All power lost mid flight

[petermag]

Thanks for the suggestions.

I had a quick chat session with 3DR and they apologised for the delay. They said the info that I had provided was very thorough and my ticket had progressed in the queue and just about at the point of an in depth investigation with their engineers. They also requested confirmation of my purchase and registration.

I also uploaded the video of the flight and crash per 3DR’s request so I thought I would share it with all of you.
One other observation with the video is that the leg for motor pod 03 is unusually visible (never had that before), and the craft also looks quite unbalanced from the start. Whether that’s a separate issue or a precursor to the impending power failure I don’t know.

https://www.youtube.com/watch?v=pqFqI6hGcqU&feature=youtu.be

 

[petermag]

Just to let you know that 3DR have confirmed that “The flight log confirms the information from the video that the SOLO completely shut down mid flight, regularly this is caused by a short circuit or an electrical failure”.
As the product is still under warranty they are covering the replacement of the Solo + gimbal, as well as the GoPro.

Granted it has been a bit of a disruption to my travels in Europe and plans that I had with the Solo, but still, I can’t fault 3DR in their relatively quick response. I honestly don’t imagine I would have gotten anything better with a different vendor.
This difference is probably what drew me to the Solo in the first place. My long term interest in photography and videography never pulled me into acquiring a drone – until Solo came on the scene. Hopefully the relationship will continue.

 

[Mauiwind]

I had the same quick and consice response from 3DR. My crash was associated with a problematic level control. Anyway, crashes and problems are inevitable with smaller UAVs in their infancy. The backing of the Solo by 3DR reminds us that Solo leaves all the other mfgs. In the dust.

 

[sixshooterstang]

I had the same thing happen.

 

[yt lee]

Very interesting and timely info

I've only been able to locate 1 prop so far (broken just before the secure point) and have been out scouring the area for the others and still can't find them.

I've sent all my info including photos (but not videos yet) to 3DR.

This is the first time I heard that all props lost. Were the arms or motors broken?

Normally, lost power in flight is battery related or lost prop. Your flight log has the battery voltage chart. If you see a big voltage drop right before the crash, then you can pin the crash to the battery.

 

[petermag]

This is the first time I heard that all props lost. Were the arms or motors broken?

Normally, lost power in flight is battery related or lost prop. Your flight log has the battery voltage chart. If you see a big voltage drop right before the crash, then you can pin the crash to the battery.

Only 1 prop (broken) was left on the Solo when it hit the ground. No arms or motors were broken. The 3 other props couldn't be located at the time. Since then 1 prop has been found - about 75 meters from the crash location.

3DR's analysis of the logs reported the following -
"The flight log confirms the information from the video that the SOLO completely shut down mid flight, regularly this is caused by a short circuit or an electrical failure, however it will be hard to determine without inspecting the vehicle."

 

[PdxSteve]

All motors completely shut off and the props continued to spin due to their inertia causing them to unscrew themselves. You must have tightened one (the one that stayed on) slightly more than the others.

It's like slamming on the brakes in your car. Yes the car slows down quickly but you continue being pushed forward towards the windshield.

 

[Maddog]

All motors completely shut off and the props continued to spin due to their inertia causing them to unscrew themselves. You must have tightened one (the one that stayed on) slightly more than the others.

It's like slamming on the brakes in your car. Yes the car slows down quickly but you continue being pushed forward towards the windshield.

So if you cut off power to the motors they stop "dead" instead of slowing down? Guess it wouldn't take much for a high speed prop to work loose in that situation.

 

[PdxSteve]

They slow down but the deceleration rate is quite fast once there isn't power driving them. Very rapid but not quite a dead stop. The magnets in the motors basically act as a brake.

 

[yt lee]

Only 1 prop (broken) was left on the Solo when it hit the ground. No arms or motors were broken. The 3 other props couldn't be located at the time. Since then 1 prop has been found - about 75 meters from the crash location.

3DR's analysis of the logs reported the following -
"The flight log confirms the information from the video that the SOLO completely shut down mid flight, regularly this is caused by a short circuit or an electrical failure, however it will be hard to determine without inspecting the vehicle."

Do you smell electrical burnt.

 

[Maddog]

They slow down but the deceleration rate is quite fast once there isn't power driving them. Very rapid but not quite a dead stop. The magnets in the motors basically act as a brake.

Makes sense..

 

[yt lee]

All motors completely shut off and the props continued to spin due to their inertia causing them to unscrew themselves. You must have tightened one (the one that stayed on) slightly more than the others.

It's like slamming on the brakes in your car. Yes the car slows down quickly but you continue being pushed forward towards the windshield.

There is no brake inside the motor. Hence there is no sudden motor stop When a motor lost power, the motor will continue to turn by the props. Prop lost are normally due to vibration.

 

[pyrate]

not true really, there have been a couple documented reports of power loss spinning the props off.
Not sure that is what happened here but it has happened

 

[PdxSteve]

There is no brake inside the motor. Hence there is no sudden motor stop When a motor lost power, the motor will continue to turn by the props. Prop lost are normally due to vibration.

I never said there is a brake inside the motor.

 

[petermag]

There is no brake inside the motor. Hence there is no sudden motor stop When a motor lost power, the motor will continue to turn by the props. Prop lost are normally due to vibration.

As others have said, and based on the feedback from 3DR, the understanding is that the props will naturally unwind if there is a sudden halt to the motors i.e. the motors act as a brake against the momentum of the blades. If you watch the video you will hear that at 26 seconds the motors shut off completely. I expect the 3 props would have spun off directly after that - especially based on the fact that one prop was found 75 metres away.

I have not had a chance to analyse the dataflash log while I've been travelling, and the fact that I received confirmation from 3DR was sufficient for me for now.
However I have uploaded the log (42.bin) here so that others can do their own analysis and share the knowledge.

 

[petermag]

Just thought I would mention a further interesting observation. Prior to my flight back to Australia, I needed to decrease my battery levels so I ran the Solo with the props removed for each battery.

When I was doing this for the battery that was involved in the crash, the Solo lost all power and switched off suddenly at 72%. I estimated that the crash occurred around 70% of battery so this is completely in line with what happened in the crash. I swapped to a different battery and discharged it successfully to 50%. I then re-inserted the battery from the crash and was able to reduce its level from 72% to 50% without any further issues.

Not sure if this is good or bad news. Possibly good in the sense that the Solo itself might not be at fault, but I might have been happier with an issue being found and corrected in the Solo rather than fearing the possibility of this occurring in multiple other batteries. The battery was only about 20 flights old at most and only ever recharged with the standard Solo charger.

Back in Australia now and waiting for the RMA labels to arrive.