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descends too slowly, how to change?
4464 13 2014-12-27
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kenton.green
lvl.1

United States
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hello,
my Phantom 2 with NDJ6 rises fairly quickly (a couple meters/second or so), but the descent is very sloooow, too slow. When it's pretty high, and I want to bring it down closer to earth quickly because the battery/flight time is getting low, I get very nervous because no matter how far down I pull the 'down' lever (including locking it down), it seems to drop very slow (a meter every few seconds or so). How do i speed up the descent? I understand that as I get close to the ground, I will need to slow it down, but when it's hundreds of meters up, I want it to drop quickly.
When I use the Phantom Assistant, the joysticks all read +/- 1000 on the channel monitors, and the joystick moves/locks all the way down, so it isn't a problem with the calibration or the NDJ6 remote control, that I can see. I can't find a tab for the descending limit.
Any help appreciated on figuring out how to better control my phantom 2.
Thanks,
Kenton

2014-12-27
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hcoduarte
lvl.2

Portugal
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Hi Kenton, as far as I know you don't have an option to change it. If you check the P2 specs (http://www.dji.com/product/phantom-2/spec), the max descent speed is 2m/s. Indeed the ascent speed is higher - 6 m/s.
2014-12-27
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Gerry1124
Captain

United States
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The descent speed is set for a reason, to avoid the VORTEX.   If you descend straight down to fast, you get into the disturbed air from the props and it will come down very, very fast, uncontrollable.  Try moving forward and spiraling when you have max down stick.  You will avoid most of the disturbed air and not get into the vortex.
2014-12-27
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rod
First Officer

New Zealand
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And when descending you can minimise vortex risk by applying lateral movement during the descent. It is not best practise to bring it straight down.  edit: ahh missed your post Gerry- so what you said!!
2014-12-27
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Gerry1124
Captain

United States
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rod@voxvideopro Posted at 2014-12-28 07:02
And when descending you can minimise vortex risk by applying lateral movement during the descent. It ...

The more help, the merrier.  
2014-12-27
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kenton.green
lvl.1

United States
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Thanks for the quick response, folks! I looked at the rise and fall time of my Phantom 2 a little more closely tonight. 6 m/s might be close for the ascent/rise. It doesn't seem quite like it's dropping at 2 m/s, but I guess I won't quibble, if it helps prevent a crash.
I haven't seen the vortex issue yet.
Thanks, I guess it is what it is,
Ken
2014-12-27
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lozomex
New

Canada
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kenton.green@gm Posted at 2014-12-28 11:52
Thanks for the quick response, folks! I looked at the rise and fall time of my Phantom 2 a little mo ...

Hey Ken, if you want to descend rapidly, simply setup your phantom2 in Naza and program your s1 switch to allow for manual flight.  This way you will have GPS, ATT, and Manual on S1.  For RTH simply shut off the transmitter.  Manual mode will allow you to literally dive and descend rapidly.  This mode disables Naza stabilization as well as pitch and roll limits so YOU are really flying the quad.  This requires experience but if you know how to fly a hell with only tail gyro than you are good to go.  This works well if you like to film in ATTI or GPS and then bring your rig down quickly from high altitude instead of waiting or risking battery loss…once you get closer to the ground, simply switch back into GPS or ATTI for ease of landing.   
2015-10-28
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Kengineer
lvl.3

United States
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Is there another app that will change this?
2015-11-1
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clkilljoy1
lvl.4
Flight distance : 15207 ft
United States
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Kengineer Posted at 2015-11-1 19:42
Is there another app that will change this?

You do not want to change the descent speed. Unless you want to get a new P2.  All helicopters can not push the air under them after a certain point when coming down. You loose lift. The p2 will start to wobble then come down with no control. If the wobble starts DO NOT apply more throttle. Your only hope at this point is to go left or right and try to get on solid air. Applying more throttle just pushes more dead air on top of dead air. I know it does not make sense. There are better explanations. DJI reduced the descent speed to try and avoid the vortex of death.
2015-11-2
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Kengineer
lvl.3

United States
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clkilljoy1 Posted at 2015-11-2 10:39
You do not want to change the descent speed. Unless you want to get a new P2.  All helicopters can ...

It is always nice to see responses from people who read something or believe they know everything.

http://www.copters.com/aero/settling.html

Settling under power is something that can happen. Not as much of a problem as running out of battery and falling from the sky from altitude, or shutting the bird off and hoping for a restart before impact, or even going manual and losing control, but it can happen.

Look at the link. If you have some forward direction, it is less of a problem. If you have altitude and direction even less of a problem. If you get on the throttle before impending impact, even less of a problem possibly even not a problem at all, bird gets home safe.

I  remember crewing an HH-46 at USN Test Pilot School and settling under power onto a grass strip, one strut broke thru the stub wing and everybody on the bird got slammed, but it sure beat the alternative... Just one of many lessons I learned first hand.

Just because you can descend faster doesn't mean you have to.

2015-11-2
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clkilljoy1
lvl.4
Flight distance : 15207 ft
United States
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Kengineer Posted at 2015-11-2 21:08
It is always nice to see responses from people who read something or believe they know everything. ...


Yes that is correct for a real helicopter, but NOT the P2. Angling on descent will help prevent. Coming straight down WITH a P2 and vortex ring occurs more power will not save it.  The p2 is not a HH-46 with all the available horse power needed to get it out of trouble. Your statement is correct for a HH-46 but not a P2. My response is based on experience with the P2, sorry I am not an actual pilot.  But telling an inexperienced P2 newbee to give his P2 more throttle will definitely cause it to crash. Going left to right might save it once it gets into a vortex ring state.  Do a search here or Phantom Pilots on "vortex ring" or "wobble of death" you will find plenty of posts as to why DJI decided to lower the descent speed, on this subject and causes for P2 and why DJI felt it necessary to limit the descent speed.
2015-11-3
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Kengineer
lvl.3

United States
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I was just trying to say that when considering the options.....  read this part again!  "Not as much of a problem as running out of battery and falling from the sky from altitude, or shutting the bird off and hoping for a restart before impact, or even going manual and losing control, if it came down faster when you stayed too long and are facing watching the bird crash or the options I outlined, settling under power is the lesser of any outlined evils.

I am also not a pilot, I spent many hours as a crewman, military helicopters have some of the same problems as phantoms, 2400 horsepower, but 15,000 lbs. falling fast, when you are actually settling under power, there just isn't enough stick to save you, so pucker up !

No one I know said give it more throttle, you imagined that I guess.

The sink rate is what it is. There really is some buffer and if you could use a little more decent rate at altitude some crashes may be eliminated.

If you get out of it before you are on the ground, it is a learning experience, if not, the strut exits the top of the stub wing.
2015-11-3
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DJI-Dave
Captain

United States
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Kengineer Posted at 2015-11-1 16:42
Is there another app that will change this?

I have never seen a app that will change this. Not for the P2. There are a lot of apps for the P3 especially now with the SDK program. But not as many apps for the P2. Sorry.


Dave
2015-11-3
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pb05life
lvl.2

United States
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i find moving forward and down at the same time is the fastest way to descend, or making circles
2015-11-5
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