Report Your Over Water Failure

[the.ronin]

Not at all? That's remarkable.

I'm not sure I subscribe to that concept ... huge floats will effect flight both in terms of dynamics and longevity. With the slightest wind you should feel the effect. This added drag along with the added weight will reduce flight time.

I never really bought into the floats since in addition to the effect on aerodynamics and flight time, drones can very well crash upside down into the water.

 

[Meta4]

I'm not sure I subscribe to that concept ... huge floats will effect flight both in terms of dynamics and longevity. With the slightest wind you should feel the effect. This added drag along with the added weight will reduce flight time.
I never really bought into the floats since in addition to the effect on aerodynamics and flight time, drones can very well crash upside down into the water.

Exactly.
The additional wind resistance of floats and their added weight will reduce the drone's speed and flight time as well as ability to deal with wind.
Floats that have no effect on flight characteristics would be truly remarkable.
It's ironic that the floats could actually contribute to the loss of a drone rather than enhancing flight safety.

 

[tcope]

I'm curious about this. I thought S mode disabled all sensors, so what could have caused it to actually flip and lose control?

Disables collision sensors. Most likely Mavic hit something.

 

[kaitokid535]

I'm curious about this. I thought S mode disabled all sensors, so what could have caused it to actually flip and lose control?

My thought about this is that a sudden strong wind caused the drone to flip.

 

[Lon Denard]

My thought about this is that a sudden strong wind caused the drone to flip.

Anything is possible but I've flown a lot of drones for a lot of years and I've never even heard of this one before. I'd be interested in the logs as well.

 

[kaitokid535]

Disables collision sensors. Most likely Mavic hit something.

No, it is in the open sea and it crashed few meters infront of me so I can confirm it didn't hit anything.

 

[kaitokid535]

Anything is possible but I've flown a lot of drones for a lot of years and I've never even heard of this one before. I'd be interested in the logs as well.

Regarding the flight log, I cannot retrieve the txt file anymore but only the .dat file

 

[sar104]

Regarding the flight log, I cannot retrieve the txt file anymore but only the .dat file

As I mentioned previously - that's not the correct file - it's just a power up, not a flight.

 

[Thomas B]

Some great info and stories here. Even living in AZ I worry about water. Also like more ground clearance for my drone, tall grass, rocky ground, etc. Invested in 2 things:

pricey, but cheaper than a drone or the DJICare fee.
And just in case, since my DJICare demands the return of the hulk...

I have the setup on my MPP now. Only use the getterback if I’m over deep or swift running water... but nothing is 100%.

 

[drekko]

Hi
I am wondering about this to, but can this be handy to turn off the downward sensors for descending down hills?

The other day my friend and I went to some mountain bike trails ( on a mountain ) when he took off I was very high in the air and following him going down hill

the height kept saying - 10 then would fluctuate back to 5 meters and back to negative

I am not sure if its due to the decent or I had to do a sensor calibration ( which i did later that night )

 

[Thomas B]

Altitude should give you a reading relative to take off, ie. if you fly done into a canyon it will show negative altitude. Function required to get to your RTH altitude if needed.

 

[drekko]

Altitude should give you a reading relative to take off, ie. if you fly done into a canyon it will show negative altitude. Function required to get to your RTH altitude if needed.

Is this in relation to my question?

So the negative height numbers are supposed to do that?

 

[Thomas B]

Is this in relation to my question?

So the negative height numbers are supposed to do that?

Sorry for not quoting. Was trying to point out that altitude should read relative to take off point which is zero altitude. Below that, like if it descends in a canyon, altitude should read a negative number.
Seems like there was a lot of fluctuation going on from your description.

 

[drekko]

Prob

Sorry for not quoting. Was trying to point out that altitude should read relative to take off point which is zero altitude. Below that, like if it descends in a canyon, altitude should read a negative number.
Seems like there was a lot of fluctuation going on from your description.

Probably due to requiring sensor calibration

 

[Thomas B]

Prob


Probably due to requiring sensor calibration

I agree. Since you did that your next similar flight should produce more cogent readings, right?

 

[Meta4]

I am wondering about this to, but can this be handy to turn off the downward sensors for descending down hills?
The other day my friend and I went to some mountain bike trails ( on a mountain ) when he took off I was very high in the air and following him going down hill
the height kept saying - 10 then would fluctuate back to 5 meters and back to negative
I am not sure if its due to the decent or I had to do a sensor calibration ( which i did later that night )

It sounds like you (and some answers to your post) are confused.
If you are seeing negative numbers for altitude, that is not at all related to the downward facing sensors because they will never show a negative height.
Negative altitude will be coming from the barometer, (the primary altitude sensor) and it will be because your drone is lower than it's launch point.

Your drone has two different ways of measuring height/altitude.
In this screenshot you see H (height) = 0
That is the barometer which is set to zero at the start of the flight. It will display the height above or below the home point.
You also see VPS = 0.1
The Vertical Position System sensors look down and show how high the drone is above the ground below it.
They only work to a max of 10 metres. Higher than that, this disappears from the screen.

Here's an example of negative height when the drone is flown down into a valley.
VPS has gone since the drone is still higher than 10 metres from the ground/trees.

 

[gspfunk]

The drone uses a barometer for altitude, not the downward VPS - there is no need to ever turn them off for normal P-mode flying. I fly low over water all the time with zero issues - it's no different than flying over land in that regard.

Edit: Probably depends on water surface (rough/waves vs. smooth).

In my experience with my Spark, this is not correct. I’m no pro and I don’t have much seat time with the MA yet, but my Spark constantly changed altitude when I was in Tortola. I was flying under 15’ high and the surf was 2-4’. Every time I’d go closer to the water to get a better shot of the Tarpon, it would fluctuate up and down several feet.

To the OP: depending how close you want to get, I’d turn the downward sensors off while you’re getting surf action.

 

[the.ronin]

Negative altitude will be coming from the barometer, (the primary altitude sensor) ...

I totally forgot about this. I even remember hacks we did to the original Naza to "better expose the baro for more precise pressure readings" lol. I wonder though if its the volatility in relative air pressure over water (as opposed to a more constant pressure over land due to less variations in temperature) throw the baro off and makes the Air get goofy.

Thanks for the post man very informative.

 

[CanadaDrone]

Edit: Probably depends on water surface (rough/waves vs. smooth).

In my experience with my Spark, this is not correct. I’m no pro and I don’t have much seat time with the MA yet, but my Spark constantly changed altitude when I was in Tortola. I was flying under 15’ high and the surf was 2-4’. Every time I’d go closer to the water to get a better shot of the Tarpon, it would fluctuate up and down several feet.

To the OP: depending how close you want to get, I’d turn the downward sensors off while you’re getting surf action.

The waves may have been getting close enough to your drone to trigger the bottom sensors (drone will rise to prevent an impact), but that is completely independent of how the drone keeps its altitude (barometer). The exact same thing would happen over land had you moved something under the drone unexpectedly. I would definitely not turn off the downward sensors in that instance, as a single misjudged wave might mean the end of your drone and waves are extremely unpredictable.

 

[Deleted member 94047]

It sounds like you (and some answers to your post) are confused.
If you are seeing negative numbers for altitude, that is not at all related to the downward facing sensors because they will never show a negative height.
Negative altitude will be coming from the barometer, (the primary altitude sensor) and it will be because your drone is lower than it's launch point.

Your drone has two different ways of measuring height/altitude.
In this screenshot you see H (height) = 0
That is the barometer which is set to zero at the start of the flight. It will display the height above or below the home point.
You also see VPS = 0.1
The Vertical Position System sensors look down and show how high the drone is above the ground below it.
They only work to a max of 10 metres. Higher than that, this disappears from the screen.

Here's an example of negative height when the drone is flown down into a valley.
VPS has gone since the drone is still higher than 10 metres from the ground/trees.

In this scenario (where a negative height is displayed), what will happen if an RTH is triggered and RTH is set to 30m? Am I correct if I assume that the drone will climb to the ground altitude at the home point and a further 30 meters above that before returning home?
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PS: first post and quite new to dronning and want to say thank you to everyone here. I have found this forum immensely informative but still learning.