Copter-3.3 beta testing

Warning #1: an issue has been found with Tower's Pause button which can cause the vehicle to fly to an old position if the vehicle has not sent a position update to Tower in some time.

Warning #2: Copter-3.3.2 fixes a bug found in Copter-3.3.1's desired climb rate initialisation which could lead to a sudden momentary drop when switching from Stabilize or Acro to AltHold, Loiter or PosHold.

Warning #3: Copter-3.3.2 fixes an issue found in Copter-3.3.1 which could lead to hard landings in RTL or AUTO if the WPNAV_SPEED_DN was set too high (i.e. >400 or 4m/s) and/or the WPNAV_ACCEL_Z was set too low (i.e. <100 or 1m/s/s).

Warning #4: a bug was found in Copter-3.3 which could cause a sudden crash if you abort a Take-off initiated from a ground station.  Video description is here.  The bug is fixed in Copter-3.3.1 so we recommend upgrading.

Note #1: AC3.3-rc8 corrected a long standing bug in the HDOP reporting.  HDOP values will appear about 40% lower than previously but this does not actually mean the GPS position is better than before.
Note #2: if upgrading from AC3.2.1 the vehicle's accelerometer calibration needs to be done again.
Note #3: set SERIAL2_PROTOCOL to "3" and reboot the board to enable FrSky telemetry like in previous versions.
Note #4: the wiki will be updated over the next few weeks to explain how to use the new features

Copter-3.3.1 is available through the mission planner.  The full list of changes vs AC3.2.1 can be see in the ReleaseNotes and below are the most recent changes since AC3.3.

Sadly this version (and all future versions) will not run on the APM2.x boards due to CPU speed, flash and RAM restrictions.

Changes from 3.3:

1) Bug fix to prevent potential crash if Follow-Me is used after an aborted takeoff

2) compiler upgraded to 4.9.3 (runs slightly faster than 4.7.2 which was used previously)

Changes from 3.3-rc11:

1) EKF recovers from pre-arm "Compass variance" failure if compasses are consistent

Changes from 3.3-rc10:

1) PreArm "Need 3D Fix" message replaced with detailed reason from EKF

Changes from 3.3-rc9
1) EKF improvements:
    a) simpler optical flow takeoff check
2) Bug Fixes/Minor enhancements:
    a) fix INS3_USE parameter eeprom location
    b) fix SToRM32 serial protocol driver to work with recent versions
    c) increase motor pwm->thrust conversion (aka MOT_THST_EXPO) to 0.65 (was 0.50)
    d) Firmware version sent to GCS in AUTOPILOT_VERSION message
3) Safety:
    a) pre-arm check of compass variance if arming in Loiter, PosHold, Guided
    b) always check GPS before arming in Loiter (previously could be disabled if ARMING_CHECK=0)
    c) sanity check locations received from GCS for follow-me, do-set-home, do-set-ROI
    d) fix optical flow failsafe (was not always triggering LAND when optical flow failed)
    e) failsafe RTL vs LAND decision based on hardcoded 5m from home check (previously used WPNAV_RADIUS parameter)

Thanks for your testing!

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


          • I really hope it is possible to take the battery case apart and solder in a new battery. You can't do this on a DJI they intentionally go out of their way to make sure the circuit sees this intrusion  somehow and renders the unit / battery useless. The 'smart battery' is mostly for revenue generation for DJI I think. My brother lost a phantom because the stupid battery wigged out and thought it was low and landed itself in a lake. Meanwhile it was fully charged before flight and his HUD display clearly showed an %80 charge remaining. I also heard they automatically discharge themselves aka 'storage' after a certain amount of time with no use. So you finally get time to go fly only to discover that fully charged battery isn't anymore. Or maybe you don't realize 'IT' discharged itself and you crash because you didn't realize it did this. Anyway.... I'm no fan of a 'smart' battery I have a brain and a charger I've been fine with it I don't need any help. If the solo battery is like this I'll not be buying a solo for this reason alone. But... I do like how it just plugs in. Very nice. 

  • Hi All and a big thanks to the Dev's and all of you guys writing and testing the beta firmware. 

    I had a problem with EKF Variance that just sprung up yesterday.  I am running Pixhawk on a Cinetank Mk2L with 12" props and t-motor MN3510 motors.  Compass id a 3DR external.  As far as FC goes it is pretty much stock config.

    However, after several flights with no issue I started getting EKF Variance warnings every time I armed.  After digging through the logs I found that the compass' were not tracking each other and a permanent offset had appeared.  The reported heading seems OK on MP and flight in STAB was ok (although very short as I didn't want to push my luck)

    I tried powering off all of the FPV gear etc. and moving the External Compass but no difference. I assumed it was hardware related but two other Pixhawk machines also started to do the same.  The small 250 was ok after a couple of recalibrations but the Y6B and the Cinetank required more work.

    Erased and reinstalled 3.3rc5 and did a complete setup and this fixed it for a while.  Rebooted this morning and once again Compass Variance had appeared.  I checked the offsets and Compass 2 had 0,0,0.  I am a bit confused as I also rebooted several times last night and it was ok.

    Finally, out of frustration I changed the orientation of the external compass and now it seems fine (After recalibrated).

    I have also tried COMPASSMOT on and off but this didn't make any difference for me.

    External compass offsets are (23,27-75) and Internal (367,-398,-352).  Delineation is 12deg 33 min.  Heading matches compass perfectly now.

    Any ideas?  I had a similar issue with another quad but recalibration seemed to fix this. I don't think it is hardware as three machines have all developed EKF VARIANCE warnings and each time (up till now) recalibration seemed to fix it.  This time I also needed to point the compass in a different direction.

    Overall though I think 3.3rc5 is fantastic in the modes I have tested.  

    • Well that didn't work.  Just wanted to confirm, what is EKF_CHECK-2 actually telling me?  I know it me and EKV Variance but I can't find anything specific in the wiki.

      When I roll back to 3.2.1 it is fine.

      Any ideas?  Thanks.

  • I did Auto Tune on rc5 again yesterday trying different props and larger battery with AUW 2.7kg.

    The stab roll/pitch seem quite diverged. Also, is it normal to see Rate Yaw  D value of 0? I notice when the quad takes off it yaws a few times before settling to the heading.

    One more question. Does lowering the roll/pitch sensitivity help with Follow Me mode? 


  • Testing 3.3RC5 using PIXHAWK and latest mission planner Beta: Flight modes have disappeared!

    I mean the "drop down boxes" letting you select what mode for various value of channel 5 aren't present any more.

    I think it is a MP beta problem as re installing latest stableversion (1.3.28) did fix the "undocumented feature"


  • PID Help..?

    I updated the firmware on my QAV 540 to 3.3rc5 and did my first test flight yesterday.   I like the audio tones for feedback that have been added and the flight was ok, the PosHold was very steady on 11 SATS with  a HDOP between 1.9 -1.8 

    It was a bit windy and it held position pretty well.  However, it was loose in the pitch axis, when adding throttle to go up or decreasing throttle to descend, it would get into a rocking mode like a seesaw.  not very extreme, and I only had to stir the stick a little to break it out. But it had a definite tendency to rock, also the yaw seemed too sensitive.   The PosHold kept the heading very well, but when in stabile mode, I had to work the rudder a little to keep a good heading.  Probably the wind was causing that.

    This is a heavy build, QAV 540 with extended arms, 380KV motors, has a tarot gimble for GOPRO, carrying 2 3S, 5100 MAH battery packs in series for 6S, the CG seems fine with my Gopro in the front and battery packs toward the rear.

    I assume the PID values need to be adjusted.  I don't have a screen capture of my current settings, I may need to post that before anyone can help me, but in general can someone tell me which PI value or values I should changing?


    Richard- Kd5zzl

    • Developer

      Hi Richard,

      To help you I need to know what size prop you are running.

      We also have some motor linearisation code in there that compensates for battery voltage drop over the flight.

      To get the most out of your copter you will probably have to do an autotune or a full manual tune. I can help you with either.

      • Hi Leonard,

        Is there a chard of wich values to set for MOT_THST_EXPO ?


        0.65 is for 10" props

        0.70 is for 12" props

        0.?? is for 13" props?

        and so on

        0.80 is for 18" props

        • Developer

          Hi Geert,

          So I wrote down the numbers for each prop size from 4 different manufactures. Some sizes don't have much data but here it is.

          0.45 to 0.55 is for 5" props
          0.62 to 0.65 is for 6" props
          0.66 to 0.68 is for 7" props
          0.66 to 0.70 is for 8" props
          0.67 to 0.67 is for 9" props
          0.64 to 0.70 is for 10" props
          0.70 to 0.75 is for 11" props
          0.73 to 0.78 is for 12" props
          0.72 to 0.77 is for 13" props
          0.71 to 0.77 is for 14" props
          0.70 to 0.76 is for 15" props
          0.70 to 0.76 is for 16" props
          0.68 to 0.62 is for 17" props
          0.68 to 0.75 is for 18" props

          So for my copters I am going to go with: 
          0.65 is for 5" props
          0.65 is for 6" props (I think the low numbers come from flexing props and I use HQ and they are stiffer than normal)
          0.675 is for 10" props
          0.725 is for 11" props
          0.75 is for 12" props
          0.75 for 16" props
          0.75 for 18" props

          As you can see, the data moves around a bit and changes a lot for different manufactures and maximum power level of the motors.

      • I am running 12-5 props.. I haven't done auto-tune, it is always windy it seems when I have the time and chance.

        I like manual, because If I can learn that, It would be valuable knowledge.



This reply was deleted.