Anyone knows or did some testing, which of 3 flight modes is most economic? In case you end up a bit far away with close to empty battery, which mode to use to have best chance of coming home safely? Or let's say your subject of interest is far, so need to use less possible battery to get there and then come back, P, S or C mode? Let's put wind out of equation for now. DJI could provide us with such information as well.

Hiya,

Why not fly test on your own MM?
3 times same distance out, fly back in 3 modes and see the batt drain value.   

With no wind ; RTH mode, speed just less than P-GPS, guess by design DJI opted for longest distance | battery drain.

cheers
JJB

That was an idea, but thought better to ask first, maybe someone did it already. Don't consider myself methodical and patient enough for such experiments anyway. Feel more sort of an artistic flyer

It is not obviously the Sport mode.
But go gentle on the sticks and the battery will last longer.

Answer is very simple: energy you have to pour in drone motors to vercome aerodinamic friction grows as speed ^3. In other words, if double the speed of your drone, the energy required will be 8 times more.

Hence, the lowet the speed, the better is.

If you're flying against wind and P mode is not enough, you are forced to switch to S. But bear in mind what other pilots said: try to lower your altitude, and you'll have milder winds

emaneg Posted at 1-11 13:19
Answer is very simple: energy you have to pour in drone motors to vercome aerodinamic friction grows as speed ^3. In other words, if double the speed of your drone, the energy required will be 8 times more.

Hence, the lowet the speed, the better is.

Well not quite correct.
A rotary winged aircraft uses huge power just to hover, since it develops low pressure above it.
As it moves forward, it becomes much more efficient, since it moves into air not yet depleted.
Helicopters hovering into wind must avoid at all costs flying backwards, since they move from effective airspeed into calm air, where a huge increase in power must be urgently applied.
Eventually yes, the forward speed takes its toll, but a sweet spot occurs where max efficiency is  found.
So, while allowing  for any sink encountered , it‘s possible to calculate the best speed to fly the furthest distance.

Not sure it proves anything but the longest “range test” video I have seen was in P Mode.

Isn't it in the specs? 30mins @14kph windless condition.

Basically Fly in Cinematic (C) mode

Dr0ne_n00b Posted at 1-11 20:39
Isn't it in the specs? 30mins @14kph windless condition.

Basically Fly in Cinematic (C) mode

Sure, in C mode flight would be longest by time, but would it cover the longest distance? Maybe P mode is that sweet spot after all

Eka Posted at 1-11 23:58
Sure, in C mode flight would be longest by time, but would it cover the longest distance? Maybe P mode is that sweet spot after all

It’s not really possible to be sure, since obviously even if the most efficient speed  in still air is found, if no progress in to wind were achieved , you’ve had it. Air moves up and down  as well, lift and sink, which is used by glider pilots who speed up in sink and hang about in lift.
It’s all a trade off.

I was thinking that the potential energy from a MM at 120M height would need to be taken into account in the fly-back profile. however it is only 0.163 Watt-hours by my math.  The Flight Battery is rated at 17.28 Watt-hours.   This suggest climb or descend to the most favorable wind, then it becomes a question of the best speed-to-fly (STF).  I'm not sure if the mode matters so much, rather it may simply be best speed.  I'm not sure, but likely the C/P/S modes simply provide a higher level of max power at full stick throw, in other words the same power is consumed at a given speed.  In other words, at 8 mph, all 3 modes use the same amount of power.   

Minnesota Posted at 1-12 03:54
I was thinking that the potential energy from a MM at 120M height would need to be taken into account in the fly-back profile. however it is only 0.163 Watt-hours by my math.  The Flight Battery is rated at 17.28 Watt-hours.   This suggest climb or descend to the most favorable wind, then it becomes a question of the best speed-to-fly (STF).  I'm not sure if the mode matters so much, rather it may simply be best speed.  I'm not sure, but likely the C/P/S modes simply provide a higher level of max power at full stick throw, in other words the same power is consumed at a given speed.  In other words, at 8 mph, all 3 modes use the same amount of power.

In other words, at 8 mph, all 3 modes use the same amount of power.   

Agree, I even say that you fly the same distance in all 3 modes ... when there is no wind.

Now just to get what speed is the most economic.. or it gets too complicated and we should take winds and altitude change into account. Anyway, knowing most economic speed in straight line flight with no wind nor altitude change might be helpful to start with.

I don't think there is one speed number, because clearly if the number was, say 6 mph, and the headwind was 6 mph, it wouldn't get back.  This suggest the best speed to fly is a function of head/tail wind.   I would think a chart with this information exists.  Is there any evidence that the MM RTH algorithm estimates the winds and flies the best speed that results in the most battery left once back home?  

Eka Posted at 1-12 04:28
Now just to get what speed is the most economic.. or it gets too complicated and we should take winds and altitude change into account. Anyway, knowing most economic speed in straight line flight with no wind nor altitude change might be helpful to start with.

Agreed , the distinction that dictates the speed choice is simply the difference between air speed and ground speed.
Into a 10  mph wind, if the most efficient mini speed is 10 mph, which is probably about right, then  the point is you’ll never get home.
It’s all done for you and isn’t really flying in any meaningful sense.Power consumption from a 2 amp/battery in a 1/2 hr  flight is approx on average 4 amps or around 25 watts.
So the most efficient speed must be sacrificed and  increased to get anywhere , and a new journey time versus time left in batt versus time at the new speed calculated.
But  powerful sink and lift components are not available to you since the mini spends its time remaining at a constant height regardless.
In reality your best hope is flat out, since none of this info is available in the time you’ve got, and is constantly varying anyway.

Bright Spark Posted at 1-11 14:06
Well not quite correct.
A rotary winged aircraft uses huge power just to hover, since it develops low pressure above it.
As it moves forward, it becomes much more efficient, since it moves into air not yet depleted.

You're right. Actually we should split the energy required in two: the one for hovering and the one for moving. My comment referred to the latter whereas, as you say, the former take advantage of higher speed for increased efficiency. They are in conflict each other so not so straightforward to find an optimal point. Finally, motors may have an optimal efficiency at a given rpm, hence increasing speed could lead to lower motor efficiency.

What we can rely on without any doubt is: lowering the height of the drone to find milder wind!

first, economic must be C.. since it give u slower maneuver.. second, dont fly too far with low battery, no guarantee for coming home safely.. maybe u need superman help.. third, come near the subject if possible.. else dont fly the drone that far.. and let the subject free.. fly more and u learn a lot.. sometimes words cannot describe what u need to know.. u need to experience it by urself..