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Old 10-17-2008, 04:23 PM   #61
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Originally Posted by andrewdoherty View Post
I agree that the NiMh's work just fine. I believe the problem is that with the movement of other classes to LiPo, it will be difficult to source NiMh in a year or two. I don't believe the main reason were talking about LiPo is the performance of the NiMh's.
Thats a good point. I would think that there is enough 12th scale guys and oval guys around to keep the demand up though. I still don't like the idea of Lipo . It costs just as much if not more to purchase, with less performance. Again, just my .02.
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Old 10-17-2008, 04:28 PM   #62
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Sure it will...1/18th scale cars like the Scalpel are allready that light or lighter and have smaller tires (smaller contact patch) and shorter wheelbases and they handle just fine. The same weight with even bigger contact patch should be just fine. It may require a change in foam compounds but I think with pinks you should be able to make it work.
Sure it works wuth the scapel, because the wheelbase and track width are setup for a 1/18th car, not a 12th scale. I think you're comparing apples to oranges in the case. I think we should just leave it where it is, and thats a brushless with Nimh. If I had my way, we would still be running brushed motors, but thats another thread.
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Old 10-17-2008, 04:28 PM   #63
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Thats a good point. I would think that there is enough 12th scale guys and oval guys around to keep the demand up though. I still don't like the idea of Lipo . It costs just as much if not more to purchase, with less performance. Again, just my .02.
I agree with you too. I dont see nihm as that much of an issue to justify a buch of new rules and regulation for batteries that are not going to be any faster.
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Old 10-17-2008, 04:32 PM   #64
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I agree with you too. I dont see nihm as that much of an issue to justify a buch of new rules and regulation for batteries that are not going to be any faster.
Amen to that my friend.
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Old 10-17-2008, 04:40 PM   #65
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By going to the lipo And the 380 motor you have elimanated 1/3 to 1/2 the weight. Will the car really want to do anything but drive in a straight line,
Firstly...as I said (and measured), you don't lose 1/3 to 1/2 weight. At least not with a conversion on a current chassis. By the time I add the motor adapter in I only see approx 15% reduction in all-up weight. That said, a car that has the rear pod re-sized for the 380 motor would lose another 10% or so but we're still not even close to the 1/3 mark.

Secondly, weight works in two ways. To your point one of those ways is to create "downforce" via gravity. The other way is as inertia. More weight is harder to accelerate and decelerate because requires more energy to change the motion. To your comment regarding the car only wanting to drive in a straight line, with less weight there is less inertia moving straight forward. For that reason there is less force needed (ie traction) to change that direction. What minimal amount we've lost in "gravity assisted traction" we've gained back by having less to "bend around the curve". I'd wager it will be a wash and we'll be able to easily use current compound tires (and enjoy even better tire wear) at least until someone develops a compound that is optimized for the lighter weight.
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Old 10-17-2008, 04:47 PM   #66
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Firstly...as I said (and measured), you don't lose 1/3 to 1/2 weight. At least not with a conversion on a current chassis. By the time I add the motor adapter in I only see approx 15% reduction in all-up weight. That said, a car that has the rear pod re-sized for the 380 motor would lose another 10% or so but we're still not even close to the 1/3 mark.

Secondly, weight works in two ways. To your point one of those ways is to create "downforce" via gravity. The other way is as inertia. More weight is harder to accelerate and decelerate because requires more energy to change the motion. To your comment regarding the car only wanting to drive in a straight line, with less weight there is less inertia moving straight forward. For that reason there is less force needed (ie traction) to change that direction. What minimal amount we've lost in "gravity assisted traction" we've gained back by having less to "bend around the curve". I'd wager it will be a wash and we'll be able to easily use current compound tires (and enjoy even better tire wear) at least until someone develops a compound that is optimized for the lighter weight.

OK, unless I've missed the point you're trying to make, 15% added to 10% is 25%, which is getting close to the 1/3 or 33% mark. As for your second paragraph, I agree with it to a point. I understand what youre saying about the inertia, but it seems to me that in order to acheive sidebite, you still need some weight to throw around to put a load on the tires. Also, with the less weight to"bend around the curve" as you put it, you also have to remember that the motor you're using isn't as powerfull as a standard 17.5. I just think the car would be to "free" in the corners. As always, just my .02.
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Old 10-17-2008, 04:48 PM   #67
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But why would you want to make all of those changes in the first place. Changing the chassis, resizing the motor mount, buying a lipo that fits and a 380 motor. Seems like alot of work to fix a class that isnt broken and is quite alive and well with nihms I think personally.
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Old 10-17-2008, 04:50 PM   #68
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I agree with you too. I dont see nihm as that much of an issue to justify a buch of new rules and regulation for batteries that are not going to be any faster.
Nobody who's really serious (and been serious about 1/12 for any length of time) is interested in the cars getting "faster". Mod 1/12 is faster than any but the truly elite of the sport can really master/control and stock is too fast for beginners.

The idea is that some of us see that the future (more than, say, two years or so down the road) for NiMH availabilty starts to get a bit murky (maybe they're available, maybe they aren't...SMC are already cutting back how many cells they match, etc as the market moves to LiPo other than us in 1/12) and we're willing to invest some time and money now to explore options rather than wait until we're maybe backed into a corner. ALSO...having gotten to experience the convenience of LiPo batteries first hand now I would like to find a reasonable way to incorporate them into my 1/12 racing. I don't really agree that LiPo is any less expensive than NiMH but it's DEFINITELY more convenient than all the witch doctor crap we need to do to keep NiMH batteries in competitive condition.

Less mass/weight is also of interest to me (and some others) not because it is potentially "faster" but because there is less inertia when you hit the wall. Less energy to absorb will mean fewer broken parts (which could lead to even lighter parts, which could lead...) and less tire wear, etc. I'm not complaining one bit about the cost of tires, etc, but how nice would it be to be able to run a race day without having to re-set the ride height on my 1/12 cars. As it is I usually have to re-set ride height once during a club race day (two heats, re-set height, third heat and main). I'm kinda lazy and REALLY enjoy spending time bs'ing with my buds at the track way more than I "like" thrashing on my cars between rounds.

For now it's an interesting bunch of experimentation but it may lead to answers to the "what's next" question if battery supply becomes limited. Without well-tested options we could find ourselves backed into a corner and some yahoo(s) on the ROAR or IFMAR board who don't even race 1/12 making the decisions for us. I'd rather not find ourselves in that position.
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Old 10-17-2008, 04:55 PM   #69
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Originally Posted by Scottrik View Post
Nobody who's really serious (and been serious about 1/12 for any length of time) is interested in the cars getting "faster". Mod 1/12 is faster than any but the truly elite of the sport can really master/control and stock is too fast for beginners.

The idea is that some of us see that the future (more than, say, two years or so down the road) for NiMH availabilty starts to get a bit murky (maybe they're available, maybe they aren't...SMC are already cutting back how many cells they match, etc as the market moves to LiPo other than us in 1/12) and we're willing to invest some time and money now to explore options rather than wait until we're maybe backed into a corner. ALSO...having gotten to experience the convenience of LiPo batteries first hand now I would like to find a reasonable way to incorporate them into my 1/12 racing. I don't really agree that LiPo is any less expensive than NiMH but it's DEFINITELY more convenient than all the witch doctor crap we need to do to keep NiMH batteries in competitive condition.

Less mass/weight is also of interest to me (and some others) not because it is potentially "faster" but because there is less inertia when you hit the wall. Less energy to absorb will mean fewer broken parts (which could lead to even lighter parts, which could lead...) and less tire wear, etc. I'm not complaining one bit about the cost of tires, etc, but how nice would it be to be able to run a race day without having to re-set the ride height on my 1/12 cars. As it is I usually have to re-set ride height once during a club race day (two heats, re-set height, third heat and main). I'm kinda lazy and REALLY enjoy spending time bs'ing with my buds at the track way more than I "like" thrashing on my cars between rounds.

For now it's an interesting bunch of experimentation but it may lead to answers to the "what's next" question if battery supply becomes limited. Without well-tested options we could find ourselves backed into a corner and some yahoo(s) on the ROAR or IFMAR board who don't even race 1/12 making the decisions for us. I'd rather not find ourselves in that position.

Wow, you've made some really interestig points here Bro. I really like the last one about Roar. Its so true, and I don't think hardly anyone really realizes it.
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Old 10-17-2008, 04:59 PM   #70
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OK, unless I've missed the point you're trying to make, 15% added to 10% is 25%, which is getting close to the 1/3 or 33% mark.
That re-sized pod is DEFINITELY out there in the future. For right now (and until the market demands it) we're looking at approximately a 15% reduction in weight and even THAT reduction pre-supposes 2s 2000mah batteries. Use a higher capacity battery and you start cutting into that 15% thus moving further from your proposed 1/3-1/2.


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As for your second paragraph, I agree with it to a point. I understand what youre saying about the inertia, but it seems to me that in order to acheive sidebite, you still need some weight to throw around to put a load on the tires.
That is done with setup, etc. Roll center optimizes weight shift over or onto tire contact patch, etc, shock angle/anti-squat and front block angle/anti-dive also adjust weight transfer. Plus we just won't need quite as much as we did.

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Also, with the less weight to"bend around the curve" as you put it, you also have to remember that the motor you're using isn't as powerfull as a standard 17.5. I just think the car would be to "free" in the corners. As always, just my .02.
The motor is less powerful but the battery is MORE powerful (remember, I'm preparing a 2s test) so my net result should be fairly similar. That's what I'm betting on anyway.

I don't have all the answers by any means, but I've thought of a lot of questions and have puzzled out some reasonable enough answers that I'm ready to commit money. Worst case scenario, it doesn't work as well as hoped.
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Old 10-17-2008, 05:13 PM   #71
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Sure it works wuth the scapel, because the wheelbase and track width are setup for a 1/18th car, not a 12th scale. I think you're comparing apples to oranges in the case. I think we should just leave it where it is, and thats a brushless with Nimh. If I had my way, we would still be running brushed motors, but thats another thread.
It is still the same amount of power in a 1/18th scale (6 cell version) with a smaller tire and smaller wheelbase. Increasing these will only increase traction and stability.
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Old 10-17-2008, 05:30 PM   #72
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Hmm... I'm sitting here with a 'Bloody Knife' and a mamba 4200 system... Hmmm...

The pictures help with "mounting" -- still not an easy thing, but, OK... What do you do for pinions? (Sorry if I missed that, but I didn't find that above)... All the 380 pinions I've seen are for mini's and they are a metric pitch, not standard 48 or 64 pitch...

I hope everyone will remember what was pointed out earlier... The RACERS can discuss and research alternatives 'just in case' supplies of NiMh dry up or we can wait and let ROAR tell us what we'll do whether we like it or not... Remember that 4-cell oval came from the racers first, as did LiPo racing, etc... We can lead or we can follow... Keep the discussion open, allow fair and even debate without letting it get personal.
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Old 10-17-2008, 06:10 PM   #73
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Hiya guys. I wanted to put my own 2p's worth in on this one although, to be honest, I have not read EVERY post on this thread as alot of it is '1500kw's this' and '2000rpm' more that type stuff. I personally don't get the need to change this class. I have raced 12th cars for nearly 25 years because it is the best class and I don't get the 'need' to change it. If it's about costs, well I don't get that idea. 1/8th buggy racers are not talking about switching from .21 to say .15 size engines just to get the costs down. From an electric racers point of view, 12th scale is probably one of the cheapest classes of racing, not only from what you HAVE to have to compete, but also from the 'add ons' point of view (tyre warmers for TC's, etc, etc). I think that if you want to bring costs down, change the format of meetings so that you only run 3000mah cells (really cheap now as nobody wants them) and original mabutchi sealed 540 motors, or something along those lines rather than changing chassis designs, LiPo cells, small size motors, etc. Further on from that, you could give up racing 12th scale cars altogether and race in a Tamiya type spec class. Don't think I'm not open to new ideas but I don't see or feel the need to change my favourite class in such an extreme way. Cheers guys.
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Old 10-17-2008, 06:16 PM   #74
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No one is talking about changing it now...this is to figure out what the future should be when NiMh cells are scarce. With LiPo and other up and coming battery technologies out there NiMh will be used less and less. Eventually a change will have to be made...the question is will we be ready for it or will we have to shoe horn something in.
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Old 10-17-2008, 10:24 PM   #75
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Sigh.
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