Bloody 'ell, quadcopters can't swim!!!!!

Ddraiggoch · Jun 13, 2016

On May the 31st I filmed at a place called Sunset Rock by Sparta, TN and experienced some odd behave where the Q500, as I was bringing it in, began to rock side to side so badly I thought it would land on it's side. It then steadied and rose straight up to around 57/60 feet ignoring every input I tried. It hovered there for about 18 seconds before responding to my anxious pulling on the descend lever.

It was a hot day with less than 2mph wind, when it did blow, and in view of the location I attributed the behaviour to thermals, after all it was pretty hot and an elevated location.

I moved to another location, a cornfield, removed the gimbal and calibrated the accelerometer and the compass.

Every flight after that was trouble free.

Until that is Sat June 11. Just before dusk I was flying in my backyard, common practice, and on bring it in it again 'went crazy' About 45/50 from me it started gyrating again and began to climb refusing to respond. I had used RTH to bring it back and I believe the acting up began when I switched back to angle mode. Thinking about it, as I have rarely used anything but angle, that was what I may have done back at Sunset Rock.

This time it did not stabilize but climbed backwards to around 45/50 ft and around 50 feet from me then simply straight down onto my roof, crashing and sliding down and off the building.

The camera and gimbal, which was the one belonging to my third system, separated from the bird and the same damage, as has previously ensued to my first gimbal slide, the horizontal piece on one side broke off.

The following day, Sunday 12th (yesterday) I connected it to the GUI and checked the motors and everything the GUI offers, including verifying the ESC allocations.

Everything looked good.

I took it to a local park and tested it out.

It seemed fine initially so I started to bring it back and it went nuts again.

Climbing high and out over the lake where it began spinning and descending ignoring all my inputs.

It finally sank, the whole system second camera and all, beneath the waters about 190 feet from take off point at a point in the lake I believe to be around 15 ft deep.

I had it in mind to purchase another back up and apply for 333 exemption in order to create a service business using the Q500's but am now dubious about moving forward on that until I can understand what brought me to be standing there watching my investment drown.

Dragonflyerthom · Jun 13, 2016

That my friend is a job for support at Yuneec. Sad story hope to hear a better one when all is fixed.

QuadBart · Jun 13, 2016

Dang, I would be curious to hear if you ever find out what happened...

Mortalis · Jun 15, 2016

My absolute first thought while reading this is safe mode 'circle of death'.
I am assuming (and you know what that means) that you have verified that you didnt accidental hit the mode switch before trying to bring it back.

flashcrash · Jun 16, 2016

You had a Ring Vortex condition. This happens when you go down
too fast - straight down.
The props get stuck in a "donut" of air above then and below them.
The props recirculate this air and can't get bite from good air.

Only way out is to go full forward, back left or right hard.

Trying to go UP with full power will not work.

You need to break out of air trap the props are stalled in.

Ddraiggoch said:
On May the 31st I filmed at a place called Sunset Rock by Sparta, TN and experienced some odd behave where the Q500, as I was bringing it in, began to rock side to side so badly I thought it would land on it's side. It then steadied and rose straight up to around 57/60 feet ignoring every input I tried. It hovered there for about 18 seconds before responding to my anxious pulling on the descend lever.

It was a hot day with less than 2mph wind, when it did blow, and in view of the location I attributed the behaviour to thermals, after all it was pretty hot and an elevated location.

I moved to another location, a cornfield, removed the gimbal and calibrated the accelerometer and the compass.

Every flight after that was trouble free.

Until that is Sat June 11. Just before dusk I was flying in my backyard, common practice, and on bring it in it again 'went crazy' About 45/50 from me it started gyrating again and began to climb refusing to respond. I had used RTH to bring it back and I believe the acting up began when I switched back to angle mode. Thinking about it, as I have rarely used anything but angle, that was what I may have done back at Sunset Rock.

This time it did not stabilize but climbed backwards to around 45/50 ft and around 50 feet from me then simply straight down onto my roof, crashing and sliding down and off the building.

The camera and gimbal, which was the one belonging to my third system, separated from the bird and the same damage, as has previously ensued to my first gimbal slide, the horizontal piece on one side broke off.

The following day, Sunday 12th (yesterday) I connected it to the GUI and checked the motors and everything the GUI offers, including verifying the ESC allocations.

Everything looked good.

I took it to a local park and tested it out.

It seemed fine initially so I started to bring it back and it went nuts again.

Climbing high and out over the lake where it began spinning and descending ignoring all my inputs.

It finally sank, the whole system second camera and all, beneath the waters about 190 feet from take off point at a point in the lake I believe to be around 15 ft deep.

I had it in mind to purchase another back up and apply for 333 exemption in order to create a service business using the Q500's but am now dubious about moving forward on that until I can understand what brought me to be standing there watching my investment drown.

flashcrash · Jun 16, 2016

I still think you hit Ring Vortex twice. once over your roof.
Once over the lake.
Only way out is to power it to the side.
When you come down try to come down at a 45 degree angle if you had the drone high up and far away.
It will come down at a 45 degree angle like that. You can have the left stick and right stick down and it will bring it down and toward you at the same time.
If you need to come right down - sway it from side to side maybe 10 feet one way and then the other.

Both of my ring vortex crashes were at Lake Tahoe at
6500' elevation

Here is my last ring vortex crash:

Here is the first ring vortex crash.

Ddraiggoch · Jun 16, 2016

It is rare for me to use anything but angle mode.

Thinking about it I had used the RTH on each occassion.

However when about 50 or so feet out I switched to angle mode and that is when the 'sashaying" took place.

The first time it steadied and rose to around 57/60 feet and stayed there for about 18 seconds before responding to anything I tried.

The second time as it started the swaying, again as I switched to angle mode about 35 or 40 feet away from me, it took off at about a 45 degree angle backwards and ignored any inputs before deciding it was time to come down straight onto the roof.

The bath time it was when I switched from RTH to angle, AGAIN, it took off to the right out over the lake. I went with it as far as the control input and it seemed to steady so i changed direction to bring it back .. then it began it's descent. Spinning and spinning until it hit water and not responding to anything, left, right, forward, back nothing.

On reflection it seemed that one of the props had gone but I could see all four spinning.

Wonder if it was a motor out?

I hope to get to trawl it out of the lake some time today.

Ddraiggoch · Jun 16, 2016

flashcrash said:
I still think you hit Ring Vortex twice. once over your roof.
Once over the lake.
Only way out is to power it to the side.
When you come down try to come down at a 45 degree angle if you had the drone high up and far away.
It will come down at a 45 degree angle like that. You can have the left stick and right stick down and it will bring it down and toward you at the same time.
If you need to come right down - sway it from side to side maybe 10 feet one way and then the other.

Both of my ring vortex crashes were at Lake Tahoe at
6500' elevation

Here is my last ring vortex crash:

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Here is the first ring vortex crash.

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OUCH!!! I know how painful that must have been.

flashcrash · Jun 17, 2016

You may have had a motor out.

Well the ST10 or newer ST keeps a log of all the flight statistics in the SD card which you install in the ST10 or newer ST flight control box.

You can remove that SD card and it may have telemetry on what happened.

Like a "Black Box" on a commercial flight.

Of course, I am not astute enough to put that card in.
My friend had that card in the controller and I removed it to put videos on with the Hero 4.

I guess I could find a small 4GB card and put it into the ST10.

If you were running the card in the flight controller box - the ST, that card may hold clues to your two crashes.

Ddraiggoch · Jun 17, 2016

It certainly behaved that way when it decided to swim for it.

Yes, I did have an SD card in the ST10+ and I used it to determine the last known GPS in order to get out there and try to trawl for it.

I have also forwarded the relevant info to Yuneec customer service.

The current there is barely none to slight so it shouldn't be far from the point of entry, having said which spent almost three hours dragging a couple of coat hooks bolted together yesterday afternoon with nothing to show for it but a suntan sigh.

Perhaps another day when I am off work.

Amazing how innovative we can be when we have to eh?

I bolted two coat hooks back to back, clamping some cord between them.

Also tying a knot in the cord every three feet helped me determine how deep the water is at that location.

It's 9 varies between 9 and 10 feet.

Could swim down and search but visibility is almost non existent and I also saw a copperhead languishing in the cool water ... Like Indiana Jones I hate snakes!!!