[NSRCA-discussion] Weight

Wed Jun 3 08:59:14 AKDT 2009

Yes, the goal is to make it cheaper. What I'm trying to do is take the weight of the batteries out of the equation just like fuel is. With rare exception, cheaper batteries equals more weight. The reason for including a mah restriction (probably 6000mah as rated by the mfg) is to keep things under control and avoid someone taking advantage with larger batteries. What I'm hearing out of my district is guys wanting to try electric and getting scared off with the high cost of kits, batteries, and motors that will make weight. I'm well aware that the Prestige, Spark, Integral, and a few others can make weight with the right batteries and motor. I'm also aware of what that costs. My goal is to make it possible for someone to build a Black Magic without the building skills of Zen that'll make weight with an Axi and Zippy packs.

Verne

---- Dave <DaveL322 at comcast.net> wrote: 
> Verne,
> 
> If you goal is to make pattern cheaper, I'm all for that (and the most
> expensive setup right now is a YS CDI setup), but I can't see how a proposal
> based on your description can effectively accomplish that.
> 
> Is the goal to reduce cost of the electric (which I can argue is cheaper
> than glow at the top levels of each) or to make electric and glow airplanes
> have the same cost for equal performance?  As electric technology rapidly
> advances, any proposal based on current day planes will be obsolete by the
> time it in place.
> 
> Limits on pack mah will certainly add to the complexity of tech inspections
> of planes....to say nothing of the fact that all "20C" lipos do not weigh
> the same thing, and all batteries of a marked capacity are not the same
> either - the door will be wide open for "creative" labeling of mah capacity
> on batteries.
> 
> Just as there are examples of overweight glow planes (I do hope you are
> getting weights on glow planes as well during your surveys???), there are
> overweight examples of electrics - neither should be accommodated by a
> change in the rules.  Each competitor should evaluate the rules, and prepare
> to compete with whatever setup best suits there budget, time, resources, and
> is within the RULES.
> 
> Electric may cost more upfront, but it is rapidly getting cheaper (and glow
> is getting more expensive).  The big hurdle for electric right now is that
> all the costs are upfront, making it expensive to enter.
> 
> Regards,
> 
> Dave
> 
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
> verne at twmi.rr.com
> Sent: Wednesday, June 03, 2009 10:52 AM
> To: General pattern discussion
> Subject: Re: [NSRCA-discussion] Weight
> 
> Bill,
> I've been working up an AMA rules proposal to address that very issue.
> Unfortunately, it won't be up for vote by the contest board anytime soon. In
> the meantime, there's one area you didn't mention in the glow to electric
> comparison and that's that an electric plane doesn't need as much internal
> reinforcement because there's virtually no vibrational effects to contend
> with that you do with glow. That equates to lighter airframes being
> acceptable as well as small, light, lipo packs to power the Rx and servos.
> An 8 minute e-flight typically uses about 50 mah. The same flight in glow is
> typically 200+ mah. All that aside, most electric pilots will tell you that
> making weight in electric is generally a pretty expensive proposition with a
> limited number of 2 meter planes available that are usually vacuum-bagged
> composite affairs. In addition, your best chances for making weight will
> also necessitate the lightest and generally most expensive motors and
> batteries. There are exceptio
>  ns, and I'm sure we're about to hear about most of them, but I'll be able
> to point to just as many examples of guys that fly overweight at local
> contests where they know they won't be weighed and the only thing they're
> really guilty of is not spending the extra money that the lightest batteries
> and motors cost. In every other way, the planes they're flying are the same
> as the ones they're competing against. The proposal I'm working on is not
> self-serving because my planes make weight, but getting there is both too
> expensive and unreasonable, in my opinion. My proposal won't be to allow
> electric planes to weigh more, it'll require that they weigh less, but
> without the "fuel". The proposal will take into account that electric motors
> are inherently lighter than their glow counterparts as well as the reduced
> structural requirements. It will limit the mah of permissible packs to
> control that end of the equation and there's already a voltage limit on the
> books which is fine as it 
>  stands. I'm currently doing survey work at the contests I go to to see
> where everybody is at weight-wise and will post my proposal on this list
> soon. After that, it's up to all concerned to voice their opinions to their
> respective Contest Board reps.
> 
> Verne Koester
> AMA District 7 
> Contest Board
> ---- Bill's Email <wemodels at cox.net> wrote: 
> >  I am certain this has been beaten to death while I was off doing other 
> > things, but can anyone explain this:
> > 
> > 
> > Rule 4.3: Weight and Size. No model may weigh more than five (5) 
> > kilograms (11 pounds) gross, but excluding fuel, ready for takeoff. 
> > Electric models are weighed with batteries.
> > 
> > Why can't an electric "deduct" the equivalent of 16 ounces of fuel??  Is 
> > a plane without fuel rally "ready for takeoff"??
> > 
> > I know it is likely a direct copy of the FAI rule, but it makes no 
> > logical sense. IC powered planes are weighed without fuel and can weigh 
> > right at 11 pounds. Add fuel and it could add another 10 to 12 ounces of 
> > weight. That's OK. But if an electric with batteries weight 
> > 11.0000000000000001 pounds it is overweight by the rules.
> > 
> > Put another way, what does a YS and full fuel weigh compared to a 
> > motor+ESC+batteries?
> > 
> > Hacker C50 14XL = 18.2 ounces
> > Hacker Spin 99 ESC = 3.7 ounces
> > 10S packs = +/- 43 to 46 ounces
> > 
> > Weight w/o batteries = 21.9
> > AUW w/batteries = 66.9 ounces
> > 
> > YS 1.70 = 33.6 ounces (955 grams)
> > AUW with tank and fuel = 45 ounces +/-
> > 
> >  So I can see an argument that the electrics have a weight advantage 
> > when it comes to just the motor and ESC. But with "fuel" electric is at 
> > a 20 ounce disadvantage.
> > 
> > So if I build a plane for electric I need to build it 20 plus ounces 
> > lighter than if I was going to put a nitro motor in it. How does that 
> > make sense. I know I am missing something important here, so educate me.
> > 
> > 
> > 
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