My  Dji Phantom 2 vision + will drop out the sky... Whenevr I try to go down my Dji will drop and not stop and crash on the floor. It drops like a stone from the sky and can't be recoverd even when i put on full throttle upwards. Honestly my Dji has been trouble from first getting it and wouldn't recomend.
Hope somebody could help me fix this. Thanks Wayne.


P.S. My gimbal is bent slightly to the left don't know why hopefully I can get some answers to that too...

You most probably caused those crashes. It's a VRS (vortex ring state) crash also refered to  prop wash. When decending full throttle into it's own turbulance, the props loose lift and the copter will plundge to the ground. Full throttle up will only make things a lot worse, it will never help. So never decend tull throttle down, even at the limited 1m/s it's enough to get a VRS problem, decend sideways or in a spiral.

This is not just a DJI problem, it happens with all multi- or single rotors like helicopters too.

Prop guards installed?
What altitude are you taking off from?

Markus I'm not even descending quick literally I'm going as slow as I can and still the problem continues. And PanamonCreel, yeah I have props guards installed and I'm taking off from the ground

waynerichardson Posted at 2015-2-9 02:34
Markus I'm not even descending quick literally I'm going as slow as I can and still the problem cont ...

no I mean what altitude above sea level is your ground level at?

waynerichardson Posted at 2015-2-9 02:34
Markus I'm not even descending quick literally I'm going as slow as I can and still the problem cont ...

PanamonCreel  meant if you're like taking off or flying on high terrain like at 1500 meters. The air would be thinner, this caould also cause your issue. Prop guards also cause your bird to become more vulnerable to VRS (even if some of you won't agree )

Oh sorry from sea level my ground level is 38m so not high at all and when it drops I'm usually another 50m - 100m I wouldn't take it any higher as of now, but what I'm curious about is why at first this never happened no matter what speed I came down...

It's a game of luck, it doesn't happen every time.  Also, the heavier your quad is, the more likely you'll get that problem. Check your phantom thoroughly for any damages like bent, scrached or chipped props, battery health, just to make sure it wasn'tperhaps  a loss of power.

Could you tell if the lights were still on and the moters still running?

Yeah all motors where fine and battery level full, but thanks anyway I'll just have to take descending extra careful. By the way you wouldn't happen to know why my Gimbal is slightly bent?

Take the prop guards off if you're confident enough, you'll gain stability ( despite what some others say )
Secondly which V+ model?  V3 or prior?  if prior try changing to the DJI 9450 Props which add a bit of lift.

waynerichardson Posted at 2015-2-9 02:45
Oh sorry from sea level my ground level is 38m so not high at all and when it drops I'm usually anot ...

Oh and when it dropped did it just fall straight down or did it wobble while the motors are running ?

waynerichardson Posted at 2015-2-9 02:58
Yeah all motors where fine and battery level full, but thanks anyway I'll just have to take descendi ...

LOL well the bent would likely have come from the crashes you had , you can bent it back but be gentle and pay close attention on not damaging the famous ribbon cable.

despite whether you believe others or cant resist the urge to point out your disagreements while making your points...

as the wind speed approaches zero the stability gain you get without them also approaches zero.  ive flown with both on and off in both zero wind and high wind and the difference is dramatically and very proportionally linked to wind speed.  my suggestion is that if you can land 99% of the time without a tipover and/or are not flying around obstacles of any kind, then sure, take them off, since you usually have some wind you'll probably notice a difference.  

Thanks for the advice gnixon2015. Oh and on decent it wobbled...

waynerichardson Posted at 2015-2-9 03:45
Thanks for the advice gnixon2015. Oh and on decent it wobbled...

Try not to descend straight down, always move laterally when you come down.  That will also reduce your chances of inducing the vortex.

waynerichardson Posted at 2015-2-9 03:45
Thanks for the advice gnixon2015. Oh and on decent it wobbled...

Yeah that wobble is caused by what they call VRS .  Phantoms are prone to this due the small frame with the props running almost tip to tip and the added turbulence the prop guards cause amplify the issue.

You might try an IMU calibration. It might help, and it won't hurt to try it

I can only support what has already been said.  You appear to have all normal flight controls until descending. It does sound as though you are suffering from vortex ring state caused by the vertical descent.  

Prop guards or not, never make a vertical descent , always come in on 2 axes, as if it were a fixed wing aircraft and you will have no problems.
Cheers!
Rod

and i want to be clear, while i do often voice objection to people using the phrase 'prop guards CAUSE vrs', they do act like wings in higher wind situations.  however, yesterday, i was flying in 15mph winds WITHOUT guards and a straight down descent did begin to induce vrs.  last week, WITH them in 4mph winds, a straight down descent did NOT begin to induce it.  i think it is a combination of many factors (air density some refer to as relative sea level altitude, humidity, wind speed, descent profile, prop guards, etc).  none of these alone directly cause vrs but all of them add a bit of potential.  i pay careful attention to each of those factors (and as others stated, i ALWAYS descend with lateral or horizontal movement combined).  but ill add on that note, that i seem to wobble less when moving laterally descending INTO the wind than when moving laterally WITH the wind but that may just be my perception not something provable from an aerospace engineering standpoint.

Thanks for the tips. However incase I do suffer vortex ring state when descending whats the best thing for me to do? Just leave the controls, or try going in a different direction e.g. forwards or left...

waynerichardson Posted at 2015-2-10 00:42
Thanks for the tips. However incase I do suffer vortex ring state when descending whats the best thi ...

Keep throttle at center ( hard to do since the automatic reaction is to increase throttle when you see it fall )  and give stick to one side so that it can " slide "  out of the vortex.

waynerichardson Posted at 2015-2-10 00:42
Thanks for the tips. However incase I do suffer vortex ring state when descending whats the best thi ...

yes, work on the lateral axes. Do not try to lift as this may just make a VRS worse.

Rod

Thanks PanamonCreel and Rod.

Could you use failsafe mode to descend slowly (0.6m/s) and automatically? As I understand it, failsafe descends slower than normal and it seemed to when I used it.

As an aside, when I fly (only 6 flights thus far) I find I use failsafe frequently as a convenience and also to train myself to trust it. I use Naza mode so I can do this with a switch instead of turning off the entire controller (which seems like a bad idea). My switches are clearly labeled to make using the Naza features a lot easier for a newbie.