Your point is pretty well made, but you forgot one thing, what R.A and i are saying is that the lipo doesnt benefit everyone the same way, you bolt in a 13.5, i bolt one in, we both get the same benefit from that, but lipo wont benefit everyone in the same way, cos some people will have to add weight to their cars to bring them up to the current limit, all i'm suggesting is that the minimum weight for cars has been based on ni-cd and nimh cells being in the car, therefore the minimum weight should be reduced to match the decrease in battery weight, and some sort of provision made to smooth out the transition phase. Each persons choice of car is made based on varying factors, if you chose a tank and R.A chose a lightweight, thats every persons choice, not everyone thinks it is an advantage, but of course, people are going to want to protect the benefits of the choice of car they made

This is a very good read.

Lets look back on this thread in say, nine months and see what has occurred.

Li Po is here, now, already. Olden day batteries are not worth the pain or expense.

As Ray mentioned, Keilor now runs: "6 minute races and its amazing how much difference that extra minute makes! 4 heats + 1 final = same race time as 3Q/3F but a shorter day and IMO more fun."

A six minute race is a lot different (well feels a lot different) to the five minute races we have been acclimatised to over the years.

I notice that there was one point that you didn't mention.

Regarding the minimum weight and the cars that are already light who choose to run lipo,
when the weight is added to bring it back up to minimum weight wouldn't that also be an advantage because they would effectively be lowering the CG and gaining a handling improvement?
That would still give them the "Edge" with the better, lighter car they chose to buy in the first place wouldn't it?
Just a thought.

depends where the "heavy" cars are overwieght, if it's the chassis then no real conceivable difference, but as you suggest something like shock towers, shocks or sprung mass, yes makes a difference.

Guys I am running Lipo in 4WD stock, I have weighted the same as NIMH as I don't want to be setting up differently when using either type of battery (yep, LAZY!:( and kids:D) Yes I do run a Roche (Feigao) motor, but anyone at our club will testify this is fast. I am yet to run with NIMH (waiting for some 4600's next week, my 4200's are a bit crusty) to see what difference the slightly higher voltage will make. I have tried running without weight added with Lipo and I can't get it to jump right on higher jumps anyway.

When Lipo is legal, there will definately be a new line of chassis designs emerge. I see the minimum weight dropping within a relative short time for sure, particulalrly due to the fact that NIMH will become obselete.

I hear some complaining of having to buy new chargers, what happened between Nicd and Nimh? Same thing guys.

It is a change for the better, that's what it's about!

Itchy, you're right, there is an advantage to being able to place the weight where you want to help CoG but theres no way that would make up for 150 - 200g and in the case of XX4, where can it be put anyway.

X5 you're right for sure, Lipo is coming, and hell i'll be running them because i see all the benefits, but people are pushing to have them legal right now etc, there needs to be a little more thought put into its introduction before just declaring open season at big events

I count 4 big meetings where they are not going to be legal for the rest of the year and they are all in NSW.

Well blink and it will be december and they will be legalised - and then we will have caught up to the mexicans and the canetoads.... :lol::lol: thats a first our northern and southern states being ahead of NSW ;)

No, I understand, and I didnt forget anything. Anyone currently running a light car will loose some of their advantage..

OK, we both bolt in a the same 13.5 BL and ESC, but your car is 100 grams lighter than mine with NiMh, so how do we both get the same benefit or performance?? The Power to weight ratio says that the lighter car will still accelerate quicker, and will most likely still have a better top speed. Advantage to the lighter car.

Put a lipo in both cars so it brings the heavy car down to the weight limit (but still may need additional weight to get it to work), and you have to add weight to lighter car to bring it up to weight, (but you get to place the weight lower, and where its needed in the lighter car and still be on the weight limit). Albeit not as great, but the advantage is still with the lighter car.

Unfortunately we cant make everyone happy.

So, you'd rather just lower the weight limit by 200g? That works. I'd be ok with that. Then we would all get the same advantage by going LiPo; NiMH would be less attractive.

It seems like it probably will be, but lets be careful not to lose any of our number during the transition. As has been mentioned before there is a significant cost associated with the change in infrastructure. It's not just the batteries themselves but also the charger and sack. We are already dealing with a similarly expensive* change to brushless technology. Please can we ensure that I don't have to change my chassis at the same time to be competitive.

Let me ask: how many times in the history of RC racing has technology changed so that it has become necessary for an established racer to change their motor, speed control, charger, batteries and chassis at the same time? Am I to throw away all my gear? The only thing that could make the situation worse is if every type of radio other than spectrum was outlawed.

In answer to someone's pseudo-unasked question. There are 2 main places you can add weight to a XX-4 (In preparation for the '99 Nats, where I was running 540, I trialled 1400 batteries that were much lighter than the 2000s around at the time). Servo taped vertically to the backbone near where the centre shaft is, and taped vertically to the servo between the servo and the batteries on the RHS of the car. If you are desperate you can also mount it up high, on top of the backbone. None of these places helps lower the CoG, in fact they all worsen the handling of the car. To add 200g I would probably have to use all 3 of these locations. I would posit that there aren't too many cars (4wd especially) that have been designed to add weight to. Most likely you will either be mounting your weight up high on a top deck or wide on the car on the lower part of the chassis - that will hurt your stability.

* I mean expensive in terms of initial cost, it may be cheaper in the long run (but that's not my immediate concern).

You obviously didn't race in the late 80's early 90's. You would change all of these probably every 6 months.

Lipos's are coming whether it be now or early next year so get over it. If your that concerned about changing chassis :confused:, motors etc then maybe you should be a good boy so that Santa will bring you something for Xmas.:nod:

Please tell me WHY you feel that you have to go out and buy all new gear if you want to run LiPo.?? Do you feel that when you loose your current weight advantage that you are no longer going to be competitive?? You most certainly have the driving skills, so why are you so concerned about your car?? (I have neither skill nor car..lol)

R.A, you have a CDC-7, (the same charger as I have) so you have no issues there. A sack will cost you between $20 - $40, and a balancer $50 - $65 depending on what and where you buy.

I am going to use the EXACT same Motor, ESC and car for LiPo as what I used for NiMh. The only extra I have added is a Novak Smart stop (@ $34au) because the ESC does not have a lipo cutoff, although I feel that this may not be needed with the 5000's.

For weight in the XX4, i introduce you to PPD Billet. http://www.ppdbillet.com/RC_accessories.html . Check out the LiPo base weight for the TC5. Cut one of those in half and place it under each LiPo.. Still need additional weight?? Then try a side weight, cut in half and stuck to the side of the liPo, or to the side of the backbone / belt cover.. BTW, the TC5 base weight and side weight, weigh approx 165grams, add 300grams for the LiPo and you have the same weight as a 4200 niMh pack..

But buying the heavier car was your choice, its about the relative performance benefit of the changes compared to what we had before, not by comparing the cars, we both benefit the same amount by putting in a 13.5, relative to what was available before in the 27turn motors, we dont benefit the same by both putting in lipo's, i dont see what your deal is, we can make everyone happy, just drop the weight limit for cars by 150-200 grams, then we both get to run our cars with lipos without changing anything, its no different to you, you weren't on here before complaining about the fact my car is lighter than yours with nimh in it, cos you chose a heavier car,

Mikey,

These weight limits have been around since the beginning I can't see why we would need to change the weight limits now. Remember 1200SCR's were probably about the same weight as todays LIPO's and we didn't increase the weight limit when batteries got heavier so why reduce it now. Are we not just coming back to what the current weight rules were originally designed for.

you dont really need to change all your gear though. its already been proven that brushed stock is just as competitive, from memory it was in the top three at the castle hill CC and has made the A plenty of times this year.

I reckon its a bit extreme to say you have to throw away all your gear.

our technology changes constantly each year

speed controls - mechanical, FET based, BEC included, high frequency speedys, programmable speedys, more efficient FET based speedies, smaller form factor speedies, brushless speedies

servos - analog, external FET, digital, internal FET, coreless, low profile

radios - AM, FM, synth FM, spektrum

motor - 540 can, replaceable brushes, aluminum composite, numerous magnet types, countless brush hood designs, countless endbells, brushless....

chargers - 240V slow charger, charge leads, 240V fast charger, thermal chargers, peak detection, linear, step, charge/discharge function, motor run in profiles and on and on....

batteries - 1200mAh NiCd et al..... - 5400mAh Nimh

oh yeah and chassis - abs plastic, fiberglass, carbon, plastic, carbon reinforced plastic, aluminium tubs

and I am sure I have left out plenty of other advancements that we have all bought in to :)

we are in a constant state of advancement in this hobby, its not different to any other hobbies. Tennis racquets are no longer wood...

this for the first time though is actually going to make our hobby cheaper to enter and much more user friendly. two packs and a brushless motor get you going - how good is that for the novice and noobs. :)

but why do guys care if they are changed, the reason we have to change them is that some current chassis will become illegal as soon as people put lipos in their car and if we're legalising a battery that is 150-200g lighter, that makes up a large proportion of the total weight of an r/c car, 10% or more, the rules werent changed to make the min weight higher as the batts got heavier, cos it didnt matter, companies were able to design light effective cars to fit within the rules, ie losi xx4, that meant people were able to still run the right weight, but a big change like this needs to be addressed properly

The big question is, why do you care if the weight limits are changed, ive clearly stated why they should be, all ive got a vague references to 1200 mah cells and people saying you cant make everyone happy, none of which offer a lot really, when people are talking about the future is coming and then we have to look at 1200 mah, please kettle and black and we can make everyone happy, by adjusting the min weights

Mikey

I see your point but as most cars in 4wd except the XX4 are overweight the vast majority of drivers on a worldwide scale are not going to have an issue.

I think thats the key point also. It has to be done at a world level and I have not seen ROAR or the Euro guys put anything fwd as yet.

Everyone in 2wd will have to add weight and that will be a good tuning tool for all to utilise.

So what we are really debating is the XX-4 drivers right?

Ben