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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  • does this version of MP still require Net framework 3.5? One a new laptop I'm having trouble installing UARTS and the ports aren't showing up in MP

  • Developer

    2.6 is released!  All aboard on the 2.6 release discussion here!

  • Developer

    The video of the 2.6 final version is on my youtube channel...
    In the description the specs of my quad.

    Bests, Marco

  • I have gone through several batteries on 2.6 Epsilon (quad 10x4.7 apm2 880kv)- so far-

    Altitude hold now fixed, can add or remove weight and it holds well. I did increase AH P to .9, rest all default.

    Have not seen simple mode problem that was in last version

    Loiter was best I have seen lately, maybe 2m drift at worst (low wind)

    Yaw seems OK, did not twist on takeoff

    The latest stable mode is remarkable. I have not bothered with autotrim, balancing blades, or any of that nonsense and it will hover motionlessly in no wind- even better, it has the best sound I have heard.  How they sound in low wind is a big clue to how well it is working.

    I did try 12x3.8 blades and the default pids left me with a little oscillation. I tried lowering a bit and it got better, but the 10x4.7 with pids at .18/0/.04 is still the best.

  • Hi,

    I have yaw burst issue. When i fly with stab mode hexa can make 360 degree yaw without touching any sticks.

    2012-06-14 22-12 1.log

  • hey all!!! just flipped my big new SteadiDrone octo, not as in flipped and crashed, I mean looped :) Will post video soon.

  • Another sucssefull flight with 2.6Delta. 2.5.4 was already very stable, but still with those yaw glitches, however 2.6 it's great. I had never had such flight stability before. Yaw may be a little slower but no glitches at all and since I don't need any agressive yaw maneuvers, for me it's working great. However, hovering a well balanced and leveled small hexa it's just perfect. I have also been making auto flights and it behaved super. For now I'm testing a uBlox NEO 6M gps, wich seems to give me better accuracy and precision. I've managed to get loiter in a 2x2mts box today without wind. In the last days I also made some flights with some strong winds of 40 / 50km/h and I must say I was impressed with how well the hexa behaved. It made the autoflight path with little deviation and loiter fought against the wind bravely. I'm flying a Xaircraft hexa pro frame (550mm motor to motor), 10x4.7 props, 6000mah 25c 3S battery (wich gives me approx 15m flight time), sunnysky 2212 980kv motors on an APM1+oilpan and it's a very well balanced setup. I give you my param file if anyone can find it usefull.

    parametros 2.6 Delta.param
  • Over 100 000 views, and many replies.

    I'm waiting for my new 2560 board, to join in the fray, but reading about many frustrated builders out there, I'm close to giving up.

    I haven't had any funnies on the rather short flight I'm doing, but then, I haven't really done much in the line of nav or position hold lately.

    Maybe the code is getting too complicated ?

    Cam ship people require basic stability, and maybe nav/rth.

    I would be happy with that, I don't need Simple mode or Acro.

    Fancy lights and maybe camstab can also be left out, on a big 'copter with professional stab gear, it can have it's own stab electronics.

    Not venting, just throwing around some thoughts.

    And impatiently waiting for my 2560 board.......

  • Developer

    ArduCopter 2.6 Epsilon is now available in the downloads area for beta testers.  Hoping that this is the final version that will be pushed out to the Mission planner.


    A couple of things to be on the look-out for:

        a) Please try Simple Mode. The copter should not spin.

        b) Empty dataflash for some APM1 users.  We have one report of this (from Dean) so I'm interested to see if anyone else has seen this.  It's possible that it could be a dataflash hardware problem exposed because of the new method we're using to erase the dataflash.


         thanks for your help!


    Changes from 2.6-Delta:
       - throttle range improvement (higher min and max) [Jason]
       - improved standard Loiter PIDs [Alan, Heino, Jason, Angel]
       - restored standard yaw control [Robert/Randy]

    Improvements over 2.5.5 include:
       - Stability improvements especially during level hover [Jason]
       - MavLink 1.0 support (use with ArdupilotMegaPlanner10.exe) [Tridge, Craig]
       - dataflash erase speed up ('+' messages removed but it only takes 6 seconds now) [Tridge]
       - Copter LEDs [Robert Lefebvre]
       - RTL loiter stage target set to home to improve final landing position [Jason]
       - flip & acro improvements [Jason]
       - circle mode target improvement for ground station [Jason]

    Bug fixes include:
       - UBLOX driver fixes (lock should now be more reliable) [Tridge]
       - enable mavlink messages during dataflash erase which resolves issue in which new APMs fresh from the factory appeared unresponsive [Tridge]
       - proper printing of lat/lon values in dataflash logs [Randy]
       - removed duplicate GPS reads [Jason]
       - resolve flooding of telemetry link with low-battery warnings [Tridge]
       - RTL bug would land if rtl_approach_alt was more than 1 [Jason]
       - WP Radius could not be set larger than 1.3m [Jason/Randy]


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