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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John: Yes. The same principals that are outlined in the wiki apply to the latest code. Some of the throttle issues were not actually related to what you could have tuned with PID gains. Those issues were fixed in 2.5.3.

John: We've addressed that many times, but I'll repeat it again here: we don't officially support older versions of the code (ie, in the Mission Planner), because we don't want to waste scare developer time doing tech support for users encountering bugs that have already been fixed.  But all older versions of the code are all available in the downloads section and can be loaded via Arduino (although we won't offer official support, there are 23,000 people here who can help).

And like I mentioned last time you raised this, we always list each new version of the code in the News section, along with a post describing all the major changes. Needless to say, we don't release code with known issues, so there really isn't much to say about that at the time of release. Once the code goes out to the 3,000+ ArduCopter users flying countless combinations of airframes and hardware configurations, some edge cases inevitably show up, which we then fix in the next version of the code. But by and large we don't know about them until a week or two after release, once a user can submit a proper issue report with a log and we can verify it. 

As for 2.5.3, the only issue I know about that's come up since release is that some people are having trouble with the compass calibration process, which depends a lot on the magnetic interference properties of their particular airframe. We've got a better compass calibration routine that's already been released for ArduPlane. If that performs well for the full userbase, we'll roll it out soon for ArduCopter, too. 

I think there is an echo in here... :-D

It is working fine for me. Make sure you have the right board type selected, the right port selected and then try again. If that doesn't work, post your APM_Config.h file here and let me know if you have an APM1 or APM2. I might be able to help.

Can I suggest you take a break from software development and spend some time on bringing the documentation up to date? 

I think many of us would benefit from some good systematic tuning guides. If you wade through the forums, you will find decent procedures for setting up stablise mode, (like in this post ), but so far setting up anything beyond stabilise seems to be a black art.   

Good tuning guides on the wiki would IMHO also help to improve the code further because I think starting from a good basic setup for stabilise/alt-hold and loiter will help produce better problem reports and descriptions.


I tried my first fpv flight today with 2.5.3.

WIth the addition of a Gopro and Video TX the quad was rather unstable with the extra weight.

Which parameters should be trimmed when flying with more weight?

Some other things I noticed is that quad sometimes had a strong backwards lean after a couple of minutes flight which wasn't there when lifting off.

Also when I can get to quad to hover nicely, after a couple of seconds it goes up or down resulting in throttle compensation.


Any suggestions?


Flying APM1, MT2814, APC 11x4,7, 5000mAh 30C, X650 V frame

I should mention that the above mini guide is for when you are actually flying and trying to dial it in.

The steps in the spreadsheet, that I find really result in the best tuning, should only be done holding the copter in your hand, above your head with sensible safety measures, at hover throttle and above.

Your airframe will not fly with no stab_p or rate_p, so tuning rate_D first MUST be done in hand.

I find tuning this method really educates you about the behaviour of each parameter, the guide, that's been further postponed due to a big contract at work, will explain.

I need a change in career...

I fully agree with Gerrit. I am one of the trad heli guys and since weeks, trying to get loiter to work. It is a try and error, as I do not know for sure, where to start tuning. Then you read in other posts that the rate PID settings have huge influence on loiter performance, etc. There are too many points where one can start.

I would be really happy if I could reach a loiter state which is not instable or let's say keeps the heli in a reasonable airspace. Until now I am always reaching a point after some oscillations or circles, where I need to take over manual control to not loose the heli or to no crash it.

Thanks for the detailed outline Chris. I'm sorry I must have missed it somewhere about the change details being posted on the news page and this is good to know now. Perhaps then just that link  could be shown on the pop up box when the Mission Planner advise there are new updates? Just a short message on the box like "please go to this link for update details" together with the link?

John: I think you're confusing Mission Planner updates with flight software updates. That pop-up you get is just for Mission Planner updates (desktop software) and reflect minor bug fixes and enhancements that don't typically affect the user experience. Flight code updates are announced on the site here. There's no automatic notification of them in the Mission Planner, but when you go to the Firmware tab you'll see that the version numbers have changed. 

Hey again guys! First off, thanks again to all who make thise code possible and put in the hard work!!

We are having some very strange issues with our big octo builds, we've got two octos, one using 25A and the other 45A esc with APM1, I've never had any issues with APM1 and octo builds, but with BOTH these we have had weird ESC issues on motor3, both on motor3 !? As soon as we power up, the motors do their normal beep beep, but 3 has a delayd fast beep beep beep beep and then the normal tone.. When throtteling up smoke comes from ESC3 ???!! on both systems the same thing happened ?? So my thinking is, as these are all brand new esc, and never had any issues before, prehaps it's a code thing due to new motor changes for octos ??

Any ideas guys, this is pretty troubling


Concerning the hovering I also noticed that when enabeling Alt hold for a while the quad stays at the correct height (sonar) and then starts to slowly yo yo. 

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