Real easy to make, fires like 50 feet with a good shot.
Step 1: Gather You Materials
x3 1 slot
x2 2 slot (light gray)
x2 2 slot(orange)
x3 3 slot
x5 5 slot
2 wheels (medium size)
Step 2: Create the Axel
x2 1 slot
x2 2 slot (orange)
x3 5 slot
take your red rod and thread it through ONE of your 5 slots pieces. Center the 5 slot piece, and then attach one 5 slot peice on each side of the centered one. Then attach one of your 1 peice peices on each side of the 5 slot pieces. Put one wheel on each end of the rod and then close it off the the 2 remaining orange peices. If you need help just follow the picture.
Step 3: Construct the Throwing Arm
You will need:
x2 2 slot
x2 5 slot
x3 3 slot
pretty easy here, just follow the pictures
Step 4: Attaching the Arm to the Axel
connect the free rod ends to the centered 5 slot piece so that it looks something like this picture.
Step 5: Making the Ammo, Firing, and Other Things
for the ammo, you will need:
x1 green (the smallest one)
x1 3 slot
just attach the rod to the connector as shown in the picture.
thread the connector on the ammo through the hole on the end of the firing arm. (make sure the end peice isnt leaning left or right as it may cause misfires and you wouldn't want that) Then, aim it in any direction (except at something you dont want to hit)
and slam your hand down onto the other end of the firing arm.
any of the peices mentioned can be subsituted and you can modify this catapult in any way you want to suit you.