steering concepts

I use a standard 303 hitec servo for rudder control. This is set up using two pieces of stainless fishing trace wire connected to each side of the servo arm as well as on each side of the rudder arm. The idea for this is that I found having just the single “push/pull” rod, I was occasionally “reversing” the rudder.
The twin wire eliminates this problem totally.

Peter, your idea of using twin wires seems right but wouldn’t twin push rods be better? My thinking is that by using a flexible coupling then only one side of the servo arm is under tension when turning, ie one wire is pulling but the other side is doing nothing(being pulled?) However with push rods, both sides are utilising the power of the servo, one side pulls,the other pushes, so the pressures on both the servo and rudder arms are equal.Or are the forces acting on rigs like this so small as to not matter?

I’ve learned, That the easiest way for me to grow as a person is to surround myself with people smarter than I am.
(what am I doing here?)lol

If you have two pushrods and they end up slightly differet sizes it can put strain on the servo,one works against the other and it can cause it to jam up…

Luff 'em & leave 'em.

On a very different level: I had this trouble with my Seawind!; took one arm away…and it works much better now…more smooth…I did same on my 36/600


if it isn’t broken, don’t fix it!

try using flexible pushrods or cables that the rc aircrafts use for control surfaces.its more smoother,doesnt bind, and works well in confined spaces.

the reason for using 2 rods is for strengt. i agree with matt. in saying that one rod COULD be shorter. . I used that system but i use threaded rod on both sides. it takes a little bit of time to set up. but it take s alot less stress on the servo. as side arm is pulling and the other arm is pushing
both work, on my IOM i use the single arm. just because i dont think the rudder needs the extra strenght

The model airplane guys have pull-pull control systems pretty well figured out:

Of particular interest is the discussion of “Ackerman” which allows the nonworking cable to be a bit slack, reducing the problem of the servo working against itself. BTW, Ackerman is the same concept which allows the steering wheels on a car to turn in different radii to prevent the tires from scruffing.

Bill K