Hobbies And Interests
Things You'll Need
Instructions
Make a rectangle measuring 10 inches by 4 inches using two long and two shorter wood strips. Hammer a nail into each of the rectangle's four corners, going through one strip of wood and into the other. This will form the base of the catapult.
Make a 3-sided square with 4-inch strips of wood. Nail the two corners together.
Raise the three-sided square vertically from the catapult's horizontal base. With the missing side facing down against the catapult's base, nail the 4-inch vertical sides into the horizontal base 3 inches from the base's corners. Ultimately, this vertical structure will stop the catapult's arm.
Place a 5-inch strip of wood diagonally between the catapult's base and the top side of the vertical arm-stop. This strip of wood should be nailed to the midpoint of the 4-inch side of the base, 3 inches from the arm-stop uprights. Nail the other end of the diagonal strip to the midpoint of the arm-stop crossbar. This will strengthen the arm-stop so it won't fall over when hit by the moving arm. If you look at the catapult from the side, you should now have a right triangle with a 3-inch horizontal bottom, a 4-inch vertical height and a 5-inch diagonal hypotenuse.
Drill a hole through the remaining 10-inch strip of wood. This will be the catapult's arm. This hole should be larger than the diameter of the 5-inch screw so that the arm can rotate freely around the screw. The hole should be 1 inch from the tip of the strip.
Screw the 5-inch screw through one of the arm-stop's uprights. This should be done 1.5 inches from the catapult's base. Then run the screw through the hole in the catapult's arm and continue to drive the screw into the other upright. You should now have a base, an arm-stop and an arm that pivots.
Nail a small cup to the tip of the catapult's arm.
Screw a wire eye lag (a.k.a screw eye) into the base of the catapult just below diagonal arm-stop support. Screw your other wire eye lag into the side of the arm that will hit the arm-stop. Screw this lag in just below the cup.
Run a rubber band from one wire eye lag over the arm-stop to the other wire eye lag. The rubber band should be small enough that it forces the arm to stand upright.
Insert a projectile into the cup. Pull the arm back from the arm-stop until it rests horizontally against the base of the catapult. Release the arm and the rubber band should snap it upward, into the arm-stop, and fling your projectile out of the cup.