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<DIV><SPAN class=753182315-05122006><FONT face=Arial color=#0000ff size=2>Bad
arithmetic ... that's less than 20% expansion or 1.2 rear-facing square
inches out for every square inch in.</FONT></SPAN></DIV>
<DIV> </DIV>
<P><FONT face="Times New Roman">Dean Pappas</FONT> <BR><FONT
face="Times New Roman">Sr. Design Engineer</FONT> <BR><FONT
face="Times New Roman">Kodeos Communications</FONT> <BR><FONT
face="Times New Roman">111 Corporate Blvd.</FONT> <BR><FONT
face="Times New Roman">South Plainfield, N.J. 07080</FONT> <BR><FONT
face="Times New Roman">(908) 222-7817 phone</FONT> <BR><FONT
face="Times New Roman">(908) 222-2392 fax</FONT> <BR><FONT
face="Times New Roman">d.pappas@kodeos.com</FONT> </P>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org]<B>On Behalf Of </B>Dean
Pappas<BR><B>Sent:</B> Tuesday, December 05, 2006 10:19 AM<BR><B>To:</B> NSRCA
Mailing List<BR><B>Subject:</B> Re: [NSRCA-discussion] cooling
area<BR><BR></FONT></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial size=2>Hi
All,</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial size=2>I'll go one step
further: measuring the exit area by looking at the bottom of the airplane is
wrong. Do you want the air shooting vertically out the bottom of the ship? Of
course not.</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial size=2>The expansion of
air in our cooling setups is practically negligible. Let's say that the air
heats up a whole 100 degrees F as it goes through the system. There is no way
that it heats up even half of that. On a normal day, the air is at at
roughly 535 degrees absolute, so a 100 degree warmup will make the air expand
less than 10%.</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial size=2>If you take a
square inch of air into the front of the airplane at 80 MPH, you want 1.1
square inches of exit ... as viewed from directly behind the
aircraft!</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial size=2>Now if you cut a
hole in the bottom of the plane, you have to ask how the air is coming out. Is
the hole really aft of the fuselage bottom "high point"?</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial size=2>Is it really on
the flat bottom? Then air is going to exit the plane at some shallow angle,
and the effective area is going to be much smaller than what you see looking
at the bottom of the plane.</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial size=2>Unless the exit
hole is huge, this means that the system is outlet choked, when flying at
speed, and adding drag to boot.</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial size=2>We really should
build aft-facing exit scoops like some older Pattern designs, or the
slick trick used on the aft end of the belly pan of the
Zeque.</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial
size=2>Later,</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial
size=2>Dean</FONT></SPAN></DIV>
<DIV><SPAN class=210254714-05122006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
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