flying below takeoff point (home)

[dgd3]

I just moved to the side of a valley. About 100 M out is a lake that is 20-30 meters below my takeoff elevation.
I would like to fly along the lake.
If I have the left control lever fully down for maximum decent what will happen when the phantom goes below the home hight? Will the motors stop and it fall the remaining distance to the lake or will it stay controllable?
Other tips welcome.
Note: its winter and the lake is frozen and full of ice fishers.

 

[Meta4]

If I have the left control lever fully down for maximum decent what will happen when the phantom goes below the home hight? Will the motors stop and it fall the remaining distance to the lake or will it stay controllable?

What will happen is that your Phantom will descend and the altitude shown in the app will show a negative number like this:

That's it.
Left stick down will never shut off your motors in flight.
It's the normal and accepted method for descending.

 

[Advexure]

IMU knows the copter is in descent and will not shut off motors even if the altitude is below the home location altitude.

 

[dgd3]

Good to know that guys, thanks.
How does the phantom know when it's touched the ground then to shut off the motors?

 

[tcope]

How does the phantom know when it's touched the ground then to shut off the motors?

It stops going down for a few seconds.

 

[dgd3]

It stops going down for a few seconds.

As measured by the altitude sensor?

 

[tcope]

As measured by the altitude sensor?

The barometer. No matter what the altitude reading, if the Phantom stops registering a decent for a few seconds, the motors turn off.

 

[dgd3]

The barometer. No matter what the altitude reading, if the Phantom stops registering a decent for a few seconds, the motors turn off.

There must then be software to prevent falling out of the sky.


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[tcope]

There must then be software to prevent falling out of the sky.

That could mean almost anything. So, yes and no.

 

[N017RW]

The barometer. No matter what the altitude reading, if the Phantom stops registering a decent for a few seconds, the motors turn off.

It may be more than just the Baro.
While that has been the consensus around here for a while, me included, there are experiences by those on boats that any motion may be cause for prevention of non-CSC shut-off.
This easily tested by hand-catching but I have never tried it.

 

[dgd3]

I hand catch then quickly full down left stick past the click that locks the lever down to shut of the motors.
Next time I'll hold the phantom up for a while not descending and see if the motors stop on their own.


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[FlushVision]

I just moved to the side of a valley. About 100 M out is a lake that is 20-30 meters below my takeoff elevation.
I would like to fly along the lake.
If I have the left control lever fully down for maximum decent what will happen when the phantom goes below the home hight? Will the motors stop and it fall the remaining distance to the lake or will it stay controllable?
Other tips welcome.
Note: its winter and the lake is frozen and full of ice fishers.

Your aircraft will continue a controlled decent until you stopped descending. The motors will NOT stop when it goes below it's take-off height. I have often flown my P below it's take-off height with no problems.. Be mindful, though, that once your controller is, in effect, above the aircraft, there is the possibility of a decreased control and wi-fi signal strength...not a problem I think if you are only 100m away, but could be an issue over a much longer distance.

Edit to say that I noticed you mentioning having your left stick fully down. Be careful doing this. Vortex Ring State springs to mind. I would advise never to decent directly down under a fully down stick: Try to descend with some lateral movement to avoid settlement.

 

[MrMedic]

There is also a lower limit just like the upper limit. Don't remember exactly what it is, 400 ft maybe? But no way to reset it like there is the max height. Search for lower limit, its been discussed on here. But your 20-30 meters shouldn't be a problem.


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[dgd3]

never to decent directly down under a fully down stick: Try to descend with some lateral movement to avoid settlement.[/QUOTE]

Yes I've read a few posts saying that and it makes sense.
I may have experienced it once with a 45 m drop from the sky from 50 m. Was very close call. Drone was out of sight and I didn't know till I watched the footage later.

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[FlushVision]

never to decent directly down under a fully down stick: Try to descend with some lateral movement to avoid settlement.

Yes I've read a few posts saying that and it makes sense.
I may have experienced it once with a 45 m drop from the sky from 50 m. Was very close call. Drone was out of sight and I didn't know till I watched the footage later.

Sent from my iPad using PhantomPilots[/QUOTE]
Hmm. I don't actually think that is VRS. Not at the beginning your issue anyway, although it looks like it could have developed into VRS subsequent to whatever caused the initial issue. VRS (Vortex Ring state) sometimes develops when descending vertically too fast, or descending with lateral movement at about the same speed and direction of the wind. When your issue first develops you aren't descending!

I notice you have prop-guards on. I wonder if they are giving you issues? Props not catching on the guards at all, are they? Just a wild thought.