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<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Re: Outrunner Cooling</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>FWIW I have made some other changes to the spinner that
have helped a little. I removed three of the spokes of my backplate to assist in
weight loss :-) as well as increase flow through the motor. Picture here
</FONT><FONT face=Arial><A
href="http://members.shaw.ca/patternwestnews/pictures/planes/tttrim.htm">http://members.shaw.ca/patternwestnews/pictures/planes/tttrim.htm</A></FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>I am also going to make some minor changes to the spinner
itself by increasing the prop cut-out forward. These openings coupled with the
ducting that Chad used towards the rear of the motor should provide
adequate cooling for the Plett. I understand the Evo has bigger openings to
assist in cooling but I think it's very important to make sure that
the backplate spokes, when mounted, align properly to allow unrestricted
flow through the openings. It's possible to block the flow if improperly
installed or if it rotates on it's own.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>I have seen Rex's spinner in action and it appears to
me to assist in cooling.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Dave R</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=trexlesh@msn.com href="mailto:trexlesh@msn.com">Rex LESHER</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> Saturday, December 16, 2006 9:52
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Cooling
outrunners</DIV>
<DIV><BR></DIV><!--[gte IE 5]><?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->
<DIV style="FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY: Arial">
<DIV>Hi guys, I've been without power for the last couple days....
The mods I did to the spinner are on the D8 website. I'm not sure how
effective my process really is. I can tell you that it works much better
than not having any opening at all. I did that experiment.... Chad
touched on the real problem and I believe he is right on. The spokes in
the backplate and the closed sides between the openings in the spinner create
too much resistance (spinning disc) for the appropriate amount of air to get
directly into the motor. I first tried just opening the sides of
the spinner, and used that for my baseline. Then, I used the
modification as shown on the D8 website. I figure that I dropped
somewhere around 20 degrees on average. After a few flights, I took the
spinner off, and the motor cooled much better. That tells me that in
order to get the greatest cooling, you'd have to create a high pressure area
in front of the motor... </DIV>
<DIV>Now, I'm playing with ducting, forcing air around the can.... Time
will tell, if I don't demag the motor!!!</DIV>
<DIV> </DIV>
<DIV>Rex</DIV>
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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="FONT: 10pt arial"><B>From:</B> <A title=mailto:AtwoodDon@aol.com
href="mailto:AtwoodDon@aol.com">AtwoodDon@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=mailto:nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, December 15, 2006 6:16
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Cooling
outrunners</DIV>
<DIV><BR></DIV><FONT id=role_document face=Arial color=#000000 size=2>
<DIV>
<DIV>Jim, </DIV>
<DIV> </DIV>
<DIV>I think Rex Lesher modified a True Turn spinner to have 'inlet slits'
to pull air into the spinner and back thru the motor. I don't know if
there were any tests to indicate if was effective. Maybe Rex can
comment here.</DIV>
<DIV> </DIV>
<DIV>I also believe there are some NASA airflow studies that indicate the
area around the prop hub and some small amount of the prop as well as the
spinner create an cone like airflow around that area that basically prevents
air from entering the spinner slots, etc.</DIV>
<DIV> </DIV>
<DIV>Hacker has a fan like attachment on the back of the large outrunners
than creates a negative pressure area inside the motor and draws air in thru
the front of the motor for cooling. there have been some tests
retrofitting a similar fan on the back of other outrunners with similar
success. Basically a trade off in weight for cooling
effectiveness.</DIV>
<DIV> </DIV>
<DIV>As you know, I run an AXI 5330/F3A with the chin cowl opening ducted to
divert incoming air upward across the AXI. It seems to work even on
the hottest summer days. No air from the cheek cowls is ducted toward
the motor, it just passes thru toward the ESC and batteries.</DIV>
<DIV> </DIV>
<DIV>Don</DIV>
<DIV> </DIV>
<DIV>In a message dated 12/15/2006 4:14:26 P.M. Pacific Standard Time,
joddino@socal.rr.com writes:</DIV>
<BLOCKQUOTE
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style="BACKGROUND-COLOR: transparent" face=Arial color=#000000 size=2>
<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><BR><BR>_______________________________________________<BR>NSRCA-discussion
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<DIV></DIV>
<DIV> </DIV></FONT>_______________________________________________<BR>NSRCA-discussion
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