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Old Jul 22, 2012, 06:14 AM
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Toledo, OHIO
Joined May 2007
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3 weird crashes today ( dji F.C.) Wookong and Naza(update)

Hi guys had three weird issues today with my DJI F.C. Both Wookong and Naza.

Short back story bought and built a Carbon Core hexa with Wookong has been flying flawless.(2 1/2 months) Everything works as it should down to RTH.

Anyway started doing fpv and had a blast and decided to buy a less expensive/longer flight time setup.

Got my Flamewheel with Naza put 20 flights on it and lost a stock prop, low level minor crash. By the way it flew awesome for all those flight most being fpv.

Ordered some graupner props and the naza gps because I want RTH for flying fpv. Set everything up and tested RTH all worked fine. I did notice sometimes when going to gps it would act as if it was way out of trim, flip out of gps and it was rock solid. Go back to gps and it would be fine. Some times the out of trim action would be so bad I hardly had enough counter direction to even level out.

Fast forward to Saturday, 30 seconds into first flight in gps mode it tilts very hard and Will not counter, I flip to atti still no luck. I am getting close to corn so I try to power climb which it did but it was tilted too far, went in. No big deal, lost model alarm kicked in and it was found fast, no damage. Take it up again after inspection and it flew awesome in manual mode, I also rechecked fail safe and all is good.

Put fresh battery in and do some fpv, several minutes in I start descending and and I seam to have no control. Goes in corn and it takes almost two hours to find it., by the way I found a lost foamy flyaway from a few weeks back also. The onboard video shows the motors trying to spin up as it was laying upside down for a short time after the crash?

Had enough and decided to fly my trusted and true Carbon Core hexa with Wookong. Plug batteries in set to gps and have full lock, arm motors and this is where it starts to get bad. Motors are armed and it climbs to about 2 feet as I was not ready I tried to lower throttle but it does nothing, I raise throttle still nothing. Mean while I still have full control of cyclic input, It started to go up in down on throttle. Oh crap I don't want a flyaway, I start to walk up thinking I will pin it down by the top cage get about 10 feet away and it goes full throttle

First thought is this thing is gone, then I nosed it down hard and went into very fast figure eights to keep it from climbing to the moon. I have thoughts of turning of the radio to go to fail safe but being that it was what I considered out of control I did not trust the system to work properly. I switch through the flight modes and nothing is helping, goes on for about 3 minutes and at about 20 feet and moving very fast and tilted sharply nose down the throttle cuts to nothing. Needles to say it hit very hard flipped over and flung my camera with wide angle lense for a good distance doing some nice and maybe unrepairable damage.

Hexa faired pretty well, looks like only one broken arm and broken gps mast and maybe gps itself, not sure.

First thing I did was check radio monitor screen and all worked as it should. I then took my 450 up to verify it was not a radio problem and it flew just fine.

Kinda at a loss, the naza has been a problem since gps was added and now the Wookong freaks out.

Anyone seen these problem before? Any insight as what I should be looking at or for. The day before the Wookong was just awesome and in fact I did some night fpv flying and tested the RTH from a great distance and it all was perfect.

This was all at my flying field in the middle of nowhere with no other people in the air.

I have video of the two naza crashes but one is about an hour and a half so I will need to cut them down before I post them.

Thanks Dave
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Old Jul 22, 2012, 08:43 AM
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Fort Worth, Texas
Joined Oct 2004
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Dave,

The naza problem sounds very familiar to one that I have had. Flying in GPS mode, I had a problem a few days ago. I took off into a hover, then boom, it wants to go some random direction, and wanted to keep going that way. I could counter it by giving opposite stick, and if I didn't let the quad get too out of shape, i could stop the movement. I could bring it back to center sometimes, but then it would go another direction. I am also having a problem with the altitude hold in GPS and Att. mode. If I fly in Manual, absolutely no problems.

I should add, I have changed the Naza over to a brand new quad, and I am still having problems.

I really am getting to the point where I trust my cheap HK controllers more.
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Old Jul 22, 2012, 09:00 AM
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Eagle Lake, Minnesota
Joined Apr 2003
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Holy crap...Now that is a bad day There have been several threads/posts about the DJI stuff having issues as you have explained. I was quick to comment that there are so many points of failure on a multirotor but yet everyone immediately jumps on DJI. What you have described is strange as well as concerning. Having two systems go bonkers after they were proven for some time is scary.

The only common denominator I see is the TX. However, that does not explain why the failsafe/RTH did not work like it did in the past. I have been brushing these posts aside for a while now but I am starting to become a bit concerned. I am flying all DJI and while everything has been working well I am now watching and waiting for events like this. I do hope you can figure out the issues, these things can drive a guy nuts


Best of luck

Mike
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Old Jul 22, 2012, 09:04 AM
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On the WKM, what version of the software are you running?
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Old Jul 22, 2012, 09:17 AM
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Solar X-rays: Active
GeomagnetiC: Quiet

From n3kl.org

Doesn't look like solar activity is to blame.
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Old Jul 22, 2012, 09:42 AM
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Well... I said it long time ago !!

There is something BAD about the naza and it`s performance !!
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Old Jul 22, 2012, 09:49 AM
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Hi Dave,

Sorry to hear that!
I have no idea what could have happened that two DJI FC went crazy on the same day. But I've been reading about people getting problems with NAZA GPS.

Regarding WKM I once had a power shutdown in mid flight. Luckily I was flying low and had no damage. But after that I could not get enough power to take off in both GPS and ATTI mode. Manual was flying fine. A few days later after connecting to software assistant, reseting everything and rearranging the electronics on the frame the problem disappeared.

Eventually my WKM had a fly away when testing RTH that never worked. Many people said it was because my Turnigy 9X radio but I believe it was down to SH GPS problems that was not known by the time.

So, to me it seems DJI GPS's are very sensitive and they can cause weird problems.
Not sure how much it could cause any real problems but I heard we have been having pretty strong Solar flare activities lately.

But as I said, I don't know what could have caused your problems, but one thing that seems to help avoiding problems with NAZA GPS is to do compass calibration before every flight. I also did the GPS postion correction for magnetic declination. After that my NAZA GPS has been working quite well and I hope it keeps like that. It has about 10 flights since GPS install.
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Old Jul 22, 2012, 11:06 AM
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Thanks guys! I am the first person to look for true causes. I will say that in 7 years of sport and contest flying I have never had a radio issue that caused a loss of control of a model.

The tilting on the naza like it is out of trim is a recurring issue for me. I have tried to lift off in gps and it acts so out of trim that I can barely get it level. Or I can be hovering in manual or atti flip into gps and it will bank very hard to one direction, flip out of gps and it will level out. This does not happen all the time but enough to be a problem. I am going to remove the radio as a suspect on that issue. I also fly 700 electric helicopters and airplanes and I have never had random out of trim issue like this. Again it does not happen in manual or atti modes, every flight before gps was perfect.

My Wookong loss of throttle control is the one that concerns me. As stated other models were flown that day multiple times with no issue with throttle. Monitor screen was checked after crash with no sign of jumping or none working pot. I have never seen just one channel not work on a flight like that.

I will work to try and find the true causes, as I am not looking to blame any one device but more to insure this does not re-occure.

Tarro

i will check version, i do not think i am on the latest version, been some time since i have been in the assistant on my Wookong
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Old Jul 22, 2012, 11:18 AM
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Quote:
Originally Posted by David Canfield View Post
Thanks guys! I am the first person to look for true causes. I will say that in 7 years of sport and contest flying I have never had a radio issue that caused a loss of control of a model.

The tilting on the naza like it is out of trim is a recurring issue for me. I have tried to lift off in gps and it acts so out of trim that I can barely get it level. Or I can be hovering in manual or atti flip into gps and it will bank very hard to one direction, flip out of gps and it will level out. This does not happen all the time but enough to be a problem. I am going to remove the radio as a suspect on that issue. I also fly 700 electric helicopters and airplanes and I have never had random out of trim issue like this. Again it does not happen in manual or atti modes, every flight before gps was perfect.

My Wookong loss of throttle control is the one that concerns me. As stated other models were flown that day multiple times with no issue with throttle. Monitor screen was checked after crash with no sign of jumping or none working pot. I have never seen just one channel not work on a flight like that.

I will work to try and find the true causes, as I am not looking to blame any one device but more to insure this does not re-occure.
David, are you sure you do not have trims in the different fllight modes? Also are you recycling power after each flight on your radio?

I have noticed if you dont recycle power on the radio, the fc will not find center sometimes. (on my setup about 1 out of 4 times)

Next time you see this, please dont power off anything and check the fc via the software.

I just find it really odd that you had two failures in the same day with differnet hardware..
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Old Jul 22, 2012, 11:52 AM
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Toledo, OHIO
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I have no trim on either model and i am not using flight modes, just using gear switch to switch between maual/atti/gps. This does not happen every time i switch into gps as it would if i had been using trim/subtrim.

I do turn radio off between flights, i do not like seeing the blinky litghts

I Admit that it is weird to have issues with two different F.C in one day.

Here are a couple commons between the two crafts. Things we can lay blame on or trouble shoot.

1. Radio/TX
2 GPS

I have been using this radio for several years with no issue.

The common factor that seams to lead to problems is when in gps mode, when in manual i would think if i had a radio issue it would still be there.

I should clear up one thing that could be to blame for the second Naza crash. The rx i am using on the naza does not have the advanced fail safe feature. So if signal was lost it would go to low throttle and drop from the sky. ( I will be replacing with new rx)

that being said i may have only two weird issues the lack of throttle control on the wookong and the tilting hard in gps ( randomly)

I still strongly believe there is an issue on the Naza gps when flipping between modes and the issue of acting out of trim. It has happened too many times on and off to be radio related.

I will get the onboard videos up in a bit.

Thanks Dave
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Old Jul 22, 2012, 03:20 PM
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Waukesha, WI
Joined Dec 2002
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Dave,

I have a DJI F550 with Naza with GPS. I took it up for my first test hops yesterday and it exhibited the out of trim characteristics that you have described. It did it inconsistently though. At times it would hold pretty well (not rock solid like it seems to for some folks) and other times I would switch from ATTI to GPS and it would bank to the right and would keep going unless I corrected. In ATTI mode it flew very solid. More solid than in GPS mode by a fair margin. The part I don't get is why it sometimes behaves very well in GPS mode (nice constant piros in a tight space) and sometimes it banks to the right and even yaws in different directions that I need to correct for.

I need to do more checking/tuning/troubleshooting but at least on the surface there seems to be some consistent performance issues with quite a few people in regard to the GPS. That has been a common factor so far. Like I said I have more testing and tuning to do but I sure am not comfortable enough with GPS mode to trust any camera gear nicer than just the GoPro at this point.
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Old Jul 22, 2012, 03:25 PM
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I have seen a lot of descriptions of behaviors, but no pictures of the set up. Where do you have your GPS mounted, what are your settings in Assistant? Did you calibrate your compass? How is your static balance? I have never had the issues reported above in either of my Naza-GPS units. I would be interested to see what the cause is in these copters.
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Old Jul 22, 2012, 03:50 PM
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Waukesha, WI
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Ed, I took measurements and entered (what I believe to be) appropriate numbers into Assistant for the location of my GPS unit. It is mounted on the upper frame at the front edge and centered. My static balance is dead on and I calibrated my compass. I will do more testing today, remeasure to make certain my XYZ are indeed correct, and post a picture. I guess what I am trying to clarify is that I am exhibiting some of the same problems as the OP so if it winds up being UE then we are both doing approximately the same thing wrong. More testing to follow.
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Old Jul 22, 2012, 03:51 PM
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Ed, sending you a PM
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Old Jul 22, 2012, 04:11 PM
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Ed, sending you a PM
Post some photos of your set up. It will help verify the settings.
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