Spooled up without issue, once the heli was 5ft off the ground, it started an un-commanded roll to the left.
The roll because more and more until my collective was full right trying to correct it. The heli then continued to roll left and crashed.

Spirit Red, firmware v3.4.3. GeoLink v1.

This heli has many flights on it and it's never a problem.

I've rebuild the head and disconnected the geolink, and i've flown it successfully.

What could have caused this?! Faulty geolink? Faulty/stuck gyro?

Did anything happen between the last successful flight and this unsuccessful flight? Meaning, any rewiring or major parameters adjustments in either one or all of the banks? Is it possible the Stabi function was engaged while the helicopter was still on the ground? Any chance you adjusted the radio gimbals but not recalibrate the channels with the Spirit unit?

No work was carried out on the heli, hence the old version of software on the unit.
It was packed away for the winter, and crashed on the first flight.
Pre-flight was fine, everything checked out ok. I gave it a really good inspection before the flight.

It performed exactly as expected on the ground during spool-up. The trouble started once it was off the ground. I suspected faulty wiring on a servo, but it all looked perfect after the crash. It was a slow roll that got faster and faster- not a vicious jerk roll that I'd expect with a servo of link failure, although I've not had a cyclic link failure before. When that happens does it slow roll or fast roll?

If I understand correctly, you flew this helicopter with the same electronic setup successfully several times (I assume last successful flight during the Fall 2022), then you stored the helicopter during the Winter, and now took the helicopter out for the first flight in 2023 and this happened. So what could have possibly happened between the last successful flight and this bad flight? Assuming the servos were working properly and the servo connections to the Spirit unit were solid, I would be looking at a faulty gyro/accelerometer sensor.

Exactly. The heli was hanging on my wall at normal room temperature for 4 months, then 1st flight it crashes. Next fight after a rebuild it's back to normal again.

I've been through all the settings etc. The only thing I can see that's wrong is the GeoLink X position is not changing. The display is frozen at 90°. Y position is ok.

I'll need Spirit support to help me with this (maybe a way to software reset the geolink? or return for repair), but I wouldn't have thought that the spirit unit uses this during normal flight- I would have expected it to use it's internal gyro instead? I don't know.

I'll wait for Spirit Support to reply after Easter holidays.

Hello,

in the FBL units there is basically nothing that could wear or damage even when not used for 20 years.
So FBL units are usually the last thing where the problem could develop itself.
On the other hand completely whole mechanics when is not used could be more and more tight, just because various powder can adhere to the shafts.
This could then result in lock of some shaft or push rod.

On the other hand there could be also no error in reality. Sometimes this problem can happen if for example you are moving with sticks before flight. Then there are conditions that could result that swashplate will not return back to center and will remain tilted even during lift off. This can happen when:
1. there is ESC fan
2. there is really big wind that is moving with the model all the time
3. model has motor already on

These 3 could switch unit to flight mode where swashplate is not returned back to center automatically. Then you have to return it back by sticks before lift off otherwise model will try to achieve inclination that was given by sticks even minutes ago.
Then during lift off it will finally tilt to this position which is unfortunately contact with ground.
This is one possibility that could happen.

Other is super high vibrations.

Or if using GeoLink then it could be some function enabled during lift off - for example return to home or other.

These are all possibilities that could lead to this problem, but failure of unit is the least probable reason.

_________________
Spirit System developer

Is there a way to unfreeze the X-position? Or can I please return for repair.

Hello,

if you can see 90° even when model is in horizontal position then this is really not good. However it will not happen itself. It could happen after hard crash. Fortunately it has no impact on behavior of the model, or performance because it is measured by accelerometer of the GeoLink which is not used for any feature when flying.
I can send you special shortcut for resetting the calibration for GeoLink.

Please make sure that your GeoLink has the latest firmware 1.2.1.

Possible it could also happen if you or somebody else did accelerometer calibration incorrectly.

Also during takeoff no GeoLink feature should be active. But if there was something active then this was reason why this happened.
In any case if you will not find why it crashed then the issue will happen again sooner or later. Do you remember what was enabled/disabled or how swashplate was tilted during lift off?

_________________
Spirit System developer

Y and compass are responding and look correct. X is always 90.
The firmware is already 1.2.1, I've owned this GeoLink since new.

What's the process to restore X ?