Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2800934 for flyrotary@lancaironline.net; Sat, 06 Dec 2003 09:56:36 -0500 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id hB6EuVxt011370 for ; Sat, 6 Dec 2003 09:56:33 -0500 (EST) Message-ID: <002201c3bc08$a5448fc0$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Expansion Chambers Date: Sat, 6 Dec 2003 09:53:01 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001F_01C3BBDE.BC330560" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_001F_01C3BBDE.BC330560 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: David Leonard=20 To: Rotary motors in aircraft=20 Sent: Saturday, December 06, 2003 4:31 AM Subject: [FlyRotary] Re: Expansion Chambers Ed, very interesting phenomenon. I would suppose a different = explanation for your findings. =20 When the system is cold an there is no air. With no air in the = system, as soon as you add ANY heat there is expansion. ANY expansion = must flow against the radiator cap and will need to be under its rated = pressure in order to get passed. As the system continues to heat up, = this expansion and pressure will continue. Once the system more or less = reaches a steady state temp, there is no more expansion and the pressure = decreases. That last 2-4 psi is accounted for by small amounts of = remaining air, and the expansion of rubber hoses. David Leonard The Rotary Roster: =20 Hi David, I like your explanation better, its simpler and that generally = means more likely. Although, the speed with which it goes to 18-20 psi = is quick, it is not as immediate as I first implied. Probably 5-10 = seconds total. So that is probably sufficient for some heat to migrate = from the combustion chamber metal to the coolant. And with little or no = air, the expansion of the coolant due to the heat would probably show up = immediately on the pressure sensor. It was however, disconcerning when it first occured as I was certain I = had a bad coolant "O" ring. Even though I never lost any coolant, it = bothered me until Tracy told me he observed the same thing. So thought = I would mention it in case someone else ran into it. Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ------=_NextPart_000_001F_01C3BBDE.BC330560 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
----- Original Message -----
From:=20 David=20 Leonard
Sent: Saturday, December 06, = 2003 4:31=20 AM
Subject: [FlyRotary] Re: = Expansion=20 Chambers

Ed, very = interesting=20 phenomenon.  I would suppose a different explanation for your=20 findings. 

 

When the = system is=20 cold an there is no air.  With no air in the system, as soon as = you add=20 ANY heat there is expansion.  ANY expansion must flow against the = radiator cap and will need to be under its rated pressure in order to = get=20 passed.  As the system continues to heat up, this expansion and = pressure=20 will continue.  Once the system more or less reaches a steady = state temp,=20 there is no more expansion and the pressure decreases.  That last = 2-4 psi=20 is accounted for by small amounts of remaining air, and the expansion = of=20 rubber hoses.

 

David=20 Leonard

The Rotary=20 Roster:

 <= /SPAN>

 

Hi David,
 
    I like your = explanation=20 better, its simpler and that generally means more likely.  = Although, the=20 speed with which it goes to 18-20 psi is quick, it is not as immediate = as I=20 first implied.  Probably 5-10 seconds total.  So that is = probably=20 sufficient for some heat to migrate from the combustion chamber metal = to the=20 coolant. And with little or no air, the expansion of the coolant due = to the=20 heat would probably show up immediately on the pressure = sensor.
 
It was however, disconcerning when it = first=20 occured as I was certain I had a bad coolant "O" ring.  Even = though I=20 never lost any coolant, it bothered me until Tracy told me he observed = the=20 same thing.  So thought I would mention it in case someone else = ran into=20 it.
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
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