[NSRCA-discussion] batteries high or low (electric pilots)

[mike mueller]

 Most planes I've had would have been difficult to move the lipo's very much. Seems like I always end up in a snug nook near the structure for the landing gears on the front to back balance. I would think that top to bottom balance would effect rolling but it's so close to the center it would be hard to detect.
 Mark is right that the lipo is around 20% of the total mass.
                                                   M2

--- On Wed, 9/16/09, Atwood, Mark <atwoodm at paragon-inc.com> wrote:

> From: Atwood, Mark <atwoodm at paragon-inc.com>
> Subject: Re: [NSRCA-discussion] batteries high or low (electric pilots)
> To: "'nsrca-discussion at lists.nsrca.org'" <nsrca-discussion at lists.nsrca.org>
> Date: Wednesday, September 16, 2009, 6:09 AM
> I think you'll find that the battery
> weight of your F3A plane is also in excess of 20% of the
> total weight.  A 10s pack is certainly over 1000gms
> making it more than 20% of a 5kg legal airframe. 
> 
> I suspect moving that amount of mass vertically has the
> same significant impact that it does on the foamies. 
> 
> That said, the same is maybe MORE true of our changing mass
> fuel tanks. While they weigh less, they flux from over a lb
> to almost nothing during flight.   Being high
> or low in the fuse will certainly impact trim.  We seem
> to just fly with it. 
> 
> My guess is you're trimming out any issues a high or low
> battery causes and moving on. 
> --------------------------
> Sent from my BlackBerry Wireless Handheld
> 
> 
> ----- Original Message -----
> From: nsrca-discussion-bounces at lists.nsrca.org
> <nsrca-discussion-bounces at lists.nsrca.org>
> To: 'General pattern discussion' <nsrca-discussion at lists.nsrca.org>
> Sent: Tue Sep 15 23:09:16 2009
> Subject: Re: [NSRCA-discussion] batteries high or low
> (electric pilots)
> 
> JAS
> 
> Base on my experience I agree with the previous
> observations about battery
> placement on foamies.  That being said, the battery
> weight can be up to 20%
> of the foamy weight, so small displacement can have a big
> effect.
> 
> The center of vertical mass mattered back in the
> top-mounted tuned pipe
> days--those airplanes pulled to the canopy in verticals
> (OK, some of this
> was design), so people reconfigured the mass.  The
> relative mass above C/L
> was probably less than 7% of airframe weight and was not
> that far from the
> CG...probably proportional to mounting the batteries in the
> belly pan of
> today's 2m designs.
> 
> Battery weight is about 10% of our typical 2M
> weights.  The significance of
> off-center mass will of course depend on distance of the
> mass from the
> center line, however, given the above observations I
> suspect battery
> placement (vertically) should be important....but no one
> with the belly pan
> mounting ever seems to complain!
> 
> Andre
> 
>      
> 
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org]
> On Behalf Of Earl Haury
> Sent: Tuesday, September 15, 2009 7:15 PM
> To: General pattern discussion
> Subject: Re: [NSRCA-discussion] batteries high or low
> (electric pilots)
> 
> Jason, looks like you're not getting any takers on this
> item. It seems 
> logical that anything of significant mass (batteries)
> should be close to the
> 
> roll center of the airplane, and I mount mine that way. I
> flew an Abbra for 
> a season with the batts centered and liked the way it flew.
> OTOH, several 
> folks have competed successfully with the Abbra with batts
> hanging low in 
> the cowl - so go figure.
> 
> Guess you'll just have to do the experiment (and let us
> know what you 
> observe).
> 
> Earl
> 
> 
> ----- Original Message ----- 
> From: "J Shu" <jshulman at cfl.rr.com>
> To: "NSRCA" <nsrca-discussion at lists.nsrca.org>
> Sent: Tuesday, September 15, 2009 1:51 PM
> Subject: [NSRCA-discussion] batteries high or low (electric
> pilots)
> 
> 
> > Has anyone (flying electric, sorry glow fliers) tried
> moving batteries to 
> > the extremes in the fuselages of their planes? Really
> low to really high? 
> > Results? I've often though about trying it, but new
> have. Just wondering 
> > if anyone has...
> >
> > Regards,
> > Jason
> > www.shulmanaviation.com
> > www.composite-arf.com
> >
> > _______________________________________________
> > 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
> No virus found in this incoming message.
> Checked by AVG - www.avg.com 
> Version: 8.5.409 / Virus Database: 270.13.100/2374 -
> Release Date: 09/15/09
> 20:00:00
> 
> _______________________________________________
> 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
>