This is the linkages section. It will be short...just as all your linkages should be!

Here is the underside of the wing. I use the Rod Chuck system that uses the inner wire within welding rods to provide a full 4-40 very sturdy linkage. Also note the use of metal servo arms. All flap and aileron surfaces are have a full 1/2" of aircraft plywood to thru-bolt the control horn.

I originally planned to use arrow shafts but they only work for an absolutely straight installation. I ended up using NyRod (black and yellow) the strongest, stiffest ones made.

This is the underside view of the NyRods and how they attach to the rudder and elevator.

This is the plywood backup typical for each control horn. One half inch of aircraft plywood for the control horn to thru-bolt.