[NSRCA-discussion] weight limits for electrics?
Chad Northeast
chad at f3acanada.org
Sun May 14 05:49:45 AKDT 2006
Troy going to 12s doesn't help much....as 12s2p 4200 from 6s2p 4200
packs is heavier (584g vs 560 per set) and costs the same (339.95 from
TP each set) as a set of 5s4p 5300's.....as well unless you propped way
down, (which is less efficient = more watts to the prop needed...so you
may not actually drop the current much) the current draw with our motors
we used now would go through the roof because of the increased voltage.
Inrunners with gearboxes would more easily deal with that, but
outrunners would need to change...there are very few ESC's that can
handle 12s today (some Castles can I think, the huge Schulze can but its
a tank and expensive as hell!).....we would lose our ability to charge
in series (which is super handy) from most chargers except for the
Schulze's.
Chad
Troy A. Newman wrote:
> Reality is the Battery is not the fuel. It is the fuel tank. It holds
> the fuel.
>
> This is the way FAI has decided to handle the situation, and as a
> result the AMA pattern folks have decided to follow suit. Right or
> wrong it is the way it is. I don't see it as unfair its just the game
> we play. If the rule was changed to allow the model to be weighed
> without batts then the advantage would swing hugely in favor of
> electric powered models. And the models would change to be 11lb birds
> before batts and then carry 8-10amp batts with huge electric motor
> that are putting out 5-6kw. Again the game jumps up another notch. The
> real loop hole right now in the rules for AMA is there is no 42V
> limit. You guys flying AMA classes should be flying on 12S. This
> reduces the amp draw and makes the smaller pack capacities better
> suited. A 10S4P 5300pack say makes 2500watts. A 12S pack would reduce
> the current draw and you might get away with a 12S2P 4200mah pack. You
> just saved a ton weight going from 40 cells in the 10S4P to 24cells in
> the 12S2P pack. Also the price is more inline as you are only buying
> 1/2 number of cells. 1/2 the number of cells means you have that many
> fewer cells to go bad, and you have that many fewer cells to keep
> balanced. The 12S system would require some products that probably
> don't exist today like good chargers to do 12s Packs, and ESC's and so
> on. This is where I would be spending my time if I was wanting to fly
> electric in AMA pattern classes. The price will reduce then and the
> current draw will be lower as a result of the high voltage.
>
> Another reality is that current setups can make weigh with the
> batteries installed and so I see no need to change the rule. Batts are
> changing quickly and new cells are coming that lower the weight almost
> on a semi annual basis. So Fly the model enjoy it and enjoy flying
> pattern with it.
>
> The weight limit has the intention of limiting the models based on
> power plant. Basically a 2M plane with a DA150 is not going to work.
> The engine displacement rule was removed years ago and a size 2m x 2m
> and a weight limit that was already in place of 5kg was used to keep
> the models from getting over blown and keep them within some limits.
>
> Many Many models out there today are at the limit or close to it. We
> have pushed the models design to the limits of the rules. If it says
> 2M that's what we built, if it said 12lb then most models would be
> close to 12lb.
>
> Its just a case of how much can you do and still be "legal"
>
> Remember this is toy airplanes and its for fun. Anybody that throws a
> fit about a guy winning with an illegal (overweight) model should have
> to answer to the firing squad.
>
>
>
> Troy Newman
>
> ----- Original Message -----
> *From:* Larry <mailto:ledunn at centurytel.net>
> *To:* patternrules at earthlink.net
> <mailto:patternrules at earthlink.net> ; NSRCA Mailing List
> <mailto:nsrca-discussion at lists.nsrca.org>
> *Sent:* Saturday, May 13, 2006 8:30 PM
> *Subject:* Re: [NSRCA-discussion] weight limits for electrics?
>
> Hi Steve,
>
> That's pretty much what everyone tells me so far, but it doesn't
> sit quite rite. Makes me feel like I will be cheating and getting
> away with it because no one checks.
>
> It also seems like there is a double standard here and that the
> rules need to be re-evaluated.
>
> A glow plane that weighs 5kg empty will definitely have a take off
> weight HIGHER than mine and yet it would be legal and I am not. It
> might even have a landing weight higher than mine depending on the
> size of the tank and length of the routine.
>
> I wonder if anyone is looking at this as more and more electrics
> are getting into all aspects of the hobby.
>
> I just saw in the Apr Kfactor in the D8 column, someone did a
> conversion and has similar issues - slightly over the 5KG limit
> with batteries installed.
>
> It seems to me that batteries should be considered "fuel" and not
> count towards the total weight OR that take off weight should be
> the determining factor.
>
> Ofcourse, as I said, I am a 100% newbie here. Haven't even flown
> in one contest yet :)
>
> Larry
>
> ----- Original Message -----
> *From:* Steven Maxwell <mailto:patternrules at earthlink.net>
> *To:* NSRCA Mailing List
> <mailto:nsrca-discussion at lists.nsrca.org>
> *Sent:* Saturday, May 13, 2006 7:53 PM
> *Subject:* Re: [NSRCA-discussion] weight limits for electrics?
>
> I wouldn't worry about the weight. A little story to go along
> with that. At the 1984 Tangerine, one of the 3 top rated
> contest in the conutry then (Nat's and Rough River) my last
> conest as a sportsman thats when we had novice,I was winning
> by a slight margin, the last round on Sunday I got beat out of
> first by .07 point, so I got second, the 3rd place guy said
> that the winner had an illegal airplane, slightly over weight,
> and wanted me to protest, I told him that the guy beat me
> flying not because he had an overweight plane, and that if he
> wanted to protest do it his self, he didn't and the ending was
> finaI. I had already talked to the guy and he said his self
> that it probably was over weight, real nice about it (EU1A)
> not the first one of those that didn't make weight.
> So the story goes I don't remember either of the persons
> names, I do remember it as a fond memory, but I bet nobody can
> give me either persons names, 22 years later. My first journey
> to a big contest with no one along for the ride or to fly,
> just me it was a ball.
> So don't worry about unless you plane on placing at Nats then
> you need to make weight.
>
> Steven Maxwell
>
>
>
> ----- Original Message -----
> *From:* Larry <mailto:ledunn at centurytel.net>
> *To: *nsrca-discussion at lists.nsrca.org
> <mailto:nsrca-discussion at lists.nsrca.org>
> *Sent:* 5/13/2006 10:34:53 PM
> *Subject:* [NSRCA-discussion] weight limits for electrics?
>
> Hi all,
>
> I am brand new to NSRCA and pattern flying in general. I
> am planning to attend my first ever event later this month.
>
> I noticed in the rules that the weight limit is 5Kg
> /_without fuel._/
> //
> How does this apply as far as electric powered planes are
> concerned? Are the batteries considered the fuel?
>
> I am asking because my plane is a Quest 90 G2 converted to
> electric power and it weighs 4.04 Kg "dry" (no batteries)
> but it weighs 5.33 Kg fully "fueled" with batteries installed.
>
> I have asked about this on RC Groups and been told not to
> worry, no one weighs planes except at the NATS.
>
> Has there been any official word on this? I don't want to
> feel like I'm cheating in a contest or "getting away" with
> something.
>
> Thanks!
>
> Larry
>
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