X-Virus-Scanned: clean according to Sophos on Logan.com
Return-Path: <marv@lancaironline.net>
Sender: <marv@lancaironline.net>
To: lml@lancaironline.net
Date: Sat, 18 Mar 2006 08:30:54 -0500
Message-ID: <redirect-1038166@logan.com>
X-Original-Return-Path: <wfhannahan@yahoo.com>
Received: from web36613.mail.mud.yahoo.com ([209.191.85.30] verified)
  by logan.com (CommuniGate Pro SMTP 5.0.8)
  with SMTP id 1037990 for lml@lancaironline.net; Fri, 17 Mar 2006 23:15:04 -0500
Received-SPF: none
 receiver=logan.com; client-ip=209.191.85.30; envelope-from=wfhannahan@yahoo.com
Received: (qmail 89072 invoked by uid 60001); 18 Mar 2006 04:14:18 -0000
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=s1024; d=yahoo.com;
  h=Message-ID:Received:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding;
  b=MYkVnZXa6zlBhvLyxa86cmjtxpHHuOjwed7vRIlRUJ1rjYOwawZQ+GqTOnHmG/gVyiGy6131mDu03FkjnfCO91yxlMIHmE6SIz3NvMYMv7QpAAYzB9YAXYzE+qxUx9ziOfr6RqdZnX9UoheWqkrHhaidd5Uv38iXCSO1hJSrRNs=  ;
X-Original-Message-ID: <20060318041418.89070.qmail@web36613.mail.mud.yahoo.com>
Received: from [71.208.8.133] by web36613.mail.mud.yahoo.com via HTTP; Fri, 17 Mar 2006 20:14:18 PST
X-Original-Date: Fri, 17 Mar 2006 20:14:18 -0800 (PST)
From: Bill Hannahan <wfhannahan@yahoo.com>
Subject: LNC2 cooling problem
X-Original-To: MAIL LANCAIR <lml@lancaironline.net>
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="0-2046224567-1142655258=:88478"
Content-Transfer-Encoding: 8bit

--0-2046224567-1142655258=:88478
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit

   
   
  Since pressure is proportional to velocity squared the pressure corresponding to 75% IAS is .75 x .75 = .562 of maximum dynamic (pitot) pressure.
   
  The lower cowl pressure corresponds to .122 of max pressure, a difference of .44 of max dynamic pressure.
   
  This assumes that the ASI static port was connected to a good static system. If it was open to cabin pressure, which is usually below static, that would make the upper pressure look better (higher) then it is, and the lower pressure worse, (higher) than it is.
   
  44% of dynamic pressure at 200 MPH is equal to 100% of dynamic pressure at 133MPH, and since airplanes cool successfully at slower speeds it should be enough, are you sure the temp probes are calibrated?
   
  To get more pressure there is more to be gained on top than bottom. Larger openings or diffusers aft of the openings would help, but I would start by eliminating leakage and making sure the baffles force all the air through the cooling fins, and that no gaps can open up under pressure, in flight.



BILL HANNAHAN 
WFHANNAHAN@YAHOO.COM

		
---------------------------------
Brings words and photos together (easily) with
 PhotoMail  - it's free and works with Yahoo! Mail.
--0-2046224567-1142655258=:88478
Content-Type: text/html; charset=iso-8859-1
Content-Transfer-Encoding: 8bit

<DIV id=RTEContent>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 8pt; COLOR: #333333; FONT-FAMILY: Verdana; mso-bidi-font-family: Arial"></SPAN>&nbsp;</div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p><FONT face="Times New Roman">&nbsp;</FONT></o:p></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman">Since pressure is proportional to velocity squared the pressure corresponding to 75% IAS is .75 x .75 = .562 of maximum dynamic (pitot) pressure.</FONT></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p><FONT face="Times New Roman">&nbsp;</FONT></o:p></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman">The lower cowl pressure corresponds to .122 of max pressure, a difference of .44 of max dynamic pressure.</FONT></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p><FONT face="Times New
 Roman">&nbsp;</FONT></o:p></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman">This assumes that the ASI static port was connected to a good static system. If it was open to cabin pressure, which is usually below static, that would make the upper pressure look better (higher) then it is, and the lower pressure worse, (higher) than it is.</FONT></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p><FONT face="Times New Roman">&nbsp;</FONT></o:p></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman">44% of dynamic pressure at 200 MPH is equal to 100% of dynamic pressure at 133MPH, and since airplanes cool successfully at slower speeds it should be enough, are you sure the temp probes are calibrated?</FONT></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p><FONT face="Times New Roman">&nbsp;</FONT></o:p></div>  <div class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman">To get more
 pressure there is more to be gained on top than bottom. Larger openings or diffusers aft of the openings would help, but I would start by eliminating leakage and making sure the baffles force all the air through the cooling fins, and that no gaps can open up under pressure, in flight.</FONT></div></DIV><BR><BR><DIV id=RTEContent>BILL HANNAHAN <BR>WFHANNAHAN@YAHOO.COM</DIV><p>
		<hr size=1>Brings words and photos together (easily) with<br> 
<a href="http://us.rd.yahoo.com/mail_us/taglines/PMall/*http://photomail.mail.yahoo.com">PhotoMail </a> - it's free and works with Yahoo! Mail.
--0-2046224567-1142655258=:88478--