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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  • I cant connect my APM2 via CLI... strange code only?!? Connection and config via Mission Planner


    I try to erase the APM for the Update but CLI doesnt work ;-( 

  • where can I find information how to tune PIDs with channel 6?

  • I've just recently found time to start playing around with a quad I built earlier this year using an APM1 and fairly standard motors and frame.  I had tested it with a version of Arducopter available in January, it was OK but needed some tuning. Before I got around to doing that work took me out of the country until a few days ago.  In picking up this project again I've loaded the the latest version (2.5.3) into the APM1 and went through the setup without any problems.  When it came to a flight test (indoors to start) I noted that the copter would start to spin around on the ground before getting airborne.  Playing around with the controls didn't really seem to make a lot of difference, likewise using CH6 to try tuning the YAW_RATE_P didn't appear to do much either, also tried a few different setting with STABALIZE_YAW_P.  I did get it in the air a few times outdoors were, other than spinning, it seemed stable if I left the controls in their neutral positions.  I've attached a log of a very short test I did indoors where I allowed the quad to spin a few times on the floor. In other tests  motors 1 and 2 and motors 3 and 4 tracked each other in speed with one pair speeding up and the other pair slowing down creating the spin.  In the attached log this wasn't the case, one pair tracked but the other pair showed a difference between the two motors but still one pair slowed while the other sped up.  I would really appreciate anyone's comments as to what the cause of this might be.  The quads motors are not tilted or otherwise mis-aligned, the ESCs were properly setup.  I am sure there is a  simple explanation and that I've missed something basic.

    2012-04-21 15-41-11.tlog

  • Question to dev team:

    is there a way how to find out from logs (something to add to loged params) that the main loop was frozen before the multicopter crashes?

  • 900mhz telemetry kit for arducopter selling out for 100$

  • Developer

    We've just release version 2.5.4 to the mission planner and the downloads area.  This is really the 2.6-Beta rebadged to be 2.5.4 (we decided because it didn't include any flight performance improvements over 2.5.3 it probably wasn't worthy of the 2.6 label).  It's includes this familiar list of improvements over 2.5.3:

    1. Improved compass offset calculations by Tridge

    2. automatic decliation on first GPS lock by Adam Rivera.  Set the COMPASS_AUTODEC parameter to 1 and it will overwrite your declination when you first get GPS lock

    3. AP_Motors architectural improvement by Randy including addition of "stability patch" for Octo and Octo-Quad

    4. LED improvement by Robert Lefebvre.  Only APM1 at the moment but will support APM2 for the next big release.

    5. Support for the 3dr radios by Tridge.

    6. improved logging of loiter and roll, pitch and yaw rate controllers.  This additional logging of the individual components (P,I,D) can be enabled by going to the terminal screen, type "logs" and "enable PID".  Next time you tune with CH6 you will see new PID-XYZ lines appearing in the logs.


    Note: we have not upgraded the Y6 code because we dropped support for the "TB_Ratio".  This will be back in the next release.


    For the next major release we are working on:

    • Revisiting loiter.  Evidence suggests we can get better loiter performance using the ground speed directly from the GPS instead of calculating it based on changes in lon & lat.
    • auto-approach - for big copters you may not want it to land but instead hang-out at a low altitude
    • architectural improvements (moving loggings and attitude.pde into libraries)
    • LED support for APM2
    • optical flow support for APM2
  • hi all:
    I found this

    To prove I have eight ultra
    You know if it works tried it?

  • First Flight... first crash ;-(

    I think the RATE ROLL P is too high... so one motormount demolished ;-(

    See the Video

  • Anyone have the same issue with the sonar?

    I cant figure out why the sonars on both my copters don't seem to give a proper readings when I run sonar test on CLI. I have done a full reset and installed the firmware a few times on both. Im running 2.5.3 on APM1 . 

    When I run CLI it starts off reading 20cm  on the ground.. so then I lift it up to about a meter and then it reads between 35 and 45cm.. I hold it over my head about 2 meters and it never reads more than about 80cm and the reading usually hovers between 65 and 75cm.

    Anyone get the same reading? is this normal?

This reply was deleted.


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