X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ms-smtp-03.southeast.rr.com ([24.25.9.102] verified) by logan.com (CommuniGate Pro SMTP 5.1.1) with ESMTP id 1514404 for flyrotary@lancaironline.net; Mon, 30 Oct 2006 10:34:24 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.102; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-096-206.carolina.res.rr.com [24.74.96.206]) by ms-smtp-03.southeast.rr.com (8.13.6/8.13.6) with SMTP id k9UFXqEQ006965 for ; Mon, 30 Oct 2006 10:33:54 -0500 (EST) Message-ID: <000b01c6fc38$d40c45a0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Coolant Pressure was Thermostat (was: Rotary Round up 2006) Date: Mon, 30 Oct 2006 10:34:02 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0008_01C6FC0E.EAD224A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0008_01C6FC0E.EAD224A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Lynn,=20 Let me ask you a question that has puzzled me - perhaps you have = observed the same if you monitor your coolant pressure in racing (which = you may not). I (and Tracy) noticed a couple of years ago that = immediately upon start up the coolant pressure would go to 20-25 psi. = Immediate fear is of course a combustion chamber/coolant galley leak = past the coolant "O" rings. However, that turned out not to be the = case. The pressure would return to normal (5-7 psi) once the engine = warmed up. This did not occur right after changing the coolant but only = after the engine had been run several times. It would start showing up = in my engine after about the 3rd flight. The best theory we could come up with is that all the air had been = removed from the coolant system and with an incompressible liquid = filling it completely - that the initial heat of combustion was = immediately causing the coolant to pressurize as even a smidgen of = expansion would be reflected in pressure (as there was no air to = compress). Once the engine heats up the metal expands and the volume of = the coolant galleys increase infinitesimally - but enough to lower the = pressure. Once the engine heated up the pressure would react normally - = although at cruise the pressure would often read zero. In fact, Tracy has designed his new RV-8 3 rotor coolant system to = always maintain a small amount of air in the header tank so as to have a = more "normal" pressure gradient. Have you had any similar experience or theory about a possible cause??? Ed ----- Original Message -----=20 From: Lehanover@aol.com=20 To: Rotary motors in aircraft=20 Sent: Monday, October 30, 2006 9:25 AM Subject: [FlyRotary] Re: Copperstate Fly-in (was: Rotary Round up = 2006) In a message dated 10/30/2006 7:50:04 A.M. Eastern Standard Time, = eanderson@carolina.rr.com writes: This was all 4-5 years ago and could be I was just overlooking = something - but, couldn't figure out what it was, so pulled out the = thermostat. Ed Sorry, I forgot about your plugs up deal. Years ago there was a sender = of some kind in the top of the center iron. I placed my water temp = sender there. When filling with coolant I could loosen that sender and = almost all of the trapped air would escape. This why I have stayed with = the make up tank idea since 1980. Some of the air will just not move out = at less than full throttle. I like the air showing up in the tank, = rather than sitting beside a hot spot killing the engine. In three heat = cycles, there is no air left at all. I keep the tank 1/3 full for the = whole season. it never uses any additional coolant. I pressurize the = coolant until the cap releases after checking coolant levels. I forgot to say that I use 10% antifreeze in the coolant. Racing in = October can get rather cool. Lynn E. Hanover ------=_NextPart_000_0008_01C6FC0E.EAD224A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Lynn,
 
Let me ask you a question that has puzzled me - = perhaps you=20 have observed the same if you monitor your coolant pressure in racing = (which you=20 may not).  I (and Tracy) noticed a couple of years ago that = immediately=20 upon start up the coolant pressure would go to 20-25 psi.  = Immediate fear=20 is of course a combustion chamber/coolant galley leak past the coolant = "O"=20 rings.  However, that turned out not to be the case.   = The=20 pressure would return to normal (5-7 psi) once the engine warmed = up.  This=20 did not occur right after changing the coolant but only after the engine = had=20 been run several times.  It would start showing up in my engine = after about=20 the 3rd flight.
 
The best theory we could come up with is that all = the air had=20 been  removed from the coolant system and with an incompressible = liquid=20 filling it completely - that the initial heat of combustion was = immediately=20 causing the coolant to pressurize as even a smidgen of expansion would = be=20 reflected in pressure (as there was no air to compress).  Once = the=20 engine heats up the metal expands and the volume of the coolant galleys = increase=20 infinitesimally - but enough to lower the pressure.  Once the = engine heated=20 up the pressure would react normally - although at cruise the pressure = would=20 often read zero.
 
In fact, Tracy has designed his new RV-8 3 rotor = coolant=20 system to always maintain a small amount of air in the header tank so as = to have=20 a more "normal" pressure gradient.
 
Have you had any similar experience or theory about = a possible=20 cause???
 
 
Ed
 
 
----- Original Message -----
From:=20 Lehanover@aol.com
Sent: Monday, October 30, 2006 = 9:25=20 AM
Subject: [FlyRotary] Re: = Copperstate=20 Fly-in (was: Rotary Round up 2006)

In a message dated 10/30/2006 7:50:04 A.M. Eastern Standard Time, = eanderson@carolina.rr.com=20 writes:
This was all 4-5 years ago and  could = be I was=20 just overlooking something - but, couldn't figure out what it was, = so pulled=20 out the thermostat.
 
Ed
Sorry, I forgot about your plugs up deal. Years ago there was a = sender of=20 some kind in the top of the center iron. I placed my water temp sender = there.=20 When filling with coolant I could loosen that sender and almost all of = the=20 trapped air would escape. This why I have stayed with the make up tank = idea=20 since 1980. Some of the air will just not move out at less than full = throttle.=20 I like the air showing up in the tank, rather than sitting beside a = hot spot=20 killing the engine. In three heat cycles, there is no air left at all. = I keep=20 the tank 1/3 full for the whole season. it never uses any=20 additional coolant. I pressurize the coolant until the cap = releases after=20 checking coolant levels.
 
I forgot to say that I use 10% antifreeze in the coolant. Racing = in=20 October can get rather cool.
 
Lynn E. = Hanover   
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