Return-Path: Received: from tomcat.al.noaa.gov ([140.172.240.2] verified) by logan.com (CommuniGate Pro SMTP 4.2b2) with ESMTP id 3179370 for flyrotary@lancaironline.net; Mon, 19 Apr 2004 16:39:51 -0400 Received: from PILEUS.al.noaa.gov (pileus.al.noaa.gov [140.172.241.195]) by tomcat.al.noaa.gov (8.12.0/8.12.0) with ESMTP id i3JKdJKa001258 for ; Mon, 19 Apr 2004 14:39:19 -0600 (MDT) Message-Id: <5.2.1.1.0.20040419143002.043a0470@mailsrvr.al.noaa.gov> X-Sender: bdube@mailsrvr.al.noaa.gov X-Mailer: QUALCOMM Windows Eudora Version 5.2.1 Date: Mon, 19 Apr 2004 14:38:18 -0600 To: "Rotary motors in aircraft" From: Bill Dube Subject: Re: [FlyRotary] Re: water coolant percentages In-Reply-To: Mime-Version: 1.0 Content-Type: text/html; charset="us-ascii"

If you dont need the high freeze protection, Id opt for corrosion inhibitors in a solution of maybe 25-30% e-g in water (for some increase in boiling point), and a pressure cap of 22-25 psig.

As noted earlier, all airplanes need freeze protection. I was flying recently in Tampa at night and the temperature at 15,000 ft was something like -10 Celsius.

Water will often freeze in the radiator if you do not have anti-freeze, even if the engine is warm. The freeze will start in a low flow (water) region and will then spread as the flow is further blocked, perhaps bursting radiator tubes as it progresses.