Running two APMs in tandem

Would it be possible to run an octocopter X4 coaxial with two apms?

I.e. one apm controls top 4 motors, second apm controls bottom four motors.

Obviously 8 ESCs and maybe even dual transmitters.

This would be a truly uncrashable system.

Iv noticed even with my octo that if you lose one motor, the thing doesnt really fly...

Thoughts any1?

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  • Also they wouldnt be on the same axis, causing weird accelerations diff's between the two.. It would just get messy. Its much better to just have a stab loop without an imax that can correct for a down'd motor.

  • Developer

    Yes, I agree with Ellison that this set-up wouldn't likely improve reliability much.  It's a bit like a twin engine plane vs a single engine plane, because a twin engine plane (apparently) can't really fly with only one engine anyway, by adding another engine you've just doubled your changes of a failure.

    I think the first step in us dealing with engine failures better is to know for sure when they've happened!  An esc with functionality (like a heartbeat) that allows the APM to know it's no longer functioning would be a great help.  Then we could build code around dealing with it somehow.

  • Interesting proposal, Gareth.

    But even with the two APM, it will only survive if the motor failure is confined to either upper or lower motors.  But the problems still is to know which motor failed and shut off or speed up the right matching one to maintain yaw.  If this is worked out, you could probably do it with one APM.

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