It's been my experience that Dzus fasteners are used an full size aircraft and race cars. The ones I have used would be too large and require too much force to engage and disengage on a balsa model airplane in the .40-.60 size range. Maybe you could use them an very large model planes if mounted into plywood, I'am not sure. I have a box full of them left over from my race car building days but never thought about using them on my model planes. jaka, are you talking about the same size Dzus fasteners as I am? What size model planes have you used them on and how have you mounted the spring. We pop riveted them into a steel ,aluminum or fiberglass panels on a race car.