Originally posted by nosram
I sincerely doubt that the UCD was originally designed as a "balanced" rudder. More like 'It looked about right, and should sell a bunch'. If it had been designed correctly in the first place, do you think there would have been all of the cross coupling?
I fail to see how a closed loop has more torque than a single push rod . A closed loop may take some of the backlash out of the system. I think that you will find that torque is force*distance, unless you reduce the distance that the rudder is moving the torque will be the same. Just my 2 cents worth.
Firstly, I don't see a great amount of coupling with my UCD. Overcontrolling the rudder will often cause unwanted pitching.
Secondly, I never said that using a pull-pull will give you more "torque". I just recommend it for the reason you mentioned (reduce backlash).
Lastly, True! Torque = Force * Distance. But an unbalanced control surface (cause by snipping off top of the leading edge of the rudder) vice a balanced control surface will require more "Force" to move an equal distance, thus requiring more Torque.