DX6i sub-trim

[owend]

Can anyone explain the sub-trim menu on the DX6i? The Spektrum book isn't clear:
is the sub-trim a programmed version of the trim switches on the transmitter?
If so, where Aileron shows a left arrow and 9, for example, how does that relate to the trim switch position?
And perhaps most importantly, should I be using sub-trim at all, in view of the caution notice in the manual?!

Owen

[David Drew]

Sub-trim is IIRC not connected to the trim switches on the front of the Tx.

It is to help set up the various servos in alliance with the mechanical set up. You do as much mechanically as you can then use sub-trim to finally get the best set-up. You should have the front trims set at central so you have further trim either way should you need it for any particular conditions - for example setting up for windy conditions.

[owend]

Thanks, David, I assume that means that the combination of mechanical setup and sub-trims should ideally be set so the heli hovers as near to hands-off as possible? (In still air, anyway, which isn't today!)

My problem is probably my own making, I had softened the settings on the DX6i for a while, and today set them back to what the manual said; the heli now seems unbalanced, needing quite a lot of forward and left to get it hovering (although it's quite blustery today, so it was difficult to be sure). Should I set the sub-trims to try to get a stable hover? As a newbie I'm a bit wary of trying mechanical tweaks in case I completely mess things up!

Do the sub-trim arrows indicate the effect - eg a left arrow on the Aileron tab being the equivalent of putting in left cyclic?

Owen

[David Drew]

I would:-

Set all sub trims & front trim switches to central / zero.

Check and adjust mechanical setup as per heli manual (what heli BTW?)

Set sub trims to make up any shortfall in the mechanical set-up.

Test hover in still air or calm conditions.

Use main trims to finally trim out any drift.


Yes, I think the direction of arrow is as per stick movement. I have a 6i for my 130 but it's in the shed and it's raining so I can't check lol.

[owend]

It's a Blade 450 3D; there's nothing in the manual for mechanical setup, although some tutorials came on a DVD. I'll have to bite the bullet and learn about mechanical setup! But not today, it's too blustery to test-fly. But at least it's not raining here!

Owen

[David Drew]

Assuming that you have equal pitch both +ve and -ve you will have zero pitch at mid-stick.

Set the sticks to mid point. All servo arms should then be at 90 degs to the links and all links should be at 90 deg to what they operate.

Hard to explain but get everything to 90 deg basically.

Tail slider should be 1/2 way (central).

That way you will have everyting at neutral travel and a decent mechanical set-up.

[owend]

Thanks again, I'll have a trip out to MY cold, dark shed!

Owen

[shades]

Just as a note if you are going to check the mechanical setup disconnect the motor first. You wouldnt want the esc to start the motor while you were moving the throttle/collective.

[owend]

Yes, I'd figured that one, but thanks for the reminder! Connect battery as usual to get power to servos, but motor disconnected (under the battery holder I think, it's not here now!).

Owen