The Turnigy Multistar 4822 690Kv is part of a line of pancake motors designed to drive large propellers at slower speed. This is precisely what you need when building mid to large size quadcopters such as my 650mm quad.
When putting it together, I decided to give the Afro 30A ESCs a try. These are pretty cost-effective ESCs with plenty of positive comments all around. However this proved to be a mistake, as shown in the embedded video below, requested by the Support team at HobbyKing.
Turns out that the SimonK firmware has a hard time keeping sync with the motors. After the video above was taken, I compiled the most recent version of SimonK and tweaked the parameters, which improved the situation quite a bit and actually made the quad usable.
Unfortunately, this was not enough. The motors will occasionally lose sync and it at least one occasion one of the motors seized up and caused a crash.
Limited testing with other ESCs flashed with the same versions of SimonK continued to show this behavior, so this is not really an issue with the ESC’s hardware.
I’ve seem comments at various fora claiming success operating “slow” motors with SimonK, and I attribute this to the improvements I got with the reflashing and tweaking of the firmware. However, my advice is this: Unless you’re getting factory matched motors and ESCs combinations, do not use SimonK firmware with pancake motors. If you’re not using factory matched Motor-ESC combinations, go check my post about the improvements I saw with BLHeli firmware and consider using this firmware instead.