I found in the on line help this variable "Motors always spin when armed (MOT_SPIN_ARMED)" but it cannot be changed using APM.
I'm interested to this feature for safety reason, ARMED = SPIN, NOT ARMED = NOT SPIN, so it is really simple.
Unfortunately the documentation is ahead of the release. That feature won't be out until AC3.1. No specific estimate on the release date yet. It's demonstrated in this video along with land-in-loiter which will also go out in AC3.1.
Unfortunately the documentation is ahead of the release.
Many corporate IT depts would kill to be able to pull this trick off...most never even get round to the documentation part...:-D