I've got a stock 3dr kit that I've just finished putting together, and it tries to flip on takeoff. I'm running x config. Arducopter 2.1 firmware.

I've run through the troubleshooting steps: checked motors with the cli motors command (successfully), made sure the correct props are on each motor, calibrated the radio and verified that the correct inputs are reaching apm, but I still cannot get this thing to take off or fly at all correctly. Apm is facing forward between the front legs, and the movements seem to show up correctly in mission planner when I move the quad around while connected to it.

If I give it a smooth throttle increase, it won't take off flat, it will just tip, so I back off the throttle. If I give it a burst of power, it will take off, but will dive off to one side and crash (just busted my first prop...)

I've run the imu test with the following results:

g   0.0209   0.0000  -0.0000  a  -0.1157  -0.0463  -9.8016.

I have downloaded logs from the last couple of flights where it was tipping when I tried to take off, but I can't figure out how to interpret them. If anyone could give me a quick rundown of the best way to view/read them that would be good. I have attached the log.

Are there any other diagnostic checks that can be run to find out what's going on? I saw another thread where someone was checking the watts of power delivered by each esc to each motor to verifiy that a esc/motor not running at full speed wasn't to blame, but I'm not sure how this would be done.

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Hi Glenn,
If you get a response from 3D robotics that solves your problem could you please share it in this thread as I also have a stock 3DR frame and kit that suffers similar issues to yours and only wants to flip on takeoff.

So I took the quad out for a go at the park yesterday.  I could get it to take off, but it required increasing amounts of roll input on the stick to get it to hover. Eventually it ended up taking off sideways at speed while at about 4m altitude, and I had to kill the throttle and put it down on the grass before it hit a building (snapping a leg in the process).

I've attached the log from this (2012-01-02 05-18 7.log), and also the next log after unplugging/replugging the lipo where it would just try to flip over to the right (2012-01-02 05-18 8.log). I could just get it to take off with heavy left roll input, but couldn't hold it in the air. I'm not sure if i'm interpreting the logs correctly... I see there are corresponding changes in the roll and ch1 out, but how can I tell if the quad thought it was level or rolling while sitting on the ground or in the air?

I guess the imu will be heading back to 3DR tomorrow, but I'm just worried they wont be able to reproduce this issue. ;(


Hi Glenn, were the issues resolved by sending in your IMU?

Yes, new IMU and it's working fine now. Frustrating that I spent so many hours troubleshooting and broke a few parts test flying when it was working intermittently before sending it off though.

Hi Glenn,

 I have a Y6 with APM2. I have exactly the same problem. How did you fix it.

I just had a faulty board. New board fixed it for me.

I also have a flipping copter ;)

I have just changed FC from a KK5.5 to a  Arducopter 2.5 (AP2 latest download) - both in X mode, using 'simple' control - everything on the airframe WAS fine before.

The effect is that it trys to flip port to starboard on take-off

I have recalibrated and checked over and over - all appears fine.

However, When I connect the motors as shown on http://code.google.com/p/arducopter/wiki/AC2_Props_2 the CLI motor test was wrong! I had to connect as though the board numbering was 2431, rather than 4321.

This actually has the effect of numbering the rotors from the starboard bow 1 to 4 in a clockwise direction (way simpler - why complicate the hardware when it is so easy in code to nominate outputs?), and as I say, the CLI motor test works as per the diagram.

Clearly one of these is wrong, but why is it not reported elsewhere (that I have found), although I would anticipate tipping more in a forward direction.

I am going to attempt to fly it in the right(wrong) configuration tomorrow as per the diagram and ignore the CLI test, as this is driving me mad!
Any comments in addition to those in the above thread would be most appreciated.

Kind regards


It's very wet out there!

Motors wired as per the diagram, and CLI NOT firing in 'sequence' (1234), but clockwise (would it worth changing the wording? or is it just me? :) ).

I did a "microflight", no sticks, 1" off the ground, then back down - working :D

BTW I noticed that as I gently increased the throttle (ready for a flip), the motors at one point surged! I though the thing was going astro! Not good in my back garden! I instantly throttled back and tried again without the same issue. Is this normal on the APM 2.5? Obviously as it was not flying before, I've done no tuning, I preloaded the novice values.

ALSO - Spinning props when Armed. I like this, but... Not so good when upside down/crashed.
Would it be better that they only ran at initial arming? i.e. when the throttle is increased passed a certain value or increased for a certain time, the action should be inhibited until the next arming?

Kind regards


I am not qualified to answer all of your concerns however the last item on the spinning props when armed causing a problem when crashed, the code turns the motor output off when it senses a flip/crash. Mine works well in this regard as I got stuck on a St Augustine grass runner and caused a flip. The motors stopped just as they are programmed to do. Good luck on getting it tuned now that you have it flying.

Many thanks for that Butch. It seems sensible. I have to say that mine did spin; since I instantly hit dis-arm as it crashed, I thought that I had stopped the motors.

Maybe there is a short delay? I assume that I can test this by arming and then inverting the airframe? Will have a play later to check. Too wet/windy/dark to fly.

As to catching on vegetation, been there :( - my copter has 'claws' that I now enclose in coloured ping-pong balls. No catching, doesn't dig-in during heavy landing and the colours help with orientation. I will change to a copter type landing gear soon and may put practice golf-balls on the ends of the skids. When I first started flying I took a square of ply with me as a heliport.

Home now.... I can confirm that the motors do stop automatically when inverted. Clearly I pre-empted the auto-stop.

Thanks Butch

did you get he flip on take off problem fixed

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