I recently upgraded some copters from an early version of 3.4 to 3.4.5 or 3.5rc2.
Normally I fly in PosHold or Auto modes. For some AutoTune and config tests I used Loiter as a starting point as usual. Interestingly, on all copters loiter dangerously sluggish with slow overshots, while PosHold is perfect. This is definitely something new.
I follwed the advices in the manual at http://ardupilot.org/copter/docs/loiter-mode.html?highlight=loiter%20tuning:
The vehicle slows to a stop very slowly after the pilot releases the sticks (aka “freight train stop”). This can be resolved by increasing WPNAV_LOIT_MAXA (to perhaps 500), WPNAV_LOIT_MINA (to perhaps 100) and WPNAV_LOIT_JERK (to perhaps 4000).
But this did not help. Is there anything else I should try to adjust?
What is the most important value to fight such a behaviour - WPNAV_LOIT_MAXA, WPNAV_LOIT_MINA or WPNAV_LOIT_JERK?
Thanks in advance!