I replaced my fish lines on my skyfly with the (E) strings from a guitar. these are the smallest ones and stopped the streching problems common to these planes. The servo end can be bent in a Z to fit the servo and the tail end, I replaced the horns with horns from an aerobird. A little tricky to fish them through but it can be done. I may try a little stiffer guitar string and see if I can elimate the rubber bands altogether. Sort of set it up just like the aerobird .