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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Thanks Anis! That was it. Sorry guys - I thought I'd read the whole thread but I guess I missed that. Seems to be working now hand held. I'll give it a try outdoors tomorrow. Wierd in a way because I spent quite a few batteries hovering it around etc. I guess I don't totally get how it auto-trims that value.

Nice morning today and noticed 2.5 was released, so I did a mission planner update to my new 3DR w/850kv motors and APM1. I think I followed the online manual to the "T" and headed out to the field for a maiden flight.

I put it in stabilize mode for a few minutes and tried the alt-hold after that, that didn't go well and switched back to stable mode. After a while, about the 8:39:10 time stamp mark I lost stability then again at 8:39:30, and 8:40:46 & 8:41:54. Then at 8:43:23 it flipped and bent a motor shaft on me.

I been trying to understand what went wrong all day and thought I ask for some help. Is this the right place to ask?

I'll share my log file if it helps and a video too soon.



I've loaded 2.5 in my DIY quad flying +, and a friend's X, heavy unknown quad, and other than having to fiddle a bit with the TRIM-THROTTLE to get it to Alt Hold, I think this code is a winner, as stability goes.

Will try all the other functions later this week.

Thanks again team !

Ch 6 can be set to 'Relay' in Mission Planner. Does this toggle any output on APM2?  Where in the code can I grab ch6 'relay' to toggle an output like camera shutter?

Great to read Evan ! I guess there will be some more asking same thing in the futur, huhu ;

Might be good to write a bit about it in the first post of this release thread, to lower futur false disapointments and requestionning ..  

I have been flying so much I haven't had time to reply. Great work dev team. This is a fantastic leap forward.

Keith, I had a look at the log and video. From what I can see in the log, nothing on the APM side is goofy (but I am no expert in log analyzing). Are you using bullet connectors? It seems more likely that an ESC or motor failed. Let me know if you can confirm. Thanks!

yes, and it's been doing this since 2.2(?) (I've been doing most flying with 2.0 and that worked well, since then it's been hit&miss). You are one of the people I refer to as having the problem too. I also speculated that quad people may not have the issue and most people here fly quads.

Adam, Yes I am using the stock bullet connectors. I had to remove the prop afterwards because of the bent output shaft, but looks like it performs ok.

I dont believe it was a motor because earlier in the flight it dropped to the left and the right.

@ Dave C. - you are amazing if that's you it's so funny. Exactly like something I might do after having too many consecutive flights with no e events, sometimes I'll just say screw it and try an untested acrobatic maneuver that will cost me a flying machine until I (and it's typically not very long) put some bench time in and repair my chopper (not always a multicopter, sometimes an align trex or mikado logo).

keep it up funny man, I literally chuckled aloud in sync with tthe video right after the can brought down the quad. :thumbs up:


Hi Todd,

I flew my Y6 yesterday at the indoor, and it flew very stable from the start, had also had to reduce STAB_P quite a lot, what I had not time to tune was the yaw, wich kept beeing too much abrup  (I and D at 0).  I'll post some video tonight when I get home, as well as the PID's; could you post yours to compare please ?

I'll also be testing this evening at our field to check outside flying.  I'll keep you posted, but this one is a pleasure to fly! Congrats once again to the dev team.

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