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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  • Developer

    ArduCopter V2.5.1ß - Perfect Loiter (APM1 - Sonar - Light breeze):
    Revision: 0566b08ae541

    I apologize for the poor video quality, not the usual which I have used, I had my fullhd cam available but I wanted to capture this loiter to make you see, after one hour of "ch6 tuning".
    The small shifts are only due to error of the gps.
    Inside the zip: parameters, log and tlog.


  • Did the arming procedure change? gps is blinking, and before the red led used to stop flashing when gps had a lock even before you armed it. Now gps is blinking and never stops blinking until I arm it, it then immediately stops blinking. Is this a correct observation?

  • Hi all,

    As I'm about to leave for the field to test 2.5 outside, just curious, is the ACCEL_ALT_HOLD operative? if so what's the difference between values 1 and 2? I understand 0 does nothing...


  • looking good guys just waiting for all the new bits and pieces to arrive from all over the world....than i will hopefully be airborne again......without a flay away this time one hopes....

  • @ Dave C. - you are amazing if that's you it's so funny. Exactly like something I might do after having too many consecutive flights with no e events, sometimes I'll just say screw it and try an untested acrobatic maneuver that will cost me a flying machine until I (and it's typically not very long) put some bench time in and repair my chopper (not always a multicopter, sometimes an align trex or mikado logo).

    keep it up funny man, I literally chuckled aloud in sync with tthe video right after the can brought down the quad. :thumbs up:

  • Developer

    I have been flying so much I haven't had time to reply. Great work dev team. This is a fantastic leap forward.

  • I've loaded 2.5 in my DIY quad flying +, and a friend's X, heavy unknown quad, and other than having to fiddle a bit with the TRIM-THROTTLE to get it to Alt Hold, I think this code is a winner, as stability goes.

    Will try all the other functions later this week.

    Thanks again team !

  • Nice morning today and noticed 2.5 was released, so I did a mission planner update to my new 3DR w/850kv motors and APM1. I think I followed the online manual to the "T" and headed out to the field for a maiden flight.

    I put it in stabilize mode for a few minutes and tried the alt-hold after that, that didn't go well and switched back to stable mode. After a while, about the 8:39:10 time stamp mark I lost stability then again at 8:39:30, and 8:40:46 & 8:41:54. Then at 8:43:23 it flipped and bent a motor shaft on me.

    I been trying to understand what went wrong all day and thought I ask for some help. Is this the right place to ask?

    I'll share my log file if it helps and a video too soon.


    2012-03-18 08-30-25.tlog

  • yay! finally can't wait to build mine

  • 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.  

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