RTH - Share your safety limit

[Viriato]

Hello everyone. This is my third deone. The previous two fell into the sea, although I accepted the RTH as soon as suggested by the device. Problem.. I flyva lot over the ocean and wind may be very unpredictable.

For you experience, where is the limit? RTH, on average, will cover what distance? Or, differently put, what would the safest distance to flight away, so we may come back safe and sound?

How much do you challenge faith? Eh

With my previous Xiaomi Fimi X8 SE, up to 3,5kilometers he would return home. Exception for strong winds in the return... Lol

 

[CanadaDrone]

I always return home with around 25-30% battery remaining - I don't need to tempt fate for an extra 3 minutes or so of flying. It's also very important to keep an eye on battery voltage - there is an option to display the voltage of the lowest cell on the main screen in DJI GO4. On top of this, it's not good for the batteries to ever be run down to almost zero. You can never trust the RTH prediction because it can't account for wind, which might be completely different 1km away or 300ft in the air compared to where you're standing.

Flying over water or if there was significant wind, I would probably return home even earlier, and/or not venture out as far. I also only ever fly within VLOS (in my country and most others, it is illegal to fly outside of VLOS without a spotter), which means I am never out anywhere near 3+km anyway, so while I take lots of precautions, my overall flying risk is probably on the lower side.

 

[Viriato]

I always return home with around 25-30% battery remaining - I don't need to tempt fate for an extra 3 minutes or so of flying. It's also very important to keep an eye on battery voltage - there is an option to display the voltage of the lowest cell on the main screen in DJI GO4. On top of this, it's not good for the batteries to ever be run down to almost zero. You can never trust the RTH prediction because it can't account for wind, which might be completely different 1km away or 300ft in the air compared to where you're standing.

Flying over water or if there was significant wind, I would probably return home even earlier, and/or not venture out as far. I also only ever fly within VLOS (in my country and most others, it is illegal to fly outside of VLOS without a spotter), which means I am never out anywhere near 3+km anyway, so while I take lots of precautions, my overall flying risk is probably on the lower side.

Thanks for sharing! In my country we do not have that specific restriction, although we have others

 

[PhantomFandom]

Hello everyone. This is my third deone. The previous two fell into the sea, although I accepted the RTH as soon as suggested by the device. Problem.. I flyva lot over the ocean and wind may be very unpredictable.

For you experience, where is the limit? RTH, on average, will cover what distance? Or, differently put, what would the safest distance to flight away, so we may come back safe and sound?

How much do you challenge faith? Eh

With my previous Xiaomi Fimi X8 SE, up to 3,5kilometers he would return home. Exception for strong winds in the return... Lol

If you are depending for the low-battery RTH to bring your drone home then I think we can see why your previous drones fell into the sea. That is a last ditch safety measure and not what anyone should be using on a regular basis. For safe return of the drone always:

• Try to have the drone back on the ground and engines off by the time the battery hits 30%
• Try to fly UPWIND first. That way the trip home is always the easier and faster leg.
• Use a local wind forecast to see what the estimated winds aloft are. Winds may be calm at the surface but strong and gusty a few hundred feet up.
• Keep an eye on my battery level. Start flying back with plenty of time to land safely; especially if the return trip must be against the wind.

So to answer your questions, there is no safe limit to using the low battery RTH. At that point you have already pushed it too far and if there is any sort of wind, there is a very good chance you wont be getting your drone back.

 

[Mossiback]

...For you experience, where is the limit? RTH, on average, will cover what distance? Or, differently put, what would the safest distance to flight away, so we may come back safe and sound?...

The best answer I can think of is "It depends". It depends on wind speed, direction, air temp, battery condition, prop type, and probably more. For instance, you can fly further on a cool day than on a hot day, simply because the air is more dense when cool. Combined with other factors it may make the difference in whether it makes it back or not.

In all cases, but especially over water, you should:

• Start with fully charged batteries
• Gauge wind speed and direction at altitude then fly out against the wind if possible or allow extra time for head wind on return
• Start return before RTH kicks in or Cancel RTH and
  • change elevation to find favorable wind
  • fly shortest route to the shore first and then to you

 

[Deleted member 93449]

As others have stated more important than distance would be battery life. I realize you can't control the wind but I would only be flying over water if the wind is coming off the water towards land when I fly. That way if you use 50% battery life as a safety margin you're almost assured to get the drone back since the return home is going with the wind.

 

[old man mavic]

as you have already lost two drones i would be very aware of the return journey keep a good check on remaining battery level and come home when you see that you have 10%more for the return journey than it took to reach the distance on the app screen, to give you a good chance of making it home also reduce altitude as wind speed is usually less at lower altitude this applies more if you are returning into the wind,

 

[Greg Webb]

Welcome to the Forum from the Sunshine State of Florida!

 

[offtheback]

Hello everyone. This is my third deone. The previous two fell into the sea, although I accepted the RTH as soon as suggested by the device. Problem.. I flyva lot over the ocean and wind may be very unpredictable.

For you experience, where is the limit? RTH, on average, will cover what distance? Or, differently put, what would the safest distance to flight away, so we may come back safe and sound?

How much do you challenge faith? Eh

With my previous Xiaomi Fimi X8 SE, up to 3,5kilometers he would return home. Exception for strong winds in the return... Lol

My RTH warning comes up pretty early.I have declined itseveral times and landed with 25% or so.YMMV

 

[GadgetGuy]

For you experience, where is the limit? RTH, on average, will cover what distance? Or, differently put, what would the safest distance to flight away, so we may come back safe and sound?

I never use Smart Return Home or RTH. As a rule of thumb, I use 3 minutes per mile for the return, knowing it will actually be 2 minutes per mile at the maximum P mode speed, allowing for wind, or lingering over a subject on the return. When cutting it close, I know that I can still make it back from 3 miles with 30% remaining battery, which is about 7 minutes before 0%.

If you are losing aircraft, I suggest you practice flying after Autoland has commenced at 10% over dry land. You can stop the Autoland descent, and still ascend with full left stick, until one of the cell voltages drops below 3.0V, which will not happen until roughly 2 minutes after reaching 0% remaining battery on the M2. You can still fly over a mile after reaching 0% remaining battery. With enough altitude, you can even continue flying down to even lower than 2.5V, while the uncancellable forced descent takes place, flying back on a glide path including the forced descent. Flying well below 0% can potentially damage the battery, but far better to risk battery damage than guarantee loss of the aircraft in the ocean, if you need the battery fumes to make it back.

 

[dannybgoode]

Over water I don’t mess around and head home with plenty spare. I played battery chicken once with my Air when it was 600m offshore and it wasn’t particularly fun. Water is not somewhere to mess around over.

Otherwise it just depends on the flight - oftentimes I come home erring on the side of caution and if I’ve got a good amount of battery left I’ll do a bit more flying close by. Luckily I’m usually somewhere with enough interesting sights to see.

 

[gnirtS]

I want to be on the ground with 30% remaining unless I'm operating very close (50m or so).

They're isn't going to be a right answer to this. Every flight is going to be different regarding wind strength, direction, gusts, shear so has to be treated separately.

Generally yes try to start going into the wind although be aware winds aloft can often be in a different direction to ground level, especially around hills, valleys and so on.

Try to look for clues such as clouds moving.

If you want to image a particular area, look around for a launch point downwind if possible rather than just fly from anywhere to it.

Winds are usually stronger the higher you go (but not always) so if fighting a wind, get lower. Don't set RTH too high because if triggered it might climb high into stronger wind to fly home.

Dont rely on automated modes to save the drone. They're pretty good but have no idea of conditions outside it's immediate bubble.

The best thing I find flying in wind is the radar mode.
This display will give you an accurate wind direction where the drone currently is and a rough idea of the strength and gusts.
If it's windy I'll always hover at the altitude then use the radar to see actual wind conditions before proceeding.

 

[GadgetGuy]

The best thing I find flying in wind is the radar mode.
This display will give you an accurate wind direction where the drone currently is and a rough idea of the strength and gusts.
If it's windy I'll always hover at the altitude then use the radar to see actual wind conditions before proceeding.

I presume you mean you are looking at the radar for the tilting of the aircraft to maintain the hover as an indication of wind speed?

 

[gnirtS]

The roll and pitch show how much its leaning and in what direction. So the amount if a guide to strength, the amount it changes is a hint at gusts.
By rotating the drone to level the roll you can then work out exactly which way the wind is coming from. (ie no roll, its directly in front or behind, pitch zero then wind is coming off beam etc).

Only takes a few seconds of hover to get an idea of actual conditions.
If you dont have a smart controller you can use RPMs to see how hard its working too.

 

[dannybgoode]

Another good indication of wind speed and direction is the speed the drone is flying.

If it is flying slower than usually then it is likely flying into a head wind and if it’s faster than usual a tail wind. It’s a bit rough and ready but helps form an overall view as to the conditions.

 

[globetrotterdrone]

Don't understimate the wind ... you won't be so lucky or so crazy, will you?

Besides that, my general rule of thumb is land with 25 % hence avoiding the loud alarm.
I stay in VLOS, so that means I seldomly go any further than 300 m, so that's pretty close and have served me well.
Although your drone can go where you may never get but carefully choose your starting location. If by any means possible, stay close to the object you like to see ... it's simply safer for all.

 

[GadgetGuy]

Another good indication of wind speed and direction is the speed the drone is flying.

If it is flying slower than usually then it is likely flying into a head wind and if it’s faster than usual a tail wind. It’s a bit rough and ready but helps form an overall view as to the conditions.

That's what I use, too. I generally fly full throttle in P mode, which is 31mph on the M2. If it slows down, take heed! I also generally take off into the wind, and return home downwind.

 

[dannybgoode]

That's what I use, too. I generally fly full throttle in P mode, which is 31mph on the M2. If it slows down, take heed! I also generally take off into the wind, and return home downwind.

I try and do that but sometimes it’s not possible so I factor that in and head back early - can always send get up for a second flight.

Also occasionally the wind direction is different at altitude. Rare but it’s worth keeping an eye on all indicators accordingly .

 

[GadgetGuy]

I try and do that but sometimes it’s not possible so I factor that in and head back early - can always send get up for a second flight.

Also occasionally the wind direction is different at altitude. Rare but it’s worth keeping an eye on all indicators accordingly .

Indeed. I'm usually within 50-100 feet above ground level, so hugging the terrain minimizes the wind, and I mostly fly within an hour of sunset, when the wind also starts to die down. Flights with no wind at all definitely add to the flight time, as the motors don't have to work so hard. With over 1,000 flights under my belt, experience helps! Every flight that makes it all the way back to the launch point is a good one!

 

[simonr23]

I like to push the limits- to a point.

I use my local weather wind report and do some simple maths around that.

mid dead calm, I’ll fly until about 50% battery remains. Means I’ll get back with about 0-1% battery remaining. For my drone/battery (x3) this equals about 9-9.7 kms each way.

if it’s 15-20kmh wind, I’ll fly into the wind until I have approx 40% remaining. This will see me land with about 5-8% battery.

If it’s 25-30kph, I just play around within a 2-3km boundary.

For reference, I’ve flown 13.7km in one direction (with a 30kph wind nearly at my back) and used 55%.
Flying back into that wind used 45%in 2kms! So had to do a ‘field landing’ and then drive to the drone to collect it.

as a normal operator, always fly into any breeze (at least as near practical) and use the inbuilt RTH warning. You’ll always make it back with a healthy/safe % of battery that way.

my flight styles aren’t going to give my battery’s the long life they should otherwise enjoy.