"Bodgy" Turnigy 9X Failsafe?

So I've read around that there's no failsafe on the stock Turnigy 9xV2 system, which seems pretty damn stupid to me.

However, I've noticed that if you actually trim the throttle up, you could set it (through calibration in Arducopter) that your min throttle value is around 1000 or so. When I turn the TX off, the throttle value drops to 900, every time. Turn it back on, throttle at min, returns to 1000.

So at this stage I know I can basically "fake" a failsafe event if I accidentally turn off the TX for whatever reason, but I'm curious, does anyone know if this behavior is the same on an actual loss of signal event as well? 

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  • Actually, one issue I think I'm having is that I can correctly trigger a failsafe event by turning the TX off in stabilize, and it'll switch to RTL or LAND, however, once I turn the TX back on, the flight mode will switch back out of RTL/LAND and into Stabilize again, instead of continuing to RTL like the wiki says it should (with no user intervention on the flight mode switches)?

  • Yep, I can confirm this actually works now. I covered my TX antenna in aluminium foil, set up telemetry on my phone, left the quad in my room and basically walked out of the house, and stood behind the big, nicely grounded metal garage door. As expected the signal dropped, and throttle value dropped to 900.

    Of course this means that your TX is going to have to be permanently trimmed up a little on the throttle, but much better than no failsafe at all! Even worst case, your TX gets reset and your trims are reset, the quad will just remain in failsafe mode, so no big deal.

  • I think what your seeing is sensible. If your tx is turned off which is getting out of range, both should trigger a fail safe. From the perspective of the Rx it cant hear the tx.

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