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<DIV>
<DIV>I agree, the rpms have everything to do with our cooling
problems... My whole problem with all this is</DIV>
<DIV>that feeding "some" air through the motor has got to be way better than
getting no air through it. I have just been</DIV>
<DIV>going by the premise that they've been cooling alternators this way for
years.... They turn around the same speed</DIV>
<DIV>as our motors do.. basically three times the engine
rpm... </DIV>
<DIV>I'm glad the EVO cools better... I need one of those anyway, and it's
a really good excuse to buy one!!!!</DIV>
<DIV>Thanks Chad, you've eased my conscience....</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:chad@f3acanada.org
href="mailto:chad@f3acanada.org">Chad Northeast</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 Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, December 17, 2006 9:05
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Cooling
outrunners</DIV>
<DIV><BR></DIV>The RPM is way too slow to move a lot of air. Tru-Turn
did some <BR>experimenting on this concept as well and found that you need to
spin up <BR>very fast to get any real flow out of it.<BR><BR>Pletty was going
to install a fan on the 30-10's, but for the same <BR>reason did not.
Their experience with fans on smaller engines for helis <BR>etc told them that
anything below about 15k rpm was not very effective.<BR><BR>I just want to
point out that the 30-10 Evo vs. the original 30-10 has a <BR>vast improvement
to cooling. I run mine at 3kW in flight peak and <BR>around 3.3kW static
(motor will deal with 3.5kW fairly easily), and even <BR>in the heat of Muncie
it rarely goes over 140F on the can. This is with <BR>a normal TT
spinner and only a single duct from the chin pointing at the <BR>motor.
You would smoke the original motor in seconds in the same
<BR>environment!<BR><BR>The stator on the Evo is hollow to allow air to flow
through the center <BR>of the motor, as well a lot more open area on the front
of the motor.<BR><BR>Chad<BR><BR>Dave Reaville wrote:<BR>> Hi
Wayne<BR>> <BR>> Actually Chad and Rex (I think???) had already
done that but I was a <BR>> little concerned with leaving sufficient
material after the spoke <BR>> removal :-) so I decided not to. I am not
sure just how much <BR>> additional flow would be created but it's
certainly worth considering.<BR>> <BR>>
Dave<BR>><BR>> ----- Original Message
-----<BR>> *From:* Wayne Galligan <<A
title=mailto:wgalligan@texasairnet.com
href="mailto:wgalligan@texasairnet.com">mailto:wgalligan@texasairnet.com</A>><BR>>
*To:* NSRCA Mailing List <<A title=mailto:nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">mailto:nsrca-discussion@lists.nsrca.org</A>><BR>>
*Sent:* Saturday, December 16, 2006 8:23 PM<BR>>
*Subject:* Re: [NSRCA-discussion] Cooling
outrunners<BR>><BR>>
Dave,<BR>> <BR>>
You could go one step further and grind an airfoil in
the<BR>> remaining spokes to aid in pulling the air
in.<BR>> <BR>>
Wayne G. <BR>><BR>>
----- Original Message
-----<BR>> *From:* Dave
Reaville <<A title=mailto:dkrev@shaw.ca
href="mailto:dkrev@shaw.ca">mailto:dkrev@shaw.ca</A>><BR>>
*To:* NSRCA Mailing
List<BR>> <<A
title=mailto:nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">mailto:nsrca-discussion@lists.nsrca.org</A>><BR>>
*Sent:* Saturday, December 16, 2006 2:09
PM<BR>> *Subject:* Re:
[NSRCA-discussion] Cooling
outrunners<BR>><BR>>
<BR>> Re: Outrunner
Cooling<BR>>
<BR>> FWIW I have made some
other changes to the spinner that
have<BR>> helped a little.
I removed three of the spokes of my
backplate<BR>> to assist in
weight loss :-) as well as increase flow
through<BR>> the
motor. Picture
here<BR>> <A
title=http://members.shaw.ca/patternwestnews/pictures/planes/tttrim.htm
href="http://members.shaw.ca/patternwestnews/pictures/planes/tttrim.htm">http://members.shaw.ca/patternwestnews/pictures/planes/tttrim.htm</A><BR>>
<BR>> I am also going to
make some minor changes to the
spinner<BR>> itself by
increasing the prop cut-out forward. These
openings<BR>> coupled with
the ducting that Chad used towards the rear
of<BR>> the motor should
provide adequate cooling for the Plett.
I<BR>> understand the Evo
has bigger openings to assist in
cooling<BR>> but I think
it's very important to make sure
that<BR>> the backplate
spokes, when mounted, align properly to
allow<BR>> unrestricted
flow through the openings. It's possible to
block<BR>> the flow if
improperly installed or if it rotates on it's
own.<BR>>
<BR>> I have seen Rex's
spinner in action and it appears to me
to<BR>> assist in
cooling.<BR>>
<BR>> Dave
R<BR>>
<BR>> ----- Original
Message
-----<BR>><BR>>
*From:* Rex LESHER <<A title=mailto:trexlesh@msn.com
href="mailto:trexlesh@msn.com">mailto:trexlesh@msn.com</A>><BR>>
*To:* NSRCA Mailing
List<BR>>
<<A title=mailto:nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">mailto:nsrca-discussion@lists.nsrca.org</A>><BR>>
*Sent:* Saturday, December 16, 2006 9:52
AM<BR>>
*Subject:* Re: [NSRCA-discussion] Cooling
outrunners<BR>><BR>>
Hi guys, I've been without power for the last
couple<BR>>
days.... The mods I did to the spinner are on the
D8<BR>>
website. I'm not sure how effective my process
really<BR>>
is. I can tell you that it works much better than
not<BR>>
having any opening at all. I did that experiment....
<BR>>
Chad touched on the real problem and I believe he is
right<BR>>
on. The spokes in the backplate and the closed
sides<BR>>
between the openings in the spinner create too
much<BR>>
resistance (spinning disc) for the appropriate amount
of<BR>>
air to get directly into the motor. I first tried
just<BR>>
opening the sides of the spinner, and used that for
my<BR>>
baseline. Then, I used the modification as shown on
the<BR>>
D8 website. I figure that I dropped somewhere around
20<BR>>
degrees on average. After a few flights, I took
the<BR>>
spinner off, and the motor cooled much better. That
tells<BR>>
me that in order to get the greatest cooling, you'd
have<BR>>
to create a high pressure area in front of the motor...
<BR>>
Now, I'm playing with ducting, forcing air around
the<BR>>
can.... Time will tell, if I don't demag the
motor!!!<BR>>
<BR>>
Rex<BR>><BR>>
----- Original Message
-----<BR>>
*From:* <A title=mailto:AtwoodDon@aol.com
href="mailto:AtwoodDon@aol.com">AtwoodDon@aol.com</A> <<A
title=mailto:AtwoodDon@aol.com
href="mailto:AtwoodDon@aol.com">mailto:AtwoodDon@aol.com</A>><BR>>
*To:* <A title=mailto:nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</A><BR>>
<<A title=mailto:nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">mailto:nsrca-discussion@lists.nsrca.org</A>><BR>>
*Sent:* Friday, December 15, 2006 6:16
PM<BR>>
*Subject:* Re: [NSRCA-discussion] Cooling
outrunners<BR>><BR>>
Jim,<BR>>
<BR>>
I think Rex Lesher modified a True Turn spinner
to<BR>>
have 'inlet slits' to pull air into the spinner
and<BR>>
back thru the motor. I don't know if there were
any<BR>>
tests to indicate if was effective. Maybe Rex
can<BR>>
comment
here.<BR>>
<BR>>
I also believe there are some NASA airflow
studies<BR>>
that indicate the area around the prop hub and
some<BR>>
small amount of the prop as well as the spinner
create<BR>>
an cone like airflow around that area that
basically<BR>>
prevents air from entering the spinner slots,
etc.<BR>>
<BR>>
Hacker has a fan like attachment on the back of
the<BR>>
large outrunners than creates a negative pressure
area<BR>>
inside the motor and draws air in thru the front
of<BR>>
the motor for cooling. there have been some
tests<BR>>
retrofitting a similar fan on the back of
other<BR>>
outrunners with similar success. Basically a
trade<BR>>
off in weight for cooling
effectiveness.<BR>>
<BR>>
As you know, I run an AXI 5330/F3A with the chin
cowl<BR>>
opening ducted to divert incoming air upward
across<BR>>
the AXI. It seems to work even on the hottest
summer<BR>>
days. No air from the cheek cowls is ducted
toward<BR>>
the motor, it just passes thru toward the ESC
and<BR>>
batteries.<BR>>
<BR>>
Don<BR>>
<BR>>
In a message dated 12/15/2006 4:14:26 P.M.
Pacific<BR>>
Standard Time, <A title=mailto:joddino@socal.rr.com
href="mailto:joddino@socal.rr.com">joddino@socal.rr.com</A>
writes:<BR>><BR>>
It would seem the best way to cool outrunners
that<BR>>
have holes in the case on the end that faces
the<BR>>
nose ring, would be to bring air in through
the<BR>>
spinner and through holes in the backplate.
<BR>>
Wondering if anyone has really thought about
the<BR>>
optimum design. I can picture internal vanes
but<BR>>
perhaps cutting off the nose of the spinner
and<BR>>
leaving a big hole would be adequate.
Anyone<BR>>
tried anything like
this?<BR>>
<BR>>
Jim
O<BR>><BR>><BR>>
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