[NSRCA-discussion] Cooling outrunners

[Dean Pappas]

Hi again,
The annular cooling entry can be done poorly too!
Go google the cooling setup on a Hawker Sea Fury. There was a fairing behind the
spinner to help the air flow inward toward the crankshaft,
and the radiators were set far enough aft that there was a decent volume plenum in front of them.
The Pletty needs a drive washer extension in order to make the annular intake work at all,
the front of the motor hides too closely behind the spinner backplate.

As for the aesthetic issue, who rememebers Doc Coleman's Cutlass Supreme?

later,

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 Chad
Northeast
Sent: Wednesday, December 20, 2006 12:29 AM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Cooling outrunners


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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