Setup/Trim - Expert v Standard

I am just double-checking my trim and am perplexed by a swash artifact:

All my 4x banks have the same (120* swash) SERVO parameters (-51,9,-18) (*). Meaning that I can toggle my bank switch on the Tx and the swash DOES NOT move (in Standard mode at center mast). Good.

When I switch to Expert mode the swash repositions according to where my pitch stick happens to be. Good.

When I now toggle between TH and ST2 - both of which share IDENTICAL (linear) pitch curves in my Tx and my servo monitor shows ZERO signal movements (bar the bank selection channel), servo 1 and 2 on the swash move slightly. Bad.

If I accurately position my pitch stick at 50%, then in Bank #0 I can now toggle between Standard and Expert mode without the swash moving at all. However, when I repeat the exercise with Bank #3, I observe again the same deflection as before.

Strictly speaking, therefore, Standard and Expert mode do not agree on which servo positions level the swash for 0* pitch in Bank #3.

Any idea why this might be?

(*) Incidentally, is there any good reason why these trims should be at all bank specific? I had thought that setting those once for all banks would make more sense?



Edited 1 time(s). Last edit at 06/05/2011 12:42PM by Ollie2893.

If all trims in the Trim tab are the same on every bank ... check the autotrim in the main page ;-)

regards (EN) / Gruss (DE)

Rainer Vetter

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You are one cryptic man, Rainer. What am I supposed to make of your answer? The bird has never been flown yet and I have not attempted an auto-trim flight. Yes, all the 3 servo parameters are the same over all banks. (Incidentally, I changed them again from my OP. I figured out that it works better to do the collective leveling with the aid of the Expert mode in Setup/Cyclic by eliminating any shearing at exactly 50% pitch and center cyclic.)

Well, could be that there are artefacts in the trim flight memory, anyway.

So, if you switch through banks, do the gauges in the main screen show different values?

For a test, you could copy one bank to all the others and see if this cures the symptoms.

An other cause could be that some "hovering pitch" (trim-like) function is set in one of your flight modes, and that the control lever is on click off center.

Regarding the live gauges in main menu, or tx calibration screen in setup mode: do the gauges move when you change flight modes/banks?

— Eddi

Born to fly ...
forced to work.

> Well, could be that there are artefacts in the trim flight memory, anyway.

Dunno. Perhaps. I am new to the vbar. Personally, I have never flown it (until a few minutes ago). It is a 2nd hand unit, though. Mind, I thought that all that would be forgotten about when I started a new Setup. But perhaps not?

> So, if you switch through banks, do the gauges in the main screen show different values?

Nope. Only value that changes is the AUX channel which switches my banks.

> For a test, you could copy one bank to all the others and see if this cures the symptoms.

That's how I originally initialized all the banks.

I actually really like the parameter bank concept but am totally baffled as to why anyone would think that Bank #0 might want a different swash trim from Bank #1? Or why Bank #3 might fly a different gear ratio to Bank #2? SOOOOO odd.

I think the Setup wizard should only contain parameters shared between all banks, and the bank-specific stuff should be done on the main screen.

As it is, it is all rather confusing.

Anyway, thanks Eddi. I decided to ignore that artifact in the Setup and simply try to fly it. I read Rainer's answer to mean that I should ultimately do my own trim flight and not worry too much about the bench setup. At this very moment, I am fighting massive tail vibes which seem to be down to governor gain. Oh well, who said it was gonna be easy... ?



Edited 1 time(s). Last edit at 06/05/2011 06:08PM by Ollie2893.

Hi again,

there are technical reasons for having some parameters per bank and not global, as would appear just logic.
Mostly it's since VBar features 4 independent memory banks and parameters that have dependencies must be saved in each bank separately and therefore can be set up independently.

As for the trims: different rpm require different trims (even if so slighly, it makes a differernce) and different rpm also require different optimizer settings, for example, although I often only do these things for the highes rpm I fly and copy to the other banks with lower rpm where I only raise gains and maybe alter expo or agility.

But reasons for such behaviour as yours shows are usually easy to discover, as being described abovel

Regards

Eddi

Born to fly ...
forced to work.

> there are technical reasons for having some
> parameters per bank and not global, as would
> appear just logic.

Well, may be so. But if you need 4 copies of the same number, then there is no need to expose this "implementational (il-)logic" to the end user (ie me) via the PC GUI. Prompt me once and each time I change the value, perform 4 copies on to the vbar controller.

Just a thought...



Edited 2 time(s). Last edit at 06/05/2011 08:08PM by Ollie2893.

Well, you're certainly right. If things were that simple, it would already be this way, I'm sure

Eddi

Born to fly ...
forced to work.