Idk, brushless never seem to have enough torque, there ussually all rmp and no humf! Also, ive never found a good brushless with a 6mm shaft 
In a planetary box, a brushless will walk all over any brushed setup. In power, efficiency and weight.
And large Outrunners have gobs of torque. I have an Axi 5330/18 outrunner spinning a 21" prop, 8mm shaft, 10mm prop adapter, on my 7 foot 1/4 scale Aerobatic plane. This motor has some serious torque. Like, break your wrist torque. 38 Volts with 120 Amp peaks on a 16,000 mAh lipo.
hobby-lobby.com/brushless-axi5330.htm
And they make a double version as well as 2 larger sizes.
Here is a perfect drop in for a speed 400 sized planetary:
modelflight.com.au/rc_model_ … 6-15-3.htm
The Mega 16/15/X series comes in many different kv (rotations per volt) and has more than twice the power of brushed 400 sized motor plus way better efficiency. Which means longer battery life and more power/speed from the same sized motor. This 400-sized motor will outperform a can 600 brushed motor by far. I replaced a modified 680 sized brushed motor in my BT Corona Helicopter with a Mega 16/15/3 (400 sized). The heli now weights less, has much more power and extended my flight times by 15%.
Did I mention that brushless in-runners don’t cause RF interference like brushed motors do? And that they are much quieter.
The downfall is the price to use brushless and brushless esc’s. But hey do range from tiny to huge (4" in diameter) and high kV (RPM) to very low kV, high torque outrunners. There is a reason why industrial equipment has been using 3 -phase motors for years, and still do. They just kick everything else’s butt. 
im not sure why we dont use them than? Besides 100$$ a pop is too expensive… even for me When I begin the Spy3 this summer if I decide to make is bigger or smaller Im looking into like 10mph motors for like a 10-15lb bot with 6mm shafts that arent too expensive. Maybe I’ll go with drill motors…
I’ve seen lots of posts about outrunners, and brushless motors for use in robotics. All of the speed controllers I have seen for outrunner motors are only one direction.
Furthermore even the brushed motors used for airplanes (although extremely powerful) are usually timed for optimum effeciency in one direction and can’t be used effectively for bidirectional applications.
car brushless controllers are produced, here is one example castlecreations.com/products/mamba.html
nick_a
have you used these controllers? if so, how well does it work at low rpm? is there a lag or rough area as the RPM spool up or is it smooth? I remember seeing an application note for sensorless commutating of brushless motors at low rpm using a core saturation technique but didn’t thoroughly study it at the time. I have to wonder if the castle creations guys are doing something like this to handle low RPM and then switching to the back EMF technique once there is sufficient RPM. Hmm…
Thanks Italian_guy299!
It’s been that long huh? Well Time flys when you’re having fun I guess. I can’t wait to see the logo on your machine. Are you going to use some kind of clear printable peel and stick media?
hmmm, idk, I still think right now for my project gearhead motors are the way to go (mostly becuase of costs) and the fact that I can always put a heavier reduction on them for more power.