3DR Quad APM 2.5 takes off but then lands

Posted by Chuck O on May 10, 2014 at 4:34pm

I take off ok, it is a little rough wants to yaw but it gets up in the air and seems to be ok. Then it starts to come down so I give it throttle.  It seems like it has less and less power and finally just lands. This takes about 15 seconds. I can repeat the above immediately.

I have calibrated the radio, Acels and compass. Also I Calibrated the ESCs. The battery has plenty of charge I tried multiple batteries.

Any ideas? 

Thanks

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Replies

  • Johann van de Venter May 11, 2014 at 2:57am

    Also check your flight modes and make sure you are in "Stabilize mode". It might be that you are in a mode where it wants to land. 

    Also make sure what your channels 6 7 and 8 is set to and ensure that there is nothing in there that might interfere with your flight. 

    Hope this helps.... good luck...

  • Andrew Gaiennie May 10, 2014 at 6:50pm
    I had this problem too, for me I was starting in rtl mode and on arming it would fly 15 ft up then land and disarm. Make sure the switches are in the right place. I also had a problem with the antenna on my controller where it had disconnected from its board. The connection would fail after a long attempt to start it and it would return to its launch position.
  • Jim Frantz May 10, 2014 at 5:49pm

    The problem may have to do with just one motor failing to put out the power called for.  Since the autopilot priority is to maintain stabalized flight the one motor causes all the others to put out less power too and eventually a landing.  

    To trouble shoot try the following:

    • test the motors that they all spin freely by hand
    • after a flight feel the motors for one that is over heating
    • after a flight feel the ESCs for one that is over heating

    If the above does not yield any obvious problems then clamp the copter to a heavy table.  Put a prop on one motor at a time and run till you identify the faulty motor/power system.  Low voltage to any one ESC often will result in a slow reduction in power from the ESC.  Test each ESC independently?  Test one power system at a time and run for an extended time and listen/watch for power problems.  Could be a bad ESC, a bad motor bearing, a bad motor, bad wiring, etc. any of which could cause the problems you are experiencing. Once you figure out the faulty power system then you can try swapping out the ESCs and Motors to further isolate the problem component.

    I'm assuming you are flying in Stabilize Mode.

     

     

     

    • Chuck O > Jim Frantz May 11, 2014 at 2:43am

      Thanks Jim,

      These are good ideas. I thought one of the motors seemed weird, thus the yaw on take off. I will check the things you mentioned. And yes I am in Stabilize I do not have enough time to switch modes, it cuts the power that fast even with full throttle.

      Thanks

      Chuck

    • Chuck O > Chuck O May 11, 2014 at 3:58am

      Wow Thanks Jim

      I changed the suspicious motor and all is well now. The information you gave was very helpful.

  • AKRCGUY May 10, 2014 at 4:49pm
    Have done an ESC calibration?
  • Andrew Gaiennie May 10, 2014 at 4:39pm
    I had this problem too, but for me it started with a bad connection with the wire in the controller antenna box and ended with a reinstall of the firmware. Works fine now.
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