[NSRCA-discussion] Electric TT Spinner

[Chad Northeast]

I have flown without the spinner to evaluate cooling, its a fairly 
significant change but the appearance offset the cooling :)  I also 
experimented with some cutouts which may be where the original post came 
from?  They were on the sides of the cone and more or less ineffective 
(no real surprise, but I wanted to try anyways).  I also milled the TT 
light backplate to act as a fan of sorts, but the RPM is way too low for 
it to efficiently put air through.  I spoke with Plettenberg about fans, 
they have also done testing and indicated that for their heli stuff you 
need to have the fan spinning 10k-20k rpm to get any effect out of it.

That being said, properly done the motors can run within limits with a 
full spinner.  160F and lower on the can measured after a flight is ok.

We have other ideas to duct air into the fuse such as smaller spinners 
and annular gaps that scoop the air and force it over the can....but 
that is much more complicated and requires some fiberglass work, and 
mods to the plane.

Chad

Keith Black wrote:

> My question is, other than looks, what is the purpose of a spinner an 
> electric pattern plane?
>  
> - Reducing drag isn't a concern as recent designs are being built to 
> be more draggy.
> - Starters aren't used with electrics so having a nose cone isn't 
> necessary for starting.
>  
> The only thing I can think of is to clean the air flow and reduce 
> turbulence from the blunt nose so air going around the fuse and over 
> the wings is smoother, however, with the prop chewing the air so close 
> to the nose of the plane I'm not sure this is significant.
>  
> Opinions?
>  
> Keith Black
>
>     ----- Original Message -----
>     *From:* Terry Terrenoire <mailto:amad2terry at juno.com>
>     *To:* nsrca-discussion at lists.nsrca.org
>     <mailto:nsrca-discussion at lists.nsrca.org>
>     *Sent:* Sunday, February 19, 2006 7:22 PM
>     *Subject:* Re: [NSRCA-discussion] Electric TT Spinner
>
>     I am adapting a 30 year old design to a pattern electric. This
>     plane was designed around the Veco .19. I think I am going to use
>     the E-Flite 450. Total weight looks to be in the 32 oz range. I
>     just started drawing the motor cowl. What I am going to try to do
>     is use a very small spinner, possibly 1 1/4, but make the ring
>     behind the spinner backplate 2" to 2 1/2" diameter. That will
>     allow air to enter the motor compartment from around the spinner.
>     Another option I have been considering is 2 cheek scoops!
>      
>     Terry T.
>      
>      
>     On Sun, 19 Feb 2006 19:48:52 EST Rcmaster199 at aol.com
>     <mailto:Rcmaster199 at aol.com> writes:
>
>         It's no big deal to make cutouts in the spinner cone. Just
>         requires more cereful balance. I've attempted it before on
>         smaller spinners but wasn't happy with the results (on wet
>         set-ups, and both cooling air flow wise and strength wise)
>          
>         Theory sounds good but in practice, don't expect much air flow
>         to penetrate into the spinner when the motor is running
>         at higher power output. The ribs that would be needed to still
>         make the spinner functional, would likely block off air flow.
>         Turbulence that could result, would likely rob power.
>          
>         BUT, one way it could work fairly well would be to actually
>         refashion or bend the ribs in such a shape that air is
>         literaly drawn in and forced through the spinner. Like a set
>         of impeller vanes. The pitch of the vanes wouldn't need to be
>         very high. It would rob some power from the motor though, so
>         the practicality could be questionable.
>          
>         On the other hand, an optimal pitch angle probably exists and
>         could be found, that robs the minimum power and provides the
>         maximum cooling air flow through the spinner.
>          
>         Matt
>          
>         In a message dated 2/19/2006 7:28:01 PM Eastern Standard Time,
>         jshulman at cfl.rr.com writes:
>
>             I didn't know they were doing that. Thought they just cut
>             out for the props
>             and have the lightened back plate.
>
>             Regards,
>             Jason
>             www.jasonshulman.com
>             www.shulmanaviation.com
>             www.composite-arf.com
>
>             -----Original Message-----
>             From: nsrca-discussion-bounces at lists.nsrca.org
>             [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf
>             Of Pat Hewitt
>             Sent: Sunday, February 19, 2006 7:18 PM
>             To: patternrules at earthlink.net; NSRCA Mailing List; NSRCA
>             Mailing List
>             Subject: Re: [NSRCA-discussion] Electric TT Spinner
>
>
>             Please advise,
>
>             What are some of your thoughts on the cut outs of a True
>             Turn Spinner for
>             cooling on an Electric Pattern Plane not the back plate
>             but the cone itself.
>
>             Pat h.
>
>          
>          
>
>     ------------------------------------------------------------------------
>     _______________________________________________
>     NSRCA-discussion mailing list
>     NSRCA-discussion at lists.nsrca.org
>     http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
>------------------------------------------------------------------------
>
>_______________________________________________
>NSRCA-discussion mailing list
>NSRCA-discussion at lists.nsrca.org
>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>