S800 issue

[Parapyro]

I have had my DJI S800 for about 6 months now and use it almost daily without any issues. For some unknown reason, while flying yesterday, as I progressed to fast forward flight the machine turned sharp left rudder! I was a little surprised and let off on the throttle and eased it back home. This was the 3rd flight of the day and nothing had been changed between flights except batteries. I found nothing wrong and took off again. Did a power check in a hover, all ok, so I gave it about 65% throttle and got the same result, full left rudder! I continued to fly to test and found that at slower speeds with smooth control she flew perfect, but when I gave her some throttle she turned left! I landed and disassembled her. I did a full inspection and found nothing wrong! Props were fine, motors were tight, nothing loose or vibrating.....I tried switching the arms around to try and isolate the issue but got the same result. Left rudder! So I connected to the Wookong assistant software and did a full re calibration Same result. any ideas????

 

[maxwelltub]

I had something like this happen before on fast descending, only it was right yaw and went in a full spin. I can't say what caused it, but I am thinking it has to do with vibration. at first it sounded like you might have mixed up some arms or props but if you switched them around then its got to be a wkm thing rather then a physical issue.

 

[rsun]

We did also have funny things when flying with the s800. We sold it and got another frame.

My friend did also have the problems and we did talk about what to do.

We made a test hexa frame in aluminium and the only thing we removed were the arms on the s800.

The V s800alu have never been better. The first time we have been trusting the s800 and it were the arms and the vibs that did give us the problems.
View attachment 11637

 

[Parapyro]

Thanks for the help. I updated the software, re calibrated the compass and now when I power up I get no green light. Still fly's exactly the same, with the same problem, but no green flashes indicating systems are good.

 

[ProPilotWannaBe]

Do you have an iOSD or some other device to record internal workings of the WKM? If you do, you can look at the receiver inputs and see if the issue is an input to the WKM; or look at the motor outputs of the WKM to see if the problem is in the flight control. If the motor outputs look good, then it's an S800 problem that doing something beyond what the WKM is commanding.

 

[Parapyro]

I don't have an iosd. When you say "Motor outputs", do you mean the leads from motor to esc? Or the wiring from esc to controller? It just seems strange that this would just start doing it for no obvious reason. It flew fine all day, nothing changed. I even had 3 flights on the same batteries that went fine and then on the next pass she started turning left?! Strange. I have torn this thing apart and found nothing out of the ordinary. I updated the software and firmware, re calibrated the compass, GPS and my radio. Now I get no green lights when I power up.......

 

[ProPilotWannaBe]

Sorry I was a bit cryptic on that. My DJI distributor showed me how the iOSD records the WKM outputs to the ESCs. So when commanding a pitch forward, you would see in the recorded the M4/M5 motors/ESCs commanded more than M1/M2. If the WKM is erratically telling the S800 to yaw, you would see it in the data.
Make sense?
But I wonder If the problem is in the S800 main board, or more likely, one of the ESCs. If one of the ESCs is over commanding the motor, or viceversa, not able to command the motor to the required rate, that would cause yawing.
As for the no-green-light, I have no idea other than the obvious one I'm sure you already checked of ensuring you are in GPS-atti mode in the Assistant Software.
Sadly I am very new to this stuff myself, so I don't have any other suggestions but very curious to know what you find out.

 

[Dewster]

Do you think that you pushed your ESCs too hard?

 

[Parapyro]

I don't know. Not sure what too hard is. I don't fly crazy with it, usually smooth forward flight to get the best aerial video possible. I never have any need to really push it as that would convey in the video. I updated the software and now do not get green flashes when I power up, although she still fly's and has the same issue when I am heavy on the throttle. Ordered 2 new complete arms with ESC and Motors, one CW and one CCW, to trouble shoot.

 

[Tahoe Ed]

If you are flying a S800, get the iOSD. It will record what is happening in your flight. I had a S800 that went down and DJI was able to diagnose the problem from the files.

 

[Parapyro]

Probably a good idea, I finally got a call back from a DJI tech. He said he thinks this is a voltage issue because I use Deans connectors. I explained that I always used Deans and that the issue is new. He said as the motors and bearings get older they will draw more amps due to wear and friction. He recommended oiling the bearings and switching to EC5 plugs. Will try that today. I hope its that simple......

 

[ProPilotWannaBe]

Interesting! Keep us posted if that is the case.

 

[Serval]

Anyone get right believe anything, but My opinion get a name "Planned Obsolescence" http://en.wikipedia.org/wiki/Planned_obsolescence

Explicit video about it https://vimeo.com/66581489

 

[Parapyro]

Dont even know what to say about that..... If I had an extra $20k I would get the Droidworks or Cinestar??

 

[ProPilotWannaBe]

Serval, can you explain to me why you believe the S800 Vibration Kit is dangerous to use? I was planning on installing it, but now want to understand the point before I do so.

 

[Serval]

Serval, can you explain to me why you believe the S800 Vibration Kit is dangerous to use? I was planning on installing it, but now want to understand the point before I do so.

Hello Sir,
Vibrations are bad for props, motor axis, bearing, wire, esc, solder, connectors, electronics etc ... all material in fact.
Vibration Absorber Kit, could not resolve Arm problem.

What Absorber vibration kit could do ? Trying to isolate the IMU, from bads informations signals (101100011000011100).
But this way isolate the "TRUTH ATTITUDE" FRAME !!!
a°/ First for electronic, Accelerometers ...
b°/ Second for pilot informations
If pilot could not understand what is going on with his frame : ZenMuse + Absorber Kit are to much "Absorbers Solutions".
When Pilot get problem, the FPV video send informations what is going on.
With to much SMOTH Absorbers Solutions, he could not get it, because it is a "WRONG ATTITUDE" FRAME.
For exemple, in this video the Zenmuse absorb Truth informations at 11'13 + 11'36.

 

[Serval]

Cinestar, Droidworx are good brandname look like expensive, so not really. Their cost are not 20 K€ for the frame.
For example, possible to take a ZenMuse + Good Reliable Frame.
And there is a absolut good way : DIY, do not forget 25mm carbon tube price

Now, it is easy to compare costs
Buying a S800 + All Gadget Parts Price (absorb kit + Imu V2 + Carbon Reinforced Arm + Props) + All Time Losing to trying S800 works (more 2,300 hours for myself).
Buying a DIY or Real Professionnal Frame : 2 or 3 K$ depends what you want.

 

[Parapyro]

Serval, although I agree with you on buying a quality frame, the lure of the S800 is that for the same price as a Droidworks, Cinestar, skyjib frame, oyu can have an S800 + Wookong system and Rx. Believe me, the next multirotor I buy will be a Droidworks, no debate there. But until then, what about the thousands of us that purchased the S800 and just want a "Fix"? If you read my original post you will see that I flew the S800 for 8 months without an issue. Then, one day with no changes to the system, it began to have problems. I will deal with these problems, make it work so this machine will earn me the money I need to buy the better one. For now I just would like to make what I have work correctly.

 

[ProPilotWannaBe]

The question still hasn't been answered: why the claim that the vibration kit is dangerous? I understand the issues described in the videos, but it does not answer the question. The kit does prevent the flip of death because the IMU will no longer command the flip due to vibrations, and likewise addresses the loss of altitude due to vibrations reaching the IMU. As parapyro said, I am just trying to ensure my system continues to work properly, and can't be seriously thinking of just jumping ship.

 

[Serval]

The question still hasn't been answered: why the claim that the vibration kit is dangerous? I understand the issues described in the videos, but it does not answer the question. The kit does prevent the flip of death because the IMU will no longer command the flip due to vibrations, and likewise addresses the loss of altitude due to vibrations reaching the IMU. As parapyro said, I am just trying to ensure my system continues to work properly, and can't be seriously thinking of just jumping ship.

Sorry for my poor English.
So yes, The Vibration Absorber Kit is good to prevent the famous DJI F.O.D, you are right.
IMU do not have the good information from frame, Pilots must carefull about what could happened.
Good Luck.