Lost Mavic Mini - Lost over water

[AlexBeyd]

Well ... that's not so strange after all. If you stood there where the HP was recorded, which looks to be elevated from the river surface & flew under that bridge ... you effectively blocked the RC/AC connection both by flying low & under a steel reinforced concrete bridge. The AC was far outside unobstructed line of sight & that most probably cut the connection ... & if you was under the bridge when that happened, the failsafe RTH would have sent your AC straight up under the bridge, hitting it from underneath ... & game over.

View attachment 122370


As all log recording stops to your mobile device when the connection is lost nothing will give a hint about what happened there after ... if the AC isn't recovered. If the AC can be saved DJI can investigate the onboard log & possibly there spot the reason for the incident. An AC that looses the connection & don't suffer from any faults before the disconnect & isn't recovered will make DJI say ... reason unknown, which in most cases means no replacement or warranty.



That's usually not the way DJI works ... they read the logs & make their decision out from there.



Speculations will not lead anywhere & will not change DJI's decision ... what's possible to read out from logs matter.

If you want somebody here at the forum to look your logs over I recommend you to start up your own thread to keep all incidents neatly separated & there attach the logs from this flight.

Yes, the landing is somewhat elevated, but c'mon 85 meter (280') - this is less than some car remote starters!... I doubt it should happen with a drone of $600 price tag. I will see what DJI say.

 

[Meta4]

Yes, the landing is somewhat elevated, but c'mon 85 meter (280') - this is less than some car remote starters!... I doubt it should happen with a drone of $600 price tag. I will see what DJI say.

The distance is irrelevant if there is a big chunk of dirt, concrete etc blocking the signal path.
That simple physics.
And if you lose signal, while under an overhead obstacle like a tree or a bridge, what do you think happens?
Look at Failsafe RTH in the manual to find out.

 

[Camino Ken]

The speed that gives the longest flight time is quite different from the speed that will give the longest distance.
The longest distance is at a speed close to Max Speed in P-GPS mode.

Where did you find or how did you determine this conclusion?

 

[Meta4]

Where did you find or how did you determine this conclusion?

People have been running tests ever since DJI made drones.

 

[Camino Ken]

People have been running tests ever since DJI made drones.

Thanks, so an empirical result. My engineering mind was just curious if someone had calculated or determined it from flight and efficiency characteristics.

 

[Meta4]

Thanks, so an empirical result. My engineering mind was just curious if someone had calculated or determined it from flight and efficiency characteristics.

Too slow and you use too much battery just holding the drone up.
Too fast (sport mode) and the motors have to rev higher because less thrust is directed to hold the drone up.
The sweet spot is somewhere in between.

Here's one of the old tests I've seen:

Best fuel efficiency tests

I've created non-scientific practical test for battery efficiency. Made 4 laps, 2,5km each and three missions with different cruising speed (10,13,15m/s). Everything else was as identical as possible. Those are my first results. HealthyDrones.com - Innovative flight data analysis that matters -...

www.phantompilots.com

It comes out quite similar for all models.
The best speed for distance/battery is close to max speed in normal mode.
The variables make any minor difference not worth worrying about.