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Fc40 won't fly normal unpredictable

Discussion in 'Phantom FC40 Discussion' started by Colin70, Nov 28, 2014.

  1. Colin70

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    I have replaced a motor after it became noisy. Also added a new wide track landing gear. Reset the compass to original placement on landing gear. Test flight resulted a flyaway due to uncontrollable flight. Retrieved the unit from a tree. No broken parts. Hooked up unit to assistant software. Did every calibration possible and reset defaults. Compass parameters are with in assistant recommended settings. Unit flys and is somewhat stable. If in gps mode and all green lights it is more unstable. In attitude mode it is a more stable flight. It tends to want to dip the left front rotor and travel on its own. It's is also accellertating mildly. Any ideas what I can do to stabilize the craft?
     
  2. Mandrake

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    I think you must recalibrate the tx radio to get throttle etc settings balanced when you swap motors. Try that . It means undoing the radio to get at the USB socket.
     
  3. Colin70

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    Do u have any instructions on how to try this suggestion? Link? Or manual copy?

    Thanks
     
  4. Colin70

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    Where is that usb socket? In the controller? I have the fc40 model.
     
  5. Colin70

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    I have done all calibration checks the dji assistant software has in it. Imu calibration, controller sticks calibrations. But I am really not sure what else ? I have restored all setting to defaults... Any thing I m not covering? The tx calibration I do not see in the naza-m v2 software! All controller movements are perfection in the software graphs. The controller orientations mounting setting are all zero s that correct? Imu Cali setting are as follows.

    Gyroscope degrees x=-0.0 y=-0.0 z=-0.1 mod=0.1
    Acceleration x=0.01 y=0.00 z=-1.00 mod= 1.00
    Compass x=-5 y=-4 z=250 mod=1792.1

    what all than means no idea? Can anyone tell me?
     
  6. Colin70

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    http://youtu.be/8yMKID7IRPE

    This is the video I took today to show how it is flying. Please notice this is drifting away in gps mode all lights green
     
  7. IflyinWY

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    Have you considered putting your old motor back in place and doing a test flight?

    Maybe you went from bad to worse.
     
  8. Colin70

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    I feel like I did, and I thought I had done well by detecting the roughness of the bearings. I just got the replacement bearings in the mail today so I'll see if the bearing fixes the roughness in the rotation of the old motor. If it does I sure will change it back.
     
  9. CarlJ

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    Colin,
    It's always a good idea to make changes one at a time so that problems are easier to identify. I would replace your original landing gear, and see if that doesn't fix your problem. The compass orientation is tricky.
     
  10. Colin70

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    yes that's exactly what I did. I went back to the old landing gear. no change. I did a advanced imu calibration last night in hopes this would do the trick but no luck. I have noticed upon engine start up before take off that one motor is turning faster than the other 3 in gps mode. I click it to attitude mode and a noticeable difference in idle speed for that one motor. But even in flying in attitude mode it wont fly right. So the next step is to go back to the old motor and see if that corrects anything.
     
  11. lostkiwi

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    You did do the compass dance after all that other stuff you did didn't you?
     
  12. Colin70

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    after much head scratching on recalibrating and another fly away I had a motor stop working. I replaced the motor and it turns out not to be the failure. I have ruled it to be a esc failure. That esc is getting voltage but isn't supplying voltage to the motor. The esc light is also not coming one and is hot. So I have ordered a new esc. I am looking for a open frame to swap all my hardware to also. Any suggestions on possible good frames?
     
  13. Tallyrver

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    After trying to add a tilt knob to my radio controller ,my FC40 was doing all kinds of crazy things. I saw this video and tied her down until I figured what the issue was . It saved a fly away .
    I upgraded to the new DJI radio with built in Lipo and tilt wheel. And all is good.


    [youtube]http://www.youtube.com/watch?v=v133Tb8Cc6E[/youtube]
     
  14. J.James

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    When you get the new esc do a compass dance to recalibrate the compass because all the calibrations for the imu in the naza assistant will not properly recalibrate the compass for north. and just about any time you have a crash or if it starts flying funky its a good ideal to do the compass dance. same as if you ever fly in a new spot far from home its also recommended to do a compass dance at the new flying spot. Here is one way how its done. https://www.youtube.com/watch?v=PyMgWmGi_XU
    or this way works also. https://www.youtube.com/watch?v=3CNjHR0PJKc
     
  15. Colin70

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    I am still fighting this phantom fc40. I thought I had figured out why this thing flies crooked in gps mode when I had a motor quit on me. Turned out to be a speed controller. I replaced the speed controller and all 4 motors. I found that the frame had cracked due to the fly away prior to replacing these parts. So I built it up on a all on a new frame. It still flies exactly the same. I wont hold a position in gps mode and drifts away. The copter is obviously not level when hovering. Any ideas?
     

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  16. Colin70

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    yes I have ran through the naza calibrations. All completed . I always do the compass dance on every pre flight.
     
  17. Damo1342

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    Hi Colin

    I have a FC40 that is doing the exact same thing, takes off, seems to settle horizontally then tilts left and drifts left and slightly forward.

    I took this video ( https://www.dropbox.com/s/wpmwx7mq2wb0j ... 9.mov?dl=0 ) of mine, its in GPS mode, and straight away it starts to drift off left, each time it comes back to the right, its me fighting to get it to stay in one spot in front of me, eventually it just seems to throw a fit and starts flying erratically until it bombs.

    This was the first time I put the prop guards on, and it behaved exactly the same as the numerous times I have tried it before.

    My partner bought it used for me for Christmas, the guy that sold it her ripper her off, and it had a damaged shell arm, and one of the ESC Green boards was snapped, although at that point it was flying fine, I bought a new shell, replaced the top half, and installed a switch in the side for the battery, as I worry about not being able to cut the power quickly if need be. With the new ESC controller ordered, I tried it out and the problem was evident straight away. I have since replaced the ESC controller and it is still doing the same thing.

    I have reset everything to default in the naza software, and ran an advanced calibration of the compass, although the readings were similar to yours and according to DJI are normal. I also calibrated the transmitter via the Naza software, although haven't taken it apart to calibrate it through the Assistant software, it calibrates fine in the Naza so not sure there is any point in doing it, the transmitter worked fine before I took the Phantom apart.

    Are you any further forward in finding out exactly what we did to them to make them act so weird ? At the moment its unflyable for me so just an expensive lump of plastic in a very nice case :S.

    All the best

    Damon
     
  18. Damo1342

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    After reading other help threads in this forum, and seeing Colin has cured his problems, I had made the same mistake, have put it right now, waiting until morning before I can test it out see if it worked, its 2am here in the UK, I have understanding neighbours, but trying out my Phantom in the street might be pushing it at this time of night :p. Going to be a loooong night !
     
  19. J.James

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    Damo1342 hope your test flight goes good. if its still doing what it was in that video it could be some thing else esp if it ever crahed hard enough to even snap an esc (btw thats crazy that it even flew at all with a snapped esc)

    But if its still doing that weird fighting its self thing can you recall when you had the shell open to do the repair on the esc if the naza controller was still stuck firmly to the main board inside and not lose or able to move around at all?

    and also after you replaced the top shell are your arms straight and are all 4 motors straight and level?
     
  20. Damo1342

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    Hi J.James, thanks for your reply. You are awesome by the way ! The test flight went well :).

    I'm not sure how the ESC got snapped, though there are screwdriver lever marks in that arm which was also the broken one, so it's possible got snapped by the last owner trying to lever the arm apart. I am amazed it still worked too, it was bent quite badly, though still joined together.

    It's been a bit of a nightmare, my partner bought it through ebay off a guy about 30 miles away from where we live, when she picked it up, he said the arm had a crack in it, so he had taped all around it, she didnt take the tape off to look, the truth was the end of the arm, the ring that goes around the motor, was completely detached, there were hex screws missing, one of the landing gear screws was missing, he neglected to put a battery in the box, the fc40 camera came with the bracket, the camera itself, and two rubber springs, no case to fit in the bracket, and a missing rubber spring, so useless really, although I have velcroed it to the battery door for the time being. Turns out the camera casing is really hard to get hold of. He did supply two used sets of stock props, and two new sets, so it wasn't all bad. My poor girlfriend when I started sorting through the box of bits and saying this is missing, that doesnt work etc. He did a real number on her, and she didn't get it for a really cheap price either.

    I have since replaced the top of the shell, the replacement shell from DJI for the FC40 has the same part number, but doesnt have the hole under the back led for the USB socket, so couldn't use the bottom shell, even though I had taken everything out of the old shell, hence putting the compass lead back out through the wrong hole. I replaced the ESC board, the missing screws, bought new batteries, and fitted a switch in the side to cut the battery should I need to do so quickly.

    All was going great until I tested it and found it was doing the same as Colin's. Took me a couple of weeks to find your conversation with him and finally find out how I went wrong with the rebuild. You have no idea how happy I am right now, I didn't think I would ever get it going again, and we definitely couldn't afford a new one.

    Anyway, thanks again, please see the following video, the thumbs up at the end is for you and Colin :).

    http://youtu.be/KumOH1ygdqY