If you like to build and launch things then this is the project for you. The Catapult will satisfy both these needs, so follow these steps to build these innovated constructions.
Step 1: Step 1: Proposal and History
Proposal: They will have a pivot point under 4 ft tall and the base will be 3 ft by 4 ft. The reason we are doing this project is to find whether the Catapult or Trebuchet will launch an object the furthest distance.
History: The first catapult was created in 400 BC in a Greek town and allowed for longer and higher shots to launch over the newly built walls. The Catapult is proven to be the most effective mechanisms during warfare.
Step 2: Step 2: Materials, Tools, Safety
Two 36” 2x4 $3.58 /each
One 30” 2x4 $3.58 /each
Four 15” 2x4 $4.88/each
One piece 18” 2x4 $4.58
10' of 550 Parachute Cord $3.99
Wood Screws 3" $13.39
Plywood ¼ - 1/2” thick, 15”x 18” ½” $10.98
Drill Press 1 1/8"
Phillips Head Bit
1/16" Drill Bit for Pilot Hole*
Safety: When cutting or using machinery make sure to use safety goggles to prevent debris from getting in your eye. These constructions take more than one person to complete so try to get help when needed.
Step 3: Step 3: Design
When we first got assigned this project we had a lot of research to do before designing our Catapult. We did not have a lot of time so we had to work quickly. We had to build a Catapult and Trebuchet because of our group size so this shortened our time even more. After looking at many designs from other builders we have decided on the two designs above.
We were given some limitations, so we took those into account and tried to create the best constructions we were able to. Our pivot height was set at 48" or 4' and 8' arm with the pivot placed in our chosen spot. Our base consisted of 2 36" 2x4's and 2 28" 2x4's.
For our designs we used SolidWorks to create it.
Step 4: Step 4: Building the Frame Part 1
1. Get two 24" and two 48" pieces of wood from your materials and the wood screws
2. Lay them out on a flat surface
3. Assemble them in the shape of a rectangle as shown above using an electric hand drill and wood screws
4. If you need to make the corners stable then add brackets
Step 5: Step 5: Building the Frame Part 2
1. Find three 28" pieces of wood
2. Attach them to the front side of the base as seen above
Step 6: Step 6: Building the Frame Part 3
1. Find another three pieces of wood
2. On the opposite side add two upright 28" pieces of wood in the corners
3. Lay the last piece of wood on top of the upright pieces
Step 7: Preparing the Frame Part 4
1. Take two 48" pieces of wood and attach them to the backside of the base
2. Attach a 24" piece of wood on the backside of the two 48" pieces of wood
Step 8: Preparing the Frame Part 5
1. Grab three 24" pieces of wood
2. Cut a 45 degree angle on both sides as seen above
3. Attach these pieces of wood to the upright wood from the step before and the 48" piece of wood
4. Attach a 24" piece of wood face down onto the two 45 degree angle pieces of wood
Step 9: Preparing the Frame Part 2
1. Grab two 24" pieces of wood\
2.Measure down 2-3/4" from the top and mark it
3. Drill a 1-1/4" hole into each of the pieces
4. Attach these pieces parallel to the top of the 48" inch arm as seen above
Step 10: Preparing the Arm Part 3
When making cuts try to make them as accurate as possible by measuring more than once because the arm is a very important part of the Catapult.
A drill press can be used to perfectly align the holes. We use a drill bit that was the same size as our axle, but slightly increased the size of the whole by moving the drill around in a circle.
1. Measure 2-3/4" from the top of the 45 degree angle pieces of wood and make a mark
2. Drill a 1-1/4" hole at this mark
3. Insert the axle into the hole you made while adding the arm in the middle as you put it through
Step 11: Preparing the Arm Part 4
1. Take a 24" piece of wood
2. Attach it long face down onto the 45 degree angle pieces of wood as seen above
Step 12: Finishing Touches
We used wooden blocks to create the bowl to launch the ball. We drilled each rectangle into eachother to make them stable.