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Old 01-16-2008, 12:41 PM   #31
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It's not PR, it's about providing accurate information.

Torque is not everything, otherwise all 27T guys would be running P2K and Core Stock motors. Besides...if you want to throw "it's just physics" out there, you should be ready to consider ALL the physics involved, not just the one that supports your "bigger is better" argument.

Generally, I find that when real-world results don't square with a theory, you should reconsider your theory...not ignore reality.
We have been giving accurate info. The last time I spoke with Anand he told me they use a 12.3mm rotor to limit the power of all the motors to make them run more like brushed motors. He said if they used a sintered rotor the same size as their old bonded rotors the motors would be too powerfull.

This was said to me at the ROAR ExCom meeting a years ago. Anand was sitting across the table from me.
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Old 01-16-2008, 12:59 PM   #32
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Novak motors have the smallest rotors, yet they seem to be regarded as the motors with the best feel, powerband and driveabillity. I don't think I'm going out on a limb to say they've really caught on out there with the kids.
Maybe of the ROAR legal motors. Personally I like 4-pole and 6-pole motors running a smaller air gap and less iron in the core. They run smoother and cooler.
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Old 01-16-2008, 01:10 PM   #33
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Maybe of the ROAR legal motors. Personally I like 4-pole and 6-pole motors running a smaller air gap and less iron in the core. They smoother and cooler.


I remember you...its a year later Kuf....5 cell is working to keep mod motors together just fine and they are running faster than 6 cell cars too!

Heck...a 5 cell sedan beat all the 6 cell sedans this year in open mod at the IIC.

If it weren't for Lipo everyone would be racing 5 cell now.
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Old 01-16-2008, 01:46 PM   #34
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He said if they used a sintered rotor the same size as their old bonded rotors the motors would be too powerfull.

This was said to me at the ROAR ExCom meeting a years ago. Anand was sitting across the table from me.
"Powerfull" (sic) is not "fast". If it was, people would be drag racing Detroit Diesel motors in 1:1 cars and LRP motors would own 1/10 onroad, because they have bigger rotors.

There's more to racing than torque and you can't hang a working theory on the word "powerful". Just throwing a bigger rotor in a motor and gearing it up doesn't make it faster in all cases. That's all I'm trying to say. If you have some other evidence to the contrary, I would be really interested to hear it.

I just tried out a 13mm rotor in my 13.5 last weekend and it felt really nice going in, but I was getting my ass handed to me on the straight...geared up 4 teeth and I could almost keep up (3.94 fdr). Maybe I'll try to go higher and see if it turns into a demon, but I don't see it happening. Felt really nice in the infield, though...it would drag down nice going in and it was really easy to drive.
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Old 01-16-2008, 03:46 PM   #35
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I don't think LRP made larger rotors to decrease the performance of their motors. I had 2 of their 1st gen and they were terrible, they needed something drastic to catch up with novak.

Just because the lrp is larger does not mean it is any stronger than the novaks smaller rotor.

Using a brushed motor as an example doesn't work. They did not increase the size of the motor to gain the extra torque. So they had to lose out somewhere else in the rev range.
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Old 01-16-2008, 04:17 PM   #36
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I noticed that the ROAR rules allow a 15.5mm rotor. If that stay the same for the new spec class I can see it being exploited to the max

It would need a whole new motor being made to fit the rotor in. If they start to allow slotless contruction that would be quite cheap to do anyway.

1/1 gearing anyone?

The final Roar specs for the rotor diameter for the Stock and Super Stock Brushless classes will be 12.4+/-0.11mm.
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Old 01-16-2008, 04:30 PM   #37
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"Powerfull" (sic) is not "fast". If it was, people would be drag racing Detroit Diesel motors in 1:1 cars and LRP motors would own 1/10 onroad, because they have bigger rotors.

There's more to racing than torque and you can't hang a working theory on the word "powerful". Just throwing a bigger rotor in a motor and gearing it up doesn't make it faster in all cases. That's all I'm trying to say. If you have some other evidence to the contrary, I would be really interested to hear it.

I just tried out a 13mm rotor in my 13.5 last weekend and it felt really nice going in, but I was getting my ass handed to me on the straight...geared up 4 teeth and I could almost keep up (3.94 fdr). Maybe I'll try to go higher and see if it turns into a demon, but I don't see it happening. Felt really nice in the infield, though...it would drag down nice going in and it was really easy to drive.
The one parameter that everybody is forgeting is that the stator can only handle so many lines of flux from the magnet. If you get the magnet too powerful and/or too large, input power is turned into heat instead of output power from the motor. Our computer program tells us when this limit is reached.After that limit the stator goes into saturation and no more power is created. Thus any more power that you try to put into the motor is just turned into heat.
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Old 01-17-2008, 12:58 AM   #38
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Using a brushed motor as an example doesn't work. They did not increase the size of the motor to gain the extra torque. So they had to lose out somewhere else in the rev range.


I'm not talking about the size of a brushed motor, I'm referring to the strength of the magnets vs. how fast they are.
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Old 01-17-2008, 06:45 AM   #39
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The one parameter that everybody is forgeting is that the stator can only handle so many lines of flux from the magnet. If you get the magnet too powerful and/or too large, input power is turned into heat instead of output power from the motor. Our computer program tells us when this limit is reached.After that limit the stator goes into saturation and no more power is created. Thus any more power that you try to put into the motor is just turned into heat.
Bob Novak
Were those calculations only done using the specification of the novak stator?

The rules do not say how much stator material has to be present. I can't see anywhere where is say you could not have a cut outs like many of the brushed stock motors have.

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I'm not talking about the size of a brushed motor, I'm referring to the strength of the magnets vs. how fast they are.
They don't have cobalt magnets, it's a marketing ploy.
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Old 01-17-2008, 06:52 AM   #40
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The one parameter that everybody is forgeting is that the stator can only handle so many lines of flux from the magnet. If you get the magnet too powerful and/or too large, input power is turned into heat instead of output power from the motor. Our computer program tells us when this limit is reached.After that limit the stator goes into saturation and no more power is created. Thus any more power that you try to put into the motor is just turned into heat.
Bob Novak
That is very interesting. Many companies use computer software to design their magnetics, Aveox for example, but most of those companies who offer a 36mm motor, use a larger rotor. It is interesting that your software says this is the optimal size where Aveox, Hacker, Lehner, Plettenberg, Feigao, Kontronik, Neu, and Mega use a much larger rotor. It could be the different use for the design, airplane/boat vs car, but it is still interesting.
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Old 01-17-2008, 07:01 AM   #41
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That is very interesting. Many companies use computer software to design their magnetics, Aveox for example, but most of those companies who offer a 36mm motor, use a larger rotor. It is interesting that your software says this is the optimal size where Aveox, Hacker, Lehner, Plettenberg, Feigao, Kontronik, Neu, and Mega use a much larger rotor. It could be the different use for the design, airplane/boat vs car, but it is still interesting.
Kufman do the Aveox have a stator? I don't think the rest of that list do.

This is the sticking point with the novak compared to those motors. The novak is one heck of a big lump of iron for a 380 rotor.

The inertia of the rotor is less of a problem with boats and planes too.

This saturation problem will just be something motor developers would overcome to get the most from a fix wind.

Bob I have a question for you. Could you not have cut down the stator instead of using thinner wire to create the low torque light motors?
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Old 01-17-2008, 10:43 AM   #42
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Kufman do the Aveox have a stator? I don't think the rest of that list do.

This is the sticking point with the novak compared to those motors. The novak is one heck of a big lump of iron for a 380 rotor.

The inertia of the rotor is less of a problem with boats and planes too.

This saturation problem will just be something motor developers would overcome to get the most from a fix wind.

Bob I have a question for you. Could you not have cut down the stator instead of using thinner wire to create the low torque light motors?

The Aveox, Mega, Neu, and Pletty motors have iron stator cores.
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Old 01-17-2008, 11:50 AM   #43
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They don't have cobalt magnets, it's a marketing ploy.
I think I understand why you keep after this. You're new huh? I'm not a veteran by any means, but I've been around long enough to remember a few things. Let me try and bring you up to speed.

They used to have 27T motors with SUPER strong, but legal magnets (in relative terms of course), and they were very "torquey" (P2K, Core Stock, etc,). They could take a much higher gear, but they weren't as fast as the newer 27T motors (Monster, ROAR stock, Cobalt, etc.) with relatively weaker magnets that had a wider powerband. They used to run REALLY hot as well...
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Old 01-17-2008, 12:04 PM   #44
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The difference w/ bl motors is that they are much much more effecient. If a compnay wants to use much stronger magnets they will actually gain an advantage. The super strong p2k magnets actually hindered the performance some what & made the motors less effecient. I still think everyone should just run mod & break them up from pro/novice/beginner classes.
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Old 01-17-2008, 12:13 PM   #45
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The difference w/ bl motors is that they are much much more effecient. If a compnay wants to use much stronger magnets they will actually gain an advantage. The super strong p2k magnets actually hindered the performance some what & made the motors less effecient. I still think everyone should just run li//bl w/ 20 minute mains. Shoot, bring multiple batteries & up the pro class to a 45 minute main. If you are competing at that level then $ isn't an issue in tc. Not to mention running a 45 minute main would take up practicly the same amount of time that triple amains would take up. 5 minute break,6minute race,5minute break,6minuterace,5minute break,6minute race leaves you at 33 minutes compared to 50 minutes. Then you just shortened the stock & 19 turn resulting in the same amount of time @ the track.
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