Brushless outrunner

[toyotatrucks83]

Ive seen a few outrunner brushless motors being used. I was hoping i might be able to find someone who wants to talk about it. I'm wanting to run one in a cc-01 scaler. Looking for similar performance as a 55t brushed motor on 2s.
From what I can find, guys with outrunner are using low kv and 3s, or even 4s and 5s. I was wanting to run 2s. I don't know if that is not possible with the outrunner setups. Any input in this subject would be helpful. Thanks.

 

[WIDELOAD]

It's not a problem running an outrunner on 2s.
The reason people run them at higher voltages is they also gear the back down (smaller pinion/bigger spur) to make them smoother down low (Volt up, Gear down).
A sensorless outrunner will never have the smooth start up/low end a brushed motor does. When JRH gets his sensored outrunner on the market it'll be different.

If you want something around the same speed as a 55t brushed look for a outrunner in the 900-1100kv range.

 

[toyotatrucks83]

Thank you very much for that info. I don't plan to change my gearing at all. Want this to be a very simple drop in. I was even looking for a 3.17 shaft size so I could use the factory pinion.
Now I don't want you to think I'm disagreeing with you at all. I just want to know about the performance. From what I was understanding is the outrunner motors are high torque because of design and many poles which aid in smooth starts and low speeds. I have experience with attempting to use brushless sensor less motors in crawlers. Cogging is pretty bad. Gearing low and using low kv is needed. All the motors I used were 2 pole. I can go on and on about the different combos and such I tried, but ultimately I found sensor less inrunners don't work well yet. With an ideal set up would/could a brushless sensor less outrunner perform as well as a 55t brushed on the same 2s battery in the same truck? Slow speed, top speed, and smoothness?

 

[WIDELOAD]

With an ideal set up would/could a brushless sensor less outrunner perform as well as a 55t brushed on the same 2s battery in the same truck? Slow speed, top speed, and smoothness?

To put it simply...It won't. Yes it will be better than an sensorless inrunner, but it's still sensorless.
Until the motor is rotating at a certain RPM, the esc is still guessing what phase it should be putting power to, hence the stutter.

I have used outrunners (and many others have) and even with low kv (850) on 3s geared as low as i could get it, there was still a stutter.
You won't get it exactly the same, there will be trade offs (be it slower, or a cog etc.). You can get it close by volting up and gearing down as i said, but sticking to 2s limit makes it a lot harder.

I would suggest having a look at Holmes Hobbies outrunners, they seems to cog the least out of all the outrunner I've tried.

 

[toyotatrucks83]

Your information has helped me tons. Thank you. I'm not dead set on an outrunner. I just really like the idea of power and effiency of the brushless motors. I have a few sensored brushless and they work great. Just really expensive. I think that for this build I'm going to stick with the brushed 55t and call it good. I worry about getting stuck in the past but if they ever stop making brushed motors there will be sensored brushless.
Also id really like it see Holmes sensored outrunner. I bet that will be a killer motor for rock crawling.

 

[WIDELOAD]

I wouldn't worry too much about brushed motors going away just yet.
Brood & HH will keep cranking them out as long as people want them and I'm pretty sure the main stream manufactures (Tekin, Novak etc.) that do it now will do the same.

 

[jereosbou]

something to consider if you want to try an outrunner cheaply is hobbypartz alpha series outrunner. i run the 400 size 970 kv alpha on my xr10. i run the hobbywing 20 amp escs and am really happy with them. on 3 cell. 2 cell works alright too but less wheel speed.
im running a 21tooth pinion in the front and 19 in the rear can stand it up on end if i punch it. low speed is not as smooth as some but the cogging isnt noticeable. atleast not in my setup. also they never ever get even remotely hot. now i also ran them in my wifes moa losi for a while though and had heat problems. so your mileage may vary. ran it in venom creper also on 2 cell with 18 tooth pinion. and had okay wheel speed as in you might have enough speed to drive out of a rollover going down hill or might not but it has plenty of power all the time and creeps along slowly very nicely. on 2 cell you might even try there 1100 kv to get back some wheel speed. anyway for 11 dollars a motor and 20 dollars an esc you can try it out pretty cheap.

 

[minijosh]

I posted some pics of my XC with the out runner HH sportsman motor. It's a direct fit but there is some trimming needed. I just gotta sort out my quark 33 esc and it'll be up and running, I got forward and reverse just can't figure out how to do reverse.