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Calibrating the compass before every flight

Discussion in 'Phantom 2 Vision + Discussion' started by JWarren, Jun 29, 2014.

  1. JWarren

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    I've been doing this and plan to keep doing it. If there is no harm or risk to the aircraft, I don't see why taking an extra minute isn't worth it. Even if you take off from the same place every day that doesn't mean something changed with the Phantom itself that you don't know about and won't know about till you are in the air. But if there is a 1% chance it will help prevent a fly-away or other problems I'm going to keep on doing it. I can see no drawbacks and if anyone can, please let me know. Thanks in advance.

    Best wishes,
    J.
     
  2. phantomguy

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    other than wear to your S1 switch, most likely not any other potential issues. That said, I always check the validity of my radar arrow as soon as Im a few feet in the air. If that arrow is accurate, I know that I have proper compass calibration. (in addition to the "compass requires calibration" not showing on the app/my Iphone screen
     
  3. Dcpmark

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    They made it clear??? What is the definition of "changing area"? Is that a mile away? 5 miles? 20 miles? 100 miles??
     
  4. JWarren

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    I have 3 sites a fly and usually never 2 in a row, so its a moot point really. I am curious though. Just what is the radius you have to stay in before you do need to recalibrate? Thank you.

    Regards,
    Joel
     
  5. N017RW

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    Short of any error message or LED indication I'd go with this:
    'indications such as flying in circles when hovering or not able to fly in a straight line'.

    Compass 'calibration' is really about compensation for the materials in close proximity to your sensor (i.e. a/c) rather than other objects nearby. The so called hard and soft iron distortion.

    The concern about nearby objects is so that the compensation remains valid once you begin flying and these objects and their effects are no longer of a significant influence in sensor output.
     
  6. vortigern

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    Good comment never thought about that maybe I too will not set the compass every flight. Do your radar check instead.
     
  7. jduck

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    I had issues with my first P2, called DJI and the first question they asked me was "Do you calibrate the compass before every flight?" I said yes and then they added "because we recommend that."

    So I do it.
     
  8. Michigan_PI

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    +1

    From what I recall, on the majority of control issue mishaps, I read "I calibrated the compass just prior to the flight"
    I don't ever remember reading a mishap that started "I only calibrated before the initial flight or when the app specifies"
     
  9. Dcpmark

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    We just had one here a day or two ago where his flyaway occurred on the only time he DIDN'T calibrate his compass prior to flight. The sample size was low, though.....I think it was his 4th or 5th flight.

    Here it is: viewtopic.php?f=27&t=19126
     
  10. xgeek

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    Have done over 100 flights and only calibrated the compass about 6 times (after every update and equipment change). I always check my mod values once a week in assistant though, but don't see the point of doing a compass cal each flight. YMMV
     
  11. N017RW

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    I calibrated the first day I got my P2.

    After about 20 flights I changed over to a Futaba T10J and the included receiver.

    I purposely did not calibrate the compass or IMU prior to my first flight to see what if any [flight] effects might occur.

    It did in fact develop a slight rearward drift due to the Rx replacement.
    Landed and re-calibrated compass ONLY and it has been fine since (15 or so flights).

    No offense to anyone... but a lack of understanding will lead to unnecessary and sometime detrimental actions or habits.
    Like anyone else I was not born with the knowledge of how the compass/sensor works but after researching numerous manufacturers' data sheets I learned just what is being done when performing compensation and have no fears of waiting until the a/c tells me it needs to be calibrated.

    As others have said YMMV.
     
  12. Channel70Productions

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    What's in it for DJI telling us to recalibrate prior to each use?
     
  13. phantomguy

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    where is it documented that DJI says to calibarate before every use?
     
  14. 480sparky

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    Page 25 of the manual.

    [​IMG]
     
  15. Dirty Bird

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    The manual says calibrate with every new flight location. If I travel more than 50 miles, or if I am flying in mountainous terrain where there is a lot of rock and potential magnetic fields, I will calibrate the compass. When I first lift off, I allow the aircraft to hover for a bit. If she seems squirrely or doesn't track straight, I will come down and calibrate. I would wager I haven't calibrated 10 times in 60+ flights, and four of those were because when I was launching off a bridge it told me to calibrate before each flight. If someone feels more comfortable doing it before every flight, that is a personal decision.
     
  16. Meta4

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    Here's what DJI say about compass calibration at http://wiki.dji.com/en/index.php/Phanto ... he_Compass

    When Recalibration is Required

    (1)When Compass Data is abnormal, the LED flight indicator will blink alternating between red and yellow.
    (2)Last compass calibration was performed at a completely different flying field/location.
    (3)The mechanical structure of the aircraft has changed, i.e. changed mounting position of the compass.
    (4)Evident drifting occurs in flight, i.e. the aircraft doesn’t fly in straight lines.

    Note they do NOT recommend calibration before every flight.

    There are people who do not understand the technology want to do something to feel safe.
    If what they are doing is not based upon evidence and scientific principles it becomes a superstition.
    The compass calibration before every flight is a case of this.
    They may as well cross their fingers or say a few Hail Marys.
     
  17. JWarren

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    Well, "Mr. I Calibrate Before Every Flight" (me) got in his second PV2+ today, updated the firmware, charged up, went to the field, looked it over, sticks down and in and off she goes, without me calibrating the compass for the first flight. :roll: Luckily I quickly realized I screwed up and sat the aircraft down easily and then calibrated. The maiden flight proceeded without problems and was uneventful. I did do some speed tests with a strong tail wind. That was pretty cool to say the least.

    Regards,
    J.