Why not brushless?

[Savas Racing]

I am considering running "berg's" for this next season, and I heard that it is recommended NOT to run brushless, and of course, I am curious to know why... I have been running an AXI Outrunner in my chassis-mounted transmission truck for some time now, and I don't see how it could not work in "berg" axles.

[Kamikaze]

My experiance is brushless doesn't have the give needed to run in a 2 motored truck. But you can do what ever you want. However a $18 integy lathe motor is all the motor you need in these trucks.

[oberon crawler]

I seriously considered outrunners (cheap ones, revolvers, crawlmasters etc.) and even sensored inrunners like Novak Goats which have a very stong powered drag brake. And in the end i put in lathes because of the following.

Outrunners have limited torque at motor shaft speed. What i mean is, sure they are very strong when geared 40:1 like at the axle output but sometimes an outrunner will snag on a rock and the rotor on a outrunner in a berg only has 2.5% of the axle torque and being exposed like it is, it would likley get stuck on every rock that it touches. (i've read that some outrunners can be stalled with a finger tip)

A sensored BL inrunner motor has a stationary case like a brushed motor but goat motors are nearly 7oz each and you'll need to fit two goat esc's in your chassis too.

For comp crawling I think brushed is ultimately more usable.

[binaryterror]

Don't forget about low motor rpm control of a brushed motor over brushless.

[Savas Racing]

I can run two outrunners on a single ESC couldn't I?

If I were to run Outrunners on a "berg" style axle, and they were protected from anything touching them, they should work just fine, right? In other words, they would behave the same as they are now in my truck?

Originally Posted by Kamikaze

My experiance is brushless doesn't have the give needed to run in a 2 motored truck.

I'm not sure what you mean by "give?"

[Harley]

Originally Posted by Savas Racing

I can run two outrunners on a single ESC couldn't I?

As far as I know you can NOT. You must run two ESC's.

Originally Posted by Savas Racing

If I were to run Outrunners on a "berg" style axle, and they were protected from anything touching them, they should work just fine, right? In other words, they would behave the same as they are now in my truck?

Protecting them would be crutial, but in the end brushed will still give you better control.

[JohnRobHolmes]

In short, I wouldn't put outrunners in a berg because they would get beat up. The novak system would work, but I do run brushed motors in my berg.

[JIA's Dad]

And GOD Spoke!!! Amen Brother!!! Holmes is the man!!!

[Savas Racing]

Hmm, well I'm glad I got that figured out... Brushed it is.

What speed controller do you guys recommend? I currently have one Mamba Max... But I can use that again in a different build, so I'm up for getting something new if there is something better. I hear the Tekin FXR is the hottest ESC right now? What are the benefits? I heard it had a great drag brake, but that is not much of a concern for me. But I like the small size.

Also, what kind of switches do you guys use for switching polarities on the rear motor?

EDIT: And if I decide not to use switches, which radio should I be looking at? The DX6? I would like a radio that I could program at least a little bit.

EDIT: I guess I will throw another question in here... For a center tranny truck, I was recommended the cobalt puller... For a "Berg" style axle, I was recommended a 45T lathe motor. Is this because I have twice as much power/two motors vs one?

[SlickRockSpider]

Originally Posted by oberon crawler

I seriously considered outrunners (cheap ones, revolvers, crawlmasters etc.) and even sensored inrunners like Novak Goats which have a very stong powered drag brake. And in the end i put in lathes because of the following.

Outrunners have limited torque at motor shaft speed. What i mean is, sure they are very strong when geared 40:1 like at the axle output but sometimes an outrunner will snag on a rock and the rotor on a outrunner in a berg only has 2.5% of the axle torque and being exposed like it is, it would likley get stuck on every rock that it touches. (i've read that some outrunners can be stalled with a finger tip)

A sensored BL inrunner motor has a stationary case like a brushed motor but goat motors are nearly 7oz each and you'll need to fit two goat esc's in your chassis too.

For comp crawling I think brushed is ultimately more usable.

Try running a scorpion 2215-22. I know of a couple people with ax-10 based rigs that are running the 2215-22 at 11.1 volts and they have no problems winning. The motor is only 27.6 mm dia with an overall length ,with output shaft, is 50.00 mm and only weighs 61 grams.

Brushless kicks ass.

I can see the clearance reason not to run a outrunner on a berg axle.



Evan

[Reflection]

Originally Posted by SlickRockSpider

Try running a scorpion 2215-22. I know of a couple people with ax-10 based rigs that are running the 2215-22 at 11.1 volts and they have no problems winning. The motor is only 27.6 mm dia with an overall length ,with output shaft, is 50.00 mm and only weighs 61 grams......

Brushless kicks ass.

How long have you been crawling with outrunners?

The Scorpion motors are very nice motors,no doubt. IMHO though the 22mm motors are a bit small for a 2.2 crawler. I think they are best suited for lite weight 1.9 scalers and such. They just ain't got the sack for a 2.2 size comp rig. Don't get me wrong,I like outrunners as well....in some applications. They can work decent in a crawler. I ran nothing but outrunners last season. A big outrunner in my super and a little crawlmaster in my 2.2
Once you find a good gear ratio and the right voltage needed to run the motor of your choice,they can work decent. I used to swear by my outrunners. I wanted the best throttle response from the bottom end,all the way to the top.....There's no way I'll ever loose the brushes in a comp rig.

In the end though....from low speed control to wide open full throttle assaults,a good brushed motor WILL kick ass over your outrunner.


Your also suggesting something that works good in a shaftie. This is in the Berg section Between the 2....gear ratios,voltage and what works is a good deal different.

[oberon crawler]

Raptor man is right, for a serious comp rig, brushes win.
A scorpion motor will work great in an social/bash ax10 where it's protected and you just want an easy no maintenance setup that's efficient and gives good run times, but the more comp orientated you go and the less protected you go the more a brushed motor comes through.

[SlickRockSpider]

I understand that the motor placement on the bergs is key, but don't count out brushless motors for crawling. A friend of mine uses 2 brushless 1100 kv Hackers on his worm axle 2.2. He finished 5th at the Axial WCC this year.





The tuber is very smooth through out the power range. He has no problem going slow or fast and he has no problem breaking these axles with a little to much throttle. So to each his own.




Evan

[Reflection]

Originally Posted by SlickRockSpider

A friend of mine uses 2 brushless 1100 kv Hackers on his worm axle 2.2.

Ryans rig definitly works great. Running worm driven axles is,IMHO,what helps him pull it off. Worm driven axles are usually geared stupid low. THATS the key in getting outrunners to work better at slow speeds. He gets his wheelspeed back with high voltage.

[SlickRockSpider]

You are indeed right that my be the reason he can pull it off. The worm drive also gives you a monster mechanical break. I know that brushless motors have very little rotation drag and the brush motors have quite a bit. Ryan runs 50 to 1 final ratio. As for the ratio I would think that he would run a a much lower one. You know volt up and gear down. But the rig runs so smooth when slowly crawling.


So they have there +s and -s.


Are you going to the nats?



Evan