Tail wag issue on the Logo 600 SE V3

After assembling my Logo 600 V3 SE with everything stock, i am seeing tail wag on all RPMs.

Here is the config:
All stock parts including stock blades.
Neo controller with Vbar control TX
Tail servo : Futaba BLS274SV

Flew on 4000 12S and 3300 12S but the same thing happens.

Motor is a SCORPION HKIV-4035-450KV running 12T Pinion.

The video however is when i was flying on a 4000 6S lipo.

Links:
https://youtu.be/Asb1ySzbPNY
https://youtu.be/W3TuOnkZEGI

Tailset up video:
https://youtu.be/Hrt-pgqTiB0
https://youtu.be/ZR52e6NaEhI

Any idea what could be causing this ?

We put on a 600 Size Hirobo tail from a old heli and it was flawless, moreover damaged the original tail grip while trying to disassemble it to check what was wrong.

Ordered a brand new tail grip assembly and this is from the maiden flight.

Any help guidance appreciated.

Thanks.



Edited 1 time(s). Last edit at 05/03/2019 05:46AM by glennj.

Hi,

on the low head speed (6s) I doubt you get it to stay completely still.

With 12s and the usual head speeds, I'm pretty sure it will be better.

On a factory new tail, I would give it a couple of flights to settle, for example the ball links are tight (but will run in eventually).
I'm not familiar with the Hirobo tail assemblies, but if you say it's from an old heli, it's probably properly run in already

Please make sure the tail is built properly, including the shims below the bolt heads in both blade holders, and symmetrically.
Please also make sure the tail blades are weighed sufficiently.

I had to look closely, on the videos, though, I would not bother messing with it, just fly the machine.

Does changing the overall tail gain make a difference?
What you could try is lowering the expert parameter I a bit (like by 5 or 10), sometimes this was reported to help.



Kind regards

Eddi

Born to fly ...
forced to work.

Yes that seems to be happening - the more I fly she seems to be getting better.

Since there is really nothing more I can think of after putting on a brand new tail grip assembly, I am flying it as is - more the flights the issue seems to be getting better.

So i hope it disappears completely soon, to give me the confidence i was expecting with this brand.

The tail is built perfectly to the word in the manual. How do i weigh the tail blades sufficiently? - Did you mean balance the tail blades - they are the stock RT tail blade that came with my kit.

Also when you say overall gain above - did you mean the tail under tail rotor or some place else?

Thanks.

Hi again,

with the tail blades, I mean balance, right. A false friend when translating to English And if it was by try and error, with Scotch Tape for example. Especially if you can see fine vibrations e.g. on the tail fin or tail control rod. Even today's CF blades are not necessarily perfect.
The vibration analysis in the VBar can also help with that, to see if there are possible issues (peaks) or not.

Simpler: try a different set of tail blades, for a quick comparison.

I mean the flight parameter Gain or Gyro Gain (depending on where you adjust, VBar Control or Setup Software), not the individual gains (I-Gain, P-Gain in the expert panel).

Kind regards

Eddi

Born to fly ...
forced to work.

Diff blades will not help, I used the exact same blades on the hirobo grips and it was rock solid.

What about the tail gain?
I am currently on 90, but it's had a few flights now.

Initially when I set it up, I had to fly on 120 to be slightly flyable.

What are the recommendations for tail gain value for this heli?

Hi,

the tail gain depends on the head speed and servo, as well as the tail blades.

Usually, if the tail is set up properly mechanically (square angles at the control rod at center position (servo arm, bell crank), about equal throws, not too high pitch angles on the tail blades so no stall can occur, center position approx. 2-3° against the torque, trim flight done and not much to do for it), and if the pre-compensation is set properly, there is not much gain required, because of the feed forward to the tail rotor.

By experience, a good (read: expensive) tail servo like a Futaba BLS can usually handle around 90, at high head speeds.
A budget class servo like the Savox Servos or similar often can only handle like 55-70 on the same model, at the same head speed, but the feel (to me, as an average flyer) is about as locked in, I can do funnels or sidewards loops against the torque without issues.

Here the old rule of thumb applies: if you want to max out the tail rotor gain, do so until you get fast (audible or visible) oscillations under load or at high speeds, then dial down a bit. But by my experience, with the VBar tail, it's not necessary to max out the overall gain, with the feed forwards, the tail holds very well even at lower gains.

That all does not much affect a slight wag, in a hover. Most of the time, the cause is mechanical in some way, a breakaway torque which has to be overcome continuously, and the servo more or less overshooting slightly.

Kind regards

Eddi

Born to fly ...
forced to work.

So with my setup should 90 be the max tail gain and anything beyond that considered dangerous or not recommended?

I got to know because as time is going by, I would be playing around with all the gain/agility values.

If you tell me something should not be that high, I will know it's mechanical for sure.

Hi Glen,

well, as being said, it depends. At low head speeds you can probably max out the tail gain, at high head speeds—probably—90 is the maximum, but it could also be possible that you can dial in more, or that you have to lower it a bit.

You can change the setting in one bank, if you notice said high frequency oscillation, switch to a 'safe bank' (pun intended ).

Kind regards

Eddi

Born to fly ...
forced to work.

Ok thanks. Let me give that a go and I will revert back here for any issues.

Thanks.