Tail is "whining" at high speed (TDR)

[Sepp62]

I set up my Spirit in my TDR with the default Settings.

Everything is working fine, tail stopps perfectly in pirouettes and there is no "dolphin" effect at high speed.

But there is one negative effect on high speed:

The tail is "whining" which means it shakes with a frequency of about 3-5 Hz and a small amplitude.

I already lowered tail gain from 60% to 52% (rudder common gain is 1.4).

Settings file is attached.

Are there any suggestions how beaviour can be improved ?

Best regards
Bernd

[ZeXx86]

Hello,

Normally, Piro Consistency for such heli size is approx. 175 - 185 for better holding performance. So you can increase this.
Decreasing Rudder Delay (even to 0) may solve the issue too.
If nothing helps, you can also try putting ball linkage closer to the center on your tail servo horn (dont forget to re-set servo end-points).
What servo do you use? For brushless servos Piro Consistency is at least 180 and Rudder Delay mostly 0.

[Sepp62]

Hi Thomas,

thanks for your quick advice. I am using BLS254.

I will increase piro consistency to 175-185 and set delay to 0.

Best regards
Bernd

BTW: Im am looking forward to the time I can do this with my DS 16.

[Sepp62]

Problem is gone with the new settings:

Rudder: 60%
Rudder Gain Multiplier: 1.2
Servo delay: 0
Pirouette consistency: 180

Thanks your your advice!

[buell47]

Hi,

i have the same effect in high speeds.
Everything is fine, tail stopps perfectly in pirouettes.
linkage ball is close to the center on servo horn.

REX 450L Dominator 6S
Tail Servo: Align DS525M

Rudder: 60%
Rudder Gain Multiplier: 1.0
Servo delay: 10
Pirouette consistency: 165
Rudder dynamic: 6

......OMG.....right now i realized, that the DS525M is a brushless servo
I should set the Servo delay to 0 - 2?

until now i don´t tried different gyro gain setting, just 60%
or what do you recommend?

regards Frank

[ZeXx86]

Hi,

servo DS525M is not brushless, it is coreless.

First from all Gyro Gain must be configured properly as it is very basic Gyro parameter. In your case you can try lowering to gain to approx 56%.

[buell47]

Hi Tomas,

i told you....i´m a noob
you are right....my mistake again

i will try it.

Rudder delay:10 okay?

thx

regards Frank

[ZeXx86]

OK, good.

Yes, 10 may be fine. You can also try low values (even 2 - 10).