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!


Views: 132832

Reply to This

Replies to This Discussion

Hi Todd,  I am still having troubles as well.  I now have my top/bottom ratio at 1.0 (was .92 and flew very solid) and I can now get off the ground but my y6 is doing just like yours in the video.  If I revert to old 2.0.50 it flys great.  I have the same board APM1/2560.  I tried disabling the motors_filtered code in motors_y6 as well to no effect.  I want to be able to fly 2.5 on my y6 because it is the best software yet!  My quads fly awesome now -- all modes.

Thanks Marco for the clarification... but how do I avoid the yo-yo?  my baro is covered... 

and No this is not the same as your X525... :) it's the X1!  hehe  I like that frame 

And yes the motor mount should be replaced by alu plates... This is just a first flight of a clean and fresh new build just for your 2.5.0 version!


Well Dany, dunno why the "yo-yo" effect is very pronounced with your configuration.
This new feature that Jason has implemented should eliminate the wide variations that an incorrect setting of throttle_hold could generate, unfortunately APM1 is obviously much more critical with the poor barometer, this problem is not so tangible APM2 and the new pressure sensor.
The system can be improved by trying to play with this parameters:


X1 and X525 are very similar... :-)

Thank you very much indeed, Sir! I'm looking forward to getting my hands on the darkest corners of the private GIT repositories ;)

Starting tomorrow I've got three killer weeks work, then a weeks holiday.

Then I've decided to devote some proper time to this project, I'll be at your beck and call for a while :)

In the meantime I'll be following closely and all ears. (my night time reading is going over various tuning guides trying to properly get my head around it all)

If you need anything testing please feel to drop me a line, even over the next few weeks I will be taking the quad to work with me ;)

I tried 2.5 today outdoor. Config Hexa X, Turnigy SK3 2826 1120kV motors, 8" props, 1.5kg AUW

(megapirate 2.5r2, flyduino mega, not original APM)

It took a lot of tuning and again different PIDs from 2.4.2 for some reason and I could not achieve "ninja" settings, quite the opposite in fact. I had to tune my Rate P's down to 0.30 or it would wobble (after a while). Rate I has to be zero or it would sometimes go crazy and stop responding (while it fights itself/myself/whatever goes in its head, looks like it's drunk). With Rate D > 0.002 it was twitching, with lower value it was not snapping to place but was very slow to level after a correction...

The strange thing is, it behaved well one moment and went mad when disturbed by wind  (not much!) - at one moment it even tilted itself almost 90 degrees, wobbled (ping pong), then levelled and all was well again. It did this many times, mostly during descent.

Another issue is yaw - yaw left was fine, yaw right was not good at all - I had to tune both Rate Yaw and Stab Yaw way up to achieve a good response to the right - sometimes I had to hold it in there for good 10 seconds before it started rotating. Also when maneuvering (or correcting) it yawed by itself - left.

It is not a hardware problem, but still the same issue that's been present for a while now, and I know I'm not alone - something's not right there for some of us. 

Also tried Loiter for a while - looked good, then flew away fast and couldn't be stopped by stick input - I had to put it back to Stabilise and fly back.

For me, 2.4.2 was way better. YMMV.

Edit: no logs, worthless, I know...

Had six flights with 2.5 from git on a standard 3DR with 850kV motors and APM1. Stabilize mode was fine without any work. Loiter was a bit harder. At the start it would move move in ever larger circles around the initial point, increasing the pitch and roll angles towards the center as the circles got bigger. I then started bringing down the loiter gains and it calmed down - I can`t say it was great, but it did hang around the initial point.  Probably can't do any more until next weekend, and want to read up on the relationship between the basic Loiter gains and the LOITER_LAT/ LOITER_LON gains before any more tuning.

Hi Andrew, try with this one and leave me your impression:


Ok so this is the second flight, battery full, did not change any tuning from flight number 1.

Yo-Yo or Throttle hold... is there, you can see that I was keeping the Throttle quite stable but the Barometer altitude was moving a lot... I have a foam piece on the Baro and yes it is APM1... 

It is not a big issue, just need to correct (small) the throttle in Stabilize mode. I will install a Sonar and try again later (it rains now!)  :(  

This time I tried the Loiter, at first it stayed quite there, but then I gave it a left/right command to see how it would react and the copter entered in a pendulum effect....  It was getting  bigger and I took back control. 

I still think it`s a solid release and I like it, now I think it`s all about tuning it correctly for my frame. 

Marco, as we have the same frame, could you post your PIDs?


Log and TLog included if it can help debugging! 


when I enter 3000 for the above IMAX if I refresh the value is saved as -276.8..... Strange or ok?

for all 3 of them... 

I tried 400 and it saved another value... tried 320 and it kept it...  looks like if I enter something bigger  it goes negative... MP bug? (did not play to find exact point) 

Fred: 1280 boards, which have been retired for more than a year, are no longer officially supported, but you should be able to run the code with Arduino if you turn off datalogging. 

this is my parameters loiter stable for me...


HI Guys

I have a DIYdrones hexa with the 850Kv motors.  I just upgraded to MP 1.1.53 and loaded my APM1 with version AC2.5.  Now the APM can no longer connect with the mission planner in any way other than "Firmware" and "Terminal". Directly connecting using the "Flight Data' tab and clicking Connect is not working at all (lots of "bad CRC" errors in Mavlink). I can get connected by first going to the terminal tab, getting the prompt then clicking the Flight Data tab and clicking Connect. However although the connection appears successful no data is actually displayed.. All works OK (or so it seems) using MP 1.1.48.

Anyone having this issue??? Is there a fix.??


Thanks ---- TOM


Reply to Discussion



Season Two of the Trust Time Trial (T3) Contest 
A list of all T3 contests is here. The current round, the Vertical Horizontal one, is here

© 2020   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service