High Speed Unstable, Uncontrolled Descents

[WessexWyvern]

Hi - I flew my Phantom for the first time today and just did some general handling to get a feel for how a quad flies. As I got a little more confident I started doing some maneuvers at high speed including descending with the left and right sticks in the fully down position. This made the Phantom very unstable although on the two times I tried it I managed to recover it (with the help of the Naza) without too much drama although it did loose a lot of altitude very quickly in an uncontrolled manner.

Is this normal behavior for a Phantom and therefore something that is not advisable or it this due to the fact that I have fitted prop-guards?

 

[DaveTown]

If your descent was straight down, you were probably experiencing the vortex ring state. You can search for that term for lots of info on is site.

If you had BOTH sticks back, you should have been flying backwards and descending at the same time, and that should avoid the vortex ring state. Not sure what the issue would have been then.

 

[IrishSights]

With the latest firmware (3.2) there is a limit of 2 m/s on decent which would avoid an uncontrolled decent as you described. So I'm guessing you have not updated the firmware to the latest. I've had 3 flights with this version with no ill effects whatever including testing the decent limit - My IOSD reported 2 m/s. I can't see flying in full speed reverse and descending at 2 m/s would give you an uncontrolled experience - unless you were flying in a gale or something!

 

[OI Photography]

Even when not coming straight down or inducing VRS, the Phantom can get pretty squirrely on descents sometimes, especially when propguards and full elevator (pitch) are added to the mix. Propguards raise the center of gravity on the Phantom and when you have it tipping as far as it will in any one direction that can make it tricky for the NAZA to keep it balanced and descending at the same time.

Technically any descent by a multirotor, even when handled slowly and gingerly, is just a controlled fall, so its one of the times you'll find the least stable handling.

 

[WessexWyvern]

Thanks. Makes sense. As I bought the p2 as a photography platform I won't be doing that sort of stuff in the future but it's nice to know.
The phantom is straight out of the box...I'm waiting for a firmware release that no one complains about before updating :lol:

 

[IrishSights]

...I'm waiting for a firmware release that no one complains about before updating :lol:

That's a long wait

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