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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Jan,  I'm having the same issues with my Y6 that you are having with your hexa.  I made a short video link earlier in the discussion.  Is yours doing what mine is in the video? 


Really?  That's the "angle boost" feature and should still be there unless we've inadvertantly broken it.

I can check it when I get home but I'm pretty sure it's still there and you should even be able to see the value as "angle boost" (or something close to that) in the dataflash logs.  I think in the ATT message.

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.

Hi Marco,

I think I may have this issue as well, I'm using APM2. I'll do the test as you suggested. If in case this is the case (compas interference) what should I do about it?



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....

Testing 2.5 today with my APM1 ATMega 2560 on the JDrones Quad frame w/ 880kv's and 12x45 props. I downloaded the latest MP and uploaded the 2.5 code this morning though the MP.  

The quad flies great! I got my Roll/Pitch PIDS tuned down a bit (P: 3.4, I 0.1, Imax 40, Stab D 0.1) and it really solid. Even in some pretty stiff cross wind. I ran a few batteries through flying around in Stabilize and in Simple Mode. 

My issue is when I switched to Alt. Hold (in a stable hover) I basically dropped out of the sky. This happened twice (over grass).  I managed to break a couple landing gear but what can you do...  Testing with the quad in my hand I see that as soon as I switch to Alt. Hold or Loiter, RTL etc. the throttle cuts way back. Seems to still respond when I pitch/roll it but not very powerfully.  

I have a sonar - I can recreate this with and without the sonar configured. Same thing.  The sonar and baro values look normal in the tuning window (both on USB and with Xbee).  I had no issue in the prior 2.4.1/2.  I tried playing around with the Throttle and Alt. Hold PIDs but didn't notice any change. Feels like there could just be setting in the MP that got changed or could it be PIDs? Does anyone have any advice on debugging this?

Thanks to the Dev Team for the new code! 

Y6 is now flying awsome!  switched to a beater frame to fiddle with the PIDs'.  Stab_P had to be decreased considerably.  Cranked up Stab_I, Stab_D and Stab_Yaw and this thing now flies on rails.  Like my quad Altitude hold and Loiter is the best yet.  Using APM1/2560.  

yay! finally can't wait to build mine

Evan, Somewhere earlier in this thread, Randy explained :

THROTTLE_TRIM parameter is too low, After an version upgrade all your parameters are reset to the defaults which is 350 for this parameter.  It will slowly update itself if you fly around in stabilize mode for a while and maintain a somewhat constant altitude.

     You can take a short-cut though and just go into the configuration screen of the AP Mission Planner and set it to 450 or maybe even 480.  That looks like the value you need.

From this page :

In relation with switching to alt _ hold mode and some other

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