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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The latest code (now in the mission planner) properly captures the manual throttle and uses it as the base for the altitude hold.

Good to here that, I saw the same thing in my logs on my 3DR hexa today.I was just about to add something that took current throttle as well since I had auto-alt turned off in my build and tuned a good trim manually. Back to git...

FYI, I think I was seeing the loiter issues fixed by #4&5 below as well Loiter was all over the place (5m circles) no matter unless I changed loiter I's 0 for it to hold vs drift.

Sorry to hear about the crash, I've had many, does give you the oppty to rebuild it better.

Good stuff.

Tridge has done two major changes (one in 2.4 and one in 2.5) which have suddenly freed up a lot of memory and cpu power.  I think this extra room has made everything work better.

Tuning loiter does seem to be a bit tough for many, so we're planning to put more logging of the pid controllers into 2.6 to help with that.

great job guys.. simply gret


After some time struggling with 2.5 PID settings on my Y6, I managed to have a quite nice Rate flight as of today.

Firmware was updated to 2.5.3 via mission planner and I can confirm the success of altitude hold. Thanks for that. I will try Loiter later today, with flying open space.

Not always easy, but nothing is perfect.

Thanks for  dev team work,


Stab PID: 5.6/0/40   (5.6 is not enough, have to try 6.0)

Rate PID: 0.145/0.01/0.005

Stab Yaw: 7/0/8

Rate Yaw: 0.145/0/0

Good Morning,


I have anxiously been waiting for the release of 2.5 and infact havent flown since 2.3 because of the promises made with the release of 2.5.  This morning I uploaded 2.5.3 and tuned up my X Quad.  There has always been a slight wobble on my Quad and with the new version that wobble is gone.  I am flying APM1.

The quad not sits rock solid and only took a few minutes to tune.  Stabalize I have left at default and Rate I have reduced to 0.089.  Rock Solid!  I do all my tuning via ch6 by the way.  I then decided to tune Alt Hold.  I only use the Baro now because I have never really had much success with the Sonar and have destroyed 3 of them.  Anyway, my Alt holds within around half a meter.  Alt throttle is at 0.210 and Alt Hold is at 0.210, ironically the same, but this is what the quad responded well to.

Now that you have read my blurb nonsense, here is a question.

Although the quad holds itself in Alt very well, it responds quickly to baro changes and ends up looking like a pogo stick.  Which other term could I change to slow this pogo affect down.  If I reduce Rate and Hold P anymore, the quad looses the plot slighty and eventually looses altitude and if I increase P then the corrections are over done and too much alt change during corrections.  Anyway, what else can I change?




Sorry Jason, don't see a flip in that log?

Jason, i'm sorry for your crash... please open new issue here, describe the problem and upload the log, thanks!
Sounds like a bus lockup or reset (damn).
I found that if the APM1 loses the link with the sonar then reset or go to lockup, and I've already reported.

It's the right log, or at lesat you were flying 2.5.3.

As you say, the reason that you don't have any logs is because your APM failed completely and didn't store any logs.  It flipped over just because it was no longer trying to keep itself level.  The motors continuing to run is just another symptom of this.

It's very hard to determine what happened actually...Could be hardware or software or a brownout...hmm...


Had a crash, when i switched into Alt-hold, strong winds as you can see from the video.

But i thought i'd try the alt hold, mistake :-( As soon as i switched it rolled over and hit,

Not much damage, Bent one motor mount and broke the landing gear on one side.

I'll try to get the logs later.

Just flew… 2.5.3   on AMP2 on large Tri


1)      The Yaw problem with hard nose down is gone..

2)      The Yaw in general just seems to work better

3)      Alt hold is fantastic…  Plus or Minus 1 foot at times..  super reliable.

4)      Stab is good as ever..


I tuned Loiter_P from 0.6 up to 3.0 and it just seems dumb…

It makes like one attempt to get back the it gives up and drifts 100s feet away..

Cant stay in 100x200 foot field…

Eddie Weeks


Kevin: Are you using 2.5.3?

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