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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did you try also replacing that same motor? I had nearly exactly the same problem and could smell burnt electrics, although it still flew. What I found is one of the windings had a loose wire that was rubbing against the inner housing. it was only slightly intermittent and made the motor/esc behave very strangely. Eventually it shorted out one of the chips on the ESC.   Id check the motor and at least test it with a different one

The only way to trouble shoot this is to put some o-scope captures of the output signal at startup. Again, based on what I know, 90% of these cheap ESCs use an Arduino chip as the controller and basically, you're taking the ouput the the 2560 pin on the APM and sending to to another Atmel 5v 8 bit microcontrollers input pin. Even if the pin was left high or low, I don't see how that results in smoke. Maybe there is flaw in the ESC code that a perfect combination on the input pin crashed it's microcontroller such that all three Mosfets turned on thus shorting phase to phase. A more detailed look at what failed on the ESC would be far more fruitful in determining exactly what failed and the root cause rather than postulating that some errant signal from the APM caused the esc to fail.


I'm not in anyway doubting your claim there might be a problem in the code as a delayed signal on channel 3 is a problem, I just consider that a different issue than burning up an ESC. This weekend, I'll try and set up my APM 2 in octo and take a look myself and see if this is reproduceable (the errant pwm) and while I'm not up to speed on the latest code, definitely can try to help determine from a signal standpoint what's going on. Worst case, I send an ESC up in smoke as well. If it does go up, might be a good time to get a look at the ESC source code (probably cannot get it), look for error conditions that could cause it to go up. Again, I'm not doubting you in any way, just more concerned there is a magic trick here that is lurking in our ESCs if given the wrong signal. Almost every ESC I have touched has the same basic architecture and the same micro. The 20A and 30A appear to be running the same firmware, so again, i have a new concern an errant signal can let out the magic smoke.

If you can, some pictures of the ESC that did smoke might be helpful. The fact that this happened twice is of concern. Again, there are two issues, one is possibly bad code making errant signals out of channel 3, and far worse, is an esc that burns when it receives this signal.

Finally upgraded my AMP2 from AC 2.1.X to 2.5.3,

What a nice improvement! I now feel that the Acro and Stabilized modes on my quad are as smooth and controllable as they are with a MultiWii board.

Need to find a bigger space to test Loiter and Position modes (what is the difference again?).

I flew my new crash quad last night ( I call it the crash quad because I built it purely for testing the extremesI can try out on AC/APM ) but I flew with my open pilot cc board and its so easy!!!.. what a great system! I hate to rag APM and I like this as well and am awed by the magnificent development and great work done on it, but OP really leaves it for dead for ease of use. I had it fitted, calibrated and flying all  in under 15min. and didn't even look at the PIDS.  Even their GCS is so intuitive and the board is small and a brilliant piece of hardware. . Only draw back is it doesn't have GPS autopilot yet and its so slow to develop. I often dream of the day that OP and AC join hands and then really make some great advancements in UAV. 

So for any of you flying the latest official code, mind posting more param files and observations?  I am having difficulties with altitude hold and loiter currently with my setup.  Flying in moderate winds also is a bit hairy.  I don't consider my setup dialed in, especially since I have payload intergration development going on.  However, in a low wind enviroment, the quad is pretty stable.

Setup:  3DR quad + extended legs, 11x4.7SF props, DT750 motors, APM 2, 4000mah batt, weight ~1450g

BTW, anyone flying with Stab_I terms greater than 0?  I vaguely remember seeing advice not using the Stab_I with the PIDT1 control scheme, but I am not sure if we are currently using that control loop setup right now.


hey jonathan,

i followed the infomation at the top of this thread. "tuning" i did see an improvement.

heya fellas, just out on the field and tried the new code on my hexa. running apm 1 1250, crash bang all i can say. sorry, yaw seems to be the culprit here, gets stuck again and you very quickly lose orientation. just broke 1 prop but i tried many times and done a compass recalibration too. is this yaw "stuck" issue prominent on hexa's only or throughout all configurations including quads?


Have you not seen the blog and posting that ther was a KNOWN issue with yaw stemming from magnetometer calibration?

i have seen it and i did do a LIVE data calibration just before i flew it today. it didnt seem to work well though. ill give it another shot. thanks.

I finally loaded 2.5.3 onto my 8X Quad after doing full CI erase and reset and recalibrate everything .  On some checking the sonar is not working and even if I hold it up to 2 meters it never reads more than 32cm. Any ideas why?

Also where can I find instructions how to use the compass declination calibration that's now new on MP? For now I just added my usual declination. Is this ok?

I have adjusted just the few of my PIDs to the setting I normally use.

STAB P/R 3.800  I 0.050 IMAX 40.

Any other stetting I should tweak and issues I need to be aware of?

My X8 Quad specs

Board: AMP1

GCS: MP 1.1.59

Copter Firmware: 2.5.3

Quad X8 (coaxial 2 motors/ESC per arm sharing one APM signal)

5000mAh3S 35-70C

Droidworx ADR Quad Standard, (72cmx72cm across)

Flight weight 2.4kgs

Motors 880kv Jdrones

8 Props 12x4.5

ESC 30A Jdrones

APM power supply. 5V, 3amp switching regulator (SVR3 Tahmazo)

Sonar XL-EZ0 (MB1200)

Declination:  -0.5899

John: Check your sonar wiring--it's working fine for me. Also make sure you've enabled it in the MP. Are you using APM 1 or 2?


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