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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Is this located in the hardware tab, right beside the compass?  There's a calibrate button that I've been using.

Can not find it.

Will complete download the mission planner insted of using the update button.





just returned from field and very glad with stabilize mode. Loiter not so good, starting circles with diameter cca 12 meters.

Wind was 1-2 m/s.

RTL good, very satisfied, AH seems to be good too, not that accurate because of sonar lack, just baro.

But AUTO doesn't work at all. When switched to AUTO, tricopter began descend, not too hurry, to me appeared like it want to land but I don't have AUTO_LAND even set in my flight modes.

Here is my setup:

Tricopter classic (not Y6), arms 40cm, TOW cca 1100g

APM 1.4 (2560), IMU Shield/Oilpan Rev-H

ACM 2.5.1beta


without sonar,

Default PIDs.

If someone interested I can upload logs.

Hi guys,

Very inspiring to read all the positive feedback on this release - well earned recognition to the developers!

Now, before I start the tuning work, I would say that time has come for an official update on the Loiter tuning Wiki!

I just checked the current writing and it is not updated (actually misguiding and texts in two places: Flying and Tuning).

The new texts should sort out how the Hold and Loiter params work as per today and how to approach tuning them.

I am available to provide feedback on new text version.

Thanks / Tomas


     ok, it does seem like a lot of people have had problems with the alt hold.  I've pm'd you so if you could send me your logs that'd be cool.


Yes, it's definitely there above the declination box.  Apparently you need to be on 2.5 of the code though.  There are two options, either to use live data (i.e you wave your quad around) or a tlog.

Yes!  + 1,000,000

If I can figure it out, I can write the wiki.  Jason jotted something down on the devlist last week but I can't find it now. :(

I'll have a punt too. If i find anything useful I'll confer Robert.

In the meantime, set your quad up as you like it, pray for little to no wind, set loiter _p to 1.0, set nav to 3.0. (or copy marcos or balloons param files (modded to your frame and position of course)

Loiter in max 4*4m box, I'm getting 2*2 most of the time.

Simples :D

I've tried this on a small light quad, a big heavy quad and one 'Jacob' tri, with rate and stab PID's ranging from almost non-existent to 'ninja'.

I'm waiting for wind now, to fill in the blanks!

EDIT - I've got APM1 for info...

I just fly my quadrocopter with the amazing firmware 2.5 and I am very happy, Stabl Mode, Alt-hold, and Loiter work fine for me, i will test RTL and Auto soon :) :) 

Here is my setup:

Gaui 500x, 900Kv, 10x4.5, esc hobbyking blue serie 30A

APM 1 (1280), 

ACM 2.5



Marco PIDs. :)

Thanks to dev Team, great JOB 

Hi Folks,

just came in ,did some test flights.Stabilize works great,rock

solid.But i can´t get atthold working,just drops down with low rev motors.Put atthold P on 0,800,makes no difference

Using Marco´s params except atthold as mentioned.Sonar is working properly.

I´m clueless.

Octo X

APM 1 2960

Set your throttle trim to about 550 in the left pane of MP, try that , if it still sinks, up it some more. I'm sure this will be 'developed' further, but it will get you in the air and alt-holding in the meantime

Oh did i have a good day at the field, video to follow - yes more homage to 2.5 and the dev team :D

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