New Phantom firmware 1.6

John Decker · Dec 28, 2015

Everyone seems to have different figures. Maybe the wind is the difference..

GadgetGuy · Dec 28, 2015

alokbhargava said:
Yes it is correct.

5 meters/sec = 11.1 miles per hour

So the (new?) RTH speed of 10 meters/sec is throttling speed to 22 mph max.
Again, I presume that is because 22 mph is the sweet spot and optimal speed to achieve maximum distance at any given remaining battery level. Anyone wish to confirm that presumption? Thoughts?

GadgetGuy · Dec 28, 2015

Chris Vedeler said:
When going out or coming back I always go full throttle. I push my P3 to the limit frequently with 2 - 3 miles out and 2 -3 miles back and significant elevation gains and losses. I don't have hard data, but my thinking is that the pull of gravity is your biggest energy drain. The quicker you get back the less energy used just being up in the air. The forward motion once up to speed is just wind resistance and the difference between 10 meters per second and 15 meters per second while significant (over 3 times the energy), it is still nothing compared to the energy to keep over 2 pounds up in the air. What is the wind speed the props must generate to overcome gravity? A lot more than overcoming air resistance moving at 15 meters per second.

One test that could be done is to let the bird hover and see how long it takes to go from 100% to 20% battery. Then run the bird around at full throttle and time that from 100% to 20%. My guess is the difference would be smaller than you think.

I wouldn't read too much into the 10 meters per second return to home. I may be that slow to increase the chances of someone or something getting out of the way if it is coming their way, or increase the chances of you regaining control before it runs into something.

Excelleny summary. Thanks for your input. I also always fly at full speed on my return, and in P-GPS, and as low as possible, to minimize the wind. I have also been told that hovering burns up battery more than flying at full speed, and the test you suggested has been performed by at least one person I know with the result being longer battery life flying full speed than hovering. Gravity is the truly the biggest energy drain. The one conflicting issue is that P-GPS is supposedly still more battery efficient than ATTI, even though ATTI results in faster speed. ATTI reduces flight time by more than the distance gained by flying at a faster speed, according to the long distance mavens. Thoughts?

GadgetGuy · Dec 28, 2015

Chris Vedeler said:
Interesting read regarding most efficient flying: Flight School 5: Power Efficiency Hover vs. Forward Flight | Quadcopter Flight School

Excellent! Thank you! According to that article, there is indeed an optimal speed that represents the sweet spot at a value below maximum speed. Flying straight and minimizing sharp banking turns also increases efficiency, after googling "helicopter transitional lift." Great stuff out there to digest on the topic!

GadgetGuy · Dec 28, 2015

Found this chart on the FAA website, taken from
https://www.faa.gov/regulations_pol...helicopter_flying_handbook/media/hfh_ch02.pdf
which points out that the Minimum drag or L/D Max value is the speed at which Total drag is minimized, and it is a specific speed which is not the maximum speed. Could DJI have determined it to be 10m/sec or 22 mph?

Meta4 · Dec 28, 2015

GadgetGuy said:
So the (new?) RTH speed of 10 meters/sec is throttling speed to 22 mph max.
Again, I presume that is because 22 mph is the sweet spot and optimal speed to achieve maximum distance at any given remaining battery level. Anyone wish to confirm that presumption? Thoughts?

GadgetGuy said:
The RTH speed is now reported to be 10m/s, which might imply that 10m/s is optimal. Any thoughts about that, or insights?

10 m/sec RTH isn't new. That's always been the RTH for the P3.
Maybe for the reason you guess and maybe not - DJI haven't shared their thoughts on that one.
But definitely something to factor in if you are ever in a potential low battery + headwind RTH situation (best avoided)

GadgetGuy said:
Excellent! Thank you! According to that article, there is indeed an optimal speed that represents the sweet spot at a value below maximum speed.

And any hypothetical sweet spot is going to vary with the speed and angle of prevailing wind your Phantom has to deal with.
So there's no simple one-size-fits-all answer.

GadgetGuy · Dec 29, 2015

Meta4 said:
10 m/sec RTH isn't new. That's always been the RTH for the P3.
Maybe for the reason you guess and maybe not - DJI haven't shared their thoughts on that one.
But definitely something to factor in if you are ever in a potential low battery + headwind RTH situation (best avoided)

And any hypothetical sweet spot is going to vary with the speed and angle of prevailing wind your Phantom has to deal with.
So there's no simple one-size-fits-all answer.

Thanks for the clarification about RTH always having been 10 m/sec. It was on the launch screen recently, so I thought maybe it was a change.
I suppose the best takeaway is that the optimal speed will likely not be full speed, but some number less than that. That seems to be consistent with a few recent flights where I have flown slower than max speed, and achieved both longer flight time and distance in the process. Not significantly more, but an extra 1,000 feet and an extra minute longer flight time than any previous flight, and it wasn't due to a lack of any wind. Better video at slightly slower speeds, too!

Gennaro · Jan 3, 2016

TC Malker said:
Upgrade at your own risk. Only downgradable to 1.5.3.

Hi, i have installed on my PH3pro the 1.5 firmware ...but i ask to you....if it possible to return at old firmware...1.3....is possible....if yes how i can downgrade the app on ios?

Gennaro · Jan 3, 2016

TC Malker said:
Where have you been? Don't you know by now that DJI now restrict downgrade firmware one version only? You can NEVER go back two. No, your way won't work.

Cold winter, hot summer.

Hi, i have installed on my PH3pro the 1.5 firmware ...but i ask to you....if it possible to return at old firmware...1.3....is possible....if yes how i can downgrade the app on ios?

John Decker · Jan 3, 2016

Gennaro said:
Hi, i have installed on my PH3pro the 1.5 firmware ...but i ask to you....if it possible to return at old firmware...1.3....is possible....if yes how i can downgrade the app on ios?

It's not that DJI restrict you to going back only one version per se, but with the 1.05.0030 release came the restriction of only going back to 1.4 DJI Forum|Phantom 3: Firmware v1.5.0030 Install Guide and Support Thread

John Locke · Jan 3, 2016

tcope said:
FlynFrank states that he spoke to DJI about this and was told that the reduction only takes place when the batteries are cold. Not an over-all reduction.

happydays said:
I flew today on all the latest software. Two batteries, 10,000 metres. Absolutely no issues. 5 m/s ascent, 3 m/s descent. As before. Absolutely no change over prior firmware. 39.7 mph (17.75 MPs) according to healthy drones. This was in Ireland at about 12/13 degrees Celsius.

I can't see why everyone is suspicious.

I use to get 11mph vertical ascent at full throttle, but not any more. My 1.6 firmware took me down to 7mph vertical ascent at max throttle in sunny 60F weather, whereas a friend who was with me at the same time with 1.4 firmware still loaded on his Phantom 3P got 11mph vertical ascent on full throttle. Seems like an overall reduction to me. Both birds had the old motors, both were bought in July. There's definitely a difference. Is everyone else getting 11mph or 7mph? (5m/sec or 4m/sec). The top horizontal speed is still above 30mph, but it just takes a little longer to get there. Next time I'm out with my friend with 1.4 we'll have a horizontal acceleration drag race, Hah!

FlyNFrank, what's your vertical ascent top speed? Will it maintain 11mph for a couple hundred feet using 1.6?