[N_Force]

This is using madbull poppers and cut out an inches at the bottom to make it shorter for around 20' shooting. A hinge has two side, one side with three contacts and other side has two contacts to joint together, for the better popper flapping when hit, three contact side on wood and two contact side on popper.
when you design your dueling tree, distance and the power of your weapon, the length of the poppers and the angle lean forward, are all the factors you have to know. If you use it indoor in close range and not switch weapon, keep the full length and play around the leaning angle to see. If not enough force to hit it flap, cut popper shorter to reduce weight. hope this helps.
This later one I set it two poppers in one section to lean forward. Good thing is keep all three or four sections in same distance.