A couple years ago we had some discussion about structural deformation (buckling) of the cockpit longerons being the proximate cause of Gontermann's death in his Dr.I crash.
Survivability lesson from the past
At the time I had proposed stiffening the cockpit bay of a steel tube replica by inserting carbon fiber rods into the longerons to help stiffen them.
I recently had an opportunity to discuss the idea with an engineer who had current experience with carbon fiber pultrusions. He recommended against use of carbon fiber to reinforce steel tube by pointing out that the carbon fiber is conductive and would likely
promote corrosion in the longerons. As others suggested, he suggested that it would be better to both increase diameter and wall thickness of such critical tubes.
So if you had been considering my crazy idea to beef up your replica's cockpit using carbon fiber, probably best not to.
