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Problems with takeoff

Discussion in 'General Discussion' started by mlees, Mar 20, 2014.

  1. mlees

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    Hi -

    I am wondering if anyone has experienced a sudden nosedive as the phantom motors are spinning up when given throttle and getting ready to take off?

    I have had this happen to me several times so far, and I thought it was because of added gimbal. But it just happened again and it was completely unloaded.

    Not sure what is going on or what I can do to correct it?

    The firmware is upgraded to V3.0 I believe and its a P1.1.1 and using standard vision props.
     
  2. OI Photography

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    Did this just start happening after the firmware upgrade? If so, did you apply the default Phantom settings file from the DJI website after the upgrade?

    Also, the current firmware version for the NAZA on a 1.1.1 Phantom is 4.02.
     
  3. mlees

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    Thanks for the reply OI Photography.

    It did not just happen after the upgrade. Its been intermittently happening 4 times so far out of about 40 flights
     
  4. OI Photography

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    No problem, but I'm afraid I'm not sure what would cause that to happen only intermittently. Does it always happen in the same launch location?
     
  5. mlees

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    You know, I don't think its location dependent. But when I let off the throttle and try to take off again I will notice that it has a bias to tilting forward again - at least until I power cycle and do compass recalibration.
     
  6. rammz

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    I had a problem where my phantom1 would flip on takeoff go to full throttle and try to bore into the ground,luckily no damage other than some missing prop hub paint. it did it 3 times over 2 days, although sometimes it would takeoff normally. later that day it stopped responding to stick movements while in gps mode. I flipped to attitude mode and brought it back to me and reengaged gps mode at a 50 foot hover. it maneuvered and landed normally. I had forgotton that the phantom 1 should not be used around wifi, my friend had a gopro cam w wifi activated during the incidents,ive since flown another 30 flights w a go pro like camera w wifi turned off and had no further incidents. ive also programmed manual mode, and if a flyaway starts to occur i'll switch to atti,and if no response go to manual and crash land it if necessary. im not saying flyaways are caused by wifi interference but am sure the flipping behavior was caused by that. it was thru this forum reading about flyaways that I rediscovered the phantom 1 is not compatible w wifi...duh,I had forgotten that.
     
  7. TechJunkieRC

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    Mine did it for the first time tonight but after watching the camera footage it was pilot error. The grass isn't growing but I had the FPV goggles on and I didn't give it enough throttle on takeoff and the grass caught the camera just enough to tip it forward. I saw it in the goggles and immediately closed the throttle so no damage. More throttle on next takeoff and no problem.
     
  8. laselvasurf

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    Mine tends to rock forward if I don't compensate on take off. It's fully loaded with the zenmuse/fpv/iosd/btu/2700mah battery. I just throttle up to 50%, wait a second then peg it with my right stick 20% or so back. Once it takes off, the NAZA does the work and I center the right stick and all is well.
     
  9. Miika

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    This is my suggestion about what is causing this problem and how to solve it.

    What is the cause?
    This has something to do with the GPS position and position hold feature of the Naza. Even if you have more than 6 or 7 satellites the location data might be inaccurate. Even if it is by 20-30cm/inch or what ever. The fix to this take off problem is the reason why I think that the GPS location data/position hold is the cause.

    How to fix this?
    If you want to take all measures to avoid problems wait until your Phantom saves the home location. Turn your radio controller from GPS mode to ATTI mode (this wont remove the saved home location as far as I know). Take off, and when Phantom is in the air, turn GPS mode back on. This way I solved this take off problem as my Phantom was nosediving all the time.

    What is the cause again?
    As taking off without GPS/position lock removes the nose dive problem we can assume that the Phantom tries to fix its position immediately when taking off (trying to move forward for small distance, but enough to make your Phantom to nosedive).

    My Phantom v1.2 did this all the time, but my Phantom v1.1.1 with Zenmuse does not have this problem.
     
  10. mlees

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    Thanks for the suggestions. I just called DJI as well and they suggested an IMU calibration.

    I'm going to try taking off in ATTI mode and see if that helps.

    The cause you mentioned above seems to make sense as it is trying to correct the unit to home position recorded vs where it thinks it is - although I would think that it would tip in any direction not just forward.
     
  11. Miika

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    It would make sense that Phantom would try to tip into any direction, unless theres something "technical" that makes the position lock to act in a way that its always forward...

    Anycase taking off in ATTI mode should fix the problem.
     
  12. RickF

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    I agree with Miika's response. Once you have GPS lock, switch to attitude mode for takeoff. When you are comfortably in the air switch over to GPS mode. Upon your return home, once the copter is overhead, switch back to attitude mode to land.
     
  13. rammz

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    Miika you night be on to something, yesterday on takeoff my phantom nosed over slightly on takeoff, no flipover but still alarming...ill try taking off in atti for awhile and see how it goes.
     
  14. rammz

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    2 takeoffs today in atti,no nose forward bias...thanks Miika.
     
  15. Miika

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    I had lot of problems taking off with my first Phantom, until I found this tip of taking off in ATTi mode. Some people say that even landing is easier in ATTi mode, thats also worth of trying if there are difficulties in landing.

    I dont like rough landings so nowdays I fly my Phantom near me and grab it with my other hand and turn of the motors with the other. This way my Phantom cant tip off in landing... I actually had my first Phantom tipping off many times at landing.
     
  16. 9Jamie

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    Anyone did the IMU calibration for nosedive issue?
    :?: :idea: :?: :idea: :?: