Hello there,
I am a noob scale-type flyer with a OMP M4 max and Spirit GT. Tailservo OMP 3515T
I love lower revs (normal 1800 iup1 1900 iup2 2000).
I put some love and time in the setup process of the Spirit, and all is fine, but one thing is persistent:
there still is quite some tail wagging, but only when hovering.
With 1800RPM it is not much (acceptable), but when switching to higher revs it gets worse. The frequency and the amplitude of the wagging increase.
Tail servo is a mini and stays cool, cyclic servos are micros and get quite hot (45-50°C) even when hovering and no 3D-stuff (which I can't).
I checked if the rudder delay is correct and tested values from 2 up to 20, didn't help. My servo is sadly not in the list.
I changed the tail servo frequency from 560 to 200, no effect.
I played with gyro and pirouette consistency values.
I checked that the tail mechanics is smooth, and it is really smooth, no stick slip or high forces needed.
I checked the timing of the main blades, which is fine.
When spooling up the heli, there is one short moment when it is shaking slightly (@ ~1000rpm), then it is smooth and the vibration analysis also says that all is good.

My settings are:
Rudder rotation speed 11
Rudder Delay 5
Gyro gain 85%
Pirouette Cons 161
Rudder dynamics 6
Cyclic gain 55%
cyclic rot. rate 10,5
cyclic feed forward 5
elevator filter 4
Flystyle 6

Can you help me where the wagging can come from and how to stop it? I would like to change to revs higher than 1800, but not with this current behaviour.

Thanks, Chris

Hello,
it is very hard to help - helpful would be an video where the behave could be seen - so only assumptions are possible - At first lower the first (normal mode) headinghold-gain 75, for the higher rpm's there is less headinghold-gain necessary try for indle-up 1 and indle-up 2 set it to 70... -
Is there really a tail wag or could it be an aileron- and/or elevator waging ?

Is your heli really good setted up ? I don't know because I can't see...are the servos 90°, is the swashplate flat, are the blades in servo subtrim tuning at 0° -
Have you set 6° geometry tuning correct ?
Pitch how much (°) ?
Cyclic ring how much (°) ?

Regards

Hi,
thank you for your reply!
I tested gyro gain down to 50%, that doesn’t help the effect.
Yes, it is definitely a tail wagging, not aileron or elevator. I sould even say it is no wagging but fast swinging. It has a frequency of approximately 2Hz.
I did the setup 3 times.
The servos are at 90°, the 6° is correct. I have +-13° pitch.
Cyclic ring is at 140 (11°)

Rudder end points left 96 right 83
I don’t have a video yet. I don’t want to try that alone.

Regards, Chris

Here some photos of the linkage in subtrim mode. I think they are good. To reach them I needed to entwr values in spirit subtrim between -86 an -33.

Further pictures

Can a OMP M4 owner tell me what value for the rudder delay is right for the OMP 3515T servo?

Thanks a lot!

Just thinking, Could it be the governor ? is there a possibility to disable it and try to reproduce the tail wag? Are you way low from the designed head speed suited for this model?

I use the governor of the OMP 85A ESC, the spirit gov is disabled. I ordered the programming box for the ESC to shut it off and test the Spirit governor to see if that could be the reason. The used rpm are from all spurces that I know the perfect ones for the M4 max, as you can see in the screenshot. And the wag gets bigger when increasing, so the low RPM should not be the source of it. Today I flew at 1700 / 1800 / 2000. should all be fine watching Jonas doing the same. But again: tail was shaking left/right. It is indeed strongest when changing the RPM, so maybe a gov thing indeed…
The telemetry said afterwards max vibration-level was +24

Hello Chris,
have you seen this tuning manual from spirit (Cyclic and Rudder) ?
https://manual.spirit-system.com/index.php?title=Tuning_Guide

Maybe turn down the Piroconsitency a bit say the minimum of 155 ?

If I remember right the rudder delay is like the I-Gain of the rudder to hold the position -

If this doesn't help, then as senaka said, turn the P-Gain of your governor (Governor Store or something like that) down -

I don't know what ESC you have the original OMP ? that does not look like so in my opinion, could that be an YGE ? You have to go in the programming mode of your ESC an set down the P-Gain maybe 4-5 points...

You have to test that and see if something changes -
This has to be achieved, it cannot be said at the "green" table...

Regards

Hi Mattes,

Yes I know the tuning guide by heart by now
I tried the low value of pirouette consistency, but it had no effect. Next I will check if the governor is causing this, as soon as I have the programming card.