Sub trims

[Steve]

I think we all know that using the rudder trim with a heading hold mode gyro is a waste of time, as it is effectively like continuously holding in a bit of left (or right) stick all the time.

But, what about the sub-trim on the transmitter? i.e. adjusting the centre point so that the servo arm and the push rod to the tail are at exactly 90 degrees after you've found the mechanical centre point of the tail?

Let's say I've found the perfect tail linkage length with 0% trim and 0% centre adjustment, but I need 20% off centre to get the 90 degrees. Can I do this and then re-adjust the linkage length without sending conflicting information from the transmitter to the gyro?

[Ade_Law]

Nope, With futaba and JR servos if you turn the horn round 90 degs on the servo to use a different arm it wont actually turn 90degs so by trying different arms you can get it exactly 90 without using sub trim.

Ade

[Smoothound]

Nope, With futaba and JR servos if you turn the horn round 90 degs on the servo to use a different arm it wont actually turn 90degs so by trying different arms you can get it exactly 90 without using sub trim.

Ade

I've tried this on my T-Rexes with Hitec HS56's and even bought extra packs of arms and even though people have told me you can get them 90 buggered if I can

[Ade_Law]

hitec is one of the exceptions... grrr.

Ade

[Steve]

So what you're saying is that the centre function on your transmitter (i.e. the sub trim) is still sending out a signal either left or right, so will affect the gyro.

Makes sense - do it all mechanically.

[Ade_Law]

the problem is that when you adjust the sub trim it doesnt move the end points by the same amount.

gives different piro rate left/right.

Ade