thoughts? my tail sub trim is set at (r)34, I tried moving the servo arm and thats the best I can get, but the concern I have is, at 34 the tail drifts right,, at 35 the drifts left , is it normal to have some minor drift one way or the other? or is there another minor trim I can set, I was told not to use any stick trim on the tail only sub trim.


450 se
dx6i

What gyro?

That is true, with a HH gyro, you don't want any regular trim. And 34 seems fairly high on subtrim as well. The only use for subtrim on rudder is to get the servo arm at 90deg....what arm/servo are you using? I have the S9650 and round arm and didn't need any subtrim.

Also, when you say the tail drifts right/left....is this in HH mode? The tail should not drift at all when in HH mode.

Give some more info: gyro, servo, heli.

If you haven't watched them yet, watch the Finless Bob video's over at helifreak....there is one on setting up the gy-401 with a S9650....there a a lot of good ones there.

Skarn

JR 7703D gyro heading hold mode , jr dg 3400g servo

trex 450 se

I have an S9650 servo with a Telebee HH Gyro and it drifts, too. The gyro instruction manual says, "When the gyro is ready, the rudder servo may run to one direction (when the gyro is in head lock mode). This phenomenon is NORMAL."

I'm a little confused myself. What good is having an HH gyro if it normally drifts to one direction or the other? Sub-trim doesn't fix it, either. In fact, I haven't found any parameter in my DX6i that does. In another fact, I haven't even flown my heli, yet. I'm reluctant to until I can find a workable solution to this problem or just don't use a gyro at all.

there shouldn't be any drift when setup properly. you gotta trim in rate mode with little gain as possible. keep working at it till the tail holding well with no trim. once its trimmed and holding in rate mode when you switch to head hold it should hold solid. i have the logitech gyro and it holds rock solid in head hold. if i can do it so can you. also per finless bob videos he said that the receiver must initalize before the gyro does. that way the gyro knows where center is.

Mal,

What that is talking about is when the heli is sitting on the ground, the servo can pull to one side and stay there. In the air, they should NOT drift as noobflyer states.

But, you do not HAVE to set it up/trim it in rate mode! Most HH gyro's only need to have the slider centered in HH mode, limit pot or ATV adjusted depending on the gyro, and it works great. I set up my 401 as per the Finless vids a long time ago on all my heli's....he does not have you set it up in rate mode....and the tail holds great on all my heli's.

Good luck,
Skarn

Drifting to one side in HH is normal when the heli is sitting on the ground, it should correct itself once you spool up and start to take off.

Well, yeah, that's what everybody says. What I did was, I slid my hand palm-down under the heli on top of the skids so I could hold it down when I spooled up and, sure enough, the tail servo drifted toward the tail. I pushed the rudder stick to get it centered and when I let go, it drifted again.

I hate to sound so dumb, but how do you switch back & forth between headlock and rate mode? Is that where I plug the sense wire into my receiver or not? That's kinda what that pigeon-Chinese-English manual sorta says, I think. In the SUBTRIM section of my DX6i, there's RUDD & GYRO. What's the difference?

mine drifts in a hover, if I give it more gain It start to wag.

I may have found my problem, I read that if you are too far out on the servo arm, the gyro is too sensitive and may not hold well.
I need to fix my servo arm anyway to fix the sub trim issue. we will see ? right now we only have 60% gain on the gyro, any higher and it wags. gyro manual says to set travel adjust at 150/150, my adjust only goes to 125 on the dx6i. should I move it all the way out anyway? I have it set at 100%,, d/r at 100% expo 17% ,