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<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>
<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="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
mailing
list<BR>NSRCA-discussion@lists.nsrca.org<BR>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV> </DIV></FONT>_______________________________________________<BR>NSRCA-discussion
mailing
list<BR>NSRCA-discussion@lists.nsrca.org<BR>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</BLOCKQUOTE></DIV></BODY></HTML>