X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from zproxy.gmail.com ([64.233.162.196] verified) by logan.com (CommuniGate Pro SMTP 4.3.5) with ESMTP id 1022186 for flyrotary@lancaironline.net; Sun, 26 Jun 2005 14:40:20 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.233.162.196; envelope-from=wdleonard@gmail.com Received: by zproxy.gmail.com with SMTP id x7so121030nzc for ; Sun, 26 Jun 2005 11:39:36 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:in-reply-to:mime-version:content-type:references; b=gP17RY4aPed3d+k89U4j01kGdO0EYBNgnq4NKweHKUa7iSewULuPNdwy/hBsBiOthPVpYcI+TLPbuiHmMgLO38pYbuYYHIu1EJTvVwjBmUVsbn5aRc0JPyHOZej6rsg+agZdXErqdf+e9c1o9jv1/SpTjot8TyXfZiMSXLiqwyg= Received: by 10.36.222.40 with SMTP id u40mr3907578nzg; Sun, 26 Jun 2005 11:39:36 -0700 (PDT) Received: by 10.36.9.4 with HTTP; Sun, 26 Jun 2005 11:39:36 -0700 (PDT) Message-ID: <1c23473f0506261139534b677d@mail.gmail.com> Date: Sun, 26 Jun 2005 11:39:36 -0700 From: David Leonard Reply-To: David Leonard To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Coolant Leak In-Reply-To: Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_867_6891204.1119811176793" References: ------=_Part_867_6891204.1119811176793 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On 6/26/05, Al Gietzen wrote:=20 >=20 > Al, all I can tell you is that the pressure would go immediately (withi= n=20 > 2 seconds) to 21-24 psi. Then as the engine warmed up the pressure would= =20 > drop to a nominal 8 psi or so > =20 > It makes sense to me Ed. Heat the coolant just a little, and it needs to= =20 > expand just a little. In order for any of the coolant to flow out past th= e=20 > cap (even just a little coolant), it must reach the pressure rating of th= e=20 > cap.=20 > =20 > How much can the coolant heat up in 2 seconds after start? Just about=20 > zero. The only thing that is heated a little in that time is the rotor=20 > housing walls. Maybe that reduces coolant volume. In any case, if you hav= e=20 > any radiator hose in the system, it will expand enough to keep the pressu= re=20 > from increasing that much. There is some weird science in here somewhere. >=20 > Al >=20 Do you mean "just about zero", or absolutely zero? Just about zero would imply something slightly larger than zero. Which=20 means that the coolant expands something just a little more than zero. If= =20 you truly have no air in the system, an expansion of just about zero still= =20 has to open the pressure cap, which requires opening pressure. If you seale= d=20 water in a steel box with no air, heating the water a fraction of a degree= =20 would raise the pressure hundreds of psi. Just a few degrees will deform th= e=20 steel box. Its not weird science, its just weird freaks of nature. If you mean absolutely zero heating of the coolant a few seconds after=20 starting I will take exception. That flame is well over 2000 deg F and the= =20 rotor housing water jacket is not very thick. Some (although small) heating= =20 of the coolant easily occurs within one second after starting the engine. Someone mentioned radiator hose expansion. I don't know about your system,= =20 but my steel braided hose is going to take a lot more than 25 psi before it= =20 allows any expansion. 25 PSI is nothing. Not going to harm any part of=20 anyone's cooling system except maybe with multiple cycles. That said, I als= o=20 believe in having an air spring/absorber. The main part of my cooling syste= m=20 I keep full, but have a 1 qt pressurized overflow can that is empty at=20 engine start. --=20 Dave Leonard Turbo Rotary RV-6 N4VY http://members.aol.com/_ht_a/rotaryroster/index.html http://members.aol.com/vp4skydoc/index.html ------=_Part_867_6891204.1119811176793 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline

On 6/26/05, = Al Gietzen <ALVentures@cox.net= > wrote:

 Al, all I can tell you is th= at the pressure would go immediately (within   2 seconds) to 21-2= 4 psi.  Then as the engine warmed up the pressure would drop to a nomi= nal 8 psi or so

<= span style=3D"FONT-SIZE: 12pt"> 

<= span style=3D"FONT-SIZE: 12pt">It makes sense to me Ed.  Heat the cool= ant just a little, and it needs to expand just a little.  In order for= any of the coolant to flow out past the cap (even just a little coolant), = it must reach the pressure rating of the cap.=20

<= span style=3D"FONT-SIZE: 12pt"> 

How much can the coolant heat u= p in 2 seconds after start?  Just about zero.  The only thing tha= t is heated a little in that time is the rotor housing walls. Maybe that re= duces coolant volume.  In any case, if you have any radiator hose in t= he system, it will expand enough to keep the pressure from increasing that = much.  There is some weird science in here somewhere.

 

Al

Do you mean "just about zero", or absolutely zero?
 
Just about zero would imply something slightly larger than zero.&= nbsp; Which means that the coolant expands something just a little more&nbs= p;than zero.  If you truly have no air in the system, an expansio= n of just about zero still has to open the pressure cap, which require= s opening pressure.  If you sealed water in a steel box with no air, h= eating the water a fraction of a degree would raise the pressure hundreds o= f psi.  Just a few degrees will deform the steel box.  Its not we= ird science, its just weird freaks of nature.
 
If you mean absolutely zero heating of the coolant a few seconds after= starting I will take exception.  That flame is well over 2000 deg F a= nd the rotor housing water jacket is not very thick.  Some (although s= mall) heating of the coolant easily occurs within one second after starting= the engine.
 
Someone mentioned radiator hose expansion.  I don't know about yo= ur system, but my steel braided hose is going to take a lot more than 25 ps= i before it allows any expansion.  25 PSI is nothing.  Not going = to harm any part of anyone's cooling system except maybe with multiple= cycles.  That said, I also believe in having an air spring/absorber.&= nbsp; The main part of my cooling system I keep full, but have a 1 qt press= urized overflow can that is empty at engine start.
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