Hi, I'm posting on behalf of a friend, he was going for a second flight on his g770, he's using a radio master tx with fbl Integration (a bit rubbish to be honest next to my Jeti integration) anyway we went into settings to tweek some things, I noticed his servos were set to 50hz so we went ahead and but them to the correct setting, I then told him to be sure to save the settings, as soon as he did this the Heli spooled up at 100% throttle by itself, we had no control, throttle cut was engaged on the tx, the sticks were unresponsive, the Heli tipped up and destroyed itself on the ground.
I have changed settings in the fbl many times using my ds12 with no issues, I'm just trying to understand why the Heli would unexpectedly spool up? Anyone have any ideas cause I'm stumped, I tried to recreate the fault using my Heli but nothing happened.
He's using a spirit pro, hobbywing 130, align 850mx.

Thanks
Jay

That is very sad.
I am afraid this could be related to SBUS and transmission from Radio master.
Some recent FrSky receivers were having troubles with SBUS so FrSky released some firmwares. But it look like this introduced some other issues.

What receiver is he using?

So it will be necessary to replicate only with his setup. Then it could be enough to change some settings.
Of course this is not normal and is very sad. This should never happen.

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Spirit System developer

Thanks for such a fast reply he's using a frsky rx8r pro.

Thanks

Were you on 3.2.0 by any chance? I crashed my heli using an FrSky X4R after upgrading to 3.2.0, which introduced an SBUS enhancement. The problem was fixed in 3.2.1 with the ‘Improved compatibility with some FrSky receivers’ update.

It coild be but this unit has been flying a different helicopter all summer and worked flawlessly

I tried to recreate the same issue by doing the same thing yesterday but nothing all acted as udd expect it should

At first, there's no reason to link Tx (radiomaster or any other trade) with Sbus. This is rather Rx related. A major ESC defect is excluded since you manage to reproduce a correct functioning. To have a spoolup with no stick input means you have lost Tx-Rx bind or the Rx gave out resulting in a failsafe configuration.

Thus, the possibilities hereafter (hypothesizing the Tx-Rx bind been lost):
- Most likely failsafe set in the TX16S menu (Otx) to "hold" or "Custom Preset" mode with a non zero throtlle position or
- Provided the TX failsafe was set in "receiver" mode, i.e. to the SPIRIT fbl module, faisafe button could has been mistakenly hit when leaving the receiver channel mapping menu since this button is in a low central position, just like any exit button or
- Throttle reverse case hit (governor menu where throttle frequency can be set)

Also, keep in mind that every time you change the Rx bound in OpenTx, the failsafe is automatically reset to none.

It is hard to find where the problem is, but possibly the only thing we can do is to implement additional safety protection.
So that motor cant spool up when software is connected or integration menu engaged.

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Spirit System developer

Failsafe in the radio was set as follows

throttle stick - idle
throttle hold - on
cyclic & tail set to hold center stick

i think the lesson to be learned is to dis engage the motor by pulling the wires apart or swapping them so the motor runs backwards and doesn't engage the 1 way bearing and spin the blades up

also in the crash to spirit took a battering is there any were in the uk it can be sent to get it checked out before i use it again

Best to send it back to Spirit. They will take good care of you. The address is somewhere on here but PM Tomas (ZeXx86) and he will take care of you