In the flight class, one should pass the test of engine shut down in the safe height, do spiral drop, and then start the engine to leave the
spiral state and back to normal flight...

I am thinking if DJI can do this. That is: fly high, (CSC) shut the motor, let it fall, and then (CSC) start the motor, regain the flight status
back to normal. Myself dare not to do this. But thinking if theoretically we can do this.

The answer is .. maybe (and maybe not).
I have seen youtube of this for a Phantom 2 but not for a P3 or P4.
You would need a lot of height for the Phantom to recover .. probably well over 400 feet.
And a Phantom that you are prepared to lose.

I have wondered about that.  In reality though, I think that in a real life scenario like that you probably wouldn't realize what happened quickly enough to have time to restart.  You would have to be REALLY certain that the motors had actually shut down before doing a CSC.  It doesn't help that motor start and motor stop are the same command.

Or are they still?  I remember reading sometyhing about 1 stick and RTH button as the new shutdown command.  I always use throttle down to shut down so I have not tried that.

Let's say if CSC shut down and then re-start is not a problem. then as #2 points out, what is the ability for DJI P3/4 to regain flight status?
Like those small drones you can toss them around and they can immediately re-position. How long/How tolerant
can DJI re-position itself?

fsong00 Posted at 2016-4-21 11:48
Let's say if CSC shut down and then re-start is not a problem. then as #2 points out, what is the ab ...

The phantom will try to turn itself up the right way if it is upside down while it is running. But who knows if it will do that if it is shut down and you re-start it. No way would I want to try it out on my aircraft, the whole question comes under the category of 'who cares anyway?'

jstjohnz Posted at 2016-4-21 11:43
I have wondered about that.  In reality though, I think that in a real life scenario like that you p ...

"Or are they still?  I remember reading sometyhing about 1 stick and RTH button as the new shutdown command. "

Phantom 4 only.
No change for the earlier models

This was asked a few months ago; Bryan mentioned this had happened to himself during an inadvertent mid-air CSC and he started it up again, by the skin of his teeth...  
I think reaction time is the crucial thing here; that first second it's dropping around 10 metres; 2nd second it's dropping another 20 metres and by the third it's around 30 metres/second.  So basically in 4 seconds where it will fall 100 metres or 330 feet. That fifth second will be the deciding factor; how long does it take to start up and take off...?  

wellsi Posted at 2016-4-21 15:44
This was asked a few months ago; Bryan mentioned this had happened to himself during an inadvertent  ...

Yeah, well this little Black Duck aint interested in finding out.

wellsi Posted at 2016-4-21 13:44
This was asked a few months ago; Bryan mentioned this had happened to himself during an inadvertent  ...

I'm gonna say Brian was fibbing about being able to restart it after a CSC and land it

As long as it doesn't roll/ tip upside down you theoretically should be able to,do this.

Try it in the simulator, I've gotten it to work in the sim but t takes about 300ft or so.
In the real works I wouldn't try it, but you are free to do as you wish but I don't know the logic of why you would even want to try anyways.

Pushing the envelope. Why did they want to break the land and air speed, sound barrier?

RedHotPoker

I've tried this in the simulator a few times, from 400ft I have a 100% crash rate.

I've also noticed performing a CSC in the simulator causes the aircraft to lurch to the side and start to roll before dropping.  I believe that computer model is true in real life.  Since the aircraft isn't falling cleanly, simply restarting the motors will achieve little, there simply isn't enough time to regain stability, then fight the vertical acceleration in time before impact.

endotherm Posted at 2016-4-21 18:26
I've tried this in the simulator a few times, from 400ft I have a 100% crash rate.

I've also notice ...

There is a clip on Youtube somewhere showing a person holding a Phantom upside down with the engines running at about head height. He throws it to one side and it immediately rights itself before it touches the ground.

You are on your own doing that one.

in the simulator the craft drops about 150 m in seconds..restarting and powering the engines and regaining control happens with drop alitude at 420m and above...would it work in a real life demonstration...possibly, using the app to control restarting may be quicker than the remote stick control, getting to over 400m to try it is a challenge in itself.

I've seen a YouTube video showing success on in the simulator. I would think though that In real life, If you inadvertently execute the CSC, the reaction time alone would doom you. Keep us posted if you try it

wellsi Posted at 2016-4-21 01:44
This was asked a few months ago; Bryan mentioned this had happened to himself during an inadvertent  ...

How about the "G" stress applied to the airframe in recovering a falling P3? How many stress cracks will the P3 receive? When I win the lottery I will perform this test and fully document the experiment and post it on the forum...or....you all can make a donation to me so I can replace my P3P if it should hit the dirt first!

My son has the cheap drone. His can do easy 360 flip in the air and many other stunts. I understand DJI is used to aerial video those formal action. But sometimes if we can push it to the limit, isn't it exciting? Like "world stunt show of DJI"?

I've got DJI Care I will try it and report back what happens lol NOT!

I've done it on the simulator....

golf_sierra@lib Posted at 2016-4-21 17:34
Why would you want to put such stress to the drone hardware?

Not that I want to do this particular exercise, but that's the excitement of flying. You could apply your question to almost anything in life where the limits are pushed.  It's called experimentation.... or fun.. .

DJI-Ken Posted at 2016-4-21 02:23
Try it in the simulator, I've gotten it to work in the sim but t takes about 300ft or so.
In the rea ...

Well stated Ken

Thanks for the simulation information. I have done similar flight in the simulator. 300 ft is ok. immediately after the CSC shutdown, then follow the CSC power on. Then immediately push the gas paddle for couple of seconds until it gain the stable altitude. The key resides on the CSC power on. because if it is not on, then you think it is ok and start to push the gas paddle, you lose couple of seconds and that will kill you;

After CSC power on DJI, the green light on the body will flash couple of times. I think this is a good indication of the power on. Then should immediately push the gas paddle. I think someone standby use a binocular for monitoring is needed. And a lot of simulation practice before stunt. For the safety height should be over 300ft as high as possible if regulation allows.

fsong00 Posted at 2016-4-22 09:54
Thanks for the simulation information. I have done similar flight in the simulator. 300 ft is ok. im ...

Again, I'm not understanding the purpose to intentionally preform a CSC high up just to see if you can do it and recover.

Why in the world can't DJI program the standard CSC to be deactivated when the aircraft is over 30 feet?  That is such an easy thing to do.  If the aircraft is stuck in a tree or something, then a more complicated procedure can be devised to shut down, something that is not likely to be done accidentally.  Am I missing something?

fsong00 Posted at 2016-4-21 20:38
My son has the cheap drone. His can do easy 360 flip in the air and many other stunts. I understand  ...

yea, well those drones dont have the aerodynamics of a greased rock that the p3 has, lol