Generally speaking full scale aircraft utilize torque tubes not rods in their application and they are not used is the same application that we are talking about in our model aircraft ailerons. They are utilized largely in control systems where there is a long run or several runs from the point of input to bell cranks and finally output tubes from that point and so on. By design they use tubes because tubes are much more rigid and light weight compared to rods, there application is simple; they are used to handle mainly compression loads and some tension loads in the control system while maintaining rigidity, they are not generally used or needed for twisting loads like we did with our models ailerons years ago, I mean like some of us still do.

Bob