APM:Plane 3.5.1 released


The ArduPilot development team is proud to announce the release of version 3.5.1 of APM:Plane. This is a minor release with primarily small changes.

The changes in this release are:

  • update uavcan to new protocol
  • always exit loiter in AUTO towards next waypoint
  • support more multicopter types in quadplane
  • added support for reverse thrust landings
  • added LAND_THR_SLEW parameter
  • added LAND_THEN_NEUTRL parameter
  • fixed reporting of armed state with safety switch
  • added optional arming check for minimum voltage
  • support motor test for quadplanes
  • added QLAND flight mode (quadplane land mode)
  • added TECS_LAND_SRC (land sink rate change)
  • use throttle slew in quadplane transition
  • added PID tuning for quadplane
  • improved text message queueing to ground stations
  • added LAND_THR_SLEW parameter
  • re-organisation of HAL_Linux bus API
  • improved NMEA parsing in GPS driver
  • changed TECS_LAND_SPDWGT default to -1
  • improved autoconfig of uBlox GPS driver
  • support a wider range of Lightware serial Lidars
  • improved non-GPS performance of EKF2
  • allow for indoor flight of quadplanes
  • improved compass fusion in EKF2
  • improved support for Pixracer board
  • improved NavIO2 support
  • added BATT_WATT_MAX parameter

The reverse thrust landing is particularly exciting as that adds a whole new range of possibilities for landing in restricted areas. Many thanks to Tom for the great work on getting this done.

The uavcan change to the new protocol has been a long time coming, and I'd like to thank Holger for both his great work on this and his patience given how long it has taken to be in a release. This adds support for automatic canbus node assignment which makes setup much easier, and also supports the latest versions of the Zubax canbus GPS.

My apologies if your favourite feature didn't make it into this release! There are a lot more changes pending but we needed to call a halt for the release eventually. This release has had a lot of flight testing and I'm confident it will be a great release.

Happy flying!

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  • Ah ok, that would explain it!

    I'm running V3.4.0 - I'm guessing this is the latest APM supported firmware? When I installed the latest firmware from Mission Planner I assumed it went to the latest firmware V3.5.3

    Time to upgrade I think..

  • Developer

    @MichaelThomas Support for APM 2.x hardware ended a year ago, no new features have been added to it since it was retired. Therefor yes, this is PixHawk compatible hardware only. What firmware version are you running?

  • No new development applies to the APM. All new features are Pixhawk only.
  • Hi @timpittenger, @tridge,

    I'm having some trouble setting up the reverse thrust function on APM 2.5.

    The reverse function on the ESC is working fine and I have set zero-point to 1500.

    I have set RC3_TRIM to 1500, and THR_MIN to -100. I could not find the USE_REV_THRUST parameter.

    When I start up the APM, the RC3_TRIM parameter reverts to the value for RC3_MIN.

    Is reverse thrust only support in the PixHawk hardware?



  • Developer
    I set mine 1500 to 2000 and leave it that way but depending on the transmitter you could set up a switch to change the range.
  • @tompittenger

    Great stuff with the reverse thrust feature!

    Do you set your transmitter throttle range from 1500 to 2000 (for example) to ensure that full stick down does not engage reverse thrust?

    If so, is there a way to manually engage reverse thrust?

  • Developer

    @Anthony, nice to see!

    If you try it with 3.5.2 then we will get new logging which should make tuning easier (new RATE and QTUN messages)

  • We tested after correcting the start up attitude to level:

    Flawless!!! (3.5.0)
  • Developer

    @Rainer, ok, thanks for letting me know! I'll be doing flight tests tomorrow and if all looks good then I will release 3.5.2

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