Cyclic bobble in tic toc

I have a cyclic bobble when doing tic toc. most noticeable when doing elevator tic toc. I tried lowering main gain but did not help. I did a trim flight and that did not help. Tried setting up the swash with swash leveler that did not help. Replaced all three cyclic servos with brand new torq BLS2208 servos I was using futaba BLS272SV. Replacing the servos did not help. The heli is very unstable in tic toc. The air frame is a Goblin 570 sport. The head assembly is free from binding. Its been doing this from the beginning when the heli was brand new. I attached the flight logs. thanks

There might be a few reasons:

- the pilot moves other axis unattentionally while tic-toc (let a buddy have a look - or for tail - lower tail agility and increase tail expo for a check flight)

- the swash might be ok in 0deg levelled but not in end positions (are all 3 servo horns levelled in the 0deg positions too? - If not, adjust the rods to the swash to get them so)

- the main head system has a bit phasing effect being off from the 90deg mechanically built in (in this case rotate the servos one click back from the usual 90deg leading control to 85deg)

regards (EN) / Gruss (DE)

Rainer Vetter

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How many flights do you have on the G570? Which dampening? hard or not so hard? How much RPM? Which blades?
Greetings Christian

P.S: I also had G570 worked all perfect with NEO.....

Greetings Christian

Im not moving other axis. I have no other problems when flying my other helicopters.

The servo horns are centered. I'm going to level the swash plate at 0 and full negative and full positive. I have to get a swash leveler because I only have the goblen leveler and that's only using to level the swash at zero.

So when I go into the geometry menu do I want to move all the setting that are marked with A back or just the top one that's set to 90 right now?

So I moved all in the center row marked with an A back one click because I think i have to move them all and it's sill doing it.

Hi Christian
I have 160 flights on it. I don't know what dampers are in there what ever comes stock I got it new and never changed the dampening. RPM is 2300 on the head. The stock SAB 570 blades.

Any thing else I can try?

Hi Joe,

can you attach your current setup please, and tell in which bank it appears mostly?

Please describe the bobble better, does it only/mostly appear on one axis, or on both, or on the respective other axis?
How much?
Does the whole heli bobble, or is it rather the chassis below the rotor disk?

Common causes are trim flight, not done or off (try without, for comparison, note then zero out the values, do one again after that or dial in the values again after that), or the optimizer flight/settings. They treat the stop and acceleration behavior. Default is half the agility (say 45 optimizer for 90 agility), you might try changing it manually by five or ten, to see if it makes a difference.

Also the CoG can make a huge difference, usually you'd say neutral or slightly front is good, but try changing it deliberately, battery one cm to the front or to the back, and compare.

All things to try and rule out or prove, so we better know where to tackle the issue.

Because in general, I'd also dare say you shouldn't see such behaviour or a NEO or on a 570 or in combination

Best,

Eddi

Born to fly ...
forced to work.

I attached the set up file. It will do it in any bank.

The bobble is on elevator only. I can see it when doing figure 8 tail down funnels on the transition I get a bounce and when doing elevator tic toc its really bad the heli is very unstable. It looks like the chassis below the rotor disk is moving.

The trim flight seems inconsistent I had -54 on elevator and 2 on ail. then I zeroed them and did it again and got - 24 ail and -41 elev its not windy out.

I also set the heli up 3 or 4 times with the swash leveler removing the head and also did the end point adjustment with the swash plate leveler so i don't know how the trim flight can be so far off.

Hi Joe,

setup looks considerably standard, nothing fancy.

Regarding bank 2 (easiest way to check, for me, just open it in computer software) I can see that Agility is set to 106.
Default optimizer would be 53 (1/2 Agility).
But it's set to 46 ... on purpose, or by automatic? That would be one thing to try, as I wrote above, set to default, try, then increase it by ten, try, compare, see if it makes a difference.

Auto trim is an educated guess-o-meter. If left alone (no stick inputs), the VBar will fly in a sort of normal mode, and listen to drift (using to the sensors), and trim until the sensors are/remain at center. As if you would adjust the linkages until there is no drift any more, in normal mode, on the tail.

So external influences can affect the quality of the trim flight, the time spent left alone does, too.
If in doubt, delete the trim flight values and try without, to see if/what difference it makes.

A swash plate levelling tool can only help to find the geometric center (which is not bad), but who said that the sweet spot is not somewhere else, e.g. with a slight angle to compensate for the tail thrust, or a slight angle to compensate for the cog, or other offsets?

Important to me is, right angles at center (or as close as possible, and even there might be a compromise ahead, angle to swash plate or angle to servo arms, at center or at which swash plate angle?), and that the swash plate moves level up and down in setup mode, so I have no servos with different travel. This I can trim, and I can trim the full pos./neg. positions, too, to equalize.

I know it's quite an effort, but if I had a second VBar NEO, I'd probably swap NEOs between helis at some point, to see if the effect stays with one NEO, or with the heli. Just to rule that out, as unlikely as it would seem to me.

Kind regards

Eddi

Born to fly ...
forced to work.