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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Hi Andrew, try with this one and leave me your impression:


when I enter 3000 for the above IMAX if I refresh the value is saved as -276.8..... Strange or ok?

for all 3 of them... 

I tried 400 and it saved another value... tried 320 and it kept it...  looks like if I enter something bigger  it goes negative... MP bug? (did not play to find exact point) 

Yes!  I'm having the EXACT same problem!


     I'm not 100% sure where you're entering the IMAX (i.e. through the configuration screen or through the pane on the left of the configuration screen) but I think perhaps wherever you're entering it you shouldn't multiply the numbers by 1000.  I'm not totally sure but that's my guess.  It saving -276.8 is a clear sign that the value has overflowed (32k is about where a 2byte int overflows).

Randy, I'm typing it in on the left pane.

MP right pane or left pane... tried both... so I guess Marco wanted us to enter 30 and not 3000 (guess it's the value if you set it in the code...??) 

So my values were already correct.... 

But when I type 100 and enter it, it stays at 100, not being changed to 1.  So....

I'm sorry, this parameters are taken from my .param file!
If you want to use it just save to a plain text file same as your "xxx.param" and load to your APM with the planner!
Do not enter for IMAX a value "3000" directly in the planner, lol! :P
Here my parameters, used for make the video of this release, use a txt reader like "notepad" and you can see this parameters.

Bests, Marco

Marco, i don't think your param file is included in that ZIP,

Or am i begin dense?

I'm ready to hit the field, would like to give them a try if poss.

Ops, thanks... here my params! :P


this is my parameters loiter stable for me...


Thank you Marco -  I will give them a try. I might get the chance for a couple of quick flights Tuesday evening before we head into the gym for our indoor flying. Other than that it will be next weekend.


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