On an LT-40, you would have to modify the rudder to get it to extend below the elevator for the type with the springs to work. That was why I stuck the thread link in on modifiying my Alpha, where I used a solid wire down the middle, in a tube, and where the exit was, the hole is slightly elongated to compensate for a "slash cut" or diagonal cut of the tube, flush with the exit. I have one that uses the spring from the rudder to tailwheel on my Tiger 60 that I built as a taildragger. It is heavier than the LT-40, and the spring setup takes the load off the servo on landing.