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Old 12-16-2008, 10:35 AM   #601
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Originally Posted by trailranger View Post
1:12 will evolve over time. Right now I see 1:12 going to 3.7V lipo because the only change that will occur is the battery pack. The 3.7V concept has gained alot of traction to becoming a organized class for the fall of 2009.



I feel the 3.7V and motor we currently use will be adequate for our racing pleasures for many years.



The 1:12 class is a fun and easy to maintain race class. For now, NiMH is good enough to race with. Next year LiPO's would be a good battery race with.



Happy Holidays, Merry Christmas! Don't forget to ask Santa for a 3.7V SMC LiPO for Christmas.

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Old 12-16-2008, 10:53 AM   #602
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The biggest problem I have with this thread is that some are suggesting that we completely tear up the rules for the whole class.

Single cell requires these two changes:

1) Change battery.
2) Add receiver pack or voltage booster.

Two cell (7.4v) guys are suggesting that we change:

1) Change battery.
2) Change motor.
3) Change rear pod design for new motor or use some cobbled up adaptor.
4) More recently change suspension design (requires main chassis change)

Both options can end up with a lighter weight rule (a good idea IMO).
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Old 12-16-2008, 12:42 PM   #603
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Originally Posted by Unregistered View Post
The biggest problem I have with this thread is that some are suggesting that we completely tear up the rules for the whole class.

Single cell requires these two changes:

1) Change battery.
2) Add receiver pack or voltage booster.

Two cell (7.4v) guys are suggesting that we change:

1) Change battery.
2) Change motor.
3) Change rear pod design for new motor or use some cobbled up adaptor.
4) More recently change suspension design (requires main chassis change)

Both options can end up with a lighter weight rule (a good idea IMO).
Not really. To run two cell packs all we need is a new motor wind for stock. Same size motors and cars. We would need new packs though. A single cell size case with 2p and then a 2s2p saddle for the t-bar cars. Mod is a none issue, you can pick your motor in that class. Im sure they wouldnt be running the 5.5 and 3.5's there running now but i bet a 10.5 on 2 cells would be pretty fast.

I have to admit that since brushless has moved down to 1/12 its been a LOT easyer to get and keep HP. As long as we can get good packs, you know the kind that when you buy 4 cells you get 4 good cells? Or after having the pack for a month you still have 4 good cells when only racing once a week???

Honestly, I dont think there is a way to get a 1s/13.5 or a 2s/21.5 to run the same as a 17.5/4 cell. Some say they have done it but, everytime I see a 1s/13.5 run its got no punch. It is the same for all 8mins though. And Im sure a 2s/21.5 would leave a 17.5/4 cell for dead on the infield.

Looks like it will be 17.5/4 cell for a few untill there is a better answer to the lipo question.

DK
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Old 12-16-2008, 01:24 PM   #604
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Originally Posted by trailranger View Post
1:12 will evolve over time. Right now I see 1:12 going to 3.7V lipo because the only change that will occur is the battery pack. The 3.7V concept has gained alot of traction to becoming a organized class for the fall of 2009.

I feel the 3.7V and motor we currently use will be adequate for our racing pleasures for many years. All this talk of going slow or going fast is purely the decision of the racer. The racer decides if they want a mod speeds or stock speeds. With 7.4V the choice for slower speeds was not an option, which is why the 3.7V has gained ground with stock racers in 1:12. 3.7V provides racers who just want to show up at a track and drive the ability to do so. Eliminating the battery voodoo process from 1:12 will make it alot more attractive to current racers and future racers.

I posted this several pages back, but I do feel smaller motors do have a place in 1:12 racing, just not right now. In the future when more mini sensored motors are available, I can see the 1:12's making the switch to those 380 sized motors in the next decade. I still feel the power source for those 380 motors should be 3.7V LiPO to allow for a broad range of speeds from stock to mod. The possible 200g reduce in chassis, motor, esc and pod mass would be enough to offset the slight reduction in power from the 380 motors. There will also be a cost benefit to making the switch to 380 motors. To compare a 380 Novak system to a GTB Novak system the mini system is $100 less and racers would applicate those savings when building a new car. Even normal wear on the car's tires, bodies, bearings and chassis may be less to the switch to a 600g car, but now is not the time for the switch.

The 1:12 class is a fun and easy to maintain race class. For now, NiMH is good enough to race with. Next year LiPO's would be a good battery race with. A decade from now, maybe those micro motors would be better fit those bulky 540 brushless motors. Give the 1:12 racers time to adjust to the changes and the 1:12 race class will stay strong and stay fun.

Happy Holidays, Merry Christmas! Don't forget to ask Santa for a 3.7V SMC LiPO for Christmas.
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Old 12-16-2008, 01:41 PM   #605
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Novak has already stated that it's hard to wind a motor with much more than 21.5 turns. So, we will need more than just a simple wind change to run 2 cell LiPo in stock.

It will take a completely new motor that we can't use in any of the other classes we run. I do run more than just 12th and I run the same motor in more than one class for onroad and offroad.
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Old 12-16-2008, 01:54 PM   #606
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Novak has already stated that it's hard to wind a motor with much more than 21.5 turns. So, we will need more than just a simple wind change to run 2 cell LiPo in stock.

It will take a completely new motor that we can't use in any of the other classes we run. I do run more than just 12th and I run the same motor in more than one class for onroad and offroad.
You can almost always go to more poles in the motor to knock the KV down but still not over pack it with wire.

I run diffrent class's also, but there all 13.5. You could run the new wind motor in VTA, 2cell stock 1/12, WGT stock 2cell, rock crawlers, I bet you could run it in the mini class also, F1, Im sure there are a few I cant think of right now. Either way I dought it would be a one use only motor.

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Old 12-16-2008, 02:00 PM   #607
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Or since ROAR now requires hard cases in LiPo manufacturers could install a voltage regulator internally in the case to regulate the voltage to 4 cell voltages. That would require less changes on the racer's end but a little more from the manufacturer's end.
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Old 12-16-2008, 02:02 PM   #608
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I've seen that posted a few times "Novak has already stated that it's hard to wind a motor with much more than 21.5 turns."

A 21.5 has a KV of 1800rpmv
http://www.teamnovak.com/products/br...spec_chart.htm

In the airplane world it's common to have low KV inrunners, I myself have one with a KV of 1200rpmv and another with a KV of 650rpmv. Both are un-sensored so I'm not sure if that's a factor in winding the motor.......BB
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Old 12-16-2008, 02:07 PM   #609
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Originally Posted by InspGadgt View Post
Or since ROAR now requires hard cases in LiPo manufacturers could install a voltage regulator internally in the case to regulate the voltage to 4 cell voltages. That would require less changes on the racer's end but a little more from the manufacturer's end.

A voltage regulator to step down the voltage of a 2S pack to the 4 round cell range would be very large, require a lot of cooling and must be able to handle hundreds of amps. I don't see that happening.....BB
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Old 12-16-2008, 02:11 PM   #610
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They can use a smaller guage wire and more windings to make it go how ever slow you want it to go. Decreasing the wire size will limit the amp draw as well.. the races could be longer even still.. 10 min atleast.
I can imagine theres not quite enough room in the stator field.
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Old 12-16-2008, 02:26 PM   #611
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Originally Posted by InspGadgt View Post
Or since ROAR now requires hard cases in LiPo manufacturers could install a voltage regulator internally in the case to regulate the voltage to 4 cell voltages. That would require less changes on the racer's end but a little more from the manufacturer's end.
That's just another thing to go wrong and be tampered with.

I still believe that 2s (7.4V) lipo and low Kv motors are the way to go from an efficiency stand point. I can see smaller motors being introduced in the future, but not now. I would like to stay away from reciever packs as much as possible.

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Old 12-16-2008, 02:45 PM   #612
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I still believe that 2s (7.4V) lipo and low Kv motors are the way to go from an efficiency stand point. I can see smaller motors being introduced in the future, but not now. I would like to stay away from reciever packs as much as possible.

-Frank
I agree

Regarding LiPo, I don't think 1s 3.7v LiPo is the solution. Why do we want to make this more complicated that it already is. With a 1s LiPo, you have to run a receiver pack, alter the setups, run different motors, different tires, etc.... This "SIMPLE" 1s 3.7v LiPo is becoming more costly by the day. Now we here that some ESC's won't function well at 3.7v.

If the day comes that we have to dump NiMh batteries for one reason or another, than a 7.4v LiPo and 21.5 motor would be the better choice. All of the electronics work better at the higher voltage, it is simpler to wire up, and the weight will still be lighter than the current 4-cell NiMh setup.
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Old 12-16-2008, 02:51 PM   #613
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Originally Posted by John St.Amant View Post
They can use a smaller guage wire and more windings to make it go how ever slow you want it to go. Decreasing the wire size will limit the amp draw as well.. the races could be longer even still.. 10 min atleast.
I can imagine theres not quite enough room in the stator field.
So what do you do when the motors turn such low RPM's that to properly gear we have to redesign the rear axles to accomodate smaller spurs and smaller diffs/diff rings.

Do you really want to run a 50T SPUR and a 76T PINION to be properly geared just to run a low Kv motor. I don't think this has been thought out far enough as to the impact of the 1/12 car design as it is.
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Old 12-16-2008, 02:59 PM   #614
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So what do you do when the motors turn such low RPM's that to properly gear we have to redesign the rear axles to accomodate smaller spurs and smaller diffs/diff rings.

Do you really want to run a 50T SPUR and a 76T PINION to be properly geared just to run a low Kv motor. I don't think this has been thought out far enough as to the impact of the 1/12 car design as it is.
Already covered.

http://www.rctech.net/forum/electric...db12r-212.html

post #6343

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Old 12-16-2008, 03:00 PM   #615
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I agree

Regarding LiPo, I don't think 1s 3.7v LiPo is the solution. Why do we want to make this more complicated that it already is. With a 1s LiPo, you have to run a receiver pack, alter the setups, run different motors, different tires, etc.... This "SIMPLE" 1s 3.7v LiPo is becoming more costly by the day. Now we here that some ESC's won't function well at 3.7v.
+1

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