Originally Posted by Toppers
At the time I seriously considered doing what the guys on Flitetest did... just make the tail wheel center with a single wire attached to a spring, relying on the rudder only to steer on the ground... not great for taxiing but probably OK for takeoff..
After some issues I tried the castering tail wheel, like flight test used, but I HATED it. Not only did it suck for taxiing, but when I would make a higher g turn at end of runway on u-turns with some speed, the spring would suddenly give and the back end would whip around.
I had trouble with original pull-pull because a wire crimp slipped twice on hard (dropped) side load. So after trying the castering setup, I went back to pull-pull cables, but I added some fairly stiff springs on each side, in the cable line. Now if I have a sudden side load, the spring can stretch and let the wheel give, without breaking or stressing the cable too much. It required stiffer springs than I would have suspected.
I also have the pull pull wires going to from spring to hard push-rods. The push-rods go to normal quick connectors on the rudder servo arm, so I can easily adjust cable tension and/or wheel centering by sliding the push-rods through the quick connectors, just like you do for rudder adjustments. So I have 3 push-rods coming off of the rudder servo, instead of 1 pushrod and 2 cables.
I'm certainly no expert, but this is working great for me, about 50 take-off & landings, many on dirt with no problems (yet). Although after watching the excellent video that Mcnowhere posted, I am wondering why we need any crimped loops at all. I think on my next pull-pull, I will try just putting the cable through the quick connector like a push-rod, and tighten the screw down on the cable. That would make like a crimp, and may make it possible to change the length of the cable and adjust tension if needed. Watching him triple check the cable length before crimping reminded me why I hated the whole process.