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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  • ArduCopter Hexacopter 2.5.3 

    All settings default

  • Now I'm back from field. Was testing 2.6b with heavy changed PID params (loiter and nav).

    Wind was around 5-8m/s and my tricopter was not able navigate and  RTH so I only played with it in wind.

    In one moment I flew bit onward and tricopter turn huge pitch and roll angle. I tried to swith to RTH but it didn't help.

    Tried to switch to stabilise and it still stayed pitched and because it was quickly approaching to ground I turn throttle to 100%. And didn't help, it hit the ground with high speed. Fortunatelly only two propellers and two bearers broken, whole electronics untouched.

    Here was my setup:



    no sonar,

    ACM 2.6b.

    Can somebody help me to analyse log from this flight, why this happend? Was it brownout or error in control loop?

    2012-04-19 22-39 2.log
  • Hello all,

    A test report conducts at the field yesterday.

    Yesterday was a sunny day, so I went to the field to do some test on last firmware version 2.5.6 beta.

    I went to the field with this 2 quads.

    First one :

    Apm 1 2560

    Xbee, mag, gps

    Distance motor to motor 45 cm

    Controller turgnigy plush 25a

    Motor turnigy 2213 22 turns 924 kv

                    Props 8x4.5

                    Custom frame.

                    Radio: futaba

    Second one

    Apm 1 2560

     mag, gps no xbee

    Distance motor to motor 54 cm

    Controller turgnigy plush 25a

    Motor turnigy 2217 20 turns 860 kv

                    Props 10x4.5

                    Frame : Lunar explorer 4 with gopro gimball from quadframe.

                  Radio: futaba

    1-      Test with first quad.

    The quad has been configured and hand tested previously at home.

    Parameters are standard except for stab_xxx_d set to 4.2

    Ch6 set to ch6_loiter_rate_p with 1.5 to 2.5 limits. This quad has flown pretty well before (2.4.2) expcept for loiter.

    So I power up the quad, wait for gps lock, try to take off, the quad start to flip… try a second take off same story.
    I’ve check HUD and heading is rotating like a fool…
    I’ve try to do a live calibration for the mag.

    Power up the quad again, wait for gps lock and again the quad tend to flip.

    Go back to the field bench, connect the quad and set :


    Check heading again and now it’s stable.
    So power up again, take off and stab mode is perfect. Flight was good except in alt mode (was very good before), quad start climbing fast. Switch to stab and hovering a little bit and try alt hold again, same effect quad start climbing fast. So I’ve check HUD and alt was -52…. Surprise I’m under the ground and alt in hud continue to falls….

    I’ve stopped test with this quad until I understood what’s happen. If someone could have a look in my logs, He is welcome.
    Everything was ok on bench test and hand test at home. The difference between home and field are the location and gps lock.

    2-      Test with second quad.


    This is with a small stress I’m powering up my second quad. So before flight I connect the quad to laptop and check heading and alt. Everything’s was ok so I take off.

    This quad has default parameters, except some woobles in descent flight, and some motor speed up time to time the flight was very good.

    No change compare to 2.5.2 except a better gimball servo movement.
    Some tuning are needed.  I understood woobbles, but erratic motor speed up scaring me a little bit. (not present in first quad).


    Some pics of yesterday:


    3692400680?profile=original It was a nice day.



    Log os

  • Well, I have another crash to report.

    I was flying with my new go pro camera gimbal to try and catch the sunset.  Mostly loiter, which did fine.  I switched to stable and flew around for about 1 min.  Making an aggressive roll, my quad dipped suddenly in the opposite direction and started to do a death spiral.  It didn't recover.   

    The gimbal took the brunt of the damage, along with the copter legs.  This makes the third time (out of about 40 flights) that I have seen an uncommanded dip/crash in stable mode while flying aggressively.  I wasn't sure if the others were related, but it does seem to be an issue.

    I am flying a 3DR quad, 750kv motors, 11x4.7SF,  2-axis gimbal, 1.6kg GW, APM 2 with 2.5.3+ (auto dec and auto learning enable).  3692400176?profile=original3692400477?profile=original3692400541?profile=originalThis is a sequence of shots where it lost control ( gopro was shooting 0.5s continuous).  You can tell the abrupt shift counterclockwise on the roll axis (uncommanded).  Third shot is the death spiral.

    Logs are attached as well.  Appreciate any analysis


  • Is the parameter file for the 3DR frame, 10" props in the downloads section current? It would be better if a screen shot of the main parameters were posted here also. I don't know why but when I load the 3DR parameters and then go to configure my radio using the setup tab, Stab P goes to 0 and I guess some other parameters change. I prefer to type then in manually. What things would cause these parameters to get changed during a firmware update?

    ScreenHunter_01 Apr. 17 17.58.gif

  • Hello all,

    Hi all, know how to configure the Declination lut?
    will complicate the issue of Declination.

  • Another Quick Question. I cant follow all ure Improvements / Threads, so:

    Must i calibrate the Mag with moving Copter / Starting Mag Calibration in MP and Flying - getting automatic the needed values? Or what i have to do actually to get my Mag working correct?

    I think my bad flying Copter in Stabilize is causing of bad Mag Calibration. So thats why i ask.

    What is the "newest" practice?

  • hello all,

    where can I find the minimum and maximum values to be set in the variables used for calibration through ch6? (eg ch6_rate_kp etc. ...)?

    in the code?


  • Helllo!

    I am on my way to test 2.5.3 and build a new ocotcopter for that.

    I used 7 yelow motors 880 kv and the same in black(one of the new ones).

    And this is my problem: after doing al the setup stuff(Software, esc calibartion, etc.), only the yellow motos spin up, the black one does not! (I tried two different ones from the blck motors just in case the first black one would be damaged)

    If I connect a yellow one on ethe same esc I connected a black motor bevor, it spins!
    If I connect a black motor to oher escs it works not. (onlyif I reconnect a yellow one, this one spins up!)

    So is there a problem mixing the two colors and where can I buy a yellow one for my octo?



  • I'm running 2.5.3 on my APM 2.  I tried to use a pitch and roll camera gimbal with this but I'm not getting anything on 10 and 11 as the manual says- .  However, A9 is working properly for camera shuttering.  The manual says that stabilization is enabled by default.  Since I did the install and setup through Mission Planner, I'm using the default.  Is there a way to manually enable/disable this?  Or is there something else that would prevent stabilization to be enabled? 

    I wouldn't think this would make any difference but I don't have the jumper installed and I'm powering inputs and outputs separately. 

This reply was deleted.


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