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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If this is really my problem, it could also explain why I'm not able to get any good loiter performance, right? I always end up with the quad racing in circles. 

I have the compass soldered on the APM1 so I'll first try the throttle almost full method.

I do have a question regarding the compass: Now that there is a calibration procedure in mission planner, what is the relevance of the COMPASS_DEC value?

... correction... should say.... without any change in altitude.

Fast oscillations during the descent... try increasing RATE_I.

Ops, i'm sorry for your crash, I hope the damage is minimal or absent.
, this two lines should not differ!
Have you tlog?

I really love this video! :-)
Dave, you are officially recruited by me (LOL) as a "beta tester" for future versions... :-)
Seriously, we wish to choose some reckless with good experienced in flight/tuning to test future "alpha" versions, that will interact with some components of the dev team (like me).
I will leave a message here on the thread for the "possible candidates".
However you're one of those, absolutely! :P

Cheers, Marco

yes... I will post it no problem... Broke a Carbon rod and a prop..  no worries..

Here is what I think the tlog is.. I dont know for sure because the file name are not simular

and the tlog file will not play on the mission planner... ?

tlog file...



This is possibly the worst quality video I’ve ever spat out, and that’s saying something if you seen my others, but I have to admit my ‘panic at the disco’ on the switches at the end made me laugh out loud when I watched it back for the first time.


Very soft settings here, was planning on tuning them right up to cope with the wind.

RTL where L is under a tree... oops! from Kamakaze UK on Vimeo.

The compass is calibrated during the flight, however, you can try to calibrate it first in the planner but remember first to disable the automatic calibration in flight.
COMPASS_DEC value are stored when you disarm the motors, and it is interesting to try to compare these parameters with both the options, after the manual calibration and with autocalibration enable after some flight.
The parameters should be very similar, if there are too different there is something wrong with the compass (magnetic interference in your setup during flight).

No, wrong tlog... try to see it first with the "play" function in the planner.
Sometime the planner doesn't play the tlog if you are connected to your APM.
In this case close and start again the planner and try to play without connecting.
Eddie, please open a new issue about this event, thanks!




That is all I can say for now... this version is super stable, no drift, no strange things... (well maybe some... :) ) 

First impression are really great, this thing is rock solid, stable and all.  I did ran out of juice battery so I did not get to enjoy it as much as I would have like. Batteries are charging now and I will be out soon to play more. 

Yes I said play! it's no more difficult, not risky (at least for now, no bugs = good news) 

I really enjoyed it! 

In my small backyard, some side wind, not much, sunny and all! wow! 

Here is the "problem" after some flights the Quad developed the "Yo-Yo" effect... you can see that my throttle was somewhat stable but the Quad was going up and down... 

This is a brand new X1 frame that I've put together for the occasion so yes it was the maiden flight! 

here is my config, 

850Kv jDrones super sexy black motors

10X45 props

20A jDrones ESC

X1 frame (did I say fold able for storage? hehe) 

3300mah Nano-Tech Battery

Weight 1.170 kg 

Only changes to the PID were for the TRIM_THROTTLE to 475 as otherwise the default was making the quad fall down. (guys please make sure to increase this value as your Loiter will bring down the Quad!) 

Turnigy X9  radio (with some mods....) 

- No sonar... nothing else... almost "Straight out of the box" ! 

And this is the video: sorry for the poor quality and zoom... iPhone taped on the patio door! :)

Attache is the complete log of that session... if someone wants to have a look at my YO-YO effect... I did not ruled out yet the low voltage on battery... maybe it was just that... will post back when I fly with fresh batteries (yes more than half one this time!) 

I want to say thanks again to all involved, from devs to testers! This is a great milestone release, let's see where we go from here. 



Hi Dany! The "yo-yo" effect is not a issue, but a new function with "throttle hold"... now is dynamic!
The value changes automatically during flight, based on detecting errors by the barometer, temperature and altitude variations.
You can write whatever you want as the value, so then if you refresh you'll find it immediately changed... :P
IMPORTANT: the barometer must be completely covered by a small sponge soft enough, especially if your APM is not protected from air currents.

PS: I think I know this quad... :-)

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