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Old 12-28-2004, 03:30 PM   #106
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So, how many companies sell 4 and 5 turn motors???
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Old 12-28-2004, 03:32 PM   #107
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JKA - The main problem is we are roasting motors. I have seen comm slots bridged by strands of molten copper, blown winds due to molten epoxy, brush shunts and motor power wires unsoldering themselves, balancing epoxy flinging off due to insane RPM and centrifugal loads. You may not run inot this at club races but the motor guys at big races see this a lot when pros really push the limits. They know you can't just fix the motors. They have come as far as materials science and design can take them.

If you think the soultion to this is brushless motors you will be replacing one set of problems with another. Blown speed control fets (this is why there is no full mod Novak Brushless on the market yet), blown rotor magnets, demagnitized rotor marnets, shorted stator windings, etc.

How do you fix this? Reduce voltage and thereby reduce wattage output (heat) and reduce RPM. The reduction in wattage output is mitigated by the 4.5oz weight reduction.
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Old 12-28-2004, 03:34 PM   #108
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Quote:
Originally posted by timmay70
I went to the ROAR Off-road Modified Nationals this past year, my track owner went the year before, also. Both races had 'hand-out' tires. These limitations were set to allow the unsponsored drivers to have access to the same tires that the Pros race. Not only were the tires limited in spec, they were also limited in quantity allowed to race.

Back on topic: I think that IF my local track were to say lets give 4 cell sedan a go, I would be one of the first to give it a shot. I raced 1/12th pan 14 years ago. Making a 1700 SCE last 8 minutes on a budget was the name of the game. Not only did we play the numbers game, we also tracked the batch codes, as some had a strange tendancy to take more abuse than others.. With the increased capacity, there is no reason why a sedan cannot make the time running even full mod with the average race cells available today.

OT: I would rather go through more foam and have the carpet last longer than pay higher prices over the long haul just so the local tracks can afford to replace the carpet more often.
Timmy, I was at those Nationals and I'm glad you got the same crappy tire choice as the pros. It was real nice to see tires worn out after half a run. Even worse having the pro's racing on them in the main.

Even running the same tires did you make the A? Where you even close? No. So it doesn't matter at a Nationals the pros are going to win. What would have been nice is that they developed new tires that didn't wear so fast and have the same traction.

For example. the gas Nats (where no spec tires are) the race was one because Proline developed the R3 for gas racing. The winner ran R3 and the guy that should have one the older compound. Since Pro-Line had an advantage with coumpund racers for that surface now have a better tire.
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Old 12-28-2004, 03:42 PM   #109
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Derek - We all know how you feel about spec tires and I respect your right to express your opinion. Luckily most racers(Pros and Privateers), your contributing editors and your publisher disagree with you!

FYI, Take Off has a new tire...The RP series. The makers of the top spec tires in the world never stopped developent.
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Old 12-28-2004, 03:43 PM   #110
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Quote:
If you think the soultion to this is brushless motors you will be replacing one set of problems with another. Blown speed control fets (this is why there is no full mod Novak Brushless on the market yet), blown rotor magnets, demagnitized rotor marnets, shorted stator windings, etc.
Now you really don't know what you are talking about!!! The increase in voltage is the best thing that can be done for brushless motors. I have been running brushless for 5 years. The thing that kills the controllers is the current not the voltage. Almost everybody in the brushless world is going to higher voltages to avoid killing controllers. Don't argue brushless, you are very wrong!!
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Old 12-28-2004, 03:53 PM   #111
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Hey Kaufman Where do you work again and what do you do?????

Keep up the good fight.....
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Old 12-28-2004, 04:07 PM   #112
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Adrian-- Actually, there is no full blown modified Novak Brushless system on the market yet due to the fact that other projects have been in the pipeline scheduled for release before it

But thanks for thinking of us
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Old 12-28-2004, 04:10 PM   #113
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I don't care. I'm gonna try 4cell 19t this weekend. How many teeth do you suggest I should add to the pinion to start with Adrian?

Maybe for 2006, the Snowbirds could have a 4cell TC class? If there's an exhibition 4cell class at the Nats in October.. I'll run it....
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Old 12-28-2004, 04:15 PM   #114
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Quote:
Hey Kaufman Where do you work again and what do you do?????
I am an electrical engineer and I work designing and building power supplies for a particle accelerator. Anything from 20V and 5,000A to 3,000V and 3A.
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Old 12-28-2004, 04:21 PM   #115
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Kufman - I too have been running Brushless for a few years in R/C air planes. Hackers, Lehners and HiMaxx motors.

You are correct in that it is massive current passing through the controller that kills them...spikes common in R/C car applications are particularly bad.

I understand how higher voltage makes the Brushless motors operate more efficiently but it is a non issue as we will never run high voltage system in cars. I am pretty sure ROAR will limit LiPo's to 2s packs whenever they get tough enough to survive in an R/C cars.

Like I said. I am not an engineer but higher voltage results in more watts, more heat to dissipate and meltdowns. I have seen roasted Hackers on 10s4p packs. High voltage is not the answer. It wasn't in the past and it will not be in the future.
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Old 12-28-2004, 04:25 PM   #116
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Going to a four cell would only be good in the beginning but will probably have its own set of problems. 1/12 pan cars growing popularity probably has more to do with its overall price and simplicity. As for spec tires, I was for it when the local clubs would find out the best spec tire for the surface, but when clubs just order a spec tire just because it is the easiest to get then thats when the idea for spec tires turns me off.
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Old 12-28-2004, 04:29 PM   #117
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Quote:
Originally posted by AdrianM
JKA - The main problem is we are roasting motors. I have seen comm slots bridged by strands of molten copper, blown winds due to molten epoxy, brush shunts and motor power wires unsoldering themselves, balancing epoxy flinging off due to insane RPM and centrifugal loads. You may not run inot this at club races but the motor guys at big races see this a lot when pros really push the limits. They know you can't just fix the motors. They have come as far as materials science and design can take them.

If you think the soultion to this is brushless motors you will be replacing one set of problems with another. Blown speed control fets (this is why there is no full mod Novak Brushless on the market yet), blown rotor magnets, demagnitized rotor marnets, shorted stator windings, etc.

How do you fix this? Reduce voltage and thereby reduce wattage output (heat) and reduce RPM. The reduction in wattage output is mitigated by the 4.5oz weight reduction.
I think brushless is the solution

The track i race at races a run-what-you-got class. As long as it is a touring car and has a tc body you are good to go. I have been racing a 5800 Novak system for over a year with no probs. For the price, it has really saved me big money while still allowing me to be competitive with all the people who have their own lathes and have to replace brushes all the time. It also eliminates maintenace which a lot of average racers would like.

Also about foams vs rubber, I think foams are the way to go. I made the switch from rubber to foams and couldn't be happier. Traction has been incredible. They do wear a little faster than rubber but a 11 bux a pair i'm not complaining and the added traction is well worth a little extra money.
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Old 12-28-2004, 04:41 PM   #118
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kufman - fight shouldn't be that tough.

most of your opposition has taken to comparing different voltages applied to identical motors and loads, which was my first thought as well. because the idea presented is to substitute hotter motors to compensate for a deficiency in voltage, we would, most likely, be drawing more current than we are with 6 cells. i say most likely, because the cars are said to be a few tenths slower. i don't know how much a few tenths impacts the current draw.

with the proposed new rules, we would have:

- a new slower stock class
- a 19t class that used to be stock w/ 6 cells
- a modified class that may be slower, or will use even less winds than they do now.

so the comparison for the replacement classes gets slightly convoluted when you account for all the changes, but it must be acknowledged that in order to get around the track in same time frame with less voltage, one would need more current. or a lighter car....
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Old 12-28-2004, 04:41 PM   #119
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Kufman - By the way...Reedy was looking for an EE with lots of advanced knowledge in magnetic fields and their manipulation. I don't know if they filled the position yet.
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Old 12-28-2004, 04:47 PM   #120
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Default count me as one who agrees with derek

"
I know. I said I love 1/12th, but the cycle of racing is simple. A class get popular and is dominated by pros then somebody says "hey I can win at this class because nobody is running it" that class becomes popular and then the factory driver dominate that.

It's why racing MTs is so popular right now. The factory drivers racing that will ruin it too. The "regular" guy wants to win.
"

oval died off because it became elitist, your average joe schmoe could no longer do well. oval and 12th are still dead in their own rights. show me any oval/12th series of races with a consistently strong turnout. now...before you immediately jump on the 'snowbirds' bandwagon, let me add the caveat of that event not also being a sedan race. the resurgence in oval/12th has came by association to sedan, nothing else.

oval/12th still has every bit the potential for battery/motor/tire wars it did 10 years ago, the racing has simply dropped to a lower level as teams do not put the resources into it that they used to.

my point is this....4 cells in a sedan is not going to change/save it. if this was true, we'd all be running oval.
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