[NSRCA-discussion] Cooling outrunners

[Ed Alt]

Sounds like you guys doing the electric power pioneering might want to 
figure out a light weight heat exchanger setup.

Ed

----- Original Message -----
From: "Chad Northeast" <chad at f3acanada.org>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, December 20, 2006 12:36 AM
Subject: Re: [NSRCA-discussion] Cooling outrunners

> Hi Dean
>
> Quite true about the magnets, but I have flown with my motor at 150F and
> on days where it doesnt get above 65F....I can not tell the difference
> in performance, probably because there is such excess power in these
> setups to start with.
>
> Pack temperature on the other hand is very important, OAT below 10-15C I
> have to start restricting cooling on the batteries or they dont get warm
> enough to provide good power.  The new extreme packs are better about
> this than the Prolites, but still very noticeable on certain days.
>
> Chad
>
> Dean Pappas wrote:
>> Bob, you're a genius!
>> I suggested this to an E-powered CL Stunt buddy in the Netherlands
>> some months ago because the Stunt guys have a long history of styling
>> planes with chin scoops placed far back. These often require a 3/4"
>> long prop drive extension to place the cylinder back farther, and the
>> use of a short venturi. They cowl much easier than computer carbs!
>>
>> Hi Chad,
>> Makes you wonder what some of these guys were thinking when they
>> placed the cooling and cheek inlets. ?? **^^$$!!!
>> The inlet airbox can shroud the aft end of the motor and the sleeve
>> dump into a front exit plenumm. Now the trick is the exit from there.
>> I think that a big elbow like a turbopropo exhaust would be cool, as
>> would be cheek cowls with no entry holes just exits. The exit plenum
>> just behind the spinner would have to duct into the cheeks. Notre that
>> flying without a spinner will wreck the cooling! A row of exhaust
>> stacks like a P-51 could be boxed in and used to suck the warm air out
>> of the exit plenum. I need to draw a picture. That'll take a while,
>> especially around Christmas.
>>
>> The colder the magnets are, the stronger they are, and the less
>> resistive the copper is, so cooler is always better for the motor. The
>> same is true for the ESC: MOSFETs are less resistive the cooler they
>> are, so everything gets better in the Antarctic except battery
>> performance.
>>
>> later,
>>     Dean
>>
>>
>>
>> Dean Pappas
>> Sr. Design Engineer
>> Kodeos Communications
>> 111 Corporate Blvd.
>> South Plainfield, N.J. 07080
>> (908) 222-7817 phone
>> (908) 222-2392 fax
>> d.pappas at kodeos.com
>>
>>     -----Original Message-----
>>     *From:* nsrca-discussion-bounces at lists.nsrca.org
>>     [mailto:nsrca-discussion-bounces at lists.nsrca.org]*On Behalf Of
>>     *Bob Richards
>>     *Sent:* Tuesday, December 19, 2006 9:27 AM
>>     *To:* chad at f3acanada.org; NSRCA Mailing List
>>     *Subject:* Re: [NSRCA-discussion] Cooling outrunners
>>
>>     Is there any reason why you can't duct the air to blow into the
>>     rear of the motor, and provide a way for it to escape from the front?
>>
>>     Geez, I'm just thinking that leaving the spinner off, or use a
>>     really small spinner, would be the way to go.
>>
>>     Bob R.
>>
>>
>>     */Chad Northeast <chad at f3acanada.org>/* wrote:
>>
>>         The problem with a lot of composite fuse models (Twister
>>         included) is
>>         that the inlets in the chin and cheeks are often right at the
>>         rear or
>>         even behind an outrunner.....so ducting toward them is very
>>         difficult.
>>         I have to agree that a proper ducting system is crucial for
>>         cooling. I
>>         use a very simple short radius 90 bend in a peice of depron
>>         that pulls
>>         air in from the chin, I see about a 20C rise in temp without
>>         it, other
>>         than that I dont really do anything special. The motor will
>>         operate at
>>         up to 170F without complaining so as long as its 20-30F below
>>         that all
>>         is good :)
>>
>>         Chad
>>
>> ------------------------------------------------------------------------
>>
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