Fail Safe

[Usman]

I was just wondering if I can get any input from members to make sure I have my fail safe feature activated in any case scenario-brown out, transmitter loss function, signal loss, whatever. My worst nightmare is having this bird take off unexpectedly and going who knows where without my control. Right now I have the stock setup with the exceptions of upgraded hitec servos installed to satisfy the increased power demands of the servos;
http://www.ebay.com/sch/i.html?_from...e+2474&_sop=15
Is there anything else I need to do in order to make sure I have a fail safe feature activated in all case scenarios? Thanks in advance!

[wulfrun]

You haven't mentioned if all the electronics (apart from servos) are "stock". Assuming you have the DX6i, stock receiver & stock ESC, there is no "fail safe" to be set up. The 2.4GHz radio gear is fairly bulletproof in terms of signal loss, brownouts or whatever other concerns you may have - they are very unlikely in reality.

However, the unforeseen can happen, so if you want to know the consequences, first disengage the motor pinion from the main gear and re-lock it, or alternatively remove the main AND tail blades from the model. Power it up, set the throttle so the motor runs and then switch the transmitter off. What should happen is the motor should cut out completely. If the model were flying, it would simply drop out of the sky wherever it happened to be.

There are some "insurances" you can make against this scenario - firstly always make sure you have properly charged, reliable batteries in the transmitter (it's better not to use non-rechargeables) and secondly do a range-check, using the transmitter's "range-check" function. If it passes the range-check at the sort of distances you'll be flying, there is no cause to worry about loss of signal. You should do a range-check each time you fly. You should also check that the "throttle hold" is set up correctly and does work as intended.

FWIW the DX6i is pretty economical on batteries and the voltage readout is fairly useful. A set of rechargeable NiMh batteries will run it for quite a few hours. Always check the readout before flying and replace/recharge if they don't read over 4.8V. If they run flat in use, there's a low voltage alarm that will give you time to land the model (immediately!) but I'd suggest that's pushing your luck to let things go that far!

[Usman]

Thank you, I appreciate it. Yes everything is stock.
What I will do is test it out, power everything up after everything is safe to do so with the blades removed and all, and then cut the power to the tx.
im just really paranoid, that's all, just figured id see what members had to say.
I appreciate the response.

[wulfrun]

Better over-cautious than too casual about things. Paranoia might limit what you do but it's unlikely to cause you harm. The opposite might well do!

[Thomas.Heiss]

Are you using Spektrum receivers?
If so make sure that you bind with throttle -100 signal.
That will set your failsafe.
Hold switch also MUST output a -100% throttle signal, otherwise your ESC might do some weird auto-learning (if the signal e.g is >-100%).


For most 6CH channel receivers failsafe only works on throttle port.

The other channel ports will use "hold last command".
So nick / roll / collective / rudder will be hold in the position before the loss of signal.


There are also some Spektrum receivers which support "preset failsafe" (on bind) like AR8000.

I can't answer this question If it may make sense to put collective to a neutral / mid stick position on loss of signal if the RX would support "preset failsafe".

Thomas