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Bad weekend - steep learning curve

Discussion in 'Inspire 1 Discussion' started by Glen, Jun 28, 2015.

  1. Glen

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    Hiya All,

    Having a bad weekend so far! Crashed into tree (My stupid fault), then my Inspire does the garage door syndrome in GPS mode.

    Went up to the Battle of Britain memorial near where I live, preparing for filming I go through my checks. On checking my compass readings I notice it was unusually high fluctuating between 17-1800 but never had any error from the App. Decided to be safe carried out a calibration. All done and reading back down to the 1500's. So took off to about 1.5m where I like to let it sit there for a short time, checking for control from the sticks, any unusual noises and my pictures looking okay, then it suddenly goes wild yawning left & right, I'm now fighting to get it under control when it backs up at speed crashing in to the glass windows behind me with such a force that it tears off the camera & gimbal mount and breaks the two rear propellers.

    This all happened so very quick my initial reaction was to regain control with the sticks. Thinking about it now perhaps I should have switched to Altti mode.

    I now think it may be best in the future to only be in Altti mode because In GPS your not in full control.

    I've been very lucky it only cost me a couple of props & rubber grommits & my dented pride.

    Kind regards
    Glen image.jpg image.jpg
     
  2. huppe

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    Never too old to lurn:cool:
     
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  3. The Editor

    The Editor Moderator
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    Sorry to hear about the crash.
    This is why I NEVER advocate or practise calibrating in the field location.
    Something was causing your compass to go into those unusually high readings and you 'calibrated it out' when you did your compass calibration.
    Once you were airborne the Inspire was clear of whatever was influencing the compass but you had calibrated with that influence acting upon it and so now your compass had an erroneous calibration.
    The result....... Well you found out.
     
  4. Glen

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    This was the only time I have, since the initial calibration when I first got the I1.
    I'm thinking now should have just left it reading higher than normal, as the App was ok with it.
    :-(
     
  5. RGD

    RGD

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    I had a similar experience with my I1 last week end. My mod value was also reading in the 1600 range but the app was still saying GPS good to go. I still can't exactly determine if it was out of control or if it was just my poor atti piloting skills. I got it back on the ground with a hard landing. So much so that I cracked the ND filter. I flew it yesterday and the mod values high again so I did the turn about and the values dropped down to the 1500s. Flew out a battery and all good. But boy it sure makes you jumpy now at take off. This is the only time it has ever happened in about 20 hrs of flight time
     
  6. damoncooper

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    Be very VERY careful about calibrating your compass where you are when mod values are high.

    As The Editor points out, you could well be baking in severe anomalous values into your aircraft if you calibrate in a high magnetic field. Nothing good will come from that.

    Better to find a new place to launch from.
     
  7. Glen

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    Thanks damoncooper,
    I should have took those readings as a warning of my location, but instead over cautiously chose to recalibrate. (Big lesson)

    I'm running low on white dot props lol
     
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  8. amkorp

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    Location:
    Toronto, ON / Buffalo, NY
    In a situation such as this one, where compass values are skewed due to location, what should be the best practice?

    Should we just take off with the compass as is and hope it sorts itself out when outside of the environmental influence? Or should we be doing something else?
     
  9. Frank Tan

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    I concur with what "The Editor" said... if i know from my previous flights that i have a good compass calibration, i will avoid calibrating at an unknown location at all costs. If the compass mod values are off, i will either move a couple hundred yards away and try again or just not take off from that location. I have seen multiple times where a particular location throws off the compass mod values due to some interference, only to see the mod values go back to the magical 1500 once i move away. Re-calibrating the compass at a bad location risks replacing a previously good compass calibration with a faulty one...

    It is also good practice to set the Inspire in hover after take-off(landing gear still down in case i have to bring it down fast), visually make sure it is not toilet-bowling, then check the sensor mod values for the compass while Inspire is in hover. It should be very close to 1500 while hovering.
     
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  10. damoncooper

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    Find a new location. If the problem persists, find a known ferrous & metal free zone and calibrate there carefully.