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FC40 Failure - Dropped like a rock!

Discussion in 'Phantom FC40 Discussion' started by dragonash, May 26, 2014.

  1. dragonash

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    [youtube]_3FqlN6AlE0[/youtube]

    https://www.youtube.com/watch?v=_3FqlN6AlE0

    So I was flying, not even for 2 minutes, getting a nice shot of my apartment complex and my patio when it just dropped from the sky! Luckily... onto a bush! Not more than 15ft high. Lost all control.

    Upon further thought, I realized that I have my router broadcasting the 2.4 and 5.8 frequencies. I can only assume when I got close to my apartment, it messed with my signal.

    It's kind of amazing since I flew my AR Drone (which operates at 2.4) all the time in the area with a ton of wifi networks around and it never lost control like that.

    $300 vs $500

    Truly remarkable

    BTW, how do I properly embed youtube vids?
     
  2. Ozzyguy

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    I regularly fly with about 5 metres of my router and I've never experienced any problem. Also in my area are 3 other wireless signals that my computer can see so i doubt that was the cause. Do you have receiver advanced protection enabled in the Naza assistant? Might be a good idea to do so if not.

    What i think is far more likely is this. Another member of this forum has his FC40(I think) fall from the sky like yours. Open the shell and check the solder(Not Sodder:) joints where the power leads connect to the main board.
    viewtopic.php?f=20&t=15368
     
  3. dragonash

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    Well heres the thing.
    It did NOT lose power. In fact, it sounded like a lawn mower when it landed in the bush lol
    When it landed, I was able to stop the motors from the remote. I should do a motor test in naza now though

    BTW, just checked naza and i do have advanced protection on
     
  4. Ozzyguy

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    Were you decending by any chance right before this happened?
     
  5. Kelso Kubat

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  6. Ozzyguy

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    You may have gotten yourself into a vortex ring state. This happens when you descend to quick into the cushion of air under the quad. This then sets up a circular current of air that feeds air from the underside of the prop directly to the top killing all your lift.
    And also explains why your motors sounded the way they did.
     
  7. dragonash

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    no decending involved.
    just going to the right

    as seen here
    https://www.youtube.com/watch?v=_3FqlN6AlE0#t=95

    the motors were still going, but it felt like they died down to warm up mode.

    Didnt need to open the hull to check connections. Did a test in naza and all motors work.

    Playing devils advocate means that the interference with another 5.8 ghz network caused the interruption in controls.
    The same has been recorded with regular phantom 1's with wifi enabled on the gopro.

    This would be similar, but only on the 5.8ghz frequency.

    However, if this wasnt the case, then this is just another "fail" for no reason. Not that DJI would do anything about it.

    Needless to say, I just lost a ton of confidence in it.

    edit:
    I must add - with a slight pat on the back - that my reaction timing was extremely quick. Since it was a slow-ish fall from the start (i noticed it would move left or right at first, then start to fall), within a split second as it started to fall, I held the ascend stick all the way up and toggled the GPS switch to failsafe and back while keeping the stick at max. It just never regained connection until 2 sec after it hit the bush.

    Nothing more I could do with the time frame given.
     
  8. Ozzyguy

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    I still doubt very much that any wifi interference caused this, to me it looks like a wind sheer down the side of the building. The Wifi problem with Gopro's and phantom one's was on the single antenna version.
    Ive not heard anyone report the problem with the dual antenna versions.
    Anyway it doesn't change the end result.
     
  9. dragonash

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    It is true that you can get very weird weird patterns when you get close to buildings. Especially in a close vicinity like this.
    You might be right. And it was a windy day.

    The other thing that nags at me is, if I did lose control completely, it should have just hovered and done its failsafe. Which supports your theory about the wind. At the same time, it does make sense that a 5.8ghz signal could - for lack of better words - hijack the signal to the controller since I was so close and cause the quad to malfunction. Since it thought the controller was still in control, it just did what it was being told to do.

    However, this totally knocked out my idea of flying in central park over the pond lol

    Wind pattern theory aside, all of us know when something just isnt right when controlling their RC. It doesnt matter if its a boat, car, plane, etc. I just cant shake the feeling that the controller simply lost its control. It didnt "feel" like wind issue or a motor failure. I cant describe it, but I asked my wife what she heard (she was watching from the window).

    She said it sounded like the motors gave out. But with all due respect to my wife, shes not the best source at describing mechanical things (I had to tell her the bicycle wheel cassette was loose on her bike. She had no clue) lol
     
  10. 2014fc40

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    Good to hear its OK Ash.

    But I'm at a loss for what a "bicycle wheel cassette" is. And I consider myself more mech inclined than anyone I know. :ugeek:

    I need to know, maybe mine is loose too....I know my gravel is, I see signs all the time.
     
  11. main0666

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    Have you checked the cells on the battery and are they are all equal, if not then if one cell has less voltage this could be damaged this will than cause the motor to loose power quickly, yet you will have some power but not enough to control your aircraft.
     
  12. Big Ben

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    You wrote you switched to failsafe. If that is with S1 it eliminates an accidental switching to Manual mode which would have given the same result. Especially since you apparently added a gimbal and another camera so weight will be higher than the standard FC40. In Manual mode your bird will drop without added thrust above centre stick.
     
  13. dragonash

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    If you have gears on your bike, its the multiple gears on the back wheel. If you can wiggle it with your hands, its loose. ;)
     
  14. dragonash

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    I think it was what was mentioned earlier. I was close to the building which produces odd wind patterns and got caught in a Vortex state. I have flown my bird a number of times since (far and high) and it seems fine.