Wookong-M 5.12a unbelievable behavior and ultimate crash

S

seascapeproductions

Member
We have just crashed our hexacopter today. After a perfect first flight, it was flying normally in GPS mode and Course Lock with the Wookong-M (version 5.12a) and we were descending straight down from about 50 feet. It suddenly totally lost control and started to fly erratically. I switched to ATTI Mode immediately but to no avail. It took off vertically going completely out of sight for several minutes. The video on our monitor showed it several blocks a mile away very high up. I switched on GO Home Mode and put it back in GPS Mode. I think it finally went into FailSafe after the batteries became low because we could finally hear it closer to us yet still very high up. It then came straight down and crashed on a large building roof several blocks from the Home Point. I was simply slowly descending from a hover with no other control than the throttle when it suddenly lost all ability for me to control anything. Any ideas on what could possibly cause this potentially disasterous situation.
 



R

RTRyder

Merlin of Multirotors
Was failsafe setup on the TX/RX when doing the binding?

The description sounds like a loss of TX signal coupled with failsafe either not setup or setup incorrectly, on loss of signal it went to full throttle and flew off and eventually did go into failsafe and attempted to return home. On the return home it probably ran out of battery power and then came down like a rock wherever it was at the time.

Ken
 

S

seascapeproductions

Member
RTRyder said:
Was failsafe setup on the TX/RX when doing the binding?

The description sounds like a loss of TX signal coupled with failsafe either not setup or setup incorrectly, on loss of signal it went to full throttle and flew off and eventually did go into failsafe and attempted to return home. On the return home it probably ran out of battery power and then came down like a rock wherever it was at the time.

Ken
Click to expand...

Failsafe was set up correctly to the best of my knowledge. I changed it from Intelligent Go Home to just Go Home with the last update (05.12a). If it entered FailSafe mode, the strange thing is it had enough battery power to begin its final descent but was several blocks away from the Home Point. And it also flew several blocks away in the opposite direction in its ascent. Sure would like to sort this out before we attempt a rebuild and new autopilot. I'm pretty gunshy right now, but lost a job today and have three more pending.
 

M

Muunk

Member

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R

RTRyder

Merlin of Multirotors
seascapeproductions said:
Failsafe was set up correctly to the best of my knowledge. I changed it from Intelligent Go Home to just Go Home with the last update (05.12a). If it entered FailSafe mode, the strange thing is it had enough battery power to begin its final descent but was several blocks away from the Home Point. And it also flew several blocks away in the opposite direction in its ascent. Sure would like to sort this out before we attempt a rebuild and new autopilot. I'm pretty gunshy right now, but lost a job today and have three more pending.
Click to expand...

Not the failsafe I was referring to. What I meant was setting the control positions on the TX that the RX will default to on loss of signal from the TX, done when binding the RX to the TX. If you skipped this step then it's quite possible that the failsafe setting the RX used was high throttle causing the flyaway. Proper failsafe settings are mid to slightly below hover throttle setting and neutral position on the others, anything else and it's anyones guess what will happen on loss of signal.

Without flight logs or telemetry it's impossible to say what caused the incident, we can only speculate on what might have happened. Best thing to do is rebuild carefully and test each component while doing so. In the process make sure each step in the setup manual is followed to the letter while configuring the flight controller as well as the TX and RX.

Just out of curiosity, how much RC and flight experience do you have, and did you build the multi or did someone else do the build?

Ken
 


D

Dewster

Member
seascapeproductions said:
We have just crashed our hexacopter today. After a perfect first flight, it was flying normally in GPS mode and Course Lock with the Wookong-M (version 5.12a) and we were descending straight down from about 50 feet. It suddenly totally lost control and started to fly erratically. I switched to ATTI Mode immediately but to no avail. It took off vertically going completely out of sight for several minutes. The video on our monitor showed it several blocks a mile away very high up. I switched on GO Home Mode and put it back in GPS Mode. I think it finally went into FailSafe after the batteries became low because we could finally hear it closer to us yet still very high up. It then came straight down and crashed on a large building roof several blocks from the Home Point. I was simply slowly descending from a hover with no other control than the throttle when it suddenly lost all ability for me to control anything. Any ideas on what could possibly cause this potentially disasterous situation.
Click to expand...

That's pretty wild. I was using Intelligent Orientation Control and had no problems until I flew the craft behind it's launch point (home position) and then turned to face the craft which was behind me. The right and left controls were reversed I think. I was trying to keep my craft from hitting a nearby tree, so you can imagine having your controls reversed and trying to avoid an object. It appeared like it lost control as I moved the sticks rapidly causing the craft to shake. I hit RTH and the craft stabilized and came back. I turned off Intelligent Orientation Control, turned off RTH, and regained control of my craft by flipping out of GPS to Attitude mode.

I flew my craft in the same manner the next day (nerves were shot lol) with the exception of flying it behind Home Position while using Intelligent Orientation Control and had no real problems. It was windy and I used Return to Home. My craft struggled in a strong head wind and it's nose was pointed 45 degrees off of Home Position even though to flew straight back. It was windy.

Did you fly your craft behind it's Home Position and turn to face it? I ask because I want to know if it was me or if my craft was acting crazy. I would be dropping bricks, if I saw my craft fly away uncontrolled. It's bad enough seeing it drop from the sky, but uncontrolled is a heart attack inducer.
 

S

seascapeproductions

Member
No, it was not behind the Home Position, but I have done so on previous flights and yes the controls reverse as you described because you have turned the transmitter around. That seems to be normal behavior.

I have discussed this crash with a lot of knowledgable folks by now, including Wookong, and no one can really explain it. The manufacturer assures me that the Failsafe was corrected set up when he bound the hex with the transmitter originally. He actually described the whole procedure to me. I received the hex and transmitter as a turn key system after it had been completely tested and had over 30 successful flights before the crash. Just damn lucky no one was hurt or property damaged.
 

T

turkeybird

Member
I had exactly the same experience yesterday with one of my F550's. I took off fast, banked, and as it was coming back toward me it just turned again and flew away. I jumped in the back of a friend's truck and we chased it across the neighborhood. I was in the back with my radio while he drove. I was totally locked out for the entire time. No radio inputs worked, not even failsafe RTH. It eventually came to a stop, and just hovered. I toggled from GPS to manual a few times... then I got it back, and brought it down in atti safely. whew! Everything is set up correctly, it's a mystery. I'm pretty uncomfortable with the thought of taking her up again.
 

S

sickan

Member
turkeybird said:
I had exactly the same experience yesterday with one of my F550's. I took off fast, banked, and as it was coming back toward me it just turned again and flew away. I jumped in the back of a friend's truck and we chased it across the neighborhood. I was in the back with my radio while he drove. I was totally locked out for the entire time. No radio inputs worked, not even failsafe RTH. It eventually came to a stop, and just hovered. I toggled from GPS to manual a few times... then I got it back, and brought it down in atti safely. whew! Everything is set up correctly, it's a mystery. I'm pretty uncomfortable with the thought of taking her up again.
Click to expand...

I lost a TBS Discovery this Sunday, flew it with Naza and GPS. This one have worked perfectly before and I have tested fail safe also, RTH and land worked the day before.

It just seemed that the Naza was heading for another home spot than the takeoff position. I took of with no flash so it indicated that it hade enough satellites locked.

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S


Sent from my iPad using Tapatalk HD
 

Vojec

Vojec

Member
turkeybird said:
I had exactly the same experience yesterday with one of my F550's. I took off fast, banked, and as it was coming back toward me it just turned again and flew away. I jumped in the back of a friend's truck and we chased it across the neighborhood. I was in the back with my radio while he drove. I was totally locked out for the entire time. No radio inputs worked, not even failsafe RTH. It eventually came to a stop, and just hovered. I toggled from GPS to manual a few times... then I got it back, and brought it down in atti safely. whew! Everything is set up correctly, it's a mystery. I'm pretty uncomfortable with the thought of taking her up again.
Click to expand...

It was SOLAR STORM yesterday, so (GSP) satellite in hemisphere was disturbed. Read a few times how multicopter fly uncontrolled around or even worse fly a way for good. Have installed android app for solar storm prediction and never fly when is active.

Hope this answer will help in the future.

Cheers
 

M

meme

Member
@Vojec, thanks for the Info, whats the Name of the App? Anyway, flying in M during Solar Storms is not a problem, right?

cheers-

meme
 

Vojec

Vojec

Member
@meme
Name of app is: Solar Activity Monitor Widget
As concern fly in M mode, never try it... too much cash involve into octo ;)
 

T

turkeybird

Member
Solar flares could explain why a MR in GPS would stray off course, I understand that the positioning errors are typically something like 10 meters off, but why would radio signals lock out in all modes? A solar storm influences the rate at which gps satellite signals pass through the ionosphere. It's the slowed signal which causes the discrepancy in position interpretation. Do they also affect radio signals?
 

Vojec

Vojec

Member
Not an expert far from that, but if IMU & GPS get an error then MC get it also and your TX command won't work, because MC won't listen TX. Just my thought .... correct me if I'm wrong.
 
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J

jbdww

Member
A solar flare would not cause the RF signal from being blocked. It may affect GPS, but not that dramatically. I do think DJI should put some kind of algorithm in there code that detects a massive change in there GPS signal, and maybe go into Atti mode if the massive change is detected.
 

T

turkeybird

Member
I agree that the RF signal shouldn't be affected by gps signal variations due to the flares, but I don't know how the flares might affect RF signals. If someone does know I would be curious to know. Sickan.... What radio were you using on Sunday, and did you find your Discovery?
 

S

sickan

Member
turkeybird said:
I agree that the RF signal shouldn't be affected by gps signal variations due to the flares, but I don't know how the flares might affect RF signals. If someone does know I would be curious to know. Sickan.... What radio were you using on Sunday, and did you find your Discovery?
Click to expand...

I was using a standard 2.4 system. Graupner MX-20 and GR-16.

No, the copter is gone :( Just ordered a new TBS Discovery :)

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S
 

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