Autotrim on V-Bar

[Tim Procter]

This is going to sound like a dumb question but.!!

On my new Align 550e I have the V-Bar Express V5.

When setting up the ESC to program it you switch your TX on at full throttle, you are then in programming mode..... Easy.

Trouble is when going to the field to to do an "Autotrim" on the V-Bar you obviously apply the throttle at full on powering up to engage this procedure.

How is this acheaved without the ESC going into setup mode first.??

[mattie-lodge]

Tim,

I don't know if this works but try putting it in Throttle hold then turn it on with full stick. Your looking for the double jump of the swash plate to confirm your in Autotrim.

[Tim Procter]

Tim,

I don't know if this works but try putting it in Throttle hold then turn it on with full stick. Your looking for the double jump of the swash plate to confirm your in Autotrim.

I actually thought about throttle hold Matt but dunno whether this will work.

Yes I did the autotrim no trouble with the nitro 700 mate, looking for the double jump of the swash.

[mattie-lodge]

It may work, I don't know if its looking for the throttle high or collective high??

[G-Bru]

Yup, throttle hold!

G

iPhone & Tapatalk

[Jamin_00]

As Grant says, hit throttle hold then power on

Done mine the othe week

[Swashbuckler]

Indeed it's high collective the vbar is looking for. If during the setup of the vbar you used a level tool to get the swash flat you shouldn't need to do an autotrim. Just run it for a bit with the cyclic and tail optimizers ticked.

[Jamin_00]

Mike, I think its worth doing.

Even though on my 550 it only is the tiniest amount of trim that has been added but by doing this is takes everything into account and makes sets it all up perfectly

There was a little bit more on my Srimok that was added but by doing this I now know exactly where to place my batts and where to place batts of different weights too.

Its a great feature imo

[Swashbuckler]

I've never seen any difference after, guess I have been lucky with my c of g. I can see what you're saying though.

[GravityKills]

yes, throttle hold *should* do.

Some background about autotrim, this is misunderstood all the time:

The "autotrim" word is misleading. It does NOT trim the heli at all, it has no impact whatsoever on drifting. If it drifts, there are vibrations or severe asymmetries in the geometry, and autotrim is unlikely to help.
As long as the sensor input is correct (no vibrations), the control loop will always trim a stationary heli perfectly.

No, what the trim flight does is determine, how much static correction is needed for center of gravity, non-perfect servo geometry and so on. This never changes, as long as the mechanical setup isn't changed.

In addition to static corrections, the V-bar applies wind corrections (= airspeed).

When the heli piros, for example right, the v-bar predicts that the wind corrections need to be rotated left by the same amount to point to the same direction, relative to wind or movement.

If the v-bar does not understand the difference between static and wind corrections, it will rotate everything by default. If so, the static corrections - which are rotated even though they shouldn't - point very slightly to the wrong direction.

That's why the heli will squirrel away in a stationary piro before the trim flight, and remain stationary when the trim flight was done correctly.

Hope this makes some sense ...

[t-rex pedro]

This thread just answered the very question I was scratching my head over! Throttle Hold - Of course!

GravityKills - Great post explaining the trim flight benefits.

Cheers guys

[ChrisB]

Yep of course. LolDOH

[Summa1988]

you know after you do the autotrim, do you take the tick back off the autotrim or leave it ticked from the vbar software?

just it was working perfect but when i connected the laptop up then had another flight, it was out of trim again?

[Planehazza]

You have to untick it yourself I think, but I'm not 100% as I haven't done it yet myself. Have you watched this?

[Jamin_00]

I leave it ticked as it wont go in to Autotrim unless your at high stick so no worries there