ORIGINAL: jrpav1
I've used the Sullivan Carbon fiber pushrods too - they work OK but like Ed said you have to check your elevator trim at the start of a day's flying. I've never flown with a full carbon DEP setup (like the Central DEPS) but I don't see how they would be much better as far as the trim issue goes. The fact is a wooden airplane with a long fuse is going to expand / contract ever so slightly whereas the pushrod may or may not change it's length at the same rate. With either type of pushrod setup you do need to support them well or you'll have a mushy elevator linkage. Not good. And yes the standard Nyrods will not work well in a Pattern plane so don't even think about it. Some guys use pull-pull cables for the elevator but that's a whole 'nother can of worms. I think I'm going to stick with the Sullivan carbon rods until I find a better way.
John Pavlick
Team Black Magic, Tech-Aero Designs
A rule of thumb that has served reasonably well over the years is to use the same push rod material as the construction of the fuse...wood - wood; glass glass, etc.
I don't agree that pull-pull cables are a can of worms (sorry John ), but these do require some finnesse to get right, and one should not be afraid to tear the set-up down (easy for pull-pull) and re-do it. I've worked with pull-pull for over 20 years and highly recommend these set-ups. These offer precision without any of the push rod hassles explained here-in.
Another very precise arrangement requiring practically no daily fiddling is the twin servos in the tail that another fellow mentioned...these minimize push rod length. Not for every set-up however since many can't afford the tail weight
FWIW 2U
MattK