DJI Double Defects Crash! TBE & Low Voltage Forced Landing!

Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

IF the battery impedance was high then the battery voltage displayed would be low.
That was apparently not the case.

T
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

Lithium batteries and modern ESCs do a very good job of holding the voltage up, even with a high impedance, failing battery.

Ohms law still applies, but the battery tends to heat up simply delivering less current while the voltage droops only a little.

I need to ask a mate who is a real expert on batteries - he designs battery vehicles for Ford and also the KERS system for F1 teams. He can explain what happens a lot better than I can!
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

I am now posting this youtube video in the hopes of providing more clues on what exactly lead to my Phantom 2's fatal crash.

[youtube]http://www.youtube.com/watch?v=-R6v_ArP2Pc[/youtube]

This video was recorded in the same location two weeks before the crash, some of the conditions were same as the crash prior to takeoff.

1. Phantom 2 was powered up before being put on the ground. (Same condition prior to the crash)
2. Gimbal twitching on its own before being stabilized prior to takeoff (Same condition prior to the crash)
3. IMU initialization failure. (Same condition)
4. Windy conditions (Same but bit less windy, see 00:30 coconut tree leaves swinging)

Note that during this flight, the right side pitch & roll stick was also not used during takeoff and was only used after it came back down and close to the ground towards end of video. The video is showing that despite IMU not properly initialized, the Phantom 2 was able to took off normally and was able to ascend normally. Even under windy conditions, my Phantom was able to gain altitude although wind has pushed it 70 meters away from home point.

What's also shown is the early auto land at 41% when it begins to land automatically. I switched off the remote controller to change it to FailSafe mode in 10:22, hoping for it to fly back towards me but unfortunately it crashed into the tree not responding to my command and not locking its altitude. It didn't have much damage that time.

With this video proof, i have to respectfully disagree with any of the above mentioned as the cause leading to my Phantom dropped into water. I have to say battery is the main culprit unless proven by someone else otherwise.

Its so sad to lose my Phantom 2 just days before DJI released the 3.06 fix for TBE, J-hook and other issues related to magnetic declination.
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

Not sure what the second video is proving. Holding it in your hands during startup won't consistently cause problems. In fact, it probably won't cause any problems most of the time. But all it takes is one time. That is the most likely suspect in the original video.
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

stmwise said:
I am now posting this youtube video in the hopes of providing more clues on what exactly lead to my Phantom 2's fatal crash.

[youtube]http://www.youtube.com/watch?v=-R6v_ArP2Pc[/youtube]

This video was recorded in the same location two weeks before the crash, some of the conditions were same as the crash prior to takeoff.

1. Phantom 2 was powered up before being put on the ground. (Same condition prior to the crash)
2. Gimbal twitching on its own before being stabilized prior to takeoff (Same condition prior to the crash)
3. IMU initialization failure. (Same condition)
4. Windy conditions (Same but bit less windy, see 00:30 coconut tree leaves swinging)

Note that during this flight, the right side pitch & roll stick was also not used during takeoff and was only used after it came back down and close to the ground towards end of video. The video is showing that despite IMU not properly initialized, the Phantom 2 was able to took off normally and was able to ascend normally. Even under windy conditions, my Phantom was able to gain altitude although wind has pushed it 70 meters away from home point.

What's also shown is the early auto land at 41% when it begins to land automatically. I switched off the remote controller to change it to FailSafe mode in 10:22, hoping for it to fly back towards me but unfortunately it crashed into the tree not responding to my command and not locking its altitude. It didn't have much damage that time.

With this video proof, i have to respectfully disagree with any of the above mentioned as the cause leading to my Phantom dropped into water. I have to say battery is the main culprit unless proven by someone else otherwise.

Its so sad to lose my Phantom 2 just days before DJI released the 3.06 fix for TBE, J-hook and other issues related to magnetic declination.

The only thing this video would appear to prove irrefutably is you are an idiot !

The video shows you are flying from surface to over 2,500ft in very close proximity to an airfield/airport. You will undoubtably be in controlled airspace at those altitudes and distance from the runway.

Maybe it is best for all concerned your craft did get destroyed when it crashed!
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

*Please refrain from name calling

I noticed in that video that the home point was all over the place, even when sitting still. There is definitely an issue with your bird. I would attempt to start fresh and reinstall the firmware and do a complete calibration.
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

The Editor said:
stmwise said:
I am now posting this youtube video in the hopes of providing more clues on what exactly lead to my Phantom 2's fatal crash.

[youtube]http://www.youtube.com/watch?v=-R6v_ArP2Pc[/youtube]

This video was recorded in the same location two weeks before the crash, some of the conditions were same as the crash prior to takeoff.

1. Phantom 2 was powered up before being put on the ground. (Same condition prior to the crash)
2. Gimbal twitching on its own before being stabilized prior to takeoff (Same condition prior to the crash)
3. IMU initialization failure. (Same condition)
4. Windy conditions (Same but bit less windy, see 00:30 coconut tree leaves swinging)

Note that during this flight, the right side pitch & roll stick was also not used during takeoff and was only used after it came back down and close to the ground towards end of video. The video is showing that despite IMU not properly initialized, the Phantom 2 was able to took off normally and was able to ascend normally. Even under windy conditions, my Phantom was able to gain altitude although wind has pushed it 70 meters away from home point.

What's also shown is the early auto land at 41% when it begins to land automatically. I switched off the remote controller to change it to FailSafe mode in 10:22, hoping for it to fly back towards me but unfortunately it crashed into the tree not responding to my command and not locking its altitude. It didn't have much damage that time.

With this video proof, i have to respectfully disagree with any of the above mentioned as the cause leading to my Phantom dropped into water. I have to say battery is the main culprit unless proven by someone else otherwise.

Its so sad to lose my Phantom 2 just days before DJI released the 3.06 fix for TBE, J-hook and other issues related to magnetic declination.

The only thing this video would appear to prove irrefutably is you are an idiot !

The video shows you are flying from surface to over 2,500ft in very close proximity to an airfield/airport. You will undoubtably be in controlled airspace at those altitudes and distance from the runway.

Maybe it is best for all concerned your craft did get destroyed when it crashed!
+1
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

Please refrain from discussing anything else that has nothing to do with my crash and anything else off topic. I know the rules and know the takeoff/landing schedules for the local airport and chose a time when there are no scheduled plane coming in or going out to do the height test. This is not USA or other countries where there are rules regulating the use of drones. And DJI's no-fly zones have not yet covered any of airports here regionally. We have the total freedom as far as that goes.

Anyone else have any other logical answers that led to the water crash other than battery issue?
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

After a quick look it seems to me like the Phantom was having a hard time trying to level out what seems to be pretty high wind. During the descent, the craft is at an angle of about 15° the whole time, and RTH then looks to have made it go down.
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

Being new to r/c a/craft I'm reading up on as many problems as I can, I'm not new to flying or the weather conditions that effect small(ultra-lights, micro-lights) a/craft, very little is said about the weather conditions that will cause grief to these r/c a/craft, things like rotors, wind shear, inversion layers, boundry layers, up drafts, down drafts & many more conditions that will literally put them into the ground, these conditions will happen anywhere, anytime, all it needs is for a down draft to be stronger than propeller thrust & down it goes, all the full throttle it has available won't help, reading books on Micro Meteorolgy that hang-glider, ultra-light pilots have to know might help to understand a few problems that the Phantoms get.
 
Re: DJI Double Defects Crash! TBE & Low Voltage Forced Landi

Being new to r/c a/craft I'm reading up on as many problems as I can, I'm not new to flying or the weather conditions that effect small(ultra-lights, micro-lights) a/craft, very little is said about the weather conditions that will cause grief to these r/c a/craft, things like rotors, wind shear, inversion layers, boundry layers, up drafts, down drafts & many more conditions that will literally put them into the ground, these conditions will happen anywhere, anytime, all it needs is for a down draft to be stronger than propeller thrust & down it goes, all the full throttle it has available won't help, reading books on Micro Meteorolgy that hang-glider, ultra-light pilots have to know might help to understand a few problems that the Phantoms get.

I think you might be on to something here. I have been flying FP and CP electric helicopters for a few years and it's absolutely true that the computer control on pretty much any quad inures you from quite a lot of "real" flying techniques.

My 450 sized CP bird is much harder to hold in a stable hover, transition to forward flight without an altitude change and also to control on windier days. I think particularly if you fly FPV with goggles, it is very tricky to actually read what the aircraft is doing - unless you switch to FPV mode on the gimbal, but even then, you are more disconnected than just flying true LOS, where you can feel and see what the wind is doing.

That being said, the lack of IMU calibration was part of the issue here, as it could not read the "flat" position of the quad correctly, so once in the air, it was trying to compensate for errors that were not there. Add to that a failing battery and the only way is down...
 

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