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Problem: Graupner MX20 Gr24 >50m range -> fly away

Discussion in 'Electronics' started by David Kellermann, Apr 21, 2013.

  1. David Kellermann

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    Hi,

    I finally had time again to work on my Cinestar after finishing some other film projects. I went out to the countryside with the co-owner of the copter to make some test flights, and something quite terrifying happened: when the copter was roughly 50m away from us (~10m above ground, flying in auto-leveling mode), it started to fly away slowly at a constant height. Fortunately, my friend reacted immediately and run after the copter with the remote and, after a 200m sprint, the connection was re-established and he landed the copter.

    We're using a Graupner MX20 with a GR24 and an HoverflyPRO Blackboard. The GR24 is attached parallel to the booms, between the two main carbon plates.

    Did we attached the GR24 in a wrong way? Should we somehow fixate the two antennas? What else could be the reason? Anyone experienced something similar?

    Cheers
    David

    EDIT: Here's a link to the log file.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi David:
    That's scary. The link for the Hoverfly GPS board's documentation is broken so I can't determine whether there is an "emergency come home" option on the board. You don't mention that you have a GPS board, so that might not even be a relevant factor.

    The link for the HoverflyPRO board (is that the Blackboard to which you refer) also has a broken link for its documentation, so there's not much to be gleaned from their web site.

    Andy.
     
  3. David Kellermann

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    I don't own a Hoverfly GPS board, and yes, the Blackboard is the second version of the HoverflyPRO board.
     
  4. Josh Lambeth

    Josh Lambeth Well-Known Member

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    To my knowledge the HF boards do NOT have a return to home option yet... which is why I didn't get that board.

    What TX/RX are you using on the gimbal? If it's the MX12 with GR16 receiver that is probably the issue. I have my GR mounted on Boom 5 with antennas hanging down and haven't had any issues even 300+ yards out.

    Scary and glad you got it back!

    Josh
     
  5. David Kellermann

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    Yes, I'm using the MX12 with the GR16. The GR16 is mounted near the pan axis. So when panning, it can come very close to the GR24. Do you think that that's the reason? The dealer told me that the GR24 and GR16 can't interfere...

    Where did you attached the GR16? And how far out on boom 5 did you attached the GR24?

    Cheers
    David
     
  6. Gary Haynes

    Gary Haynes Administrator
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    David, at 50m distance I doubt that it was an issue with the Graupner. I used to fly CS8 with the recv tucked into the space between booms 4 and 5 and weaved the antennas left and right from there along the edge of the carbon bottom plate. Saw that on an early video someplace. Probably wouldn't have helped with long range but I was flying out to 200m+ without problems.

    Looking at your Graupner file at 524.82 seconds the LossPack (guessing that means Loss Packets. Hopefully someone understands/speaks Graupner) and continues until 1043.58 where all contact is lost with the TX/RX. Values on the RF RXSQ screen go to flat line. You regain a connection at 1202.94.

    Could you have had a disconnect or power interruption through a loose connector to the recv? Might want to check that.

    I you have the Hoverfly GPS then that also has a log file to an SD which can be analyzed. Simply copy to your computer and change the file extension to XLS and you can read it in Excel.

    To improve range you could get one of the Modifly items from Quadrocopter. Basically a small mast that attaches to the battery plate and mounts the recv vertically with the antenna sticking up like rabbit ears.
     
  7. Josh Lambeth

    Josh Lambeth Well-Known Member

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    There have been reports that the telem. channel on the GR16 can interfere with the telem channel on the GR24 since they are on the same channel. I would make sure they are as far away as possible from each-other. Maybe re-position the gr16 lower on the gimbal. There is another thread floating around on the forums with a discussion about it as well.

    Josh

    P.S. I am using spektrum on my gimbal as well as the GR16 (but that is bound to my MX20 so it automatically turned off the telem so I don't have that issue.)
     
  8. David Kellermann

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    I checked all the connections, and they are fine. I don't have the Hoverfly GPS. And the Modifly Rabbit looks great. Will get it our make something similar myself.
     
  9. David Kellermann

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    How can I switch off the telemetry on the GR16? Or, other than placing them as far as possible away from each other, make sure that they are not interfering?
     
  10. Gary Haynes

    Gary Haynes Administrator
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    David there are a number of posts on the forum on how to 'trick' the Graupners.
     
  11. David Kellermann

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    Do you know if that solution worked? Or can you point me to other threads or solutions?
     
  12. Gary Haynes

    Gary Haynes Administrator
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    It has worked for some of the posters. I run an MC-32 with 2 GR16's. One on the Modifly for the copter, the other down on the gimbal cross are to control the 2 Axis and Radians. I did a range test a couple of months ago and got range of 1.5miles.
     
  13. Ozkan Erden

    Ozkan Erden Distributor

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  14. David Kellermann

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    Hi Ozkan,

    I saw that thread and quoted it earlier here. My question is if this solution (binding both receivers to one transmitter, than newly bind the first master to the other transmitter) ever worked or if there are other possibilities.

    Thanks for the help, Gary. I'll try it out today.

    Cheers
    David
     
  15. Sedric "Zellevision" Sari

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    This could be an GR24 and GR16 mix problem. We have 4 CS to test on, and mix is:
    • CS6 GR32+GR16 = No problems
    • CS8 nr1 GR32+GR16+Spektrum = No problems
    • CS8 nr2 GR24+GR16 = range problems, trying now with spektrum too. First test without any warnings, about 150m away but at that range only 25% reciever quality.
    • CS8 nr3 GR24+spektrum = no problems.
    All telemetry running from the main reciever.
    We now that the GR32 has 4 antennas and have stronger recieving quality. It seems like the GR24+GR16 mix is the most problem maker here.
    All running on MK FC and latest FW's
     
  16. David Kellermann

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    I followed Gary's suggestion and it seems to work. Will test it tomorrow.

    Cheers
    David
     
  17. David Kellermann

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    Gary's solution worked out. Next problem arose... flying back to land the copter, it suddenly lost height. I thought that the batteries might be empty and gave more throttle. The copter stopped falling, but rolled to the side and flew into some grape wine wires (holding/guiding the plants... no idea what the correct English word is). Fortunately, only two props broke. Does anyone know what could have caused this failure? I was flying only for 3min with two fully charged 8Ah batteries (8000mAh Turingy nano-tech).

    I uploaded the clip with the accident (sorry haven't flipped it yet) and the log file:

    Clip password: failure
    Log File

    Would be glad for any help!
    Cheers
    David
     
  18. Tim Joy

    Tim Joy Active Member

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    I would guess some kind of power failure coming from whatever powers the RC system. What ESC's do you have? How is it powering the 5V side? Is it just 1 esc or more? or something else?
    This could explain both incidents.

    Your clip is Access Denied, make it password protected so we can see.
     
  19. David Kellermann

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    The clip should now be accessible with a password.

    I use Copter Deluxe 40A ESCs. The 5V comes from the main batteries via a Copter Deluxe UBEC. The ESCs are still working...

    I'll check the ESCs again tomorrow and have a closer look again at the batteries.
     
  20. Gary Haynes

    Gary Haynes Administrator
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    David

    Unable to read the log files. Says they are .bin file in the zip. Can you reload them individually and not zip them? You can attach them directly by using the upload file button rather than putting them on another site.

    And as Tim mentioned we need the Vimeo password to see the video.
     

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