ArduCopter 2.5 released!

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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  • Developer

    For those of you with yaw related issues please see my new blog post. It may help you.

    If the link is broken just give it a few minutes. I think the blog post is still waiting for approval in the moderator's queue.

  •   What would be the noticeable difference having 1100kv motors compared to 880kv motors on a quad?

  • Just took my quad out for it's first real-world flight in the nice Alaskan spring weather (33 degrees F, winds 5mph).

    First, 2.5.3 is pretty solid and responsive (I still have some tuning to do I think with STAB and RATE), and the alt-hold works perfectly again! There is still the throttle-yaw issue, however.

    Loiter was nearly unresponsive and when I switched to loiter mode, the quad decided to go play elsewhere until I called it back (I stopped it when it was about 10m from the loiter set point). I assume this is just a matter of parameter tuning to get it to work properly.

    Also, I imagine the yaw issue will affect loiter performance since the yaw action is not commanded by the Tx, and therefore the quad is no longer aligned to true magnetic directions... just a thought.

    3DR Frame, 880kv, 12x4.5, 3000mah, APM2(AC2.5.3), Default parameters except: STAB P 3.5, RATE P 0.11

  • just tested 2.5.3 in my backyard.  Seems pretty rock solid to me.  Less random yawing. 

    I noticed that my simple mode didn't seem to be working.  I don't believe it worked for me with v2.5 either.  Is there a way to check, other than the MP setup screen, if it's enabled?

  • T3

    I'm quite new to Arducopter but I've had my APM2 board in my octo and now in a quad.  The small quad with 10x4.5 props. 

    With 2.4 firmware I had very good sonar alt_hold.  Held in a range of less then a foot.  Then I changed to the new firmware 2.5 and after two days of reading the forum I had it working ok.  The attitude control was very good.

    Now with the with the 2.53 firmware it won't even fly smooth.  I did a reset and have the new default setting. The sonar will try to hold altitude but goes up and down 4 feet and I have to have the alt_hold Kp set at 4 instead of .5.  Yaw jumps 25 degrees and when I set it back it just jumps back again.  The quad acts like there's some major bug that I loaded with the new firmware.  So far I've broke one arm and around 15 props trying to tune my quad.

    I reloaded 2.53 from a different computer and see no change.

     Is there a way to completely remove the firmware and setting?


  • Hi,

    what value i must change to get stable ATL HOLD?

    My config is: Quad 3DR frame set to X, esc from diydrones store, T-motor 2208, 10x45 propellers, sonar.

    With the default pid for alt hold when i fly under 1 meter and activate alt hold the quad fly well and stable at right altitude (under 1 meter) if i fly at 1,70 or more meters when i activate alt holt the quad goes up fast at 3 or more meters.

    I must change throttle rate P or altitude rate P?

    thanks and sorry for my bad english

  • Flight testing on 2.5.3

    Mid size custom quad:

    QUAD+APM2.JPGGIT version AC 2.5.3 c25ae4bcaec3

    Size: 500mm motor-to motor
    weight: 712gr
    Motor: T-motor MT 2212-16
    Wind: from calm to mid wind at the end.

    General: it flown very well. No major issues.

    LOITER. After some tunning (close to deffaults) loiter quite well in both heigth and position. See image: Radius about 1m, heigth < 1m (only baro).
    YAW. Still some small problems but good enough to flight with confidence (see logs Yaw-Mag Heading and image attached). It´s clear the relationship throttle level-yaw effect.
    AUTO. Not good. It performs the work but very imprecisely compared with previous versions (<2.4). Also it travels from one point to other not heading correctly (there is about 45º yaw) although trajectory is OK. One reached the point it turns with a very large radius. Not nice
    RTL. When close to take land. it jumps like a rabit. Not nice. Throttle should drop down much much more quicker.
    STAB. I have some glitches (not too offen).

    I have some videos. I´ll post when ready.


  • Four good flights on a 3DR with 2.5.2 yesterday until the rain came. Loiter was O.K., RTL kind of worked, but overshot a couple of times before finally settling in and landing (make sure you have a lot of open space for it to land on, and that you can keep yourself in a safe location...), but it did work. Some in-flight video below. This is using a "BOB-4" OSD module controlled by an APM1 in my ground station. I like the fonts over those of the 7456 based units and It let me make an altitude bar for the last 2m (sonar based, so good for the landing on goggles),  reverse video for warnings (towards the end of the video), and simple vector graphics (although no double buffer, so need to always erase then draw).

    Some in flight video is here 

  • Developer

    ArduCopter V2.5.3 - Long Loiter with heavy X8 in strong wind (APM1 - only baro):
    GIT Revision: c25ae4bcaec3

    I do not remember who had asked me a demo with long loiter, anyway here my daily video with my heavy X8 in Loiter for six consecutive minutes, with very strong and gusty wind, without sonar, only baro with the latest fix by Randy.
    And the testing continues.... have fun, without crash!!!


  • Hi All,

    Thanks to all involved in bringing these continued releases. It is hugely appreciated and allows us to have more fun.

    I updated to 2.5.3 this morning and took it out for a test.

    I Have never had any issues with any of the releases and the defaults have always given me a pretty good flight. Unfortunately this has come to a screeching end.

    I have a stock 3DR quad with 850s and a 3S lipo.waited for 3D fix on GPS

    I've disabled the sonar in the today's flight as it appears to be busted (confimered that there is no varying output voltage with changes in distance)

     - Alt hold is, like someone else said, a pogo stick. Set around 1.5 - 2m height and it bounces from that to touching the ground to shooting some 5-10m above my head before I switched back to stab and recovered. it seemed hell bent on going somehwere.

     - General flight is very poor. Wild oscillations on decent lots of unwanted yaw and drifting. had one minor crash because of it. More on that in a bit.

     - Auto to waypoints does not appear to work. I set 5 points around a field and it sort of headed for one then in the approximate area decided to head back towards me. Seeing as it was not following the route I switched back to stab and tried to recover. Due to yaw and oscillations, I had a small crash - hit the ground in motion and it flipped. No damage though.

     - second attempt at auto and instead of heading to waypoint 1 it went hell-bent off to the left of it and seemed to have no intention of going near it. I aborted before I was out of my depth.

    Went out again this afternoon and normal flight is not very friendly. I had a sneaking suspicion it was going to end in tears so stopped after a couple of minutes. Forward was not really forward, backwards was not really backwards, both had a yaw to them or just went off to the side.

    There is also a drift to the right now. On 2.4 I had a bad drift to the left, lots of trim to correct it. 2.5 it was gone, 2.5.3 it's back but to the right, not as bad though. 

    Not sure what is different but as I said, I have always had a decent flight with the defaults (other than the recent throttle trim thing) but some some reason, the quad is being a bit rude with 2.5.3

    Conditions were chill (10c) with a very very light headwind. Hardware wise, no different from 2.5 to 2.5.3 other than disabled, but still connected, sonar.

    Please please please - it is all constructive. If I were a clever man then I would roll my sleeves up and help. But alas, you lot are better than I and I appreciate the work you're doing towards this. I'm not knocking it at all. Just some feedback.

    Logs from today should be attached. I think 150 would be the longest one from this morning with lots going wrong. Don't know how to tell.



    2012-03-25 08-28 150.log

    2012-03-25 08-29 151.log

    2012-03-25 08-29 153.log

This reply was deleted.


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