A trebuchet is a specific version of the catapult that uses a counterweight to create the force to fling an object from a sling at the end of a pole. A Trebuchet to demes taits the transfer of gravitational potential energy into kinetic energy. Which is why I am building it for my physics Teacher.

Supplies

2 x 4's (Three 8-foot boards)
3/4 inch plywood
1-inch outside diameter PVC pipe
4 2-inch swivel and locking wheels
5 1-inch 2-hole pipe straps
5/8-inch medal bar with threads
4 5/8-inch Hex nuts
4 5/8-inch washers
2-inch star-bit screws
3-inch star-bit screws
1/2-inch Phillips-head screws
1/8-inch twine/string
adjustable weight dumbell
duct tape
Cheesecloth or other flexible fabric
1 nail with no head

The tools

Miter Saw
Drill
Circular Saw

Step 1: Cutting the Wood

Using a Miter saw cut the wood to you desired lengths.

Step 2: Make the Stands

When making the stand I made a frame at the bottom to outline the base and make 2 4 foot boards to make the stand the arm would attach to. I used brackets to screw the the stand to the base and tried to level it before adding the arm.

Step 3: Attaching the Wheels to the Base

i used 4 locking wheels and screwed them into the bottom of my base.

Step 4: Securing the Pivot Point to the Stand

I should of used bolts and a washer but used multiple screws to attach the ball barring to the stand.

Step 5: Making the Arm

I used a 8 foot board and cut 2 1 foot pieces of wood to go around the central pivot point and drilled a hole at the end of one side of the to make the second pivot point. In the future try to make holes level.

Step 6: Securing the Arm to the Pivot Point

I treaded the steel bar through the ball bearings and attached the bearings to the stand.

Step 7: Securing the Weight to the Arm

I made a second pivot point to the end of the arm to attach the weights to. I attached the dumbell to it using duck tape which latter failed to stay.

Step 8: Making the Sling and Pouch

i cut a piece of a bag and so the edges would not come undone I taped them with duck tape then cut 2 piences of string the same length and attached them to the sling.

Step 9: Connecting the Sling to the Arm

I used a eye screw which I tied the sling to connect it to the arm.

Step 10: Firing the Trebuchet

When firing the trebuchet it first worked when only having 2 pounds on the end of the arm. In the second test I uped the weight and the dumbbell started to tear the duck tape that connected it the the arm and eventually did. I will fix the flaws in my project over the summer.