In the gov, there seems to be a bug that could damage the drive train.
To reproduce, on the bench:

Set a target speed. I'm using 3600. I'm using "fast" spool-up, which takes about 10 secs (so ~360rpm per sec ramp-up speed).

Take off the blades!

1) Spool-up in Idle up, watch the RPM screen until it gets to 3600 and settles.

2) Next, hit throttle hold. Watch the head speed reduce to 3000, then turn off throttle hold.

At this point, i'd expect the spirit to increase the speed back up to 3600 at a rate of 360rpm per second (10 secs to 3600 from zero).

For some reason, the spirit gov requests a head-speed of ~500 rpm, causing the motor to brake hard which, if loaded with blades and flying, i think could strip the main gear or cause the tail to rotate.

I've not tried this in the air, only on the bench.

I am afraid but something is wrong in your setup.

Requested RPM must be 3600 RPM again. And after Throttle Hold the spoolup procedure will start from the beginning smoothly.

Likely you have improper Throttle Curve for Hold. This should be approximately 0% - see Diagnostic tab.
Even if this would occur it will not damage anything if your model has one way bearing - which is case for the most helicopters. Only micro helicopters could have this issue.
Motor should not brake anytime. If yes, then ESC settings is not good. Please turn off brake feature there. It is suitable for planes for example.

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Spirit System developer

I've checked. My throttle hold is set to zero percent.
When I turn off TH, requested RPM is 3600, but it starts spooling up and then jerks to 500 rpm, then starts climbing up again.
If I flick TH on, wait a sec turn it off, then on, it jerks a few times.

Please try this out on the bench. I don't think that it's my setup that is wrong. There's a bug.

Brake it disabled (HW plat v4).

We are testing Governor for years like this. Please note behavior without blades is very different as there is no load.

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Spirit System developer

I'm not able to test this with blades on. I can't see how loading up the motor would make a difference as it appears that the gov is requesting a speed that is much LESS than the current RPM value when spooling back up after a throttle hold.

Can you please try this on the bench.

Yes, we are testing it also with no blades. But behavior without blades is different for each motor/ESC/drive train.
I am perfectly sure there is no bug. I dont need to convince you, but if it is really needed I can record video if I will find some free time. But likely it will not help anything.

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Spirit System developer

Hi- I found the problem. The manual needs a minor update:

http://manual.spirit-system.com/index.p ... RPM_output

For the V3 escs, you must set Flight Mode: "Airplane" and Brake Mode: Off.

For the V4 escs, you must set Flight Mode: "Ext. Gov" and Active FW: "Disabled".
or Flight Mode: "Airplane" and Active FW: "Disabled", brake force 0% and brake mode Disabled.

With the above settings, "Airplane" and "Ext.Gov" appear to behave the same.

Active FW: "Disabled" is very important.

Hi,

thank you very much for the details!
We have updated guide.

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Spirit System developer