finally got my brushless - RC-Monster Forums

ygguB naM · **finally got my brushless -** 07.14.2006, 10:24 PM

I got my bk worrior 12020 and lehner basic 5300 for my b4 that came in just before i went to the track. After i got it setup and reved it for the first time, me and everybody elses jaws droped, on the track it had about twice the power and the same top end as a 7turn brushed on just 6cells! I have some questions though, i get cogging at low rpm so i have to role on the gas the first 1/4 of the of the trigger, it's not a big deal on my promatched 3600's but on lower mah packs, it's almost undrivable, is there anything i can do about it and will it stop on higher voltage? There's also a thread on it here http://forums.radiocontrolzone.com/s...d.php?t=221546 and i can get some pics up later.

captain harlock · 07.14.2006, 11:12 PM

You might decrease the cogging problem with higher voltage.

Also, im my Futaba 3PK and some other transmitters, you can adjust your motor's acceleration so that it jumps directly from the lowest point of acceleration to a haigher level of acceleration. It simply wont cog since you are actually taking off from like 10% of acceleration. You can actually make your car launch at 100% of acceleration by only touching the throttle trigger, but 5-10% is very ideal.
Hope you have this feature in your radio.

BrianG · 07.15.2006, 12:01 AM

At slow rpms, the ESC has a hard time reading the rotor position so it turns off and on giving you the cogging effect. Some ESCs are better at reducing this issue than others though.

You can try with the Captain suggested (good idea!), but don't set your Tx to accelerate too high or you'll damage the drivetrain or just spin the wheels from the instant torque. You just need to adjust it to the point where it doesn't cog at minimum throttle.

Gearing down a little might help too, although you'll lose a little high end speed.

MetalMan · 07.15.2006, 12:22 AM

Like BrianG said, gearing down might be the solution. If it can't start the motor on it's own, then there's too much of a load to get it going. Gearing down should fix it, but if it doesn't, let us know.

ygguB naM · 07.15.2006, 12:54 AM

I don't think my Airtronics mx5 has that feature so i think the only way to adjust that is to get the UBS link from bk-electronics.com. I got it geared 23/81 but there was a guy with a rustler that used a 30t pinion and he was fine so i can't see gearing being a problem.

squeeforever · 07.15.2006, 01:56 AM

The Rusty and B4 probably have different ratios in the trannies...

ygguB naM · 07.15.2006, 02:09 AM

Quote:

Originally Posted by squeeforever

The Rusty and B4 probably have different ratios in the trannies...

The rusty's still alot heavier and needs a smaller pinion for the same motor than the b4.

coolhandcountry · 07.15.2006, 08:12 AM

I found a ratio on b2 2.4 the rusty is 2.72.

crazyjr · 01:06 PM

the ratio is 2.6 according to this http://rc10.com/shusting/CatalogHub/...c10b4_kits.htm Its in the second paragraph under the second picture

ygguB naM · 07.15.2006, 10:58 PM

I just got done running the car in my parking lot and at the end of the run, motor and controller were almost to hot to touch for one second, i don't know if it's the weather (it hit 112 here in vegas) or something else.

BrianG · 07.15.2006, 11:16 PM

That hot weather certainly won't help. Components can only stay as cool as the ambient air temperature...

skellyo · 07.17.2006, 11:19 AM

Quote:

Originally Posted by ygguB naM

I got my bk worrior 12020 and lehner basic 5300 for my b4 that came in just before i went to the track. After i got it setup and reved it for the first time, me and everybody elses jaws droped, on the track it had about twice the power and the same top end as a 7turn brushed on just 6cells! I have some questions though, i get cogging at low rpm so i have to role on the gas the first 1/4 of the of the trigger, it's not a big deal on my promatched 3600's but on lower mah packs, it's almost undrivable, is there anything i can do about it and will it stop on higher voltage? There's also a thread on it here http://forums.radiocontrolzone.com/s...d.php?t=221546 and i can get some pics up later.

I've got a 7718/5300 combo in my B4. I have almost no cogging with it running a 21T pinion and 6 GP3300's. The only reason I have to roll on the trigger is to keep the rear tires from breaking loose. I also recently ran it with some foams on a long wide sidewalk for some speed testing. It was GPS'd at 37.2mph and slipping the clutch most all the way.

ygguB naM · 07.17.2006, 04:25 PM

Quote:

Originally Posted by skellyo

I've got a 7718/5300 combo in my B4. I have almost no cogging with it running a 21T pinion and 6 GP3300's. The only reason I have to roll on the trigger is to keep the rear tires from breaking loose. I also recently ran it with some foams on a long wide sidewalk for some speed testing. It was GPS'd at 37.2mph and slipping the clutch most all the way.

Gearing can't be the problem cause it still coggs when i rev the motor without a pinion gear.

squeeforever · 07.17.2006, 08:28 PM

Quote:

Originally Posted by ygguB naM

Gearing can't be the problem cause it still coggs when i rev the motor without a pinion gear.

Actually, it will cog no matter what at low speeds since cogging is the ESC not being able to sense the position of the rotor... Chances are, it's gearing.

ygguB naM · 07.18.2006, 03:10 AM

Got some pics.