I've used that Dubro , drum and spring brake myself. We were flying from a 240' paved runway . There were alot of go- arounds. But that brake made many more of those aproaches "in the window" for a full stop. It was just fun to use it. And it was neat to hold the brake on and run up the engine. It works great !!! Very simple mechanism. There is a small coil spring that is wrapped around a drum brake. The drum has 3 prongs on it and you just stick them between the spokes of the wheel. One end of the spring is attached to the nose gear and is fixed. The other end of the spring is connected to your elevator servo via fishing line. Pull the line and the spring constricted around the drum. Braking was variable and linear. And the entire rig was very light weight. Just to be clear, you use only one brake and its on the nose wheel.