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Sudden Crash New Mavic 2 Pro

sar104

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I have had this exact type of crash. The barometer is not a perfect judge of height. The drone calculates height relative to take off. I don't think 12 feet is that big of a difference in my experience. I fly in the negative all the time. The video shows the vegetation immediately after the failure. I don't get the sense that the drone fell 10+ feet before we saw grass. A Phantom 2 had several inches of clearance to the props, a Mavic has almost none. You may as well have sent it back but if it was damaged, DJI won't refund it. If you got it from a retailer, you may have better luck with them.
Maybe - but the flight only lasted 60 seconds or so. I would have expected the barometric height to be good to a meter or so in that time. And note very good agreement from the vision height measurement:

height.png
 
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BudWalker

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I have had this exact type of crash. The barometer is not a perfect judge of height. The drone calculates height relative to take off. I don't think 12 feet is that big of a difference in my experience. I fly in the negative all the time. The video shows the vegetation immediately after the failure. I don't get the sense that the drone fell 10+ feet before we saw grass. A Phantom 2 had several inches of clearance to the props, a Mavic has almost none. You may as well have sent it back but if it was damaged, DJI won't refund it. If you got it from a retailer, you may have better luck with them.
This flight was only 70 secs long so the barometric pressure didn't have time to change and cause the barometer derived height to drift all that much. And, there is very good agreement between the barometric height and the ultrasonic height data.
1549220637801.png
 
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sar104

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This flight was only 70 secs long so the barometric pressure didn't have time to change and cause the barometer derived height to drift all that much. And, there is very good agreement between the barometric height and the ultrasonic height data.
View attachment 61739
Pipped you by some fraction of a moment, according to the timestamps...
 
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BudWalker

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Maybe - but the flight only lasted 60 seconds or so. I would have expected the barometric height to be good to a meter or so in that time. And note very good agreement from the vision height measurement:

View attachment 61740
We were both posting this at the same time. Another good example of great minds thinking alike.:)
 

BudWalker

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Lon Denard

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Maybe - but the flight only lasted 60 seconds or so. I would have expected the barometric height to be good to a meter or so in that time. And note very good agreement from the vision height measurement:

View attachment 61740
Hmmm... so you're saying that the drone dropped 10 feet before we saw vegetation? It looked immediate to me. However, I fully admit that you're better at this than I am. BTW why does the graph continue to go down?
 

sar104

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Superimposing, the ultrasonic infrared system was reading 3.6 m when the motor slowed.

Graph4.png
 

Lon Denard

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This flight was only 70 secs long so the barometric pressure didn't have time to change and cause the barometer derived height to drift all that much. And, there is very good agreement between the barometric height and the ultrasonic height data.
View attachment 61739
Wait, the M2P has ultrasonic sensors?
 

sar104

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Hmmm... so you're saying that the drone dropped 10 feet before we saw vegetation? It looked immediate to me. However, I fully admit that you're better at this than I am. BTW why does the graph continue to go down?
I just can't tell the height from the video. The barometric altitude going so negative is unusual - I don't know the answer to that either.
 

Lon Denard

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On the M2 they switched to infrared, but same measurement.
Same type of measurement but are they as accurate? I'm not sure. Besides, as I've mentioned several times, my drone says I'm flying in the negative all the time, sometimes relatively close to the ground. I'm wondering which sensor is alpha and which is beta? AFAICT, the infrared sensor are affected by relative temps but I'm looking into that. This is very fascinating material to say the least.
 

Lon Denard

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Superimposing, the ultrasonic infrared system was reading 3.6 m when the motor slowed.

View attachment 61741
Okay, but I'm seeing a recovery like when you cut the throttle abruptly and jam it on again (or have an obstruction). Do we have the data for the other three motors? Are they normal all the way to the ground?
 

Yhodah

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If they choose to do that I will definitely return the drone and give up on drone photography. It is clearly too high risk for my use................... I fix broken humans for a living. I do not want to create any. Unlike your return of items you broke. I did nothing wrong. I would not ask for Walmart to take back an item I broke. I purchased it with my chase platinum. They will make it right if all else fails. They fixed a new lens I broke. Great card. And btw.... I have care refresh. Activated before I turned the drone on. So it will get fixed. Life is good. I thought it might be useful to bring an unusual failure event to the light of day. And if I continue to fly it I will need to be sure I have adequate liability coverage.
 

Yhodah

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I am six feet tall and was looking up at the drone when it fell. I was going to walk very close to it for the lapse shot. The issue here is if there is a flaw, lets get it fixed.
 

Yhodah

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Hmmm... so you're saying that the drone dropped 10 feet before we saw vegetation? It looked immediate to me. However, I fully admit that you're better at this than I am. BTW why does the graph continue to go down?
And note I took the video into final cut to slow it down to frame by frame. Only a few frames in the entire event.
 

Yhodah

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This is from my surveillance video cam. Slow motion of the first crash. I feel certain it is the 08 data

 
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