Version 2.5 of the ArduCopter code is now available in the AP Mission Planner and in the downloads area!



  1. The first ArduCopter code release optimized for the APM 2.  Leans and drift should be much reduced or even eliminated for most users.  This was accomplished through a number of core improvements to the DCM implementation by Tridge like this one and this one.
  2. Loiter and waypoint following should be improved due to a D term bug fix, some tuning and the improved DCM performance mentioned above.
  3. On start-up, the yaw heading is updated with first successful mag read (so you should no longer see the slow rotation from north to your actual heading).
  4. Increased output rate to ESCs to 490hz.  This update rate is also user selectable using the new RC_SPEED parameter.
  5. hexa copter stability patch bug fix (should resolve slight flattening when pitching forward and accelerating very rapidly).
  6. improved baro filtering
  7. fix to dataflash logging of Mag heading
  8. addition of H1 swash plate type and bug fix for proactive yaw compensation for collective pitch changes for TradHelis.



The default PIDs are optimized for a 3DR/Jdrones quad with 850 motors and 10" props. If you're using more powerful motors/props, start by turning down Rate Roll P in 25% steps.

While some testers have reported very good flights with the default PIDs, some have reported that this release is a little "sharper" due to the DCM improvements and have found they needed to:

     reduce stabilize P by 10% (i.e. 4.5 -> 4.2)

     reduce stabilize D by 30% (i.e. 0.15 -> 0.10)

     increase rate D from 0 to 0.001

Tuning loiter can be tricky.  Refer to the discussions which will appear below for more community feedback on what parameters work best.


Please post your feedback in this discussion.  For enhancement requests  and bug report, please add them to the arducopter issues list.  When possible please include logs (tlog and/or dataflash) and tell us whether you're using APM1 or APM2 and what version of the software you're using (presumably 2.5 but tell us anyway!).


Thanks for this release go to the developers (both in the core team but also those who have provided bug fixes through the issues list) and also the community members who participated in the previous release thread and provided some great detailed information in the form of issue reports and logs which allowed us to nail some bugs!


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Yes Adam!
Thanks Jo, and now vote the enhancement! ;-)


may i disable compass in 2.5? with older board i remember it was explicitly said that if compass is disabled i should unplug gps - but it's not that easy with purple board, where both compass and gps seem to be soldered to the board..


Interesting,  I have seen this before on my quad, and I don't use an Stab_I terms.  I don't have a sound argument, but I remember reading that to not use Stab_I if using the PIDT1 control scheme, which i believe is what we use still.  Is that a correct assumption?


     The lines coming together (which means the APM is never successfully getting to the pitch you're inputting) are unlikely to be caused by a lag between the radio input and the apm response.  It goes on for far too long and the gap is always on the same side so it appears the APM is never able to get the quad to the desired pitch, it keeps falling short (as opposed to overshooting which results in a wobble).

     Good move on testing the ESCs frequencies..sounds very possible that the ESCs can't keep up.  There's a lot of room between 490 and I guess just going down until it gets more reliable would be good.

I had a crash last week testing 2.5.3 with a similar behaivior that some people reported. Quad leaning to its back.

an initial take of was attempted at 40-45% and i could land it. on the 55-59% i had the crash where i broke one propeller and end of the game.

here you have the log.




the next version 2.6 has more logging of the loiter values so hopefully that will help people tune it better.  What you'll be able to do is go into the terminal screen of the mission planner, type "logs" then "enable PID".  Then when you're tuning using channel 6 it will dump the error, P, I, D and output values to the dataflash log.  Hopefully this will help a bit in that you'll be able to see the individual contributions of P,I and D parts of the PID controllers.


This extra logging will also be in the roll, pitch and yaw rate controllers.


One thing that's also confusing about tuning loiter is that the LOITER_RATE parameters are only visible in the left pane of the mission planner's configuration screen.  These rate parameters are key to controlling the conversion of desired speed to lean angle so we will likely move them to somewhere more visible on that configuration screen.


     You can disable it through the mission planner:

            1. click on firmware button in the mission planner

            2. click on the apm setup button at the bottom

            3. go to the hardware tab and uncheck magnetometer (or maybe it's called compass).

     Hmm..I wonder why you'd want to turn off the compass if you dsiabled the GPS.  Certainly the GPS is not useful without a compass...but if you're not doing loiter or RTL, I don't think it matters if both are left on.  They don't really negatively effect performance as far as I know.

Anyone else notice in the APM, that flight-modes don't change when switched to? 

Just constantly shows Stabliize.


yet in the Radio setup, it correctly selects the right flight mode.

Even in CLI it shows them correctly.


But Flight-Data section and even the STATUS tab, just shows Stablize and nothing more.


did you have GPS lock Nick? I think the flight modes don't work until you have GPS lock because that's what they are working from

you are absolutly correct!

Was testing indoors the entire time.


Went out, got the GPS lock...and BAMM!....its working!



Should've of tried that first.  I could of sworn, that I used to be able to test indoors before and still have the mode switch.

Maybe it was changed in the new versions of APM.


Now its time to test v2.5.3

hey randy,

tried some flying with compass disabled and it seems that it's holding yaw better without compass.. not sure why :(

is there anything broken with camera stab in latest versions? with roll servo attached bird rotated like mad.. had same issue with 2 different boards - on older one i thought it might be consequences of crash (some sensor dead or whatever), but today i had exactly the same issue with octa and purple bird.. and pitch servo is wobbling strangely... something very fishy :S :( let's put it that way - camera stab is either working in some new and mysterious way, or something is broken :)

attaching log files (all of them, one of the first one should be the "rotating" one..)

would be great if you could take a look...


I tried today the new version 2.5.3. After the two and a half minutes quadro flip and crash. Can someone wiser please tell me what was wrong by looking at the log file?

APM2, Quad X, ROXXY 2827-34 760kv, APC 12x4,7, 4s 6000mAh, flight weight 1700g, default PID:s


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