SimonK vs non-SimonK ESC

I have been away from the APM scene for a while, looking at getting the new PixHawk board. I have been spending most of my time with the 250 range quads with 12A ESC setup for some crazy fun FPV flying. I am getting back to some more programming and looking at my next frame & platform.

I wanted to get feedback from the group as I have found some varied info.

  1. With the APM I read somewhere that non-SimonK actually work better with the APM - what is the truth and/or overall opinion behind it. I am looking for something with some stable flight for auto-missions, so the crazy responsiveness I expect on my 250 quads, I don’t need as much on this.

  2. SimonK and calibration. I was told SimonK ESC should generally not be calibrated, the endpoints are in the firmware and actually calibration can cause problems with how the firmware handles things? If not can you skip the calibration step, do people adjust the endpoints in the advanced settings?

Thanks everyone looking to get back into some automation work again.

I’m not an expert by any means… but in my own experiences (5 APM builds) I have found evidence to support the contrary to your claims.

Of the 5 builds, 4 used Afro 30A ESCs with SimonK on them. The remaining copter used Opto 30A with a proprietary firmware on them.

I think when people say “you shouldn’t calibrate your SimonK ESC” that really means that they come pre-flashed with general params set and should be RTF. I have tested this with a few sets of ESCs and it is true. That being said, every time I used new ESCs or even changed flight boards, I soon re-calibrate my ESCs for consistency.

In none of my experiences has this caused any negative impact on flight performance, instead only boosting agility, motor responsiveness, and slightly improving my flight times.

I’m building a new Tarot T810 with Pixhawk and SimonK ESCs and calibrated them a couple of days ago, if you check my video you can see that the motors didn’t start simultaneously before the calibration.

A little more about my build

You must calibrate your ESCs for reliable operation. The ESC manufacturer doesn’t know anything about your radio. This will be necessary until we do away with such crappy interfaces as PWM and hopefully move to more robust interfaces like CAN. A copter has already flown with no PWM onboard.

If you really want your motors to reliably start at the same throttle, you need ESCs that have a crystal oscillator to stabilize their CPU clock. Otherwise, the oscillator circuit ends up changing with temperature and motors don’t start at the same throttle any more.

SimonK’s fast response times are not necessary for larger copters, and SimonK tends to be susceptible to sync issues on such setups. Ultimately, it is the builder’s responsibility to ensure that their aircraft is safe and part of that is testing to ensure that the powerplants are not capable of losing sync. That said, I would imagine that SimonK has been constantly improving.