Just dont get the obvious distaste for the use of cardboard for fin material. I have a 37 year old KB-5 NOMAD that has taken the type of abuse no balsa fin or stabilizer would ever stand for. It has never detached, never dinged from its plastic cone and come in hot tail first on more than a few occasions. The ply did start to fray on a few occasions and was coaxed back to flat with thinned white glue. Overall, good material choice for some designs. Glad they were able to think outside the box and introduce different materials.

It also allows for some wicked fin designs that defy grain considerations without need for lamination. Tough to create, though; I've cut rings and some fins, sloppily. If only I had a laser cutter!