I've been fine-tuning my Align TB70 in the Spirit GT, but cannot get the tail to sit still in flight.

Here's my setup:

Align TB70 (w/ 490Kv)
Spirit GT
Hobbywing 260A v5
Savox SB2292SG (cyclic)
Savox SB2291SG (tail)

The heli flies straight and true. But the tail hunts and wags no matter the rudder gain setting I try, even at 0. I've tried the range 0-100, and the only noticeable difference is extreme tag wag on the ground at higher than 75% rudder gain. I've tried every range, trying the tail multiplier from 1.0 to 1.3. No change.

One setting I don't understand is the Pirouette Consistency. 50-250, it barely changes the tail.

I've checked my mechanical setup, and the tail is free and easy to move by hand and servo. The servo I'm using claims @8.4v: 0.042 sec/60 deg. So, it's fast. And strong.

The X and Z axis shows minimal vibrations when I use the Spectrum Analyzer. But, the Y axis shows extreme vibrations. I've checked every nut and bolt, rebuilt the tail rotor assembly, and ensured everything is mechanically free to move.

I'm at my wit's end here. Is the Spirit GT too sensitive to use on the TB70?

Any suggestions?

Hello,

there are pilots with TB70 and Spirit units flying without a problem.
Regarding vibrations, Spirit GT is likely the least sensitive unit for a vibrations you can get today.
But if you can see extreme vibrations, there is unfortunately something wrong and you should fix it.
If you can share a vibration plot I can help you.

Sometimes you can replace everything but it will not disappear. Only single missing washer can cause very big problems.
However the issue you have is not directly related to vibrations at all. Vibrations are only a side effect likely.

If tail is not reacting to a Gyro Gain it mean that mechanics will not allow servo to move freely. For this reason you can't see almost no difference. Normally you will notice 10% clearly.
In other words you can set anything in the unit and it will never work properly until the mechanical problem is found. It will happen with each FBL unit.
If mechanics is butter smooth, it will work immediately well even with stock settings with almost no tuning needed.

I suspect there is something wrong with tail rotor hub. Likely axial washers are not oriented well or something does not fit there. This is creating also very likely such vibrations.

For your model set Pirouette Consistency to 185 and it will be good.
You can share your 4ds file settings too. I will inspect it.

So the main problem is in the mechanics - anywhere in the tail. Make sure there is absolutely no friction in the push rods. Push rod is not bent or moving through a slider with friction. It should move so easy that tail slider will move itself when you will move with model to a side.

Also set Rudder Delay to 0.

_________________
Spirit System developer

I've attached the spectrum analysis charts and my settings file.

I've rebuilt the tail section exactly to Align's specs. There are no missing pieces or hardware. I'm not sure what else to repair or replace. The tail rotor hub is new.

However, I will run the spectrum analysis without the tail installed to see the result.

Hello,

thank you for the plot.
These vibrations are unfortunately terrible, I would say more than extreme. I highly recommend to not fly in this condition.

It seems they are coming from motor, but interestingly also from the tail.

Please note, when you install tail blades, vibration level will further multiply by a factor of 3 - 10 usually. So it is miracle it could fly actually.
Could you start the motor without any other gears?

In this way we can find if it is starting from the motor itself. If so, it will be a faulty bearing or something like that.

Is the Spirit unit installed with supplied tape? Isn't there some cable or connector that is touching Spirit unit itself? And causing additional vibrations?

_________________
Spirit System developer

It actually flies okay, other than the unstoppable tail wag.

Anyway, I've attached some spectrum plots with no tail and other parts attached.

The tail rotor shaft is bent, but just a little. I've never struck the tail, so that is odd. But I ordered another one, and it's on its way.

I'm not sure what to do about the motor. I've only put maybe 8 hours on it.

First you could try to reduce Governor gains if it is used.
I am afraid something is vibrating there so much I have never seen.

Please do not fly with a bent shafts, because with each flight there is excess wear of a bearings. This mean other components can be damaged and will require replacement.
If there is bent shaft it could cause wag as well, because mechanics will not move freely under high RPM.

_________________
Spirit System developer

I'm using the governor in the Hobbywing (1800/2000/2200), not the Spirit.

I have new parts coming today, and after I replace them, I'll run another spectrum analysis.

I replaced every tail piece and part. And I replaced the main shaft and bearings to rule out those issues.

According to the Spirit's scale, the vibrations are still high. The new parts lowered the level, but it is still high.

So, I swapped the Spirit for a Spektrum FC6250HX, and lo and behold, the tail does not twitch on my TB70.

Then, I put the Spirit on my Align 550e and used Spirit's settings for the 550, and the tail twitched like crazy. It did not do this with the FX6250HX installed.

So, is this a Spirit issue in the box or software, or will Spirit units not work on my Aligns? I am within the return period.

I have my Spirit GT on an old Trex 600N with pretty stock electronics, low specs in terms of today's gear, and that is Aligs DS610 servos on cyclic and a Futaba S9254 on the tail, everything running at 5.8V. Previously I had a DS650 tail servo on the tail which ceased to work because of tail shaft stickiness problem. However I've always been amazed by the tail performance, even with an old coreless servo like S9254 the tail holds very nicely, and this heli vibrates like hell, in idle 1 without blades if I hold my hand on it sends vibrations through all of my body down to the tip of my toes. Kidding aside, I want to say that Spirit GT is a unit, that at least for me, showed very good tail performance out of the box without little tuning or tinkering, if any.
Make sure your tail slider runs smoothly on the shaft (I'd recommend disconnecting the tail servo rod and manually do this check periodically), try another hole on the servo horn, lower the gains, try different foams under the unit or another location on the frame.

My 550E flies flawlessly with the 6250. It twitches and oscillates with the Spirit installed. I cannot seem to dial this out on this heli, too.

The steering rod on my TB70 couldn’t be smoother or more effortless. All of the mechanics are square, too.

I ran the vibration analysis on the 550E, and it’s off the charts in each axis. But the 550E flies straight and smooth with the 6250. For me, the claim that the Spirit is the least sensitive to vibrations isn’t valid.

I’m afraid this unit is going back either for repair or return. I’m tired of wasting battery with a twitchy tail that can’t get dialed out.

To boot, the wifi-link for this unit is flakey and is now locked into client mode.