Sport mode or regular when low battery

[bkushner]

Has anyone explored a situation where say you have 25% battery left you're doing 30 miles an hour towards home you're not sure if you're going to make it however if you kicked in the speed mode you're going to go faster but I assume you use more battery, in that situation which would be better to do or lesser of two evils? Thoughts?


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[Meta4]

Sport mode gets you less miles per gallon.
If it's critical to get the most miles, sport mode is not the right choice.

 

[Snowwolf]

And it can suddenly kick in th 10 second auto landing, I have had that twice with my p4p so keep eyes peeled on the screen so you can quickly cancel the landing

 

[bkushner]

Sport mode gets you less miles per gallon.
If it's critical to get the most miles, sport mode is not the right choice.

I was just curious as to what to do in that scenario.

 

[Meta4]

I was just curious as to what to do in that scenario.

The best thing to do is not get in that situation ...
But if you do, previous models got the best fuel economy at just a fraction below max speed in P-GPS mode.
It is likely that the P4pro is the same.
You can get an extra 6 mph or so if you turn off obstacle avoidance.
If you are up high and have a nasty headwind to fight, get down lower where the wind isn't as strong.

 

[ServiceCall]

And it can suddenly kick in th 10 second auto landing, I have had that twice with my p4p so keep eyes peeled on the screen so you can quickly cancel the landing

How do you cancel the auto land?


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[smiller]

Has anyone explored a situation where say you have 25% battery left you're doing 30 miles an hour towards home you're not sure if you're going to make it however if you kicked in the speed mode you're going to go faster but I assume you use more battery, in that situation which would be better to do or lesser of two evils? Thoughts?

Sounds like driving faster so you can get to a gas station before you run out gas

 

[azgeek]

How do you cancel the auto land?

IIRC, there is a red icon that is displayed during auto landing. Pressing that icon brings up a dialog box asking you to confirm cancellation. Once cancelled, the bird should hover in place. I've done this a few times and it worked just as advertised

 

[ServiceCall]

IIRC, there is a red icon that is displayed during auto landing. Pressing that icon brings up a dialog box asking you to confirm cancellation. Once cancelled, the bird should hover in place. I've done this a few times and it worked just as advertised

Thanks


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[Jshank]

I have very little experience with this. But wouldn't the drone get the best "gas mileage" in atti mode? Doesn't that turn off most of the gps?


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[F-4Driver]

If you're at a high enough altitude begin your slow descent to your landing spot but keep moving! A 12-13 mph level airspeed, not ground speed, should give you the most efficient flight home and if you're descending all the way, that helps, so you could allow another 1-2 mph more airspeed. If you are fighting a wind home, well that was poor flight planning, so always have a plan B you can go to and constantly evaluate your options as you vector home. I try to plan my flights as if I were over water and landing anywhere but home is not an option, so I plan them so I consume about 30-40% battery to reach my objective, leaving 60-70% to get home in case there's a problem along the way vs using up 50% and not having another 50% to make it home! Those that Scuba dive may be familiar with the rule of thirds see where it can apply here. After repeating the same course several times, then I gain a little confidence to push the numbers a little more.

As long as you're moving, it shouldn't matter if you're in ATTI or GPS mode, but if you're hovering in a strong wind, then yes, GPS mode will consume more power as it fights to hold position in space. If you're on flat ground then get low where the surface winds are usually less than say, 100+ feet up.

 

[Jshank]

If you're at a high enough altitude begin your slow descent to your landing spot but keep moving! A 12-13 mph airspeed, not groundspeed, should give you the most efficient flight home and if you're descending all the way, that helps, too. If you are fighting a wind home, well that was poor flight planning, so always have a plan B you can go to and constantly evaluate your options as you vector home. Those that Scuba dive may be familiar with the rule of thirds, also applies here. I try to plan my flights as if I were over water and landing anywhere but home is not an option, so I plan them so I consume about 30-40% battery to reach my objective, leaving 60-70% to get home in case there's a problem along the way. After repeating the same course several times, then I gain a little confidence to push it a little more.

As long as you're moving, it shouldn't matter if you're in ATTI or GPS mode, but if you're hovering in a strong wind, then yes, GPS mode will consume more power as it fights to hold position in space. If you're on flat ground then get low where the surface winds are usually less than say, 100+ feet up.

Great explanation, that makes a lot of sense. thank you.


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[Meta4]

I have very little experience with this. But wouldn't the drone get the best "gas mileage" in atti mode? Doesn't that turn off most of the gps?

GPS doesn't use enough power to male any measurable difference.

A 12-13 mph level airspeed, not ground speed, should give you the most efficient flight home.

That's much too slow. Perhaps you mean metres/sec?
Some good testing here a little while back showed around 13 m/s (in still air) to be the most economical.
Descending while coming home is a good idea to save doing that after you get home.

 

[F-4Driver]

Our mileages may vary, as they say... It's a good idea to add these emergency/most efficient flight home regimes to our list of "basic building blocks" so when the time comes, you will not be in panic mode.....you'll know what each of your drones (like airplanes and helicopters) can do most efficiently.

 

[azgeek]

It's a good idea to add these emergency/most efficient flight home regimes to our list of "basic building blocks" so when the time comes, you will not be in panic mode.....

Excellent advice.

 

[bkushner]

That's exactly why I brought it up to begin with it didn't happen to me I was just curious so I know what to do if it happened

 

[neven]

Someone did the math and I did some real life tests. Both resulted in 13.5m/s (30mph) being the speed that will get you furthest in no wind conditions. The most interesting find while testing was that flat out is more efficient then RTH speed of 10m/s.
On topic of descending while returning home on fumes I would suggest not to. It will start to auto descend at 10% anyway so having some altitude buffer is nice.


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[bkushner]

Good information Hope someone test a lower speed like 20. Which is more efficient. 20 in regular or 25 in speed

 

[Meta4]

Good information Hope someone test a lower speed like 20. Which is more efficient. 20 in regular or 25 in speed

The testing has been done by Neven (above)
He set up a very clever experiment to test the relationship between speed and efficiency.
It's well worth reading for the details: Best fuel efficiency tests
Lower speeds aren't as efficient because the Phantom has to use a lot of energy just to fight gravity and maintain altitude.
For distance/battery efficiency you need to use the sweet spot where you are covering the most distance without revving the motors too hard and that sweet spot was shown to be around 13 metres/sec (29 mph)

 

[Barking Deer]

I don't think 25% is an emergency, but if you don't think you can make it home then just land the thing and take a hike. A little walking is better than watching it drop like a box of rocks.