in your opinion what is the best pushrod system for a med size plane say a hog bipe ? I dont particulary trust the ones that come with the kit

I hesitate to recommend pull/pull systems to anyone who hasn't figured out for himself how he wants to rig them, since I have never seen two systems done the same way--even my own keep evolving. But if I want to get a plane in the air without a lot of fuss, nyrod is the way to go. Only caution is that you should glue (I use goop) the outer tube to fuselage interior or some structure at either end plus every 4" or so, to keep it from flexing on the push-stroke. This should be done before the fuselage is completely covered, while you still have access through bottom and/or top. Get your servos installed and linkage tested before covering. When everything is installed and working, then remove whatever's in the way and do your covering. Try to keep the metal ends on the short side as well, preferably nmt 4". Nyrod is the popular standard, used by lots of fussy builders, no reason why it shouldn't work for you.

The biggest mistake most new users of nyrod make is to have a long unsupported end between the exit at the rear of the fuse and the flying surface. If you must have a length that you cannot tie the outer case to within two inches of the elevator horn, insert a long wire into the end that exits the fuse. This is not as simple as it sounds, the wire must be integral with the part that threads into the clevis. You could use a very long threaded rod but that poses problems of getting it screwed very far into the inner nyrod. Just make sure, that whatever you do, the part exiting the fuse will not bend under air loads. I have seen where people have put a 1/16 wire all the way from the servo to the flying surface using the inner nyrod as a guide only--this does work well--with the clevises soldered to the 1/16 inch wire..

Agreed.

The most important aspect of the pushrod/linkage type is how the entire system functions as a unit. You can use nyrods, and relatively small linkage parts, as long as they're well supported. If using the typical nyrod setup, just glue some small supports into the fuselage or wing to support the tubes at several points, and be sure it's rigid enough before you finish enclosing the fuselage or wing. (I recommend silicone rather than CA for this, because vibration or the occasional rough landing can break the CA loose. Silicone can take this and still hold on.

There's a lot of talk, some of it worth studying, concerning effects of temperature and humidity on certain linkages, and only you can decide how much precision you need. One thing I will say is that "hi-tech", expensive parts are not necessarily needed. Competitors tend to use these for several reasons, which not only include their real concerns, but also the idea that sometimes it's simply easier to "get the best and eliminate the worry". (and, I suppose many people simply use what is the most popular at the time) Just remember that before carbon fiber existed, all planes did not "fly badly". Often in modeling, a little thought, backed up with some good workmanship, is enough to produce competitive planes without breaking the bank.

I agree about not leaving unsupported nyrod ends between the fuselage and the stab. They normally give you 1-1/2" of threaded 2-56 rod to use for the ends, which leaves the unsupported sections we are talking about.

I buy a 12" length of 2-56 rod that has 1-1/2" of threads on one end. If there is a 3" gap between the fuse and the flying surface, I cut the rod 5" long. I put the plain unthreaded end of the rod into the nyrod. Then I take my cordless drill and chuck on the threads. I thread the rod into the nyrod about 1/2 - 3/4 " and use the remaining portion for the clevis. I haven't had the threads damaged by the chuck. The result is the same as if you were using the 1-1/2" rod ends supplied by the manufacture.

John