[NSRCA-discussion] Cooling outrunners

[Chad Northeast]

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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