[NSRCA-discussion] Cooling outrunners

Chad Northeast chad at f3acanada.org
Tue Dec 19 20:29:50 AKST 2006


We actually asked ZN about producing an add-on piece to do just that on 
the Twister while at the Worlds in France.  They were concerned about 
making a composite piece that small strong enough so it never really 
went past discussion.

Dez however, did run a smaller spinner on his motor for a while.  IIRC 
it made a small difference to the temperature but not enough to overcome 
the  decreased aesthetics :)

The motors are around 2.25" OD, spinners up around 3.25"+, so even 
dropping down to a 2.75" spinner still provides a lot of blockage to the 
motor can.

Chad

Rcmaster199 at aol.com wrote:
> One way this could be done is to allow enough annular room around the 
> spinner, completely bypassing the cheeks and chin. You only need about 
> 1/8" annular opening. Just use a smaller spinner than needed and 
> fashion the model nose to recess the spinner slightly into the annulus.
>  
> I have done that on Temptress (engine powered) with good results.
>  
> Use the cheeks and chin to route air to the bats.
>  
> MattK
>  
> In a message dated 12/19/2006 9:28:10 AM Eastern Standard Time, 
> bob at toprudder.com writes:
>
>     */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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