Flight time question...

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Waiting on my refurb P4 to arrive I naturally have been devouring manuals, articles etc. Of note to me is the difference in flight time expression compared to my (returned) P3A.

Flight time of P3A and P3P is expressed simply as 'approx. 23 minutes'

Flight time of P4 is expressed as 'approx. 28 minutes in ATTI mode'

While I understand the need to differentiate given Sport mode, does this mean LESS flight time than the rated value in P-Mode?

Thanks!
 

msinger

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The actual P4 average flight time is very close to the P3's average flight time. DJI is showing the max possible flight time in the P4 specs. The average max flight time is usually about 4 minutes less than their max. So, expect to get about a max of 24 minutes of flight times in good weather conditions.
 
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alokbhargava

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ATTI mode will always give you more flying time than GPS mode as in GPS mode aircraft control system keeps controlling all the motors at any time to follow a defined/ calculated path irrespective of external conditions such as wind pressure. It may thus spend higher energy to keep the location accuracy. Whereas in ATTI mode you technically control movements manually and keep judging based on actual movements and initiate corrective actions yourself. Thus GPS mode gets you better comforts at the expense of more energy consumption thus less flying time.


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I get about 24 minutes. If I hang on Lume Cubes which adds some extra weight, it drops to 13-14 minutes.
 
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alokbhargava

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What's the weight of Lume cubes added compared to drone weight? Where are you taking energy from for lume cubes to glow?


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What's the weight of Lume cubes added compared to drone weight? Where are you taking energy from for lume cubes to glow?


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290 grams for two with their Gen. I brackets that broke in half in first week (Cheap 3D printing.) of ownership. Second bracket broke later on. They claim they have beefed them up in their newest version which may put them over 300 grams for a pair with the brackets on the P4. I still am waiting on their second generation ones to show up so no info there. No exactly fast service as I am only two days UPS from them if they ship out of San Diego, CA.

Lume Cubes run on their own internal battery charged by a USB port (No charger supplied, and they take about 2 hours to charge.). Waterproof to 100 feet they claim, and they do get hot! Hot enough that turning them off by their little buttons will burn you so have to be careful there. Kelvin is around 9,800K so they do have a blueish/purple tint against their clam of 6,000K. I have some Lee Zircon LED correction filters on order to warm them up a bit in Kelvin.

Run-time at full power is about the duration of the P4 flight (~23 minutes) and they can thermally shutoff and reset if they get too hot. The prop wash seems to help with their cooling and thermal matters.

They are showing some possible smaller and maybe lighter weight model for next year on their site.
 
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Thanks for the info all. Just out of curiosity what do you use Lume Cubes for?
 

alokbhargava

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Thanks for the detailed description. I have heard a lot about them and they are getting very popular I believe. 300 gems is a substantial weight though just 14% of P4 weight. It's surmising to me that flying time goes down from 24 mins to 14 minutes. If what you observed is correct then it means that props + motor system efficiency dips drastically with increased downward load. If all what we say is true then it means P4 has not been designed to carry payloads and is just a fun drone. Drones for transportation purposes should have flat load efficiency curve in the operating range.




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Thanks for the info all. Just out of curiosity what do you use Lume Cubes for?
Supplemental close-up lighting for sunrise or sunset. Foreground needs accurate color too, hence the Kelvin matter.

P4 isn't really good a night camera, imho. You have to be quite close with the LED's off the Lume Cube and the noise and the not-so-hot high ISO of the P4 is limiting as well. For a still photo, you are looking at 3 seconds or so at about 20 feet with them at full power and ISO 400. Maybe tilt them down 15 degrees to for coverage (25 degrees was too much for me.). It may cover about 80% of the frame at that distance (Think vignetting.)

And yeah, the added weight drags the flying time down too. Makes sense though because if the P4 weighed maybe only a few ounces, it would likely fly all day.
 
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