Juice,

In principle, this system would work fine. The only problem I see is that you need to keep the cable in tension. If you don't, you will have some slop in the system that you definitely don't want. If you do, your servo will be bearing that load all the time. I don't know whether you want the drivetrain of your servo to be bearing tension all the time. It would be possible to have a static pulley on the servo end, and drive the cable the same way you couple to the elevator horn. It is still not a slam dunk to maintain the correct tension in the cable. I would be more comfortable with rigid rods. If you are really concerned about weight, carbon fiber tubes could be used. To get everything internal, the way you are with the pulleys, you could have the two rods coupled to a pivoting bell crank where you currently have the aft pulley, and couple one of the rods to the elevator control horn. This control horn would then need to accommodate the movement of the rod, which is the advantage of a pulley and cable.

Good luck.

banktoturn