WarbirdairRacer,
I would suggest that you use carbon fiber pushrods with short lengths of 4-40(3/32) piano wire at each end. On my previous pushrod that flexed and bent, the arrowshaft did not flex or bend, only the 4-40 threaded rod at each end of the shaft did. If you make your whole pushrod out of this material it will flex. If you try to run the 4-40 wire through a pushrod tube you will have to install many support braces which will be difficult to do with the fuse already complete. The arrowshafts can be purchased at your local archery shop. I paid 20 bucks and got three of them and glued dowels into each end. You could also take Hattend's advice and buy some pushrods through B&B or central hobbies. Trust me, arrowshafts are the strongest and by far the easiest to install. Also if you want to fix the tail properly you need to lengthen the arrowshafts anyway.......so you might as well buy your pushrods since you will be at the archery shop anyways.