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cooling brushless motors?

cooling brushless motors?

Old 09-03-2007, 05:35 PM
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Originally Posted by CountryHick View Post
I think you will find they are made to use the bonded rotor because they run against brushed stock motors in the same class (Brisbane Australia). The bonded rotor 13.5 yields about the same power as a good brushed stock motor. The 13.5 with a sintered rotor is far more powerful giving to much of an advantage.
Generally correct, though even with the bonded rotor the 13.5 can make a bit more power than a brushed stock. But the thing that makes it an even match in the car, is that you simply CAN'T gear the 13.5 properly with that rotor, even with all the tricks we've tried, if you really gear that thing to take best advantage of its powerband, it will STILL overheat & get shut down. But you can still gear it to run well, & so setup it will run in the car VERY closely to brushed stocks, & that's why some tracks are requiring it that way. But as has been said, it's only a matter of time, my local track first allowed the 13.5 in the same way(with bonded rotor only), but they finally recently agreed to let us use it with the sintered rotor, since so many of us have it anyway(& I also like that running it so much in club racing saves wear & tear on our best brushed motors, can save 'em for those big events where they're neccessary)....
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Old 09-03-2007, 08:56 PM
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all i have to say is, i must have bought the only good 13.5 ever produced by novak, maybe i should send it back to find out why, the only time my motor ever clogged was for the first couple of feet off the starting line. i bought the sintered rotor and while the clogging went away, my lap times didn't change, in fact my best ever 8 minutes with a bonded was faster then my best ever with a sintered, i had a big internet "discussion" with the local expert on everything rc related, and was told i was full of crap, recently here in the NW we had our annual big outdoor race of the year, to prove a point i ran the bonded rotor, i won four heats and the first two a mains going away, (actually went into cruise mod so the race numbers were closer then should have been) this was geared at 4.7 then changed to 4.9 without a change in lap times, the motor only ran a little cooler, the motor i have is the older black end bell can with the large bearing with out ribs. if youv'e seen pictures on the paved nats indoor track, i gear it 5.4 on that layout without a overheating problem and thats with both rotors, and haven't had any of the affore mentioned problems. it may be important to mention that i am using a lrp speed control, i was using the lrp comp one until the lrp tc spec came out now i use that one. anyway, just thought i would expand on MY experiences with the novak 13.5.
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Old 09-03-2007, 09:08 PM
  #33  
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Originally Posted by skypilot View Post
all i have to say is, i must have bought the only good 13.5 ever produced by novak, maybe i should send it back to find out why, the only time my motor ever clogged was for the first couple of feet off the starting line. i bought the sintered rotor and while the clogging went away, my lap times didn't change, in fact my best ever 8 minutes with a bonded was faster then my best ever with a sintered, i had a big internet "discussion" with the local expert on everything rc related, and was told i was full of crap, recently here in the NW we had our annual big outdoor race of the year, to prove a point i ran the bonded rotor, i won four heats and the first two a mains going away, (actually went into cruise mod so the race numbers were closer then should have been) this was geared at 4.7 then changed to 4.9 without a change in lap times, the motor only ran a little cooler, the motor i have is the older black end bell can with the large bearing with out ribs. if youv'e seen pictures on the paved nats indoor track, i gear it 5.4 on that layout without a overheating problem and thats with both rotors, and haven't had any of the affore mentioned problems. it may be important to mention that i am using a lrp speed control, i was using the lrp comp one until the lrp tc spec came out now i use that one. anyway, just thought i would expand on MY experiences with the novak 13.5.
What were your temps and how old was the bonded rotor. I have similar thoughts about the 4300. The dang thing thing had some awesome RPM with the bonded. Until it got used a bit.
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Old 09-03-2007, 09:22 PM
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at 5.4 on the indoor track they average 145 - 155, (cheap temp gun) at 5.2 around 165 -170 but not faster, at 5.7 120-130 but slower. on the large outdoor track 165-175 with 4.7 was afraid of shutting down during mains so went to 4.9 temp dropped to 145. lap times the same. bonded rotor is one that came with motor, don't remember excactly when i bought the motor. as far as i know, novak came out with a 13.5 with black end bell ring, then a 13.5 with black end ring that had the large end bell bearing then the orange end bells, mine is the black end bell ring with the large bearing. i installed the sintered rotor shortly after they came out, like on this forum it was suggested that the bonded rotor was ok for "stock" racing but the sintered wasn't. i said there was no difference and only put the bonded rotor back in a few weeks ago, altogether i would say about 20 batteries or so on the bonded rotor but i could be wrong and probably am, but it is not new, i also have another bonded rotor from a 6.5 that i upgraded and that has zero run time on it.
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Old 09-03-2007, 09:46 PM
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Originally Posted by skypilot View Post
at 5.4 on the indoor track they average 145 - 155, (cheap temp gun) at 5.2 around 165 -170 but not faster, at 5.7 120-130 but slower. on the large outdoor track 165-175 with 4.7 was afraid of shutting down during mains so went to 4.9 temp dropped to 145. lap times the same. bonded rotor is one that came with motor, don't remember excactly when i bought the motor. as far as i know, novak came out with a 13.5 with black end bell ring, then a 13.5 with black end ring that had the large end bell bearing then the orange end bells, mine is the black end bell ring with the large bearing. i installed the sintered rotor shortly after they came out, like on this forum it was suggested that the bonded rotor was ok for "stock" racing but the sintered wasn't. i said there was no difference and only put the bonded rotor back in a few weeks ago, altogether i would say about 20 batteries or so on the bonded rotor but i could be wrong and probably am, but it is not new, i also have another bonded rotor from a 6.5 that i upgraded and that has zero run time on it.
With the 4300 I was getting approx. 14 batteries out of one rotor at full on racing. The cooler the longer it would last. My lap times were close as can be from 130 to 160, no difference really. Thats why I always tried to keep it between 130 and 140. It was slow at 120 and lower. Possibly best overall performance was at 135 to 140 as far as battery was concerned. The hotter it ran the more the battery would drain. Roll outs I never tracked, running foams they would change some.
When the first SS-5800's came out my son and I ran the heck out of them and never had thermal issues, I never had thermal issues till the GTB came out. I wonder if the motors changed or the ESC's. They had the bonded rotors back then and a friend is still running his in off road 4-wheel buggy and its from the original ones from about 5 or 6 years ago. He must be very conservative on the pinions.?
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