• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

water grave

lurambler

Junior Member
#1
I've just lost my second UAV to Lake Erie. What's going on?!? It has a bit of history as a ship graveyard, but I haven't heard any Bermuda Triangle like stories along the lines of what I'm experiencing.

First time I took a DJI hex up and got it about 50 yards over the water and it started dropping and would not respond to transmitter. Even though I used a battery from my 'charged' LiPo bag, I chalked it up to pilot error for not doing a voltage check before take off.

This time, I was going up w/ my Y6 (pixhawk) and had 16.4 volts on my 4 cell. I got about the same distance over the water and kerplunk, same thing happened. It just dropped w/ no response to transmitter. No low voltage alarm. This was actually the second flight for this mission. First one out was no problem. Brought it back, swapped out batteries and disaster that second time.

I have never had that response or experience any of the many times I've flown over land. Would there even be anything salvageable other than maybe the frame if I could recover it? I'm thinking not, and it's why I never went diving for the first one down.

- Possibly hanging up my Tx after this
 

Cyberdactyl

Misfit Multirotor Monkey
#2
Sorry to hear that. I know the feeling all too well of losing them.

Maybe not fly over water until you've had several successful flights?
 

nilsen

Senior Member
#3
Sorry to hear that

Hey lurambler,

That sounds horrible, I can only imagine it although I had a similar experience with my first phantom and luckily not with my large hex, the phantom with gopro hero 3 black, and FPV and upgraded motors took a dive into the sea.

The gopro is dead and so were 2 of the esc's however the motors and FC as well as reciever(futaba) and other components were and are fully reusable.

Is lake Erie salty or brackish? If not then I think a lot of the components will be reusable, even perhaps the FC as they are usually quite resiliiant to water and lets hope the battery just shorted itself out and didn't keep the the pixhawk powered underwater.

As to the reason, I use an APM and it has landed on it's own when detecting low battery so maybe it was the same for you, dodgy battery maybe?

Either way, sorry about that but I think worst case you'll have to replace the electronics but the motors should still be ok.

Good luck salvaging it, I would definitely try and find it.
 

RAM

Posted a thousand or more times
#5
Maybe the coast guard is using a drone jammer :).

Seems odd that it happens in the same place. You said you recovered it. Did you take a boat out to the place it fell, and if so, did you test the radio at that spot?
 
#6
the only "great lakes triangle" i'm aware of is simply a matter of math, where the more traffic you have in any given area the more times you roll those dice... the more times you have a boat run into trouble.

i don't think there's anything supernatural at work here...

then again, there could be some magnetic ley-lines situation going on that i'm not aware of that might screw with electronics.

http://en.wikipedia.org/wiki/Ley_line

:D

i live in NW ohio, near lake erie and the maumee river, i had planned on flying my new H quad over the water... stories like this terrify me.

sorry about your loss, maybe build your next one so it floats... i've seen some real cool sealed systems here and on youtube, you might want to check that out.

I've just lost my second UAV to Lake Erie. What's going on?!? It has a bit of history as a ship graveyard, but I haven't heard any Bermuda Triangle like stories along the lines of what I'm experiencing.

First time I took a DJI hex up and got it about 50 yards over the water and it started dropping and would not respond to transmitter. Even though I used a battery from my 'charged' LiPo bag, I chalked it up to pilot error for not doing a voltage check before take off.

This time, I was going up w/ my Y6 (pixhawk) and had 16.4 volts on my 4 cell. I got about the same distance over the water and kerplunk, same thing happened. It just dropped w/ no response to transmitter. No low voltage alarm. This was actually the second flight for this mission. First one out was no problem. Brought it back, swapped out batteries and disaster that second time.

I have never had that response or experience any of the many times I've flown over land. Would there even be anything salvageable other than maybe the frame if I could recover it? I'm thinking not, and it's why I never went diving for the first one down.

- Possibly hanging up my Tx after this
 

lurambler

Junior Member
#8
To try and respond to all in one message:

@Cyberdactyl - I've been convinced to stick w/ it in general, but you're right, I won't be flying over water anytime soon. Odd thing is, I have had many successful flights, several over rivers, and never experienced the same kind of situation where the UAV just drops out of the air like it did. Something about me and this lake though...

@nilsen - Lake Erie is fresh water (http://en.wikipedia.org/wiki/Lake_Erie), so IF I was able to recover it, there might have been hope for something salvageable. The first one that went in was probably in a spot deep enough where it would have required a scuba diver to retrieve. The second, and most recent, may have been shallow enough to recover by simply diving down snorkle style. I attempted that this weekend. Unfortunately I came up empty. The water was pretty choppy and I could barley see my hand in front of my mask underwater. So, I walked a pattern in chest deep water hoping to kick upon it.

@makattack - I had the default 3DR Pixhawk battery failsafes and alarms for low voltage and current. That feature has actually helped me in the past where I would get an audible alert once it sensed my battery getting low and even a second alarm if/when it would get critically low before auto landing. I heard neither of those during this accident. And, the voltage read I had at takeoff should have allowed me at least 5 minutes of fly time, not less than 1, which is about what I got.

@RAM - I was not able to recover it. How would I have, or how can I in the future, test the radio at that spot?

@octodreamerFNG - I almost want to encourage you to go out and fly over the lake simply for selfish reasons so I can know if others are having the same problem. But, I can't do that in good conscience b/c I don't know the root cause of my losses and wouldn't want the same to happen to you. It's tough b/c if doing AP, that's where a lot of the really good shots are at, as you well know I'm sure. I'm familiar w/ your area of Ohio.
 
#9
I don't think i could ever bring myself to take my tri out over water. Loosing my $400 tri would kill me, I couldn't imagine loosing a couple of $1000+ machines!
 

makattack

Winter is coming
Moderator
Mentor
#10
Did it "land" (under power, controlled like it was landing) in the water or "fall" (all motors stopped) in the water? I guess if it was failsafe triggered, and you had throttle failsafe enabled (the default is gps failsafe only) it would have RTL'ed as long as you had GPS lock. If you had throttle failsafe (RX lost connection, etc), and no GPS lock, the multirotor would have attempted to land...

http://copter.ardupilot.com/wiki/throttle-failsafe/
 
#11
Did it "land" (under power, controlled like it was landing) in the water or "fall" (all motors stopped) in the water? I guess if it was failsafe triggered, and you had throttle failsafe enabled (the default is gps failsafe only) it would have RTL'ed as long as you had GPS lock. If you had throttle failsafe (RX lost connection, etc), and no GPS lock, the multirotor would have attempted to land...

http://copter.ardupilot.com/wiki/throttle-failsafe/
It made no attempt to RTL. It was far enough away, and I was in a state of internal panic, that I couldn't say for sure if the motors stopped. Throttle was at least at 50% when this happened. I thought I had GPS lock, but at this point I'm questioning all my pre-flight checks. As well, I know my low voltage alarms were set but it may have been far enough out and too noisy to hear. It happened so quick that what I remember as my warning time to get back on the ground could not have elapsed.
 
#12
makattack - the throttle failsafe page you linked to has what to me sounds like the most probable issue;

Operation of failsafe using a Spektrum Satellite receiver

When using a Spektrum Satellite receiver with Pixhawk, the failsafe will trigger after receiving no data from the satellite receiver for two seconds, and not immediately when the transmitter is turned off. This behavior is due to the satellite receiver being directly connected to Pixhawk without connecting to the main receiver.


That's exactly how I was setup w/ the Skektrum satellite. No way to tell if there was a 2 second interruption in comm from Tx to Rx at this point. Would have been nice to dig into those logs.