Lost Model Experience -- Settling with power

I'm interested in knowing what techniques others have used to make it easier to find a lost model after a crash.

 

While in Stabilize mode I lost control of a Gaui 330 during descent and it crashed into a tree canopy around 100' above ground level.   Most of the quadcopter remained in the tree canopy with a few pieces falling to the ground at crash time.

 

I believe the loss of control was due to Settling with power (http://en.wikipedia.org/wiki/Settling_with_power).  I had done several rapid descents prior to the crash and all recovered prior to hitting the ground.  The tree canopy cut my safety margin by 100' and the last descent resulted in the crash.

 

Model as flown:

Arducopter 2.0.39b

APM 2560

APM IMU Shield Rev-H (+Xbee 900, GPS, and Compass)

Hitec Aurora 9 firmware 1.0.8

Optima 9 receiver

flying weight 850 grams

All six (6) modes set to Stabilize

APM calibrated  with transmitter channels 1-5

ESCs calibrated manually

All APM parameters set to default

APM Mission Planner 1.0.63

Gaui X-S with central frame extension and stock ESC and motors

2200 mAh 3S 40C LiPo battery

Lighting kit (red left front, green right front, strobe rear center)

Weather conditions:  Dawn, no wind, clear skies.

ESC-Motor connectors: 2mm barrel connectors

Wiring harness to ESC connectors: JST RCY

Battery to wiring harness connectors: Anderson Powerpoles

 

Aside from flying too close to the tree line one of the mistakes I made was to disconnect BEC circuits from ESCs #2-4.  This left ESC #1 BEC as a single point of failure to power the transmitter after a crash if motor/ESC #1 is still attached.

 

In a similar tree canopy crash the quadcopter power remained on and I was able to turn lights on/off and rev the throttle to pin point the location.  Reving throttle dislodged the quadcopter from the tree canopy and it was recovered with trivial damage.

 

I also noticed that after the quadcopter was more than 300' away it was hard to judge rate of ascent/descent when changing the throttle.

 

For my next multicopter I'd make these changes:

* paint chassis with reflective paint and or UV sensitive paint.

* Add a Lost Model Alarm (passive, active, or both).

* Securely attach an Rx battery pack to RC receiver.

* Avoid descending straight down

* Rate of descent/ascent alarm

 

 

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Replies

  • There is another option is weight is not too much of an issue, or you are really interested in getting your unit back.

    The solution would be a phone enabled GPS tracker, one small enough to strap to a cat normally they are really rugged and can be pre programmed to  phone GPS coordinates to secondary device via SMS.

    Independent 40 hr battery 17g,  GPS unit 20g EXC. battery

  • I've wondered about this type of thing... I use a "SPOT Device" for outdoor activites. It's a bit heavy for a quad maybe, but on a larger craft, it might be a stupid simple solution.

    What is the range on the 900 Xbee anyway?
  • Distributor

    I would recommend the use of a telemetry kit, as long as you have power to the APM / Telemetry kit and it has not been damaged you can look on a laptop and see the flight path and where it is "now" I see from your profile you are in the US, so I would recommend you look at the kit here.

    I also sell the telemetry kits here in the UK & EU where we are not able to use the 900 Xbee’s, the telemetry kits also help with rapid tuning of the PID values, no need to keep connecting to the laptop with the USB lead!

     

    I hope this might help you with any other "lost" quads / planes.

     

    Regards

     

    Martin

    www.buildyourowndrone.co.uk

     

    

     

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