Oops again!!!! :(

[Aussie Paul]

I have been enjoying flying the P 3 standard that I bought, to keep my hand in, while trying to fix the P 2 vision + and the P 3 Advanced. Several nights ago There was some lightning and thunder and I hovered above the front lawn hoping to catch some lightning shots but not to be, just got a little wet.

Storm approaching last night and thought I would try again. Climbed up a little and shifted drone so I could see from sitting on my required chair just out of the garage rain line. Started to get some warnings and she drifted downwind away from me and when I tried to bring her back didn't seem to want to and warnings re electrical interference. I decided to conduct a RTH and she climbed to the 70 meter I had set. Getting further away so decided to take over and get down lower. Still not achieving desired results. Now showing poor signal strength and called to wife to help look. Finally disconnected so jumped in her car and headed off in what I thought was the right direction. A couple of splashes of signal saying it was getting further away.

Eventually came home so dejected. I set about retrieving flight data and could see that it went on a different flight path to what I thought. It appears to have stopped around 5 meters from a dam of water. As I am not up to walking more than 50 meters we drove to have a bit of a look at the layout of the land as there are horse trainers in the area. Unfortunately the entrance to the racing track was closed and locked. I realised now that it was not close to any general public, and would be safe until I worked out how to retrieve the drone.

Went home to have a bite to eat and our daughter in law, who is enjoying drones with me, turned up to help. We drove to the locked gates and the was a track next door and she was able to walk (in the rain) to retrieve the drone. I had printed the flight path to give her a clue what to look for. After a couple of phone calls and her climbing an observation tower she orientated herself and found the drone.

Here is the flight so everyone can enlighten me as to what I have done incorrect (I am never wrong of course).

DJI Flight Log Viewer - PhantomHelp.com

Aussie Paul.

 

[RodPad]

Glad you found it, it must be in good shape, any kind of storm like that must have some winds.

Looks like the wind was taking it away from you, you have some 8 mph speeds like 2m 40s, but your distance was increasing. The return home speed I think is like 8 mph, but it was being pushed away at 8 mph. That would be maybe 16 mph wind?

Your RTH elevation would have increased the wind speed. If you took over the controls and did full power better chance of getting closer instead of drifting away. The Phantom will fly about 30 mph, that would have made a 15 mph return instead of a negative 8 mph.

I learned some time ago, go up your elevation, flip it to Atti and watch your drift speed and direction for a second or two.

@Fly Dawg,
Do I even have a clue?

Rod

 

[Fly Dawg]

Looks like the wind was taking it away from you, you have some 8 mph speeds like 2m 40s, but your distance was increasing. The return home speed I think is like 8 mph, but it was being pushed away at 8 mph. That would be maybe 16 mph wind?

Looks like a relatively simple analysis to me. But, I would say the wind was much greater than that. More like 20-25 and gusting at times the way the aircraft was struggling and being pushed away.

 

[RodPad]

So the HSpeed is Negative values?
The larger the numbers the faster or slower it was being blown away?
Your graft 300 seconds (15 mph).

300 seconds / 60 = 5 mins.

5 mins on flight log (9.5 mph)

What I'm I missing?

Rod

 

[Fly Dawg]

What I'm I missing?

I did not graph the pitch and roll values....They were all over the place. The aircraft was really struggling to maintain speed. Wind speeds are not linear. If you have flown in any wind at all, you will note that ~20mph winds are too strong, depending on your altitude. There are around 3 disconnects in the graph, thus you cannot include those in wind calc.

 

[Meta4]

Here is the flight so everyone can enlighten me as to what I have done incorrect

Around 1:20 we see the drone is holding position at 37m altitude
At 1:53.6 and 103 m distance, 37m altitude, you initiated RTH.
As the drone climbs to 70m we see it can't maintain position and is being blown off course at 7-10 metres/sec
That suggests a strong wind as the Phantom has no trouble holding position in a 10 m/s wind.
When RTH starts flying back it's making slow progress of about 0-3 m/s.
However it's not always in the right direction.
The wind is gusty and the drone is alternately gaining and losing distance.
The wind increases and at 2:30 the drone is going backwards at 6 m/s.
At 2:41 you begin to bring it down to 53 metres and the speed drops to 2-5 m/s but it's still going backwards.
At 3:25 the wind drops briefly and the drone actually gains about two metres toward home before the wind increases again.

But at 3:26 you climb back up to 67 metres again.
The Phantom continues to burn battery in RTH while it's being blown backwards at 0-7 m/s
You take it out of RTH mode a few times but never do anything that helps correct the situation and go back to RTH again.
At 15:34 with the battery level reaching 13%, the Phantom gives up and commences autolanding 1.6 km from home.

What's the lesson here?
1. The wind is always stronger up higher.
Early in the flight we saw how the drift speed increased as the altitude increased.
2. RTH is a slow driver and in calm air it will cruise along at 10 m/s (you can fly at 16 m/s when you do the driving)

Leaving the drone up high where it could not fight the wind was a serous problem
Leaving RTH to do the driving was another.

What you should have done was to get the bird down out of that wind and taken control to fly home at lower altitude.
You should also be aware of the wind strength and direction before launching and after.
If you are going to fly in windy conditions, launch and try flying into the wind (not downwind) and check the drone's performance against the wind.
If the wind slows the drone significantly, you know you will have a problem if you have to fly against it.
3. In a strong wind situation, never fly away downwind. Your return trip is going to be fighting that wind.
4. Setting a high RTH altitude can have negative consequences.
If you don't need a high RTH, don't set a high RTH

 

[captainmilehigh]

Excellent analysis Meta, well done. [emoji106]

 

[Andy9]

Yes, very precise analysis. I think the first error happened, when you decided to fly in such weather at all. Everything after that were just consequences. The craft was doing really fine and did everything possible to come back. At last it even land beside that water although it might go into. Really fine piece of technology.
I'm not sure if P3 has sport mode but in spite of that switching to ATTI would very likely brought it back. Obviously there were no high obstacles and at lower altitude you could do that much easier.

Usually when I'm going to fly and not sure about the weather I always put the craft up to see how it handles the wind. It must fly against the wind at about let say half of its normal speed otherwise I would not fly.
But the wind at storms are unpredictable and can suddenly change the speed and heading.
You can be happy. Not only got it back but you even got the free lesson.
.

 

[Aussie Paul]

Thanks everyone, exactly as I thought, pilot error. I was unaware that the RTH function was limited to a set speed, although I probably read it. My old brain does not function remembering so well these days, particularly under stress!!!

As soon as I realised things weren't going well I believe I initiated RTH expecting it to come to where I could land it. After that I was playing "catch up" and losing!!!
Quite a few lessons learnt AGAIN and still have aircraft.

Aussie Paul.

 

[RodPad]

@Aussie Paul,





Rod