X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cartier.micfo.com ([67.15.58.72] verified) by logan.com (CommuniGate Pro SMTP 5.0c5) with ESMTPS id 776320 for flyrotary@lancaironline.net; Fri, 21 Oct 2005 21:26:28 -0400 Received-SPF: none receiver=logan.com; client-ip=67.15.58.72; envelope-from=bob@bob-white.com Received: from bgp01386375bgs.brodwy01.nm.comcast.net ([68.35.160.229]:33796 helo=quail) by cartier.micfo.com with smtp (Exim 4.52) id 1ET88c-0005Xk-1d for flyrotary@lancaironline.net; Fri, 21 Oct 2005 20:25:34 -0500 Date: Fri, 21 Oct 2005 19:25:36 -0600 From: Bob White To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: specific heat of air Message-Id: <20051021192536.031f3e27.bob@bob-white.com> In-Reply-To: References: X-Mailer: Sylpheed version 2.1.4 (GTK+ 2.4.9; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-PopBeforeSMTPSenders: bobw2,nmrv,rlwhite,sales@roblinphoto.com,webmaster@bearnutupholstery.com X-Antivirus-Scanner: Clean mail though you should still use an Antivirus X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - cartier.micfo.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - bob-white.com X-Source: X-Source-Args: X-Source-Dir: Hi Ed, Al's number was .02 BTU/cu-ft. - F and your number is 0.241 BTU/lb - F. Per the web site you mentioned, density is given as 0.08018 lb/cu-ft. So if I'm doing the conversion in the right direction: 0.241 X 0.08= 0.019 which is about 0.02. Are both numbers correct? Bob W. On Fri, 21 Oct 2005 20:46:02 -0400 "Ed Anderson" wrote: > Al, I went back to some of my spreadsheets and I have for constant pressure (Cp) as > > 0.25 BTU/Lbm/F > > Here is web site which gives it as 0.241 BTU/LBM/F at 32F Sea Level > > http://www.uigi.com/physical_prop_e.html > > So looks like you have the decimal off a bit. > > Sorry, it took me so long, been out at the aircraft all day putting on the new right gear leg, and brakes, etc. > > Ed A > > > > > ----- Original Message ----- > From: Al Gietzen > To: Rotary motors in aircraft > Sent: Friday, October 21, 2005 2:59 PM > Subject: [FlyRotary] specific heat of air > > > Ed, or Bill, or somebody; help me out here. I was reviewing my calcs for air flow requirements, and find I used 0.02 Btu/cu. ft -F for the specific heat of air. I don't know where that came from, and can only find it in joules/Kg - K. By the time I do all the conversions to British units and mass to volume I now get quite a different number. > > > > What is a good number for air at about 1 atmosphere and, say 90F; in Btu per cu ft per degree F? > > > > Thanks, > > > > Al > -- http://www.bob-white.com N93BD - Rotary Powered BD-4 (projected engine start in November) Custom Cables for your rotary installation - http://www.roblinphoto.com/shop/