Height stability over water

[GeraldV]

M2P arrived Friday and had the chance to take it fopr a few test flights over the weekend. Today was hovering over a river about 5m above the surface and i noticed that the drone fluctuated its height often dropping down by around half a meter, was a little unerving given i was pretty low anyway. The weather was very calm and the river had little movement either. (I had all the obstacle avoidance turned on and not in beginner mode). Is this to be expected or are there any sesnors that should be turned off when flying over water?

Loving the drone! Stunning photos, quiet and flawless connectivity - a big step up from the air.

Appreciate any help.

 

[Turn11]

the drone fluctuated its height often dropping down by around half a meter, was a little unerving

Flying that close to water can be a problem or even cause loss of AC.
This is from page 22 of the Mavic 2 User Guide. If you haven't read it front to back I strongly suggest reading it, perhaps more than once.

 

[parkgt]

Over a still pond mine flies fine at 10 feet.

 

[GeraldV]

There was a little movement in the water, but nothing like a "wave". Not noticed this issue with the Mavic Air before.

As for flying over water what is the recommended minimum height?

 

[neggy]

Mavic and water do not mix.

They do not like reflective surfaces, the downward sensors have trouble with reflections.

If you want to keep your drone, stay high above any body of water at least 30 feet

 

[Elton Hammonds]

I calmed my nerves about losing my M2P in my lake and being unable to then file a claim by using the flotation skids from iRepairMD.

 

[GeraldV]

Mavic and water do not mix.

They do not like reflective surfaces, the downward sensors have trouble with reflections.

If you want to keep your drone, stay high above any body of water at least 30 feet

Great advice. Many thanks!

 

[GeraldV]

I calmed my nerves about losing my M2P in my lake and being unable to then file a claim by using the flotation skids from iRepairMD.

These look a great option! As I live on the coast a lot of my flights are over water and I like to get low to take shots of the surfers at the local beaches.

How have you found them to handle? Any significant loss of maneuverability or battery life impacts? Like you my main concern is losing the craft beneath the surface and being unable to recover it.

 

[Elton Hammonds]

These look a great option! As I live on the coast a lot of my flights are over water and I like to get low to take shots of the surfers at the local beaches.

How have you found them to handle? Any significant loss of maneuverability or battery life impacts? Like you my main concern is losing the craft beneath the surface and being unable to recover it.

The foam pontoons do affect the aerodynamics, but the flight control systems in the M2P handle them well. I've flown in constant 12-14 mph winds and it wiggles around a little, but the camera gimbal seems to stabilize the video well.

The weight, like any weight, will reduce flight time, but I carry 4 batteries, so I don't see it as a problem for me.

 

[GeraldV]

The foam pontoons do affect the aerodynamics, but the flight control systems in the M2P handle them well. I've flown in constant 12-14 mph winds and it wiggles around a little, but the camera gimbal seems to stabilize the video well.

The weight, like any weight, will reduce flight time, but I carry 4 batteries, so I don't see it as a problem for me.

Good to hear. Have fired them an email asking if they can ship to Europe. Worth it for the piece of mind.

 

[Rastus]

Is there a way to disable the downward vision system when flying over water? I did a search in the manual and did not see an answer.
Thanks

Flying that close to water can be a problem or even cause loss of AC.
This is from page 22 of the Mavic 2 User Guide. If you haven't read it front to back I strongly suggest reading it, perhaps more than once.

View attachment 48352

 

[LapetusOne]

Is there a way to disable the downward vision system when flying over water? I did a search in the manual and did not see an answer.
Thanks

There should be. On the inspire 1 pro I would turn it off when needing to hover closely over water.

 

[tcope]

The downward sensors _DO NOT_ control altitude unless in Active Track or Terrain mode. So turning on/off the downward sensors over water will have no affect and they did not change the altitude of the Mavic in this case... as confirmed in the manual as well.

 

[tcope]

Is there a way to disable the downward vision system when flying over water? I did a search in the manual and did not see an answer.
Thanks

There is a setting in the DJI Go app to turn on/off the downward sensors.

 

[tcope]

Flying that close to water can be a problem or even cause loss of AC.
This is from page 22 of the Mavic 2 User Guide. If you haven't read it front to back I strongly suggest reading it, perhaps more than once.

As I mentioned in a prior post, the downward sensors do not control/adjust altitude unless in Active Track or Terrain mode. As you pointed out, the manual confirms this. The downward sensors only control altitude when in those two modes and they are also used when landing (about 1' off the ground). it is only in _those_ situations where the downward sensors are used. So the downward sensors should not cause any issues when flying over water. This is a throwback to the P2 and P3 when they were used to maintain altitude up to 20' or so.

 

[MaxHam]

As I mentioned in a prior post, the downward sensors do not control/adjust altitude unless in Active Track or Terrain mode. As you pointed out, the manual confirms this. The downward sensors only control altitude when in those two modes and they are also used when landing (about 1' off the ground). it is only in _those_ situations where the downward sensors are used. So the downward sensors should not cause any issues when flying over water. This is a throwback to the P2 and P3 when they were used to maintain altitude up to 20' or so.

The downward sensors are pointed out by DJI particularly for flying if there is no GPS.
So they are deactivated if there is a GPS fix unless being in those two intelligent flight modes??

 

[tcope]

The downward sensors are pointed out by DJI particularly for flying if there is no GPS.
So they are deactivated if there is a GPS fix unless being in those two intelligent flight modes??

I'm not sure this is what DJI states. DJI _does_ state (as confirmed by the manual.. and I've confirmed it as well) as I mentioned above... downward sensors do not adjust altitude unless the Mavic is in Active Track or Terrain mode.

The are not deactivated... they just do not adjust altitude.

 

[CanadaDrone]

I understand the possible risks involved, but I have flown many times only about 2-3 feet above water (still and moving) and have never even seen the slightest height fluctuation - this is with a Mavic Air but I assume the same technology is used for the sensors. As far as I know the Mavics use GPS for normal height data outside of some specific flight modes so it shouldn't matter much what you're flying over as long as you follow best practice for GPS (12 satellites or more before take off).

I have flown over rivers, streams, lakes, waterfalls, etc. many times barely above the water. With good GPS I have yet to witness a height fluctuation.

I also think there would be WAY more crash reports if flying too low over water was likely to cause a sudden, significant altitude drop but you don't really hear about that.

 

[MaxHam]

I'm not sure this is what DJI states. DJI _does_ state (as confirmed by the manual.. and I've confirmed it as well) as I mentioned above... downward sensors do not adjust altitude unless the Mavic is in Active Track or Terrain mode.

The are not deactivated... they just do not adjust altitude.

DJI says it in the manual. Note the AND below. But we all know that DJI manuals are sometimes vague/inaccurate.
I haven't tested with the M2P having these sensors switched on since over water I always switch downward sensors off due to my experience with the P4P:
It tends to get sucked down over water with its ultrasonic sensors being on.

 

[MaxHam]

Great advice. Many thanks!

Don't let people scare you.
DJI drones are perfectly over water. Read the post of 'CanadaDrone' above.
I have done more than 1200km with my P4P and 85km with the M2P by now, approx. 25% over water.
And sometimes as low as 1ft. The latter one only over calm water and at low speed obviously.

The following I recorded at approx. 6ft above the water line with the MP2.
Main Rule for me: NEVER have downward vision sensors on being low over water.

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