Losing grip – Hobbywing FOC and Castle Mamba X?

Hobbywing AXE R2-FOC or Castle Creations Mamba X – you might wonder which one to spend your money on? So do I. Or, rather, so did I until I tried them both. Ever since I put a Castle Mamba X in my Axial Yeti in 2016, I have been fond of the system, to the point where I now own four of them. However, last year when my SCX10 got to heavy for the Mamba Micro X it was running, I decided that it was due time for some honest comparisons.

Long time no write by the way, life’s gotten in between. It happens.

Anyway, there’s a lot to be said for sticking with something that works – in my case Castle – but it can be very enlightening to try something new. As fond as I am of the Castle ESC’s auxiliary channel, I have been intrigued by the FOC system ever since I read about it. I know that it’s been around for a few years or so now, but humor me.

According to Hobbywing with Field-Oriented Control (FOC) “the motor and ESC are able to match the RPM of the motor to your throttle position under all driving conditions.” Sounds cool, but what does it actually mean? It means that current terminology has gotten old.

What we call electronic speed controls ought to be called electronic throttle controls instead (ETC), while the FOC system should be called an electronic speed control. See, with a Mamba (or any traditional) ESC, at any given throttle position of your transmitter the ESC delivers a specific amount of power to the motor. Depending on circumstances, that amount of power will make the car go slow (uphill) or fast (downhill). Just like when you’re walking and talking at the same time. Come uphill, your speed will go down if you still want to have enough breath left for talking, whereas downhill you’ll be able to walk faster at the same amount of exertion. Told ya, throttle control, not speed control.

A FOC system on the other hand turns things around. At any given throttle position the ESC will make the motor turn at a specific speed, changing the amount of power delivered depending on circumstances. Less power as the car starts going downhill, and vice versa, all the time keeping the speed stable. Cool, right? Kind of as if you were walking on a treadmill and your mate changed the incline up and down, without changing the speed. In order not to fall off or stumble, you’d have to either work harder or go easy depending on the wims of your mate.

That’s it for theory, what about real life? Well, today I’ll just say that it’s a rather different driving experience. Have a look at the picture above, that’s a nine pound crawler. In order to go down that hill, I didn’t let go of the brakes as per a traditional ESC. Rather, I pulled the trigger and crept down an inch at a time. Now there’s plenty of opinion to be had on this style of driving, but no one can argue that the Hobbywing FOC certainly delivers an impressive amount of control.

To read another column, hit the link. To say hello, write to martin at bigsquidrc.com.