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Trex 500 and Spirit GT Tail Oscillations.

Posted: Fri 06. Jun 2025 20:43:53
by helicopterjeff
Just after take off, the tail starts violently oscillating.

My normal solution before the GT was to turn the gyro gain down.

I've read the guides on tuning, but I'm not sure how to turn the tail gyro sensitivity down in the software.

The rudder common gain is 1x and doesn't go lower. Stabilization is set to normal and it is set for flybar.

The tail servo horn is at 90 degrees and the tail link is the same. (this is how it was setup prior to installing the GT and didn't have issues using a standard heading hold gyro)

I double checked the travel for the tail servo as well, its just to max on left and right.

Any suggestions?

Thanks!

Re: Trex 500 and Spirit GT Tail Oscillations.

Posted: Sat 07. Jun 2025 7:13:41
by ZeXx86
Hello,

you have to adjust Gyro Gain in your radio by default.
At the Diagnostic tab in the software you will see current Gain.
I recommend to start with 50%.

Re: Trex 500 and Spirit GT Tail Oscillations.

Posted: Sat 07. Jun 2025 9:32:54
by TrueBuild
I found this a very useful video for some gyro systems; https://youtu.be/o2ee2VDAENg :)
He is compensating for the torque of the rotor blades and thus giving the gyro less work to do it seems.

Re: Trex 500 and Spirit GT Tail Oscillations.

Posted: Sat 07. Jun 2025 19:31:04
by andy6409
I had this problem with a 500X
It was caused by the align esc governor if you are using that

Re: Trex 500 and Spirit GT Tail Oscillations.

Posted: Thu 12. Jun 2025 14:46:49
by helicopterjeff
I will take a look at the radio end, i have a question about that though- isn't the yaw channel also used to set the stabilization mode? (turn it on/off)

Re: Trex 500 and Spirit GT Tail Oscillations.

Posted: Thu 12. Jun 2025 14:48:06
by helicopterjeff
TrueBuild wrote:I found this a very useful video for some gyro systems; https://youtu.be/o2ee2VDAENg :)
He is compensating for the torque of the rotor blades and thus giving the gyro less work to do it seems.
I have used that video in the past. It helped a lot with a different model.

Re: Trex 500 and Spirit GT Tail Oscillations.

Posted: Sun 31. Aug 2025 14:17:29
by helicopterjeff
i finally got it. learning the GT controller has been an adventure.

I realized the rate channel was set very wrong....now ive got it so ive got three sensitivities based on what im doing.

Thanks for all the help!