X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 5.0c5) with ESMTP id 776260 for flyrotary@lancaironline.net; Fri, 21 Oct 2005 20:46:47 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-025-165.carolina.res.rr.com [24.74.25.165]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j9M0k01v015432 for ; Fri, 21 Oct 2005 20:46:01 -0400 (EDT) Message-ID: <005801c5d6a1$fa8ab440$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] specific heat of air Date: Fri, 21 Oct 2005 20:46:02 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0055_01C5D680.7333F4F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0055_01C5D680.7333F4F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al, I went back to some of my spreadsheets and I have for constant = pressure (Cp) as=20 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 -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 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 ------=_NextPart_000_0055_01C5D680.7333F4F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Al, I went back to some of my spreadsheets and I = have for=20 constant pressure (Cp) as
 
0.25 BTU/Lbm/F
 
Here is web site which gives it as 0.241 = BTU/LBM/F at 32F=20 Sea Level
 
http://www.uigi.com/phy= sical_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=20 day putting on the new right gear leg, and brakes, etc.
 
Ed A
 
 
 
 
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Friday, October 21, 2005 = 2:59=20 PM
Subject: [FlyRotary] specific = heat of=20 air

Ed, or Bill, or = somebody; help=20 me out here.  I was reviewing my calcs for air flow requirements, = and=20 find I used 0.02 Btu/cu. ft =96F for the specific heat of air.  I = don=92t=20 know where that came from, and can only find it in joules/Kg =96 = K.  By the=20 time I do all the conversions to British units and mass to volume I = now get=20 quite a different number.

 

What is a good number = for air at=20 about 1 atmosphere and, say 90F; in Btu per cu ft per degree=20 F?

 

Thanks,

 

Al

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