ArduCopter 2.5 released!

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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  • heya fellas, just out on the field and tried the new code on my hexa. running apm 1 1250, crash bang all i can say. sorry, yaw seems to be the culprit here, gets stuck again and you very quickly lose orientation. just broke 1 prop but i tried many times and done a compass recalibration too. is this yaw "stuck" issue prominent on hexa's only or throughout all configurations including quads?

  • So for any of you flying the latest official code, mind posting more param files and observations?  I am having difficulties with altitude hold and loiter currently with my setup.  Flying in moderate winds also is a bit hairy.  I don't consider my setup dialed in, especially since I have payload intergration development going on.  However, in a low wind enviroment, the quad is pretty stable.

    Setup:  3DR quad + extended legs, 11x4.7SF props, DT750 motors, APM 2, 4000mah batt, weight ~1450g

    BTW, anyone flying with Stab_I terms greater than 0?  I vaguely remember seeing advice not using the Stab_I with the PIDT1 control scheme, but I am not sure if we are currently using that control loop setup right now.

  • I flew my new crash quad last night ( I call it the crash quad because I built it purely for testing the extremesI can try out on AC/APM ) but I flew with my open pilot cc board and its so easy!!!.. what a great system! I hate to rag APM and I like this as well and am awed by the magnificent development and great work done on it, but OP really leaves it for dead for ease of use. I had it fitted, calibrated and flying all  in under 15min. and didn't even look at the PIDS.  Even their GCS is so intuitive and the board is small and a brilliant piece of hardware. . Only draw back is it doesn't have GPS autopilot yet and its so slow to develop. I often dream of the day that OP and AC join hands and then really make some great advancements in UAV. 

  • Finally upgraded my AMP2 from AC 2.1.X to 2.5.3,

    What a nice improvement! I now feel that the Acro and Stabilized modes on my quad are as smooth and controllable as they are with a MultiWii board.

    Need to find a bigger space to test Loiter and Position modes (what is the difference again?).

  • Hey again guys! First off, thanks again to all who make thise code possible and put in the hard work!!

    We are having some very strange issues with our big octo builds, we've got two octos, one using 25A and the other 45A esc with APM1, I've never had any issues with APM1 and octo builds, but with BOTH these we have had weird ESC issues on motor3, both on motor3 !? As soon as we power up, the motors do their normal beep beep, but 3 has a delayd fast beep beep beep beep and then the normal tone.. When throtteling up smoke comes from ESC3 ???!! on both systems the same thing happened ?? So my thinking is, as these are all brand new esc, and never had any issues before, prehaps it's a code thing due to new motor changes for octos ??

    Any ideas guys, this is pretty troubling


  • Hi

    I tried my first fpv flight today with 2.5.3.

    WIth the addition of a Gopro and Video TX the quad was rather unstable with the extra weight.

    Which parameters should be trimmed when flying with more weight?

    Some other things I noticed is that quad sometimes had a strong backwards lean after a couple of minutes flight which wasn't there when lifting off.

    Also when I can get to quad to hover nicely, after a couple of seconds it goes up or down resulting in throttle compensation.


    Any suggestions?


    Flying APM1, MT2814, APC 11x4,7, 5000mAh 30C, X650 V frame

  • Is anybody else perhaps also having problems uploading the new code with "Arduino 0100-relax"?  I can upload the code just fine from within the Mission Planner but as soon as I open Arduino my red and green lights on the APM stops flashing and when I try to upload the code it just times out...

  • Yes, I don't know if you'll agree but i am just grateful for it to work properly.  

    No need to overcomplicate, on when armed, flashing faster when batt lower.

    I use the lights for getting orientation and to allow for some dusk flying but agree that an added feature would be great like driving an LED for GPS lock.  

    I might also add this code would be able to drive a 12v buzzer through the IC, so you could add a buzzer channel?  This opens up beeps for GPS lock, beep on arming, alarm for low batt etc etc....probably shouldnt be over looked if its easy to implement?

  • Ok Ok, lets figure out, what we have....

    the "old" cell monitoring is gone. the "new" is only monitoring the whole volts of my lipo, ok. thats okay.

    so i know the 3,2,1 - blink code and the u4eakes code. both are working with the actual code?

    all i need is some switchable led patterns, a lipo warning pattern and, the important thing for me, the gps fix option. but to have the gps led stripe is extra, maybe on top of my copter, so that i see, wich status i have inflight. starts blinking, if the satcount is under 6 maybe ^^

    as i know, all of them are in the new code? or what u meaning robert?

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