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 V2.6ß - Long Loiter with APM2 and 3DR U-Blox GPS unit prototype:

    Hi guyz!
    I see many videos a little shaky, sure of having hit the right parameters/hardware? :P
    Here my "daily" video with long Loiter test, good watching!


  • Awesome.

  • It's been nothing but tuning so far.  Finally got 4 modes working fairly decent!  Acro, Stabilize, Alt Hold and loiter (somewhat).  I say somewhat due to high winds when tested so it was hard to tell exactly what was going on.  But it did seem to sit still during lower speed winds.  

    Video doesn't show much except shakes from the wind!

    APM2 on xAircraft DIY Hex Frame
    Running Arducopter 2.5.5 in 
    X config. Fighting high winds from tropical storm Beryl.
    Testing Stabilize, Alt Hold and Loiter
    Bad day for testing but it did well considering the wind.
    Camera shaking is from the wind, not from bad PID settings that would cause oscillations.
    Loiter starts around 5:30. (Once I got GPS lock).

    MB1200 Sonar
    GoPro utilizing roll/pitch mount
    1000kv 2212 motors
    20amp esc Hobbywing
    4000 40c 3s lipo
    10X45 props
    Futaba 7C - 6 modes with mixing

    Not sure on total weight.

    It's hard to see in the video but Winds on the day of the video were about 15mph - Need to adjust Hld_Lon_I and Hld_Lat_I I'm assuming. Suggestions are welcome.

    I've also attached my param file if anyone is interested.


  • Hi, masters of the sky!

    The other day I proudly could show my stable hexa:

    Unfortunately yesterday was a day of disaster. Four propellers and some parts of the frame became garbage.
    During a new try this morning the +hexacopter insisted to rush forwards strongly, as if the front motor was too weak.
    Back home the Planner showed
     For some reason the hexa believed that it was on its way upwards, didn´t it? Then it is OK for the front motor to take it easy and what will happen?
    I pressed LEVEL, went outside and the hexa behaved well.
    My question is now: When do the level parameters change?

    You can always trust a Canon Camera's horizon marker. You can always trust your iPhone bubble marker.

    Looking forward for information,


  • Moderator

    Quick Question: What may be the reason that I am unable to see any movement in my tlogs? They are just showing a gps lock and thats pretty much it. Do I have everything else disabled somehow? I didn't change anything wrt to logs.

  • Moderator

    Hi Guys,

       I'd like to give a shout out to Rui Marques. I used your PIDs to start off with and things were alright.. Stab_P 3.2 is certainly too low and the pitch/roll was really sluggish and it sounded very different.  All of the other values worked like a charm. I know that I would certainly love to have a set of Xbee's to kill the walking to and from a laptop to plug-in just change a value. Around 4.3 was where I found stab_P to be half decent.

    I still have a bit of an issue with the mystery Expo in my setup. I used a completely new model memory and re-calibrated the radio in MP and I've still got what seems like expo. No mixes were used and I only had the ability to switch into loiter. I'm going to try another few packs tomorrow evening to see about that dampening value to see if thats contributing to my issues or not.

    I was actually out hovering over my two cars (2009/2010) so I must have been feeling a bit of trust today for sure. I was back doing altitude pumps to test for yawing and actually some side to side aggressive flight. It still needs a bit of more yaw control though from what I can tell.  Nothing at all against Russ, but I'm ditching the CM-2 legs for sure. The copter flew great in minimal breeze but a gust yaws the copter easily it seems. Wait.. isn't there a PID for that? Either way, I'd like to make things more vertically compact and I am going to do some small legs out from the booms.

    Loiter: When I switched into loiter mode it seemed like the motors were really pulsing like 'pitch pumps' on a heli. I never let it do too much or go far but I'd venture a guess this will certainly need some tuning as well.


  • Moderator

    Can anyone explain the Dampening values that are in the MP, including the Dynamic one? Thanks.

  • Hi Dev People,

    Mission Planner tells me the latest code won't fit on a APM1 1280 board anymore ?

    If I manually upload, are there any functions I can switch off to still install ?

  • Moderator

    Gustav: I'm not ragging on the code.. just venting about my troubles thats all. I've got another three 5000mah batteries charged and I am going to try and start with the PIDs that Rui stated above and see where that gets me.

    Jasonw: Where did you get those landing gear legs?

  • hey all,

    I've got a large hex that I'm having trouble tuning.  I've got rate_P at 0.04 and tried stabilize_P at 3.0 and 3.5 (couldn't tell a difference).  I can't fly as much as I like, so my testing opportunities are few.

    Is there an actual guide to tuning somewhere?   I can find a sentence here or a snippet there, but no actual guide.  There is a page of instructions on the wiki, but it doesn't seem to be all that helpful unless you've got a normal sized quad.

    Besides the controllability issues, it seems to be confused about what level is.  In this video clip, you can see about 10 seconds in and again about 2:15 in where the hex pitches back and flies toward me (I'm to the right of the camera) it's doing so with the stick neutral.  I've ran the "level" calibration multiple times.  Any clues?

    log files attached below; sorry, forgot to get the params file before I left for the weekend.



    here's another clip of it lifting 8lb of payload, for a GVW of just over 20lb / 9kg:

    2012-05-25 13-59-13.tlog

    2012-05-25 13-59-14.rlog

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Aug 25