Technical, Techniques, Hints, and Tips > The "Black Arts!" ( Electrics & Electronics )

'....the motors go into full reverse……but why?'

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Morning all, it seems the only time I post on these forums is when I have issues! Sorry!
Anyway, Ive just come back home from a little sail at the lake where something very dramatic happened.
I was sailing my new to me (second hand model brede lifeboat, 1;12th scale)

Previous owner has fitted 2 x electronize speed controllers 30 HV ones, and a planet TX RX receiver is the radio setup.
Anyway, gently sailing around nice and relaxed until suddenly the boat kicked into FULL REVERSE! Ive now got the boat diving stern first into the water!!!! And im out of control with water washing over the stern deck! ( a good minute or two passes with me desperately trying to regain control all the time knowing water must be pouring into the hull)
Luckily somehow it came to a stop after this terrifying moment.
Now im pretty sure ive gathered why this happened….the signal between the TX and RX was lost….ive proven this because on the bench….when I turn off  the TX, the motors go into full reverse……but why?
I assumed if signal is lost it should go into a failsafe mode right?

Im nervous about using the model now until I understand or put measures in place to stop this happening again.

It sounds like the RX did revert to fail safe mode...

The position of the throttle "failsafe" may not be what you want or intended i.e. full stick down = full reverse, this would be the default setting of the failsafe for an RC Aircraft where full stick down is low throttle setting (likely to be the setting as the radio set was manufactured)

What radio set (Make/model) do you have?

Often the failsafe is set by the position of the RC control "stick or switch" to the required "failsafe" position with RX powered on - TX powered off, then TX power on - but sequence/process does vary depending on the radio set.


Yes, that is undoubtedly the failsafe for gas motors, dropping the throttle to zero (which means full reverse in a bi-directional stick setup).  Simplest fix is to use a different channel for the throttle, moving the ratchet mechanism over if you want. 

The more involved solution is determining why the model lost signal in the first place.  That would involve checking the Tx and Rx power supplies for issues. 

Im using a planet T7 TX and RX....throttle is setup on LH stick using spring centering

For further information, the speed controllers are

Electronize FR30HX

I dont know much about these, they are discontinued? Does anyone have any litrature on them, for example, setup, settings?

Do they have an inbuilt failsafe ect?


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