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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  • Which sonar is better to use with APM1.4?

    It seems the beam patterns and W output are the same so what advantage does the 1260 have over the 1200?

  • Hi Everyone

    I have just noticed a noticeable improvement in stability after some changes to ESC setup. I am using the standard ESC's supplied with the DIYDrones kit  and the 880kv motors.

    Upon going through the documentation for these ESC's I saw that the default timing setting is Low, and while I know the ESC's should sort out most timing issues automatically I know medium is the recommended setting for multicopters.( I changed the timing to medium as per the instructions that came with the ESC's.

    I decided that while I was doing this I might as well throttle calibrate each ESC individually as well. When I first built the quad I throttle calibrated all the ESC's together as in the Wiki, and this seemed to work well enough, the quad was quite flyable. 

    I can say there is a visible improvement in stability after these changes. Whether it was the throttle calibration done individually or the ESC timing I can't say, but it was well worth the exercise. 

    Hope this helps someone who may be struggling with stability. 


  • It must just be me... I have had 2 crashes of two different Tri-copter over the last week...

    Both crashed the same way...   Bank right ~40 but when try to return to level, the craft goes to 80-90 deg, then crashes..

    I would attach the tlog but the xbee was destroyed in another crash weeks ago..

    I fly every day and about once a week I shoot video or pictures as part of my side job....

    First crash... AMP 1.0 with 2.5.4...

    Second crash AMP 2.0 with 2.5.4


    in this fig... red line is my input (roll)...   Green is attitude measued by AMP2.... all seem correct to me.... ...

    For most of the flight.. hard turns and banks.. they are very close... like it should be...

    but at the end... they diverge and the tri.. crashes...  

    new 2 x 5000 mah batteries...motor logging was not on...

    I know there is not enough info here for someone to tell me what happen...  but I can't fly anymore...

    Here is link to it flying properly

    Eddie Weeks

    2012-05-09 17-02 153.log

  • Hi guys,

    I was almost done for the day when a friend showed up at the field with his Harpoon II with it's 90mm jet, I just couldn't resist, I only had one full battery left. Just had to try to "chase" it. It ended beeing a slow follow up and down the runway, but cool anyway ;-)

    It would have been better with less wind....

    here's a short video:

  • Is it possible to compile with AVR studio? (New to this environment)..

  • There is evidence of redundancy with my octo Arducopter, first flying with 8 engines, then with 7 and then with 6, the strange movements are the result of my stupidity and not attributable to the plate, I must say that flew much better in the I did test before burning, I could nervousness jejejee the camera .... the video is up.
    Sorry for my English, translated with google.

  • Ok, perfect. I hope the wiki gets updated with these details at the same time the functionality will be made available. I believe it is currently a little out of date.
  • What’s the easiest way to have waypoints to show up when I play back a mission? I am learning how to use the mission planner and have not found the correct button to push.

  • Ok, I had less than an hour today so here's what i did.

    Ripped out the Crius multiwii out of the tricopter, (leaving a very lightweight 'Jakub' foldable tri frame, with two slightly bent arms (the front two - due to a hard nose in, so the propshafts are pointing outwards slightly)

    I screwed in 4 plastic stand-offs, so i could rubber band the apm2 in place, (this is a box fresh APM2 - my first one) unhooked two of the red wires from the ESC's, hooked all the wiring up inc reciever, uploaded 2.5.4, went through setup, then calibrated my esc's (all at once), just in case. Armed it, hand tested, quick garden hover, then got my mate to do this video.

    This is stock params, obv need a tune but it's still lovely to fly despite chunks out of the props, bent legs, untuned params, the lot. It simply works. I know this is not much help to those having problems with tris but I suppose my point is this is proper out of the box stuff. Have you read ALL of the wiki? This is DIY, you may have missed something?!

    Are you using recommended ESCs/motors? Always a good idea for your first go - only when you get it flying should you try different motors etc if you're new to this game.

    There was one bit of weird behaviour in loiter (at 1:50) where the tri set off on its own and had to be brought back in stab, I've fitted the xbees and am waiting for the rain to stop and i will try to recreate it.

  • Yesterday upgraded my APM1 to 2.5.4 software and made some flights. At first i made some little PID tuning, so my quad flys almost perfect.

    When i began to test and tune alt hold/loiter modes (low altitude at first), motor on one side suddenly stopped just after switching from loiter to alt hold. My quad was real lucky - made one 360 deg. flip and fall on landing gear without damage.

    After this accident, i checked all cables and connections (really i have only one connection - from ESC to APM, all other are soldered), and made some more flights. But next time i meet same problem (switching loiter -> alt hold = stop motor = spins = crash) at higher altitude (10m). This time crash destroyed 4 props, 2 motors, battery (it made a lot of smoke around).

    What can it be? Now i'm afraid to meet this problem again and cant understand reason of this... Please, help me. Thanks!


    p.s. In flight log, crash happens at 53% (time 23:02) 

    2012-05-05 22-58-19.tlog

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