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Interesting flight - Compass error

Discussion in 'Pro/Adv Discussion' started by WetDog, Dec 22, 2015.

  1. WetDog

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    Started out a test flight in my yard - a place where I have flown dozens of times before and, IIRC, the last place I calibrated the compass. I checked my compass MOD value - 1530, which is typical and had green everywhere. Did not recalibrate. As I got to about 50 feet I noticed the back LEDs blinking yellow. Looked at the screen and the app complained of 'COMPASS ERROR'. I put in in hover and noticed it was wandering back and forth - to be expected with a compass error. So then I started bringing it back. This was an exercise in manual flight since this part of my yard has a bunch of trees and a deck. I purposely fly here to practice control for landing on the boat. But I had a heck of time herking it in - it wandered back and forth, should have switched to ATTI mode but then the LEDs went green and she behaved normally.

    Did a giant slug of iron magma just burrow under my house or is this a typical error?
     
  2. msinger

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    It's not a typical error. But, if it happens, you should land immediately and calibrate the compass.
     
  3. WetDog

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    Which I did. Waiting for the battery to charge - of course all my other batteries are being charged as we speak. But this argues against believing that a MOD value in the 1500's is OK and that we SHOULD calibrate the compass each new flight.
     
  4. ryantrax

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    I've had this happen to me before too. I was however around lots of metallic sculptures so I thought that was the reason for it. I did go to ATTI and it flew fine to bring it back to me.
     
  5. WetDog

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    I'm worried about the magma. Wouldn't be all that surprising around here. Either that or the neighbors finally finished the bomb shelter they've been talking about for years.

    But this is another great reason to practice manual control on a small drone. Had I not been able to get it under control in the first few seconds it would have happily plowed into the 150 foot spruce trees in the back. You have to be able to muscle memory those sorts of things. Thinking isn't going to help much.
     
  6. Ed209

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    Happened to me when flying over a cemetery... Pitched way more than it normally does and got up to 50mph (no wind). Luckily I switched to ATTI and landed it safely. Do you live near a cemetery or on an ancient burial ground?;)
     
    ryantrax likes this.
  7. Pointyhead

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    I did my second day of flying today at our local church cemetery. I should have noticed something was up when I had to calibrate the compass three times before takeoff. I finally found a spot in the middle of the access road where I got a good calibration. Then when I would fly lower than about 30 feet, the bird got squirrelly like you'd expect in really strong winds. I never noticed the lights changing or getting the compass error on the display, I just flew high and walked over to the parking lot where I landed. I guess hundreds of metal boxes in close proximity to each other has some major effect at low altitudes.
     
  8. AirSpace2016

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    Can I confirm if you get a compass error if you switch to atti mode should it operate normally or does the compass error still cause problems. I know the difference between GPS and atti, not tried to land it in atti mode yet but have flown it high above trees and attempted to keep it stable by countering the wind etc as practise.