Cool, now that you have a picture up the reason you are having trouble with soft springs is two fold the primary reason is the design of the tailwheel it self. It has considerable trail (caster) designed in.

Note the further back from the steering axis the wheels footprint is the greater the trail i.e. moment arm. The effect of this is with any side force such as the start of a ground loop the this strong moment arm will put far greater loads on the spring than what you might expect. A tailwheel with less trail can use springs with less tension.

This brings us to the other option here and that is the spring itself. Yes you definately need more resistance to tension but the real answer is not just a heavier spring its a different type spring.

Its likely you have been using tension springs, springs that pull apart. compression springs are more desirable with a larger airplane. Sorry I have no picture but these have rod claws inside that the links attach to and all loads compress the spring. This type spring is used on most more modern full scale taildraggers.

Using this type will increase the springs strength with larger loads untill it is fully locked. Yes I beleve the steering should never be free wheeling.

Yes I am aware most full scale airplanes have a full swivel feature but this is for a different purpose to make very tight manuvers while parking or pushing the airplane backward, we simple do not need this.

Indeed many full scale airplanes that have this automatic full swivel feature also have a rigid pilot operated tailwheel lock to prevent sudden loss of control on takeoff due to the wheel suddenly going to full swivel if side loads are high.

You will find these compression springs at many good hardware store in their spring selection bins.

Another option I recently did with a fifty CC ship which is a Yak something or ruther ARF. I used a tailwheel similar to your but installed a steering arm fixed rigidly to the bottom of the rudder. The steering arm on the tailwheel was behind the arm on the rudder. Now rather than use springs at all I choose to use wire links that provided rigid connection between the two steerring arms. This arraignment provided extremely pleasent ground handling to this larger taildragger in other words it handels on like the proverbial piece of cake and on takeoffs or landings, its a delight.


John