Almost crashed - Vortex Ring State?

Lutz G · Aug 29, 2016

The other day I was at 805 m (height above sea level) in the Volcanic Eifel (Meerfelder Maar) - it was very hot. My descent rate wasn't very fast IMO - like usual I'm pretty cautios - but I'm not used to the mountain stuff with updrafts...

So what do you think happened - Vortex Ring State? I have a P1 1.1.1. with P2 Props (never had problems like that before) and Zenmuse H3-2D Gimbal

Right to the Aaaaction - here

4wd · Aug 29, 2016

It looks like it, on a hot day you might be in a thermal of rising air and the 'descent speed' could be too high even without actually descending.
I recall seeing a video where a phantom 2 was flying normally until it went over a hot metal roof then it just tumbled.

You probably know recovery is difficult but flying sideways is best option, also avoid descending straight down of course.

The P3 more or less eliminates this issue even descending faster as the motors are slightly canted.

robinb · Aug 29, 2016

The early phantom were prone to VRS, the way to avoid it is not to come straight done, move drone in one direction or another.

Lutz G · Aug 29, 2016

4wd said:
It looks like it, on a hot day you might be in a thermal of rising air and the 'descent speed' could be too high even without actually descending.
I recall seeing a video where a phantom 2 was flying normally until it went over a hot metal roof then it just tumbled.

You probably know recovery is difficult but flying sideways is best option, also avoid descending straight down of course.

The P3 more or less eliminates this issue even descending faster as the motors are slightly canted.

Interesting - thx. Know about the flying sideways stuff - but hadn't problems before with my
standard procedure

Falcon900 · Aug 29, 2016

Lutz G said:
The other day I was at 805 m (height above sea level) in the Volcanic Eifel (Meerfelder Maar) - it was very hot. My descent rate wasn't very fast IMO - like usual I'm pretty cautios - but I'm not used to the mountain stuff with updrafts...

So what do you think happened - Vortex Ring State? I have a P1 1.1.1. with P2 Props (never had problems like that before) and Zenmuse H3-2D Gimbal

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Right to the Aaaaction - here

Which way was the wind blowing on the ground? Was it coming from over the lake and then over the village toward the P1?

Lutz G · Aug 30, 2016

Falcon900 said:
Which way was the wind blowing on the ground? Was it coming from over the lake and then over the village toward the P1?

If my memory serves me well almost no wind at all. Couldn't say which way it was blowing...
But very hot....

Falcon900 · Aug 30, 2016

Lutz G said:
If my memory serves me well almost no wind at all. Couldn't say which way it was blowing...
But very hot....

You were probably in the turbulence of a thermal with a bit of VRS. Also even if there is light wind at the surface, a stronger wind can be blowing just a short distance above the surface. There will be some wind shear when the aircraft transitions from a windy level to a lower level with less or no wind.

Lutz G · Aug 31, 2016

Falcon900 said:
You were probably in the turbulence of a thermal with a bit of VRS. Also even if there is light wind at the surface, a stronger wind can be blowing just a short distance above the surface. There will be some wind shear when the aircraft transitions from a windy level to a lower level with less or no wind.

What's VRS? Do you think I could have crashed - or is it just pretty spectacular footage, and the Phantom would recover anyway (was at 140 m alt - so enough time left)?

Falcon900 · Aug 31, 2016

Lutz G said:
What's VRS? Do you think I could have crashed - or is it just pretty spectacular footage, and the Phantom would recover anyway (was at 140 m alt - so enough time left)?

Vortex Ring State.,. Its when the quad flies through it's own rotor wake. Descent is where it happens. Google it for more info.

Lutz G · Aug 31, 2016

Falcon900 said:
Vortex Ring State.,. Its when the quad flies through it's own rotor wake. Descent is where it happens. Google it for more info.

Ooops - should have known that (mentioned Vortex Ring State in #1) - wasn't aware of the abbreviation

Lutz G · Sep 1, 2016

4wd said:
The P3 more or less eliminates this issue even descending faster as the motors are slightly canted.

The P3 will be my next multirotor - will be interesting how good the slightly canted motors work to avoid Vortex Ring State.

Szon3 · Sep 2, 2016

Right there is your problem p2 props. They cause VRS when you come down fast with a camera on it. Never had that issue until I tried the p2 blades .Went back to p1 and it went away

CactusJackSlade · Sep 3, 2016

Are you talking about 3:05 in the video? If so I think your Phantom was flying just fine, your GIMBAL kicked out. Look closer at the video, while the gimbal is wagging around you can see the body is still pretty horizontal to the horizon. Did you have to reset your camera pitch control after this incident (3:19 in your video)? If so that is another indication the gimbal kicked out. This is what I see anyway..... Gimbal kick out can happen at high wind speeds when the motors are overcome by air drag. I had a gimbal with a motor going bad and this happened frequently.

Lutz G · Sep 3, 2016

Szon3 said:
Right there is your problem p2 props. They cause VRS when you come down fast with a camera on it. Never had that issue until I tried the p2 blades .Went back to p1 and it went away

But the P2 props are soo much better in terms of flight time, and speed, that I will keep them. I already practiced flying sideways during descent yesterday - had to came back very fast cause it starts raining.
Worked - without any Vortex Ring State stuff...

CactusJackSlade said:
Are you talking about 3:05 in the video? If so I think your Phantom was flying just fine, your GIMBAL kicked out. Look closer at the video, while the gimbal is wagging around you can see the body is still pretty horizontal to the horizon. Did you have to reset your camera pitch control after this incident (3:19 in your video)? If so that is another indication the gimbal kicked out. This is what I see anyway..... Gimbal kick out can happen at high wind speeds when the motors are overcome by air drag. I had a gimbal with a motor going bad and this happened frequently.

Right - I had a "Gimbal Tilt" - but why? Because my Phantom was suddenly moving very fast wiggling - the gimbal never did that before - that's a sort of "save gimbal motors mode" of the zenmuse, only
activated when the gimbal gets very high loads...

BTW: Found this (Glider?) Clip. He was starting on the other side of the maar - my starting point was on the other side. He mentioned tricky conditions and rotor-air. What's that?

Lutz G · Sep 5, 2016

The other day I had to come down very fast during filming wind turbines cause it starts raining. The crap weather website forecast was "sunny and dry" ;->
Worked perfect this time avoiding descending straight down...