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A GREAT reason to open up ANY R/C Aircraft.

Discussion in 'General Discussion' started by BlackHawk388, Jun 24, 2015.

  1. BlackHawk388

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    [​IMG]


    In the picture above, there is a grey wire routed over one of the GPS antenna leads on my P2V+ V3.

    It goes from the GPS module itself to the PCB. I'm not going to dismount the PCB to find out exactly what this wire does. I suspect it provides power of some sort in addition to the other two wires attached in the same fashion.

    Wire insulation on metal is something we in aviation would fix and/or repair IMMEDIATELY. Then, install such devices as to prevent chaffing in the future. Things like this have brought down aircraft throughout our history of flight. Simple, small things that had the engineers of been paying attention to could have saved lives. In this case, drones. The vibrations from rotary wing aircraft are pretty severe, much more so than fixed wing aircraft. Just the nature of the beast. While this drone isn't capable of variable pitch blades, it depends on motor speed to produce lift instead of a continuous engine speed and variable pitch, the vibrations experienced in flight are almost as severe as a variable pitch aircraft.

    I wonder if this isn't a contributing factor to some of the true flyaways recorded by various DJI/other drone/aircraft owners. Wire against wire isn't something I'm terribly concerned with. However, wire against a hard surface IS something I will remedy before the cover goes back on and the next flight. It is critical that any solution one uses is nonconducting. So cloth tape or foam strips are what I'm left with at first glance. Some of the internal IMU wires are laid right up against the IMU module itself. Not good. Not at all. Other wires lay right up against the PCB. Again, NOT good at all.

    I've also noted some other wires against hard surfaces. I'm going to leave the cover off and get myself some foam strips and cut them to size to place in-between the multiple areas I've identified. Cloth tape has a way of coming off in high heat areas.

    This isn't acceptable out of a $1200 setup. The drone, two batteries and a nice case. If the drone is damaged, nothing else is worth much when I compare the drone to the articles that came with it.
     
  2. N017RW

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    The GPS module is in the lid.
     
  3. BlackHawk388

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    The antenna seems to be in the lid. The module itself should be what you see in the picture with the two gold colored connectors going to it. It looks to be a combination WiFi/GPS module. Am I wrong?
     
  4. N017RW

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    Yes, you're wrong.
     
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  5. BlackHawk388

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    Thanks for the heads up, then. I'm not accustomed to such small GPS receivers. In Aviation, the GPS computer is completely removed from the antenna to prevent signal contamination. I'll have to look into this further to satisfy my curiosity.
     
  6. peter west nz

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    That is the wifi module with the two coaxes going to the patch aerials either side of the battery. I did take change these for 2 X 2db dipoles mounted on the leg webs. I thoroughly recommend it for more consistent fpv.
     
  7. N017RW

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    You come across very knowledgeable but don't expect mil-spec or even full-scale execution in these 'toys'.

    Pull off the grey shield material and you'll see the GPS module.

    GPS data is first sent serially to an embedded processor on the main PCB which is then sent to the FC along with Compass and Battery data.
     
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  8. dirkclod

    dirkclod Moderator
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    GPS in lid gps puc.jpg Plugs in here Compass.jpg last place on the right .
     
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  9. BlackHawk388

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    Thank you for YOUR knowledge! Using my debit card, I peeled back the copper shielding to discover this GPS processor/Antenna module.

    Quite interesting and you are very correct. I've got to put aside my military/civilian aviation experience when dealing with these things.

    The way I see it, everything I can learn about this drone is something I can use to make it better. Thank you for your time and experience.

    [​IMG]
     
  10. BlackHawk388

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    More critical wires laid up against a hard surface. These are motor wires that provide power to one of the motors. While not known for sure of course, this could explain why some drones have had a single motor failure resulting in a crash.

    Solid strand copper against the hard PCB of the ESC surface isn't going to end well after a given amount of time. How long that time might be, I'm unsure. I just know that over time, this WILL fail as routed and constructed. One more set of wires I'll be isolating. This is why I prefer multiple strand wires on a critical area. You can have a condition that eats through one or two of the strands without killing the whole wire. If it's a single, solid wire, then you've got a very small circumference to carry the current before not only wearing through begins to affect it, but then cracking. At least with multiple strand wiring, there will typically only be one wire that is damaged and then, cracked through in a high vibration area like this.

    [​IMG]

    I will keep this thread updated as I go through the drone. I'm now convinced I need to remove every single component in an attempt to isolate critical wiring areas. Perhaps DJI will take this into account in future builds.

    Since this P2V+ V3 was a gift, I'm much less willing to take chances with it as I would be were it my own money invested.
     
  11. dirkclod

    dirkclod Moderator
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    Dang bro ..Hate ta see what ya do to a new car :eek: just kidding.jpg :D;)
     
  12. Clipper707

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    Super informative post, BH388 and contributors. I want to open mine up once I get back to base.
     
  13. dirkclod

    dirkclod Moderator
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    No telling what you gonna have in yours Clipper :eek:
     
  14. BlackHawk388

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    I hear you. But I bought a new 2015 Ford Explorer Sport last December. I've already made a few modifications to the turbo housings and wiring around the engine ECU housing. As well, the rear lift gate wiring was WAY too small to handle the continuous use by me and my family. As well, the wheel speed sensor wiring wasn't up to snuff to truly handle the load sway as detected when pulling a trailer. I've replaced some of that wiring with smaller gauge. I won't even get into what I did with the 2011 Mustang GT. And Ford is one of the better companies when dealing with under rated wiring for the task placed on them.

    You should see the crap from BMW and Audi I've had to fix. Horrible.
     
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  15. Marlin009

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    While it's not new information, you are corroborating what we've heard about the motor wires since they came out with the 2312 motors. The silicone booger was one fix, mine got a wrap of heat shrink tube around the ESC when it went back to DJI for upgrading the ESC's. Good stuff.

    There are a couple of long threads on here about it. A couple of members have made the stranded wire change on a lot of birds.