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Notchy Servo Movement Cyclic and Tail

Posted: Sun 17. Jun 2018 16:55:58
by CFerry
Hi,

My Spirit Pro has been flying very nicely in my Diabolo 700 and I'm very happy with it.
However, I'm trying to solve an odd behaviour that I've never seen before on any other helicopters: on the bench, all 3 cyclic servos sound and feel very 'notchy' or 'rough' when i move the collective up and down, but ONLY with collective. With cyclic movements, they are all very smooth. The behaviour is always the same whether I do quick or slow stick movements. The tail servo also is notchy.
Is this normal? Is there a setting that I can use to fix this?
In flight, there are no observable problems.
My servos are Promodeler S74245BLHV for cyclic and MKS HBL980 for the tail. Servo frequencies all set within the servo specifications.
Thanks
Chris

Re: Notchy Servo Movement Cyclic and Tail

Posted: Sun 17. Jun 2018 17:01:24
by ZeXx86
Hi,

this could be caused by too slow refresh rate from your receiver.
Spirit unit is transmitting the data few times faster than an usual receiver does.
So you can see how it is really transferred with a fast servos.

If your radio support faster transmission, then it can be improved significantly.

Usually with 50Hz/20ms you will feel such behavior. With 100Hz is it much better. But in both cases it is normal.

Re: Notchy Servo Movement Cyclic and Tail

Posted: Sun 17. Jun 2018 19:21:35
by CFerry
Okay, I will check to see if I can change the receiver/tx refresh rate. I'm using Spektrum DX8 G2 along with Spektrum sats.
Thanks very much for the explanation! So if I remains notchy, it's not a problem for the servos?
Thank you
Chris

Re: Notchy Servo Movement Cyclic and Tail

Posted: Mon 18. Jun 2018 7:19:24
by ZeXx86
No, it is not a problem.

You can just verify if your connection is running at 11ms. This depend on how you have bound the satellites.

Re: Notchy Servo Movement Cyclic and Tail

Posted: Mon 18. Jun 2018 11:59:32
by CFerry
The default frame rate in the DX8 is 22ms. I changed it to 11 and rebinded an all servos are much smoother now!
Thank you for your help! ;)
Chris

Re: Notchy Servo Movement Cyclic and Tail

Posted: Mon 18. Jun 2018 13:36:50
by ZeXx86
Good job. Thank you for the message.