....try to decipher what our new Novak telemetry gear is telling us about g spots.....

Yeh I know it's an old argument now, that bridge has been crossed.

It will be interesting to see just how the "new" cars handle with a lipo. If my already slightly front biased 501x gets any lighter in the tail it will kick off the jumps (ask Ash peeler about this interesting handling trait during his worlds campaign) and so I'll either have to diet the nose, and those who know my 501X already know it's been on a serious diet or ballast the rear. For my money, weight distribution is critical, and so for that reason, I'll be sticking with Nimh's until I can redesign some chassis. Having said that, bring on the Lipos and leave the weight limit the same. Most cars won't be far under, as the B44 with 4600's weighs over 1800 anyway. This I know, because I was heaping it on Newman over his Tubby Tubs '44 at the Nats when compared with my light as a feather ZX-5. Unfortunately I was not the one who came home with the title.

I'd say it probably depends on which class you are running. In Mod the weight distribution is going to be more important than in Stock for sure. Stock, the extra speed you get from losing that much weight is going to be far more beneficial.

Weight
 

I thought I would join in while the main topic is weight.
I run in onroad and have bought a couple of cheap lipos. With one of the Yeah racing 3200s in my car I have had to add over 250 gms to bring my car up to weight. (I did this as I believe rules should be followed by everyone for parity in racing.)
I did, however, strike a problem. Have any of you tried to add this amount of lead to a T2 007 ? I even had to stick 50gms to the bloody battery and the same to the brace.
So to make this a less painfull experience even a drop of 100 grms would be a godsend.

Terry

That's a good point Ash. We've been talking about offroad and forgetting completely about onroad. Just because most 4wd buggies are tanks doesn't mean the TCs are.

Ok, now I could get this wrong. Somebody please correct me if I do but: Mod TC is about to go to 5 cell, yes? Meaning that shortly Touring Cars will appear on the market designed for less weight. I'm guessing here but wouldn't the weight limit be changed to accommodate this move. If so, then what about Stock? Will the weight limit change there too? If not, and Stock TC is still running 6 cells then not only will Stock TC drivers using LiPo have to add weight to their car to meet the limit but their handling will be off (by the testimony of others in this thread) as well (since the new TCs will be designed for lower weight limits).

So, given the scenario I just outlined it would make sense for TC weight limit to be reduced in Stock (as well as Mod) to accommodate the new circumstances. And if in TC why not elsewhere?

The other possibility is that 5 cells will be the norm (in Mod) but the weight limit isn't changed. Thinking logically manufacturers would then tend to build slightly heavier TCs. If they do, then the problem with LiPo in Stock would be less pronounced for these newer cars, and no rule change would be required. If you had an older car though, you would have the same problem that Team Ash does. And when you are adding that much weight to a car not designed to have weight added to it, it is very easy to lose some of it during a race (or get your mass accounting wrong) and end up light on the scales at the end of the race. I don't think anyone enjoys being disqualified in this fashion, so we should try and avoid this scenario.

I would like to ask: has anyone (painy) been doing much running with reduced numbers of cells? For those who have, have you found the reduced weight to make handling difficult? Or is there a trade off somewhere else we are not considering? What are your experiences?

And could somebody let me know what the deal with 5 cell actually is? (Then I can stop playing hypotheticals.)

Pete, if you are still reading this thread it would be interesting to get your thoughts on the weight issue.

Terry, check out the PPD Billet website.. http://www.ppdbillet.com/RC_accessories.html .. I'm sure you will find something suitable on there to add weight to your T2 007.. I have ordered The TC5 base weight and TC5 side weight for my TC5 as I could not work out where to put that much lead.. The Yeah Racing Lipo itself is very light at 210 grams, so it goes without saying, that by using a heavier lipo you wont need to add as much (ballast) weight..

Kevin (from PPD) recommended the Universal adjustable side weight and also the stainless inserts for Cyclone and Xray owners that have limited space under bulk heads / top decks.. This will also depend on what battery you use / buy (re its height)..

Cheers

Warning: parody follows (not to be taken seriously).

Around the Pit Table
-------------------

Joe Racer: Hey Jack, you seem to be struggling out there, what's up?

Jack Racer: I don't know man, I've got all the latest motors and batteries and my set-up is the same one used by the World Champ.

Joe Racer: Let me take a look. (picks up car). Ah, here's the problem, you're running the old style machined weights. You gotta get the latest ones they're the bomb.

Jack Racer: I don't know, I already upgraded from lead weights to machined steel. My car feels pretty fast with the extra steel on board. What's the go with the new weights?

Joe Racer: The Mark II weight is made of depleted plutonium so it's way denser. Plus it glows in the dark so it's worth like at least 3 tenths a lap.

Jack Racer: Wow, I gotta get me one of those. How much does it cost?

Joe Racer: The latest weapons grade one is only $300, but I'm looking to upgrade so I'll sell you my old one for $80.

Jack Racer: No way man, I'm not getting left behind again. It's weapons grade plutonium for me too!

5cell TC has a reduced weight limit to accomodate the battery restriction. I think this is apporopriate, as 5 cells produce less torque than 6. I don't run mod, just read the rules when entering events. My MSX is underwieght with 4200's, and my high tech ballast is the humble 20c peiceX2 (22gms) plus 1.5gms DS tape. Gets me legal, though. I would hate to think how badly the car would handle with a drop in battery weight down one side. I suppose that oval racing's always an option:lol:

Unless there is a 6V (nominal) Lipo, there is no point comparing them to a 5cell nimh.

I have a trackpower brick, and had no trouble ballasting it down the outside to get the car 50:50 down the centreline using tyre balancing weights. As yet, I'm not convinced there is much advantage over 4600 Nimh's. I'm going to be jumped on for this, but since I stopped buying 1245+ matched cells and started just using "Dirtys" my battery problems have disappeared, and my car is still as fast and cometitive as anyone elses. I don't discharge b/w uses and balance about once a month. Also I only charge at 5A. No explosions, no problems. I would definitely not do anything different with a Lipo, as a topped up battery is always best, no matter what it's chemistry. I found this with my Lipo planes. Added to this that the Nimh doesnt require amp restrictions to accomodate it's charge cycle, so a given capacity nimh will charge quicker than it's Lipo Equivalent. Take a few of these things into account and Nimhs don't look to bad after all.

The long and the short of it is that it seems pretty simple. Legalise Lipos, keep the weight limits and let the racer decide what's right for them.

Same goes for off road (which is what I primarily love to race).

i wouldn't rule this out think of 5 cell compared to lipo in mod tc.
weight advantages are two fold power to weight and handleing.
having said that never used 4 cell anything only 6 cell and lipo.
i do think lipo its the future lighter aand higher capacity then nimh it wins hands down and donw say nimh is safer id rather a pack catch fire then explode and i think we have all seen the results of explosive nimh, its a matter of time till they kill. i just think let people spend what they want and race to their budget,
btw weight is easier to add than loose so id rather a light pack and bring it up to weight

Lipo, Nimh, Ni-cad. They all have their dangers. I don't see any of them requiring less respect than each other, and as most people know that Lipo is in fact a safe option, I'm pretty sure that the lipo danger argument is becomming a red herring.

You said it, you'd rather have to add weight than subtract it, so Lipos should be a choice open to you. I'm already under weight, so Nimhs should be something I can stick with if I so choose because my Nimh's provide a lower battery CG than a ballasted lipo, and the Centre of mass of the battery compared with a low height position of ballast Lipo is closer to the CL. This results in a lower polar moment of inertia. A car that takes my fancy that is designed around Lipos would get Lipos and I wouldn't think twice about it. Right now my Fav cars are designed around Nimh's and I would like the option of keeping them on a level playing feild - i.e. no reduced weight limmits.

As people can probably gather, I'm for Lipos, just not for reduced weights.

The drop in the minimum weight for 5 cell TC was to accomodate the loss of the weight of a cell, which supports my argument for a reduction in min weights for lipo, you want choice for the racer, if u dont drop the min limit, then you dont leave them a choice to add weight or not

Yeah you do. 6V Lipo=lower weight limit, 7.4V lipo = same weight limit. Now just persuade a manufacturer to produce a 6V(nom) lipo. Chemically, it isn't a problem.

Less power + less weight is not the same thing as same power+lower weight.

5cell mods against 7.4V Lipos? there goes your level playing field unless the cars are now SOpowerful on 7.4V that no one can drive them, and i think we know this is not the case.

The other classes that are six cell should not render the Nimh obsolete by making their racing position untenable just yet in my (probably not worth a hell of a lot) opinion.

If you update your car to one designed around lipo, that's a valid choice, and you'll want to run Lipo. If in future weights are reduced, remove the ballast, and gain the weight advantage. At least there will be a period of time where the changeover can occur. Remeber that at this point in time, many newbies still turn up with an 1800 ni-cad stick pack, and can be reasonably competitive in the less power hungry classes.

Anyway, my B4 with a trackpower brick just monos like a dog, and all the suspension tweaks in the world won't bring that CG forward. It needs ballast!! it also needs the right ratio of sprung to unsprung mass, and this sees me run it over the weight limit in stock, where weight matters (yes ballast goes against my grain, but sometimes dynamics have to win the day).

We need to cater for a majority of participants, not just those who want to take up the new techs ASAP. I'm sure that most clubs have a split between die hards and social racers, lets not ostracize the latter, even though I tend to fall into the former category.

-a

Maybe you should talk to Josh Pain. He's running 4 cells in 2wd Mod for better balance! You see, if you put less weight at the back then your CoG comes further forward.

(Sorry for giving away your speed secrets Josh.)

agreed that this moves the CM of the Battery forward, but alas, us control motor guys can't do without our volts, as we cant compensate for 4cells with a 3.5 BL motor.

We could talk about vehicle dynamics all day, assuming that you can split lipos up into torch batteries and move them around........

I guess I forgot, you can already do that with sub c's:weird:

I have to ask... how can you POSSIBLY be underweight with an MSX:confused:... I own one and with typical modern electronics its, usually, at least 30g overweight with no weight added... I think at scrutineering yesterday in 5 cell it was 1478g (1450g weight limit)

This is an area I am trying to understand... I am not sure why LiPos seem to only be 3.7v / cell... I read it should be possible to make them other voltages yet no one seems too in RC world...

LiPo is not going to replace NIMH totally while there are classes that need other combinations of voltages IE 4.8v, 6v...

On a different note and to add another cog to grind - Who has seen and is interested in the new 1/10 pan car tourers... Even Associated has jumped on the wagon...