another crash with wookong

[aForcefulThrust]

So I had another crash today, I'm not sure if you know about my first crash as I didn't make a thread for it, but just posted about it here: 2 devastating crashes in a month using Wookong

I had a similar crash to this one about a month ago. During this flight it was flying very well, just like it always did. No hiccups or signs of anything out of the ordinary. I tried POI mode out for the first time and it worked beautifully. Towards the end of my flight, just flying around in GPS-ATTI my hex began to spin uncontrollably, very fast. It seemed to spin in one spot, still holding position. The spinning got faster, and faster, it was so fast it was impossible to tell the orientation of the hex (faster then if you were holding 100% yaw on the stick). At this point, I was thinking "Oh **** what can I do". I flipped on IOC in home-lock mode to try and bring it back to me. Around the same time I did this is when the craft started to wobble a little, right before it flipped upside down and flew into the ground. All that happened in a matter of about 10-20 seconds. Looking back at it, I should have maybe gone manual mode and tried to stop the spinning, or just throttled down and landed where it was.

I got my WKM about 12 months ago, and had a faulty GPS unit. Got the GPS replaced before I ever flew with my WKM. I flew probably over 100 flights on my hex and it flew fine, never any problems. Before my crash I had updated to 5.24 firmware, and set up a channel to use POI and IOC modes. I did a quick hover around the house with the new FW, and everything seemed to be fine, even flew more stable I thought.

I'm still also at a loss, and can't figure out why my hex crashed. except maybe it was a firmware issue.. I will be going back to an older firmware before I fly again.

That was my first crash, on 5.24 firmware. Rebuilt the heli, I changed out all my motors because I thought I could have damaged the windings in some of them with screws that were too long, and a speed controller. I also rolled back firmware to 5.16 on WKM.

This crashed happened on the second test flight. I was flying around and everything seemed fine. GPS hold worked well. I did a few climbs and came back down, but mostly just hovered low. About 8 min into the flight, I noticed it was acting a little weird, the motors would get something like a power surge for a few quick times. I landed immediately, but left the motors idling. I decided to take off again real quick and just hover low just to see if the motors would surge again. Well this time, it just went haywire. Right after I took off again, the hex became completely unresponsive to my commands. I tried flipping it in manual mode to land, and tried CSC command to stop the motors but nothing would work. The heli climbed up about 30 feet, then landed HARD, snapping the gimbal when it landed. after it landed, it tried to take off again all by itself!! It did not take off level though and just flipped forward hitting the ground. This is when the batteries came loose and unplugged

In this video, this is after I landed it the first time, and took off again to try to reproduce the motor surging problem I saw. Everything after takeoff was all done by WKM and was unresponsive to my controls.

This is the second crash I've had where it seems WKM just went crazy on me. I'm at a loss... I know it seems like it could be the transmittier/reciever.. I use dragon-link and I completed a successful range-test with the receiver after the build and after the crash too. Maybe someone else could offer an idea of what caused this?

 

[sixshooterstang]

Ouch! Sorry to hear! Seems that for a grand you would get better product support (and reliability). Another reason I use Arducopter and am suspicious of DJI products. Firmwares are not released until they've been properly beta tested by APM/PX4 flyers.

 

[ddikie]

So i had a crash on my maiden flight 2 days ago with 5.24 and have just rebuilt the model and tomorrow will do another maiden flight so better to use version 5.16..or did your crash happen on 5.16 not fully sure which version to roll back too?

 

[Cornforth Images]

aForcefulThrust

I am sorry to hear about your crash. This is absolutely terrible and disgusting news to read. The fact that DJI can get away with pumping out crap and all of us falling for it is ridiculous. I'm trying to dispute all of my credit card transactions with Helicopter World based on my own experiences and everything that I have read on this and other forums. I've heard that 8 Phantoms alone spiraled out of control and crashed into the ocean during the recent whales shark congregation in Mexico. I'm just grateful that all of my DJI stuff is no longer useable so that I can build my next copter using new, more reliable components. Good luck to you, too.

 

[DucktileMedia]

DJI= disposable junk incorporated

Seems curious why your landing seemed somewhat controlled in the video. Normally things go haywire and not come straight down unless the motors just die. maybe those power lines had something to do with it.

 

[dazzab]

Sounds much more like a hardware issue than an issue with the Flight Controller. I bet once it got warm something didn't like the heat.

 

[sixshooterstang]

minor short or dud unit somewhere maybe? a bad winch controller in my axial wraith was causing the whole system to be glitchy.

 

[aForcefulThrust]

Thanks for the input guys! It very well could be a short or bad ESC i suppose, the motors surging in power was very weird. What steps could I take to find out if that is the problem? what has me worried is the complete loss of control I had over my hex.. even manual mode was unresponsive. It's a big hex swinging 17 inch propellers.. Very scary moment to loose control.

 

[DennyR]

I just learned of a local wannabe guy who crashed a large gasser heli into some cars and a power cable whilst attempting a to shoot stills with a 7D. I just wish these guys would leave that kind of work to professionals. Before they F/U the whole business. He could have killed someone. No insurance, and no DCA permission to carry out AP. He could have ended up in the slammer and a good lawyer would take his house.

 

[gDallasK]

My bad experiences with Arducopter were exactly the reason I returned to DJI. No problems since!

 

[aForcefulThrust]

My plan is to replace my power distribution board and all ESC's. This should confirm either a wookong problem or electrical problem. Since it's allot cheaper to replace ESC's and my power board I'll do that first. After that I will strap the hex down and empty a few packs on it to see how it does. If the test there is fine, I will tether it to the ground with a 50ft rope and let it hover for quite a few flights.

I will post back with my results when I'm able to do these tests.

 

[chris24g]

looks like your wkm went into failsafe. thats why it gained altitude and was not responding to controls. you have a radio link issue. i have been flying wkm from day one release.

 

[sixshooterstang]

problem solved. Wookong is in fact broken. It is having random drops in throttle signal to 0. Tried new cable. Tried a completely new radio system. All other channels but channel 3 work correctly. So thanks DJI!

 

[maxwelltub]

What motors are you using? They dont sound so good? I stay on 5.16 and would urge other to do so. Sorry for the crash man

 

[aForcefulThrust]

Thanks for the input guys.

looks like your wkm went into failsafe. thats why it gained altitude and was not responding to controls. you have a radio link issue. i have been flying wkm from day one release.

That does not explain why it tried to take off again by itself after it landed hard and the gimbal snapped... :/ i am still in the process of replacing all my components, a new rx is on the way. All new motors and speed controllers now too. The only thing that will remain is the wookong fc.



Sent from my DROID BIONIC using my fingers

 

[aForcefulThrust]

problem solved. Wookong is in fact broken. It is having random drops in throttle signal to 0. Tried new cable. Tried a completely new radio system. All other channels but channel 3 work correctly. So thanks DJI!

That sounds right... but i also lost control of all other movement too. Im still stumped on this.

What motors are you using? They dont sound so good? I stay on 5.16 and would urge other to do so. Sorry for the crash man

i was using sunnysky 4112 320kv motors. Ive used them for plenty of flights before this happened, they were always warm but not hot on landing



Sent from my DROID BIONIC using my fingers

 

[gtranquilla]

quote:- "About 8 min into the flight, I noticed it was acting a little weird, the motors would get something like a power surge for a few quick times. I landed immediately, but left the motors idling. I decided to take off again real quick and just hover low just to see if the motors would surge again. Well this time, it just went haywire. Right after I took off again, the hex became completely unresponsive to my commands. I tried flipping it in manual mode to land, and tried CSC command to stop the motors but nothing would work."

Sorry that you had the crash and repeated problems....

Based on personal experience with similar behaviour using an F550 c/w Naza..... I was able to trace the problem back to airframe vibration (motor/prop balancing issues).

IMHO - The NAZA and WooKong sensor don't handle vibration well such that flight controller gets confused which leads to deliquent behaviour!!!

I use WKM firmware 5.20 with great success, no need to move back and not willing to update due to others having issues with 5.24 etc.

 

[Benjamin Kenobi]

I've also been using 5.20 and loved it. 5.16 works great too. Alas I used 5.24 the other day as I wanted to try the motor test function but now they've removed 5.20 and I can't roll it back. Shame, because I need the limiting functions to operate in certain areas and 5.16 only has height. 5.20 is not listed on the releases page anymore, just 5.18 and 5.22.

Please correct me if I'm wrong or you know another way to get 5.20 firmware back on. As the assistant downloads the firmware during the update it just comes up as 'interrupted'. Was 5.18 any good? I remember hearing of problems with it.

Sorry to hijack.

 

[gtranquilla]

There is a posting somewhere on MRF listing a wide range of firmware versions that someone has had the foresight to save on their hard drive....... if I can locate it I will pass it along..... I don't recall what fw I used before 5.20.

The range and elevation limit feature work well..... sometimes too well......

I was doing aerial video of a 500 yard fairway, when suddenly the MR was not behaving as I expected.
When flying LOS around 300 yards it is extremely difficult to determine the MR heading etc. but eventually brought it back safely.

Figured it out later while looking at the aerial video..... at 300 yards, the landing gear suddenly swung forward into the FOV.
The MR hit the 300 yard limit like a brick wall!!!! :shame:

I've also been using 5.20 and loved it. 5.16 works great too. Alas I used 5.24 the other day as I wanted to try the motor test function but now they've removed 5.20 and I can't roll it back. Shame, because I need the limiting functions to operate in certain areas and 5.16 only has height. 5.20 is not listed on the releases page anymore, just 5.18 and 5.22.

Please correct me if I'm wrong or you know another way to get 5.20 firmware back on. As the assistant downloads the firmware during the update it just comes up as 'interrupted'. Was 5.18 any good? I remember hearing of problems with it.

Sorry to hijack.