coralcape

My Feedback: (4)

My problem is pull pull rudder setup. I am using a large servo arm, say 4" and connecting to rudder horns, also 4" hole to hole. I have tried running the wires straight back and also crossed over. I am getting slack on the port rudder when I give starboard rudder and vice versa. How can I prevent this slack? Thanks, red

beepee

coralcape,

I guess the slack is coming from the fact that the horn set on the rudder is not even with the hinge line. Looking straight down on the hinge line and imagining a line perpendicular to the rudder/vertical fin centerline that perpendicular line should pass through the holes of the rudder control horns. If the horns are ahead, or behind, you will not get even motion as you describe. Apart from that if the rudder is binding and there is flexibility in the control components, the same thing can happen.

Let us know how you get it sorted out.

Bedford

coralcape

My Feedback: (4)

Bedford, thanks for the quick solution. You were correct about the horn placement. I just finished moving it as close as possible to the hinge line and this took almost all of the slack out. The plane is a TBM 30% Yak with 45% bevels on the control surfaces, so I couldn't get it exactly perfect. I'll have to look for a different type horn to make it correct. Thanks again, I'll remember this. red

Taildragger726

Hey Red, a solution would be an offset arm on the rudder servo like this; available from TBM



I have one for a Hitec you can try.

Rcpilot

My Feedback: (78)

The rear bellcrank has the offset on the ends. These wires are crossed. The entire servo tray is mounted 1/8" higher on the right side. This prevents the cables from rubbing as they cross. The horns on the rudder are even with the hinge line. No slack on either side at any throw or deflection. Even tension.

Got lucky. [sm=tongue_smile.gif]

I want to try one of those SWB floating trays. [8D]

coralcape

My Feedback: (4)

So we're saying I can make up for the offset on the rudder servo by using offset servo arms? Interesting, I would never had thought of that. I was thinking instead of making up rudder horns that would allow the point of connection to be in line perpendicular to the hinge. My problem with that was the end of the horn would contact the fuselage, before full throw. I'm a DIYer and tend to make what I need. I can see a new servo horn in the future ) Thanks again folks, red
PS, I assume that I would offset the servo arm the same distance as the rudder horn, correct?

Taildragger726

Yup!