After months of testing AC3.1 is finally available in the Mission Planner and GitHub.

Warning #1: If the vehicle is left landed (but armed) while in AltHold or Loiter mode for more than a few seconds, the vehicle may suddenly jump into the air the moment the pilot raises the throttle above zero.  The reason is the baro altitude may fall while the vehicle is sitting on the ground.  In AC3.2 this bug is fixed because we reset the target before take-off.

Warning #2: Motors will spin (slowly) by default as soon as the copter is armed!  You can switch this feature off by setting the MOT_SPIN_ARMED parameter to zero.

Warning #3: if you see "Bad Gyro" on the HUD then you may have a blown 3.3V regulator.  See this thread for details.

Warning #4: if you use a sonar set the SONAR_GAIN parameter to 0.8 or lower

Warning #5: Trad Heli users should now connect their main rotor ESC to APM's RC8 output

Warning #6: Trad Heli BUG causes loss of collective control in ACRO mode if swash type set to flybarred (i.e. not flybarless).  Will be fixed in AC3.2.


The major improvements over AC3.0.1 are (full list here):

1. Pixhawk support (Tridge & PX4 development team)

2. Autotune of Roll and Pitch gains (Leonard/Randy)

3. Drift mode (Jason)

4. Improved Acro (Rob/Leonard) and new Sport mode (Leonard)

5. Arming, Take-off, Land in Loiter or AltHold

6. TradHeli improvements (Rob) including:

a) support for direct drive tail rotors

b) smoother ramp-up of main rotor

c) reduced collective for better control in stabilize mode (STAB_COL_MIN, STAB_COL_MAX params)

7. Support for SingleCopter (Bill King)

8. Performance improvements resolve AltHold troubles for Hexa & Octacopters

9. Safety Improvements:

a) GPS Glitch detection (Randy)

b) Motors spin when armed (Jonathan Challinger)

c) crash detector shuts off motors if copter flipped for 2secs

d) batt failsafe option to RTL instead of LAND, gps failsafe option to trigger AltHold instead of Land

e) more pre-arm checks of inertial nav speed,

10. Bug fixes:

a) optical flow working again (although performance is still not great because not integrated with inertial navigation)

b) ROI working (use DO_SET_ROI command)


How to upgrade:
Click on the MissionPlanner's Initial Setup >> Install Firmware screen.  The version numbers should appear as "ArduCopter-3.1", then click the appropriate frame icon and it should upgrade as per usual.

Special thanks to Marco and the many beta testers on the AC3.0.1 thread who put their copters at risk during the testing of this new version and uncovered many problems so that you don't have to!  Here are some of their videos: loiter in wind, patio sonar, autotune, autotune2, roi, beach, acro, vrbrain, tricopter, train spotting, radio failsafe, the tree, double loiter


If you haven't seen it recently, please check out the ArduCopter wiki.


Feel free to post comments below and we're going to use the new APM Forum for support issues so please post your support requests there.

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Happy new year!

I'm really not sure about the spektrum.  It's got a place to plug it in so I would have expected it to work.  I haven't heard of anyone using it though.


     No, although it can be used to communicate with sensors like a serial port the details of the communication are different.  The advantage of I2C over serial is that you can attach many sensors to a single I2C cable port and the flight controller can talk to all of them.  The disadvantage is that I2C is much slower and also not as robust.  So if one sensor dies it can (not always) cause the master to be unable to talk to the other devices using that I2C port.

Hi Guto, try with the latest version on the GitHub, follow my instructions inserted a few posts back.

Hi Marco, I will do it right now... (ArduCopter-v1.px4)


Hi Randy, I'm going to check Marco's information and I'll return with a feedback soon...


Marco, you are right my friend!

Now I see "ArdpuCopter v3.2 dev" on terminal and the spektrum receiver return to work!

Next step will be fly this version, see you... ;-)

Really nice, enjoy!

Randy, yesterday I tested the developer version (as suggested me Marco) AC3.2 and the spektrum satellite receiver is working again, now what we can see are sure that in the version 3.1 it is not implemented yet. Thanks!

Hello today killed his quadrocopter _-OO-_
today fell, before the fall was an oddity убераю gas % to 40 to decline and he knocked engines, let the gas up to 60% he started and stopped and started to take off clears up again to 50-40% again, jamming



Hello guys!

I was watching the Marcos Robustini's Videos a lot of times, and I'm impresed how works his hexa!

So i'd like have a guide or any idea what parameters change and how to get a rock solid loiter as his hexa.

Best Regards!

Hi Diego, thanks for your post, this gratifies my work.
Unfortunately it's not just a matter of tuning, those benefits are achieved considering many other factors as a well-balanced setup,
but experience is the most important and unfortunately it's impossible to teach it to others, must be earned over time.
If you want my parameter file I can post it here, but he will not suffice.
So roll up your sleeves and you'll see that you too will! ;-)

Cheers, Marco

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