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<DIV>Dean</DIV>
<DIV> </DIV>
<DIV>That's a nice job of handling the air to an outrunner. I do something
similar with the Hacker - taking motor air into the cheeks and forcing it past /
through the motor, then dumping the "outside the case" air at the rear
of the cheeks, the air through the motor dumps into the fuse. Battery air is
ducted from the chin opening to the top of the batts into an open bottom "box"
(which isolates them from motor air) then passes downward through them and
exits the fuse (similar to Dave's set-up). A small scoop forces air over the ESC
which is mounted to the inside - top of the fuse behind the motor. Essentially
each heat generator receives its own forced air cooling and sees non of the heat
from the other sources. </DIV>
<DIV> </DIV>
<DIV>The "shrouds" keeping the airflow where the heat is are as important as the
ducts to get it there. Adequate low pressure exits keeps everything
moving.</DIV>
<DIV> </DIV>
<DIV>Earl</DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=d.pappas@kodeos.com href="mailto:d.pappas@kodeos.com">Dean Pappas</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, December 18, 2006 10:58
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Cooling
outrunners</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=822123515-18122006>Hi Jim,</SPAN></DIV>
<DIV><SPAN class=822123515-18122006>I have fiddled with this a fair bit, and
the setup I am using now produces very modest temperature rises on the
AXI.</SPAN></DIV>
<DIV><SPAN class=822123515-18122006>I see less than 15C rise after a P-07
with 84 A W.O.T. current draw at the beginning of the flight. After the
flight, static W.O.T is more like 75 or 76 A.</SPAN></DIV>
<DIV><SPAN class=822123515-18122006></SPAN> </DIV>
<DIV><SPAN class=822123515-18122006>The inlets total up to just about 1 square
inch, which is ducted straight to an airbox that surrounds the front of the
motor. The inlet airbox is about 5/8" deep from front to back, and has
plenty of volume, just because it needs to evvelop the front of the motor and
the cowl inlets. The airbox has a hole through wich the motor can passes, and
the hole is extended with a sleeve that runs back to near the aft end of the
rotating part of the motor.</SPAN></DIV>
<DIV><SPAN class=822123515-18122006>The wrapped balsa sleeve has maybe 1/8"
clearance around the motor. The high pressure air in the inlet airbox is
forced to either flow closely over the outside of the motor or through the
holes in the motor. </SPAN></DIV>
<DIV><SPAN class=822123515-18122006>For motors such as the Pletty, where the
prop drive does not stand proud of the front of the motor can, a drive
extender washer maybe 1/2" long will improve cooling by providing some volume
inside the inlet airbox, and allowing the air to "turn" to flow along the
motor axis. This is actually important.</SPAN></DIV>
<DIV><SPAN class=822123515-18122006></SPAN> </DIV>
<DIV><SPAN class=822123515-18122006>The warm air then dumps into the aft end
of the motor compartment, which is segregated from the rest of the cooling
pathg to the batteries.</SPAN></DIV>
<DIV><SPAN class=822123515-18122006>An separate outlet gets rid of this air.
In my case, it is simply a hole in the bottom of the "scale" cowl of the
Funtana. Ideally, the aft end of the cheeks that everybody seems to be
putting into their designs would be an ideal low pressure-high velocity
outlet, but everybody belnds them into the fuse instead of leaving a back end
exit like the Pylon guys.</SPAN></DIV>
<DIV><SPAN class=822123515-18122006>You could just have the motor sleeve dump
into the fuse above the batteries, but rear-facing exhaust stacks or a
fake turbo-prop exhaust would look cool and be functional. I'll try to
post some low-res pictures on the list.</SPAN></DIV>
<DIV><SPAN class=822123515-18122006></SPAN> </DIV>
<DIV><SPAN class=822123515-18122006>later,</SPAN></DIV>
<DIV><SPAN class=822123515-18122006>Dean</SPAN></DIV>
<DIV><SPAN class=822123515-18122006></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>-----Original Message-----<BR><B>From:</B>
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org]<B>On Behalf Of
</B>J.Oddino<BR><B>Sent:</B> Friday, December 15, 2006 7:13 PM<BR><B>To:</B>
NSRCA Mailing List<BR><B>Subject:</B> [NSRCA-discussion] Cooling
outrunners<BR><BR></FONT></DIV>
<DIV>It would seem the best way to cool outrunners that have holes in the
case on the end that faces the nose ring, would be to bring air in
through the spinner and through holes in the backplate. Wondering if
anyone has really thought about the optimum design. I can picture
internal vanes but perhaps cutting off the nose of the spinner and leaving a
big hole would be adequate. Anyone tried anything like this?</DIV>
<DIV> </DIV>
<DIV>Jim O</DIV></BLOCKQUOTE>
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