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Old Dec 18, 2012, 06:49 PM
Registered User
Central California
Joined Dec 2006
2,511 Posts
Quote:
Originally Posted by coptograaf View Post
Hi guys,

I'm new at this forum not a pro like most of you. I'm flying an octocopter to make photo's and videos. My transmitter is a DX 18.
Last week my octocopter crashed. The distance between the transmitter and octocopter was appr. 200m at an alt. of appr 60m. I lost total control of the octocopter as if the there was no connection anymore between the transmitter and the octocopter. Shortly before the octocopter hit the ground it seemed as if the (full throttle) command was picked up a few times, but the octocopter crashed anyhow. (damage 3500,=!!!, camera, cameramount, octoframe)

The (Dutch) supplier of the octocopter analyzed the datalog and found no systemfailure and denies therefore any responsibility. On this forum I read others had more or less the same problems using the DX 18.
Can anyone help me find the cause of this failure. I'm absolutely sure I did nothing wrong so it has to be a system failure. I can send the logfiles if necessary but they are to large to add to this message.

Regards,
Menco
I generally stay out of these guessing games but you say you have a datalog?
Is this an SPM .tlm file? Or another type of log? Logfiles for a reasonable amount of flighttime generally arent huge files unless it is a compiled collection of many flights in one file.Can you weed out the specific file for the flight in question and attach it so someone else can have a look?

One thing stands out to me in your statement."Failsafe did not properly engage".
This may be a huge clue.It leads me towards a power issue.Without data it is all a big guess though.
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Old Dec 19, 2012, 05:52 AM
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United Kingdom, England, Cheltenham
Joined Apr 2007
42 Posts
Quote:
Originally Posted by coptograaf View Post
Hi guys,

I'm new at this forum not a pro like most of you. I'm flying an octocopter to make photo's and videos. My transmitter is a DX 18.
Last week my octocopter crashed. The distance between the transmitter and octocopter was appr. 200m at an alt. of appr 60m. I lost total control of the octocopter as if the there was no connection anymore between the transmitter and the octocopter. Shortly before the octocopter hit the ground it seemed as if the (full throttle) command was picked up a few times, but the octocopter crashed anyhow. (damage 3500,=!!!, camera, cameramount, octoframe)

The (Dutch) supplier of the octocopter analyzed the datalog and found no systemfailure and denies therefore any responsibility. On this forum I read others had more or less the same problems using the DX 18.
Can anyone help me find the cause of this failure. I'm absolutely sure I did nothing wrong so it has to be a system failure. I can send the logfiles if necessary but they are to large to add to this message.

Regards,
Menco
Earlier this year after purchasing the DX18 I had two unexplained crashes. Both models range checked fine but both were lost to unexplained issues. I had TM installed on the second model and replayed the data and could not find anything wrong. The fault was intermittent as I had some successful flights with the same models and others.

The first crash I just put down to one of those things, but the second made me suspicious as the model was being flown close in, straight and level by one of the expert flyers in the club.

I then sent the transmitter back to HH UK to investigate. They informed me that there was an issue with the RF board and replaced the transmitter.

I would suggest sending the radio back to Horizon for testing.

Dave
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Old Dec 19, 2012, 07:05 AM
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Joined Dec 2012
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At this link http://flickr.com/gp/87299040@N02/Qrhr6u/ you can find some pictures of the octocopter after the crash
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Old Dec 19, 2012, 10:52 AM
Wherever you go there you are
7oneWo1f's Avatar
United States, MN, Minneapolis
Joined Nov 2011
8,453 Posts
That's a lot of CF.
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Old Dec 19, 2012, 11:03 AM
Michael
United States, ME, Wells
Joined May 2008
1,122 Posts
Carbon Fiber???

+1 I was thinking the same thing.

The receivers appear to be mounted on a CF plastform and surrounded by CF arms, etc. At least one antenna appeared to run against the platfrom in an interior position, shielded by the receiver and lots of CF. The second antenna seemed to be on the edge of the CF platform, but the end was close to one of the octo arms.

I would look at a better way to mount the receiver and especially the antennae away from all that CF. Of course, this applies to the satellite receivers, as well.

Michael

Quote:
Originally Posted by LoneWolfRC View Post
That's a lot of CF.
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Old Dec 19, 2012, 11:13 AM
Air, Ground & Water
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Canada, ON, Rockland
Joined Aug 2008
24,077 Posts
That maybe true but the real issue for me having a DJI Naza is that when setup properly it will either auto-land or return to hom when GPS is connect in the event of a failsafe condition of the Naza MC.

The problem is in the event of a rf signal failure the receiver needs to do it's job and tell the Naza MC to go into failsafe mode. This requires Preset Failsafe to be active, this requires an extra step or different Bind Procedure to properly be acitvated and working.

It's a real shame that thing look sick (good sick).
Hope you get this resolved. Good Luck.
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Old Dec 19, 2012, 11:18 AM
Michael
United States, ME, Wells
Joined May 2008
1,122 Posts
Return Home

Excellent point. Even if the CF issue was addressed, there still is the need to fully incorporate the features such as "return home". I am a belt-and-suspenders person, so the more layers protecting my equipment, the better.

Michael
Quote:
Originally Posted by freechip View Post
That maybe true but the real issue for me having a DJI Naza is that when setup properly it will either auto-land or return to hom when GPS is connect in the event of a failsafe condition of the Naza MC.

The problem is in the event of a rf signal failure the receiver needs to do it's job and tell the Naza MC to go into failsafe mode. This requires Preset Failsafe to be active, this requires an extra step or different Bind Procedure to properly be acitvated and working.

It's a real shame that thing look sick (good sick).
Hope you get this resolved. Good Luck.
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Old Dec 19, 2012, 12:58 PM
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United States, MA, Holliston
Joined Aug 2008
404 Posts
Based on the pictures, the copter had a TM1000 module installed which means there should be telemetry for the radio link. What was the fade, frame loss and hold data when the model crashed? If this was already posted then sorry but I did do a quick look back through the tread and couldn't find it. If there where no holds, then the radio didn't go into fail safe meaning something else went wrong...
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Old Dec 19, 2012, 01:21 PM
Dave Raines
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Cincinnati, OH
Joined Aug 2004
706 Posts
Quote:
Originally Posted by LoneWolfRC View Post
That's a lot of CF.
Yeah!...makes me wonder how much effort went into sat-rx placement. I would have been testing the hell out of it with a flight log just to see if there was a good spot to put the receivers
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Old Dec 19, 2012, 03:35 PM
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Vienna, Austria
Joined Oct 2010
2,589 Posts
Okay, with a telemetry module there should have been data on the RF link ? Range check ? On the last picture you can see a satellite on the opposite side of the RX, but also on top. This could really be caused by RF shielding of the CF, especially if the copter is up in the air. Did you check the telemetry reading on the radio ? Do you know your radio and what it can do ? I have a suspicion that coptograaf is more a "user" ?
I would have placed 3 sats on the arms of the Octo. That is the only position on a carbon monster like this to place the sats, especially if you plan to fly high/far. Which Airware is on the DX18 ? Did you install the latest version ? This also increases the RF performance.
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Old Dec 20, 2012, 01:00 PM
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France, IdF, Paris
Joined May 2007
71 Posts
for when choosing U.S. with DX18 EU
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Old Dec 20, 2012, 01:05 PM
AndyKunz's Avatar
Illinois
Joined Sep 2001
23,984 Posts
Quote:
Originally Posted by AIRBUSA800 View Post
for when choosing U.S. with DX18 EU
There is no US/EU differentiation with the code for any of the radios, only for languages presented. Everything else is identical and works off the settings you configure, or are configured at the factory.

Andy
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Old Dec 21, 2012, 08:59 AM
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Vienna, Austria
Joined Oct 2010
2,589 Posts
And you cannot set the output power to US level.
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Old Dec 21, 2012, 09:10 AM
AndyKunz's Avatar
Illinois
Joined Sep 2001
23,984 Posts
Yes, that's part of the factory-level configuration.

Andy
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Old Dec 22, 2012, 03:23 PM
Team Twisted!
Benton3dflying's Avatar
Joined Aug 2012
287 Posts
Dx18

Heys Guys,
I am having alot of messages that are telling me to register my radio. I have done it, but the message keeps poping up. How do I get rid of it?
Benton
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