Students at UPEI's School of Sustainable Design Engineering have been challenged with the task of building the best possible snowball launcher for an upcoming campus snowball fight. Why? Becuase what fun is it to throw snowballs by hand? Take the weekend to build this super cool and durable snowball catapult to impress all of your friends, but more importantly, to hit them with snowballs!

Note: Please play safe! If you are using the catapult to throw snowballs, make sure you do so in a safe way. We recommend that all those participating in the snowball fight wear appropriate winter attire and safety glasses. Also, don't throw snowballs containing ice or debris, no one likes that that guy...

Have fun, and enjoy!

Step 1: Tools and Materials

Materials

3" wood screws
1-1/2" wood screws
1-1/2" nails
3 screw down eye hooks
Metal bracket
Bungee cords
35"x20" piece of plywood
2x4's
Small wooden dowel or any small rod
Snowball containers
3/8" diameter pipe or rod

Tools

Hand drill
Drill press (recommended)
3/8" spade drill bit
Measuring tape
Hammer
Plyers
Miter saw
Jigsaw
Table saw or scale saw
Square or straight edge

Personal Protective Equipment

Safety glasses
Steel toe boots

Step 2: Preparation

Once you've gathered all of the materials needed for this project, start by cutting all of the pieces; you will assemble them in the next step. It's a good idea to trace all of your cuts for the pieces before cutting; this will prevent mistakes and ensure that you use the least amount of material.

1. If your plywood is not already cut to the correct dimensions, cut the base out of plywood using a table saw or scale saw. The base is 35" long and 20" wide as shown in the image. Ask for assistance from an adult if you are not familiar with these saws.

2. Cut the catapult arm out of 2x4 as shown in the image using the miter saw. The catapult arm is 36" long. Using the drill press and the 3/8" spade drill bit, drill a hole through the center of the catapult arm 24" from the end of the arm.

3. Cut the two catapult stabilizers out of 2x4's as shown in the image using the miter saw. Make sure that one end of the 2x4 is a straight end, then, cut the 2x4 at a 45 degree angle at 30" on the longest sides. Using a jigsaw, cut a notch 1-1/2" wide by 1-1/2" deep in the stabilizer arms starting at 9-5/8" from the top of the stabilizers. Using the drill press and the 3/8" spade drill bit, drill a hole through the center of the stabilizers 7-3/4" from the top of the stabilizers.

4. Cut the 4 support pieces out of 2x4's as shown in the image using the miter saw. Make sure that one end of the 2x4 is a straight end, then, cut the 2x4 at a 45 degree angle at 24" on the longest sides. Using the drill press and the 3/8" spade drill bit, drill a hole through the center of the support pieces 1-3/4" from the top of the pieces.

5. Cut the catapult stopper out of a 2x4 as shown in the image using the miter saw. The catapult stopper is 11" long. Using the jigsaw, cut a notch 1-1/2" wide and 1-1/2" deep at the center of the stopper.

Step 3: Support Assembly

Now that all of your pieces are cut, it's time to start assembling! In this step, you will assemble the support pieces.

1. Drill together two of the support pieces. Make sure that your 45 degree angle cuts are pointing such that when the supports are standing they lay flat on the base. You can use the 3/8" diameter pipe or rod to ensure that the holes you drilled are perfectly lined up. Use a square or straight edge to ensure that your pieces are connected at exactly 90 degrees as shown in the image. Repeat this step for the last two supports.

2. Install the support pieces to the base. As shown in the images, the support pieces are placed 11" apart from each other from the farthest pieces. Measure 10" to the center of the base and 5-1/2" to each side of the center. You can use the support pieces to make lines around where the piece will go. Estimate where the other side of the support pieces (8" apart) will be placed and do the make the same marks there but measure only 4" from the center.

3. Using the drill, attach the supports to the base using the 3" wood screws starting at one end. You may need help from a friend to ensure that you are lined up with the marks you have made on the base. Now attach the other side of the supports to the base using the same method.

4. Now that your support pieces are attached, attach the stopper piece by placing it between the two farthest support pieces. The stopper is positioned approximately 2" below the top of the support pieces and is against the closest support pieces with the notch facing up. Using the 3" wood screws, screw the stopper in place from the outside fo the support pieces.

Step 4: Catapult Arm and Stabilizer Assembly

Now that your supports are assembled and attached to the base, it is now time to assemble the remaining pieces of the catapult.

1. You can now insert the 3/8" diameter pipe or rod through the supports. Insert the pipe or rod through the first support. Insert the first stabilizer, followed by the catapult arm, and then the second stabilizer onto the pipe or rod before pushing it through the second support arm.

2. Ensure that the catapult arm is in the center of the pipe or rod, and attach the stabilizers to the base. You may want to leave approximately 1/16" between the catapult arm and the stabilizers to prevent them from rubbing against each other when launching snowballs. Use the same method used to attach the support pieces to the base for the stabilizers. You can now screw the stabilizers into the stopper using the 3" screws.

3. Make sure that your catapult arm can move around freely before moving to the next step.

Step 5: Bungee Cord Assembly

Your catapult is almost ready to go! Just a few more finishing touches to make it functional.

1. Attach the bungee cords to the catapult arm using the 1-1/2" screws as shown in the image. Insert the bungee cords through the bracket before attaching the bracket because the bungee cords may not fit through the bracket after it is attached.

2. Depending on the sizes of your bungee cords, the following steps may differ. Pull back your bungee cords until you begin to feel tension. This is where you are going to screw in your eye hooks. You may want to out a single eye hook in the middle of the catapult and two others on the sides so that your bungee cords remain separate. Once the locations of the eye hooks are marked, screw them into the base. You can now hook your bungee cords to the eye hooks. Do not test your catapult arm just yet.

3. Before testing your catapult arm, use the pliers to squeeze together the ends of the bungee cords to prevent them from unhooking as shown in the image. Wrap tape around the squeezed ends of the bungee cords for safety.

Step 6: Time to Launching!

The final step is to prepare your catapult for launching snowballs.

1. Attach the snowball containers to the end of the catapult arm using the 1-1/2" wood screws. You may only insert one container or multiple containers with a maximum of three containers if you wish.

2. Insert 6 1-1/2" nails in the stabilizers as shown in the image. Make sure that each pair of nails is placed at the same height and that you spread the pairs approximately 1-1/2" apart from each other.

3. Test your device outside!

4. Use the small wooden dowel on the nails to measure the distances of snowballs. Moving the dowel down will make the snowballs launch further. Record the distances traveled of each snowball and record them directly above the nails for future reference.

Your snowball catapult is now complete! Enjoy, play safe, and have fun!