Another A2 Crash - Pictures, Graphs, and Video

Discussion in 'Cinestar 8' started by Josh Lambeth, Aug 5, 2014.

  1. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Hi everyone,
    We had a bad day on Friday. We had a crash with our new SynDrones x8 frame. During a flight the copter started to spin hard to the right. After a few seconds it paused and started spinning to the left as it headed to the ground. After talking with DJI they asked for me to send the data file from the crash. Today I received an email stating the reason for the crash was because motor 1 maxed out at full throttle. They sent me a graph showing this. However the graph they sent me does not look like the graph I have. Also I don't understand why m1 would go full throttle in the first place?! Any thoughts on this?
    Setup is SynDrones X8HL
    DJI A2 w/Datalink and iOSD MKII
    KDE 55+ ESC
    KDE 4014 380KV Motors
    TMOTOR 18x6.1 Props
    Total AUW is 27lbs.
    Files are below. The graph on the left is the one I have. The graph on the right is the one they sent me.
    crashcompare.png

    You can download the data log here to review: http://www.filedropper.com/fly011

    Here is a video showing the timing between the crash and the graph.



    DJI is insisting that the copter started spinning due to the fact that M1 went to full throttle. As you can clearly see in the video the copter is spinning long before the motor ever hits full throttle. When I pointed this out to DJI their response was "It has been shared but it does not change the interpretation of the data on the flight logs. I understand that you feel differently but your interpretation of what happened is no more valid than ours."

    They have since gone quiet and won't respond to anything I send them. All my motors and ESCs are being sent to KDE to be inspected. I know 2 motors are for sure shot due to the crash.. I also know that during the flight none of the motors stopped spinning. The copter was in the air long enough for me to clearly see it and I didn't see any motor stop or slow down.

    If you are flying the A2 system I very strongly recommend you stop and ground your system before it's too late.


    I would love to hear feedback/ideas/ect of what you think may have happened.

    pic1.jpg pic2.jpg

    Josh
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,375
    Likes Received:
    1,162
    Awww, damn, Josh. That's not a pretty sight.....

    I'm not familiar with the A2, but I do have to ask these kinds of questions:

    1. Why does DJI's graph differ so significantly from yours?
    2. Why would *any* motor go to full throttle if it was not being commanded to so by the flight controller? (And why don't we hear it -- one motor should be going like a banshee on heat....)
    3. Can you actually get any flight data from the log files that demonstrates what the flight controller was commanding?
    4. I'm not sure DJI's response portends well for the future of DJI customers for aircraft and the Ronin -- it doesn't quite exude "we care about you as a customer" does it?

    Andy.
     
  3. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Hey Andy,
    No it's not... especially when it happened considering this was with our BRAND NEW MoVI M5 and Canon 1DC onboard! :eek: Luckily I got the landing gear down in-time and it saved the camera and gimbal.

    To answer your questions:
    1. Because it wasn't my graph. They sent me the graph of someone else. I called them out on this and they didn't believe me. If you look closely you don't even see lines for 8 motors. Only 6. They have, 3 times now, mixed up my information with someone else. Later they claimed I was using Maytech ESCs (which I wasn't and in my report file I told them I was using KDE) and just recently they told me that they don't recommend me rolling back my firmware to an earlier version (which I never asked them about). They keep getting things mixed up. It's amazing to me!
    2. Great question! I've never heard of this error before... and in the video you can't hear it. The motors are only about 45-50% throttle in hover. You would def. hear if one went full throttle.
    3. Yes. I have the iOSD which logs almost all flight data from the A2 controller. The graph that is in the video is what the A2 was commanding Motor 1 to do. It has no way of logging what the ESC is doing on it's own. How they came up with the ESC went to full power due to an error is beyond me.
    4. Not at all. Absolutely horrible customer service.

    Josh
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

    Joined:
    Oct 30, 2012
    Messages:
    3,979
    Likes Received:
    807
    That is horrible to see, Josh. So sorry about this.
    I have no experience with the A2, but as Andy said, this is not good news at all.
     
  5. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Some good news from this crash is the new frame held up REALLY well! Other than the one CF tube and battery tray, nothing else broke (on the frame anyway).

    Josh
     
  6. Tristan Twisselman

    Tristan Twisselman Active Member

    Joined:
    Jun 30, 2012
    Messages:
    416
    Likes Received:
    25
    I am so sorry to see this Josh. There is no way your copter was over weight with your setup and it definitely sounds like something went bad in the flight controller. Did you try flipping to manual mode? I DJI customer service is horrible. At least in my experience and every other person and even 2 hobby shops i have talked to. They are out to make a quick buck and are all about quantity over quality. I really wish the Synapse was ready because we need a serious industrial type flight controller we can count on.

    This isn't an A2 but It is a WKM still and DJI product.
    While I fly WKM in my main copter with v2 imu I have still had issues with mine and it do weird things. I really hope you find out what happen and caused this. Damn good job keeping it away from that pool and bringing it down as smooth and controlled as possible. Impressed! :cool:
     
  7. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Thanks. I was fighting the copter the entire time. The last 20ft I couldn't even see it because of a building between myself and the copter (I was standing in the parking lot). I just kept throttle up until I heard it hit then shut off motors (not knowing both batteries came off during the crash which cut all power).

    I am really hoping DJI admits it was their fault... but I'm not holding my breath. I am thinking about legal action against them however.

    I also agree, Synapse needs to be released ASAP! I need something I can rely on. In the meantime I think I will rebuild using MK again since it seems to be the most reliable at this point.

    Josh
     
  8. Tristan Twisselman

    Tristan Twisselman Active Member

    Joined:
    Jun 30, 2012
    Messages:
    416
    Likes Received:
    25
    Also the fact that it yawed one way then the other like that seems like a glitch in the A2 system for sure and not a motor or esc issue. Did you get a chance to check motor temps when it landed? I know you said they where all spinning but when Bryan had his lose a motor it was yawing out of control...Could it have just been spinning due to the air from the other motors? I really hope you figure this out asap, crashes are horrible but crashes that where out of your control are even worse.
     
  9. Tristan Twisselman

    Tristan Twisselman Active Member

    Joined:
    Jun 30, 2012
    Messages:
    416
    Likes Received:
    25

    It is sad to say but I think a lawsuit is one of the only things that is going to even possibly get DJI to figure their stuff out and start treating their customers with respect and taking responsibility.
     
  10. Tristan Twisselman

    Tristan Twisselman Active Member

    Joined:
    Jun 30, 2012
    Messages:
    416
    Likes Received:
    25
    Forgot to add link in my above post. It is there now.
     
  11. Steve Maller

    Steve Maller UAV Grief Counselor

    Joined:
    Oct 30, 2012
    Messages:
    3,979
    Likes Received:
    807
    I wonder if that's part of the reason DJI nuked their USA sales organization. After all, how does one sue a Chinese company? I don't believe there's a way. That said, they do have a presence in Los Angeles now according to their website. But it seems their support organization is in Shenzhen.
     
  12. Gary Haynes

    Gary Haynes Administrator
    Staff Member

    Joined:
    Jul 6, 2012
    Messages:
    5,211
    Likes Received:
    460
    Josh sorry to hear this. There is one bright spot. watching your video even with the wild gyrations and rapid rotation of the copter the MoVI did an amazing job of keeping the camera stable. Of course then it appears to have gone heads over heals.

    That said customer support is king for any business. Have you posted this over on MRF? Wonder what Tahoe Ed would be saying?
     
  13. Tristan Twisselman

    Tristan Twisselman Active Member

    Joined:
    Jun 30, 2012
    Messages:
    416
    Likes Received:
    25
    I just spoke with a buddy who had one of his friends recently crash the A2...flying fine then starting yawing until a crash. Bryan's X8 that crashed in the water and everyone blamed the motor shaft breaking for the yaw...I am starting to think the motor shaft broke once it hit the water and the yaw issue was due to the A2. That is 3 different A2's, 2 with KDE Motors and one with Tiger motors all crashing in an uncontrolled yaw...
     
    Jason Herring likes this.
  14. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Yes I believe there is a serious flaw with the A2 system causing an uncontrolled yaw situation. Can you have your buddy contact me? I will PM you my email address.

    Gary, I have posted over in the MRF and Ed has been very UNhelpful. He is the one I quoted in the original post and hasn't offered any additional help what-so-ever. Here is a link to where our conversation started on that thread:
    http://www.multirotorforums.com/sho...e-ALL-go-Again&p=176605&viewfull=1#post176605
     
  15. Tristan Twisselman

    Tristan Twisselman Active Member

    Joined:
    Jun 30, 2012
    Messages:
    416
    Likes Received:
    25
    Josh, another thing. They are claiming that M1 went full throttle and caused the crash. I haven't looked at the logs yet but will now. Did the other motors slow way down? If it was a motor issue then all of the other motors would have had to slow down to keep the heli from flipping or drifting off...If M1 went full throttle why didn't the others speed up to stop the Yaw? Is it just me or does the heli seem to stop spinning just before impact? Could that be when M1 went full throttle is just before impact and actually stopped the out of control yaw? Everyone is so quick to blame KDE or the ESC. Think about how complex the flight controller is compared to the motors and speed controllers. Also you can have a motor issue or esc issue and usually be able to land safely. I am strongly thinking this is an A2/Flight controller issue. Especially because it has happen with more than one person and they where all running different motor/esc combos...common denominator is the A2, all Octos, one a flat octo.
     
  16. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Yes they are claiming M1 went full throttle.

    The graph in the first post is showing all 8 motors. It's hard to see but not all motors went full speed, just a few and they did it at the same time. I will post graphs of each motor so you can clearly see which ones went full throttle and which one didn't. They do change part way through iirc.

    Josh
     
  17. Sam Fleishman

    Sam Fleishman Member

    Joined:
    Mar 30, 2013
    Messages:
    211
    Likes Received:
    17
    I've been flying wookong for a while now. They stopped coming out with firmware updates because of the A2. I feel like wookong is pretty solid. D that's what I will continue to use. With v2 IMU.
     
  18. Nick Wolcott

    Nick Wolcott Member

    Joined:
    Sep 21, 2012
    Messages:
    67
    Likes Received:
    4
    I feel your pain. I just had a bad wreck myself. It's never fun.
    Just out of curiosity, how hot of a day was it? Were you in Altitude hold, or whatever dji calls it?
     
  19. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Ambient was 95*F and no, I was just in ATTI mode. The non GPS one though.

    I had done previous testing in temps way above what it was that day. (Some test flights were just hovering at weight in 110*).

    Josh
     
  20. Jason Smoker

    Jason Smoker Active Member

    Joined:
    Oct 23, 2012
    Messages:
    858
    Likes Received:
    67
    So sad to watch a heli go down!! I dont think I will ever trust dji products 100 percent!
     

Share This Page