Brushed motor torque changes with RPM and will go up as the motor comes up to a running state. You need to add a clutch to that rig so that you can run the motor at more than stall. Stall torque in a brushless motor is harder to measure because of the logic in the ESC that prevents the motor from spinning up when it feels resistance, but brushless has WAY more torque that brushed in all ways.
I agree with Carl you would need to know the torque curve of the brushed motor to test at the given RPM as it goes up then down in torque. Brushless motor are the same in reality except the torque goes up the faster it turns. Then throw in outrunner vs inrunner
I'm building this rig to get a simple comparison between several small boat brushed motor candidates I've been collecting. If I want to get deeper into it, the Mk2 rig I have in mind will be able to measure torque throughout the rpm range and could test brushless motors as well. FYI, the statement "brushless has WAY more torque" is a bit misleading. The 300 and 500 series brushed motors typically used in the hobby would be better compared to brushless inrunners than the higher torque outrunners that are being adopted. Outrunners are a pancake style motor where the windings are larger in diameter than they are in length. This configuration has a higher mechanical advantage over typical motors (windings are longer than its diameter) which results in higher torque (at the cost of lower rpm). If a brushed pancake style motor with comparable winding diameter could be identified I think your would find that it would have a higher initial starting torque than a comparable outrunner for the reason cited above, there would be no ESC logic fiddling with the motor trying to determine if the motor has started spinning and in what direction. The first motors I used in my Mogador were brushed pancake motors. They are very torquey and accelerated the Mog very well. Unfortunately they had weak brushes that failed when they got wet. I think brushed motors still have a place in the hobby, particularly for smaller and beginner boats if the right motors could be identified.
I am not a fan of BL in boats and I plan to use brushed were possible. But... there is areas that BL would give an advantage such as "large BB's" drive
You might consider an 8000 rpm 775 series brushed motor for direct drive in a big BB. 3.8 inch pounds of torque. http://www.banebots.com/product/M7-RS775-12.html
In a funny coincidence, I just acquired one of these today. While not marked as an RS775, the specs I measured were identical. Mine came out of a 36 volt Black and Decker weed whacker.
