Flying Over Water - Questions

[_Pilot]

I fly over the water from my sail boat. I set the "RC Signal Lost" to Hover. That way if something happens with Drone/RC communications it will hover until I can get the signal back and not return to home and land in the water.

 

[skyeboysteve]

I fly over the water from my sail boat. I set the "RC Signal Lost" to Hover. That way if something happens with Drone/RC communications it will hover until I can get the signal back and not return to home and land in the water.

Why not set your your home point to dynamic--so that your "homepoint" follows your tablet/phone's GPS? That way it will return to your last known position before RC connection was lost.

 

[_Pilot]

Why not set your your home point to dynamic--so that your "homepoint" follows your tablet/phone's GPS? That way it will return to your last known position before RC connection was lost.

Will it hover when it returns to the last known position or will it commence a landing (into the water) when it arrives at the dynamic position?

I like the hover option because there is just too much change while operating a drone from a boat. Hover is the safest. Allows you to go to the drone and catch when the low battery option forces a landing.

 

[skyeboysteve]

Actually, it does, but not very much.
Switching from P-GPS to P-ATTI increase the speed with about 2 m/s.

Example:
Check this video @0:19 when he switch to atti:
Just in case ..Look this video | DJI Phantom Forum

Amazing video, but he most likely had a slight tailwind from around the 5 o'clock bearing. You can tell how he's crabbed on the map after switching to ATTI.

Yes, his P3 pitches down more, but that's because in ATTI mode it's not slowing down to compensate for tail wind. In any case, the point can be made that if you do have a tail wind, the fastest way home is in ATTI mode. Unfortunately, there's a higher percentage of time regardless of direction of travel where you'll have to fight any wind present--unless it's directly behind you.

 

[skyeboysteve]

Will it hover when it returns to the last known position or will it commence a landing (into the water) when it arrives at the dynamic position?

I like the hover option because there is just too much change while operating a drone from a boat. Hover is the safest. Allows you to go to the drone and catch when the low battery option forces a landing.

Good point! That would be a nice option to have--dynamic homepoint WITH a hover option at a specified altitude above homepoint altitude.

 

[_Pilot]

Good point! That would be a nice option to have--dynamic homepoint WITH a hover option at a specified altitude above homepoint altitude.

Agreed.

 

[skyeboysteve]

Though that being said--it's more likely to return within RC range with dynamic homepoint, at which point you could cancel the landing sequence... unless of course your RC battery dies...

 

[skyeboysteve]

I keep VPS on all the time. I've flown ATTI five feet above the water with 55mph ground speed on a few occasions. The sonic altimeter seems to work just fine below 10 feet over water. Granted, I haven't flown over 10 foot ocean swells yet, but the P3 does a great job of not "flying off a cliff" either. For example, I've had it follow (automatically) the slope of my roof at a two foot alitude, then maintain it's "absolute" altitude (with a small drop of a few inches) when leaving the roof for the yard--instead of plummeting down at 500 feet per minute to 2 feet off the grass.

One thing I like to use ATTI mode for, is at the beginning of most flights: to see what the actual wind direction and velocity is at a given altitude--it's often quite different than what's shown on uavforecast, for example (as much as I love that site).

Here's the last video I did--for a friend who's trying to sell his sailboat. The opening scene is at about 15 feet above the water, moving at 50mph. I still had a bit of a cross wind component, and mixed with a crab angle to compensate for both the wind and his motion, his boat appears at one side of the screen.

 

[_Pilot]

Though that being said--it's more likely to return within RC range with dynamic homepoint, at which point you could cancel the landing sequence... unless of course your RC battery dies...

Yes, it is difficult to cover all options. I change things as my environment changes.

 

[Simonb3526]

Wow. That was moving fast. I fly over water a lot and never switch modes. If I get speeds like that in there! I always keep Vps on no issues. Nice vid.

 

[Meta4]

Yes, his P3 pitches down more, but that's because in ATTI mode it's not slowing down to compensate for tail wind.

No .. it may pitch down slightly more but no mode slows down to compensate for wind.
In GPS mode with the stick full forward and a tailwind, your Phantom goes as fast as it can. It would be ridiculous for it to slow down.
When hovering, your Phantom can hold position in the wind and it can fly straight in a cross wind but a tailwind will carry it along and boost its speed too.[/QUOTE]

 

[Meta4]

Why not set your your home point to dynamic--so that your "homepoint" follows your tablet/phone's GPS? That way it will return to your last known position before RC connection was lost.

Except the "dynamic" home isn't isn't really dynamic like it was on the P2.
It doesn't continue to update to movement of the controller.
It only resets to the current location of the controller at the time of reset.

 

[skyeboysteve]

Thanks Simon. . So far I haven't had any issues switching mode mid flight.

 

[skyeboysteve]

No .. it may pitch down slightly more but no mode slows down to compensate for wind.
In GPS mode with the stick full forward and a tailwind, your Phantom goes as fast as it can. It would be ridiculous for it to slow down.
When hovering, your Phantom can hold position in the wind and it can fly straight in a cross wind but a tailwind will carry it along and boost its speed too.

That USED to be the case, until presumably recent firmware updates--at least on my P3. I tested this last weekend, and while in GPS mode, with a 23 mph tailwind at 200 feet, I was getting only 37mph ground speed. Flipped over to ATTI, and it shot up to 60mph. But yes, back in June when I first tested this, GPS mode didn't seem to maintain a maximum ground speed like it does now.

 

[skyeboysteve]

Except the "dynamic" home isn't isn't really dynamic like it was on the P2.
It doesn't continue to update to movement of the controller.
It only resets to the current location of the controller at the time of reset.

I've used the follow me feature, with the follow me mode set to track "home point", then set "home point" to dynamic, and it followed me just fine. But perhaps the "follow me" feature was "cheating" anyway, or simply behaving like it would in the normal follow me mode?

 

[Meta4]

That USED to be the case, until presumably recent firmware updates--at least on my P3. I tested this last weekend, and while in GPS mode...

That makes no sense. I'll check myself when conditions are right.
When you are going forward, there is no setting to tell the P3 and GPS that you only want to travel at X mph. You just tell it to go forward at full speed.
If the air is still you will go at about 15 m/sec. If the air is also moving in the same direction (a tailwind) you will travel at 15 m/sec + the tailwind.
The GPS is for position holding and flying straight but it makes no effort to maintain any set speed.
If it did, you'd expect it to also speed up to manage a headwind and that doesn't happen.

 

[skyeboysteve]

There does seem to be a preset maximum "tilt" so it's only going to go so fast (airspeed) into a headwind (same as max tilt in ATTI). However, lately it seems the P3 throttles/tilts back if it has a tail wind in GPS mode to maintain a "no-wind" ground speed of about 35-37mph. It didn't use to be that way. Before the only difference between the two modes was that GPS would hold a course based on your heading, and stop when you let off the stick. Now it seems to also govern max ground speed.

 

[SOLARFLARIN]

1. Disable VPS - it gets disoriented over water
2. Check the winds direction. If going with the wind, coming back will take a significant longer time, so make sure you have enough charge with your battery.
3. Check the wind, yes again- if it is too strong - you may not be able to get it back.
4. Know how to fly in Atti mode - sometimes you will need the extra speed it provides
5. Be careful of seagulls. they are known to dive onto phantoms

What is VPS?

 

[Fast13]

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[Othan1]

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Same here. I don't disable VPS, I just fly. Does fine.