11-21-2011, 10:59 PM | #1 |
Rock Crawler Join Date: Oct 2010 Location: Reno
Posts: 646
| Brushless outrunner
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. |
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11-21-2011, 11:10 PM | #2 |
Rock Crawler Join Date: May 2009 Location: Queensland, Australia
Posts: 610
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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. |
11-21-2011, 11:40 PM | #3 |
Rock Crawler Join Date: Oct 2010 Location: Reno
Posts: 646
|
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? |
11-21-2011, 11:56 PM | #4 | |
Rock Crawler Join Date: May 2009 Location: Queensland, Australia
Posts: 610
| Quote:
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. Last edited by WIDELOAD; 11-22-2011 at 12:25 AM. | |
11-22-2011, 12:09 AM | #5 |
Rock Crawler Join Date: Oct 2010 Location: Reno
Posts: 646
|
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. |
11-22-2011, 12:28 AM | #6 |
Rock Crawler Join Date: May 2009 Location: Queensland, Australia
Posts: 610
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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. |
11-23-2011, 07:40 PM | #7 |
Newbie Join Date: Mar 2010 Location: llano
Posts: 47
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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. |
11-23-2011, 08:26 PM | #8 |
Quarry Creeper Join Date: Aug 2004 Location: North Las Vegas
Posts: 371
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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.
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