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View Poll Results: Have you experienced a Phantom Flyaway?
Yes I have, and I never got it back. 114 15.51%
Yes I have, but I managed to recover it. 113 15.37%
No, I have not. 508 69.12%
Voters: 735. You may not vote on this poll

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Old Jun 03, 2014, 02:36 PM
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Joined Jun 2014
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I am a Ham Radio operator, grew up with a Piper Tri-Pacer under my butt and have extensive experience in both the RF and computer electronics fields. I just bought a Vision 2+ and am currently running the very latest firmware. 20 flights, no problems yet but I have been very careful to meet all of the pre-flight requirements before starting the blades.
When I got the thing though and looked it over I did see what I personally think are significant design issues that could certainly contribute to this fly away issue. It seems that DJI makes connection to everything (GPS, magnetometer, camera, gimble, etc.) with open, unsealed molex connectors and unshielded cable.
First, the molex connectors. Considering the amount of vibration and wind flow generated by the motors and props there is very little doubt in my mind that these connectors are going to get dirty and some connection somewhere is going to be lost in a reasonably short period of time. If that is a critical connection in the data flow somewhere you are going to crash or fly away. My solution initially is going to be to pop those connectors apart and apply a little silicone contact grease to the connectors, put them back together and seal them with a bit of the weather seal putty that I use on outdoor antenna connectors.
The next issue that immediately caught my attention was the use of flat unshielded cable to make both data and control connections. This unit has multiple, reasonably high powered radio transmitters in it. It is not hard for me to believe that if one of the solder joints crystallized due to vibration or one of the connectors suddenly increased in resistance due to being dirty, that an rf induced signal could occur on one or more of the control wires and no matter what the onboard computer said it would just go wherever the signal told it to go. My longer term solution for that is going to be to replace those wires with shielded cable and better connectors.
Maybe DJI will change these construction techniques in the future but I am sure that I'm going to have to work through this with my Phantom solo.
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Old Jun 03, 2014, 02:55 PM
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TheQuestor's Avatar
United States, TX, San Juan
Joined Mar 2013
3,578 Posts
Quote:
Originally Posted by N4LXP View Post
I am a Ham Radio operator, grew up with a Piper Tri-Pacer under my butt and have extensive experience in both the RF and computer electronics fields. I just bought a Vision 2+ and am currently running the very latest firmware. 20 flights, no problems yet but I have been very careful to meet all of the pre-flight requirements before starting the blades.
When I got the thing though and looked it over I did see what I personally think are significant design issues that could certainly contribute to this fly away issue. It seems that DJI makes connection to everything (GPS, magnetometer, camera, gimble, etc.) with open, unsealed molex connectors and unshielded cable.
First, the molex connectors. Considering the amount of vibration and wind flow generated by the motors and props there is very little doubt in my mind that these connectors are going to get dirty and some connection somewhere is going to be lost in a reasonably short period of time. If that is a critical connection in the data flow somewhere you are going to crash or fly away. My solution initially is going to be to pop those connectors apart and apply a little silicone contact grease to the connectors, put them back together and seal them with a bit of the weather seal putty that I use on outdoor antenna connectors.
The next issue that immediately caught my attention was the use of flat unshielded cable to make both data and control connections. This unit has multiple, reasonably high powered radio transmitters in it. It is not hard for me to believe that if one of the solder joints crystallized due to vibration or one of the connectors suddenly increased in resistance due to being dirty, that an rf induced signal could occur on one or more of the control wires and no matter what the onboard computer said it would just go wherever the signal told it to go. My longer term solution for that is going to be to replace those wires with shielded cable and better connectors.
Maybe DJI will change these construction techniques in the future but I am sure that I'm going to have to work through this with my Phantom solo.
Personally I think you are over-engineering the issue.

On the many dozens of flight controllers, GPS units/3dr radios/external mags/etc, I have used the BEST ones are the ones that use the molex and or picoblade connectors.

With the low voltage [5.5v and 3.3v] and low amps that pass through them there is little chance for any heat or bleeding to cause any issues with the solder pins or anything else. They are FAR better than many of the cheaper boards that use Dupont connectors as the means to route all the signals.

The Molex/Picoblade connectors also handle vibrations extremely well and I have never personally seen or even heard of anyone having one fail. They are snug as a bug in a rug and are a pita to remove lol.

You might consider twisting the wires to mitigate any noise but other than that I would personally not put that much effort into them and worry more about making sure the props and motors are perfectly balanced to minimize any vibs that could possibly cause and joint failure.

But then that's just me.
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Old Jul 07, 2014, 09:27 AM
Registered User
Joined Jul 2014
3 Posts
Two lost Phantoms - gone with the wind?

I have been flying the Phantoms for more than a year, and think I know the stuff about RTH. Nevertheless, I have recently lost my Phantom Vision.
I was about 150 m away from me, height 30-35 meters, when I lost visual contact (against the sun) and due to nearby heavy machinery I couldn't use my hearing neither. And the display on my phone reported "control signal lost". Believeing in RTH I waited a few minutes - but no, it never turned up. In "Find my Phantom" I could see the last position in a completely wrong direction. Followed that track - nothing. And I did have a good GPS fix before starting out.

The other loss was of a Phantom 1.2.1, equipped with Ground Station and FPV. Admittedly, I had been flying in an altitude of 100 meters, when I lost contact, Again, RTH didn't work, and I could hear it flying off, some high treees barring me from seeing it and giving bad FPV. I could just hear the sound getting more and more remote, fading out - there was plenty of battery (equipped with 2x2.8 A). Not recovered, probably lost in a barley field.

My suggestion is loss of GPS-signal, making the P sensitive to the prevailing wind. But I think I am done with DJI - at least for some time-
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Old Jul 16, 2014, 07:44 AM
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Joined Sep 2006
3,929 Posts
Personally, I think many of the fly aways are due to a stuck IMU. The quad thinks it's banked.

The priority of the flight controller is:

#1) Fly the aircraft
#2) Level and Alt
#3) Navigate

So when the IMU sticks, goes into full bank or pitch trying to level itself (even if it was already level). Basically it banks and flies away trying to get level.

IMO the best thing to do if RTH doesn't work is to switch to manual mode and either try to fly it home, or shut it down and let it fall.

Of course if you are out of radio range you are completely out of luck because RTH is not going to work.

When we were a DJI distributor we saw many Nazas returned with stuck IMUs. Smacking them on the table would free them up temporarily.. but often the problem would return and they would need to be smacked again. They usually ended up going back to DJI who would return them again since they worked fine when they arrived. Rinse and repeat.
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Old Jul 16, 2014, 09:30 AM
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rcpilot23's Avatar
Perth, Western Australia
Joined Feb 2007
1,287 Posts
I lost my second and last DJI product
Phantom 2 with 2d Gopro 3
after 25 flights it decided it was time to return to china
did exactly what you have said.
hard bank and gone
never again
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Old Jul 16, 2014, 12:06 PM
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Joined Mar 2014
170 Posts
Does holding the sticks the same way as starting a phantom also shut it down mid flight?
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Old Jul 16, 2014, 02:28 PM
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eirlink's Avatar
Ireland
Joined Mar 2013
3,359 Posts
Quote:
Originally Posted by DCIV View Post
Does holding the sticks the same way as starting a phantom also shut it down mid flight?
YES
so be careful !!!
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Old Jul 22, 2014, 03:39 PM
EVFlyersBoss
bobzilla's Avatar
United States, NV, Henderson
Joined Jan 2005
66 Posts
What I find quite funny and amazing, is reading this thread and then seeing an AD for the DJI Phantom above...Why would a company still be trying to sell this junk and shame on RCG for allowing ads for the sale of them. Just google "flyaway dji" or "lost quadcopters", hundreds upon hundreds lost.
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Old Jul 22, 2014, 03:49 PM
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Joined Mar 2014
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Quote:
Originally Posted by eirlink View Post
YES
so be careful !!!
Well it seems nothing really works in these fly away stories so I guess if mine starts and non GPS mode doesn't fix it then I will go for motor kill.
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Old Jul 22, 2014, 03:56 PM
EVFlyersBoss
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United States, NV, Henderson
Joined Jan 2005
66 Posts
Some Psychological help here: https://www.facebook.com/djiflyaway
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Old Jul 22, 2014, 07:44 PM
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Joined Jan 2011
2,302 Posts
we can close the case completely about doing updates to prevent flyaways. firmware updates, hard calibrations, have nothing to do with preventing flyaways.

not long until Im at two years w no updates no calibrations except for field every once in a while

what this means is, nobody understands what prevents or causes them, we're all still guessing. 100% of you polled last year would agree that you have to update this and that to prevent a flyaway. yet, the most uncared for phantom on the board rth rock solid as needed.
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Old Jul 22, 2014, 08:08 PM
OFF TOPIC POSTER
Des Moines IA
Joined Dec 2005
4,794 Posts
"flyaway dji" , hundreds upon hundreds lost.[/QUOTE]

Link please.
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Old Jul 22, 2014, 08:12 PM
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United States, GA, Dalton
Joined Jul 2014
222 Posts
Vision+, 89th flight, GPS locked to 11 sats, 500' out, GPS mode, hard bank, no response in GPS or ATTI, no response to failsafe trigger. Gone.
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Old Jul 22, 2014, 08:22 PM
EVFlyersBoss
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United States, NV, Henderson
Joined Jan 2005
66 Posts
Quote:
Originally Posted by eckace1 View Post
"flyaway dji" , hundreds upon hundreds lost.
Link please.[/QUOTE]

you bet buster..don't have to look to far..view this thread (vote)

and some more here: http://www.phantompilots.com/viewtopic.php?f=4&t=1401

and here: http://www.djiguys.com/Forum/viewtopic.php?f=4&t=1846

and here: http://fpvlab.com/forums/showthread....NAZA-Fly-Aways

and here: http://www.multirotorforums.com/show...Away-IMPORTANT

ok..I think you should get the point by now.

but I especially like this letter from an attorney: http://www.phantompilots.com/viewtopic.php?f=4&t=1552
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Last edited by bobzilla; Jul 22, 2014 at 08:28 PM.
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Old Jul 22, 2014, 11:56 PM
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United States, OR, Mt Hood
Joined May 2014
307 Posts
N4LXP,

Your post is right on. I work with real UAV's for a living and those JST/Molex connectors are a constant source of issues. Corrosion being the first and broken wires and pins from vibration as another. They work fine in that laptop sitting on your table but they definitely are not suitable for command and control functions in any kind of aircraft.
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