OctoQuad X8 Crash During AUTO Mode — No Prior Warnings, Loss of Control at Final Stage (Log + Video Attached)

ArduCopter
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1

Hello,

We encountered a crash with our OctoQuad X8 drone during an AUTO mode mission. The incident occurred near the final phase of the flight, where the drone unexpectedly lost stability and drifted toward the rear-left quadrant, ultimately resulting in a complete crash.

:pushpin: Context Summary:

  • Frame type: OctoQuad X8 (coaxial, upper-lower configuration)
  • The log file is lengthy; however, ARM was executed shortly before the incident, followed by an immediate transition to AUTO mode
  • No pre-flight warnings, errors, or abnormal behavior were observed in the log or ground station prior to the crash
  • The vehicle and payload were both completely lost

:paperclip: Attached are:

  • The full dataflash log (BIN)
  • A video showing the moment of failure

We are currently reviewing all potential causes. Your insights, similar case experiences, or suggestions on areas to focus on in the log would be highly appreciated.

Thank you in advance for your support.

Log:

Flight Video:

1 Like
2

What were you thinking launching that craft in Auto on default parameters? Or a take-off in any mode for that matter.

It was completely unstable. Graph the Attitude fields and the RC Outputs and see for yourself.

3

Yes, I attempted to fly the drone using the default parameter values, as I am currently unable to run an Autotune due to the size of the vehicle. What would you suggest?

4

One would never run Auto Tune on default parameters either.

It looks like that was built as a manned craft.
See here Code of Conduct

1 Like
5

We are not producing it as a manned drone. It is a conceptual design and will include a mannequin model inside, so there is no issue—don’t worry. I’m just focused on making sure this drone completes its first flight successfully. I’m open to any kind of ideas

6

If it is a proof of concept and it will not be used in Manned flights, you can do what AirCar did with their 350Kg drone and use ArduPilot methodic configurator software to get this flying safely and reliably.

Or … you can continue using your trial-and-error approach, and continue getting the same kind of results you’re getting.

7

Were you able to check the flight logs? What could be the issue?

8

It’s a waist of time to look at logs of very incorrectly configured vehicles. There is little information to extract from them.

I personally like to use my time to avoid issues from happening in the first place.
Rather than “saving time” by not doing any of the best practices, and then use that time diagnosing crash logs.

9

Build a small octoquad and gain experience configuring and tuning that.

10

Actually, I already tried this on a small drone. It’s not the first drone we’ve built.

11

I do not deter any other forum users to look at your .bin file and provide you with whatever information can be gained from it.

But you will save time and money by correctly using the software I posted before posting any other log files.

12

Did they do a writeup of their process at all? That would be an interesting blog post

13

it seems you are having a bad propeller position. Kindly do the following.
Arm the vehicle in Altitude flight mode and check the running props at minimum speed for the direction of rotation on each prop and confirm here.
Minimum rpm speed is just before take off at lowest throttle. position.
Also check if there are any props installed wrongly ( inverted) !!