How to Build a Catapult
A catapult, huh? You've been watching an old cartoon with the apparatus involved? Yeah, they can be pretty fun and interesting, but now you want to make one, for whatever reason. (Do you remember having to make them for science class in middle or high school?)
Let's start by discussing the different types of catapults:
- Trebuchet: This model uses a counterweight to launch objects, similar to how a teeter-totter works. The counterweight pulls one end down so the other end shoots up quickly.
- Mangonel/onager: This is the type you most likely see on TV, with a rope or spring that is released so the end comes up by way of torsion (remember your physics?).
- Ballista: It looks like a crossbow, and shoots spears, arrows, and similar sharp objects.
- Miscellaneous: I'm sure you've seen the spoon catapults, or perhaps the clothespin catapult.
Safety and Necessary Precautions
Before you get started, however, there are a few things you should think about:
- Research catapults so you understand what they do and how they work. This is for safety's sake, and so you don't waste your time making something that won't help you.
- You definitely have to think about what the catapult is going to be for. It is for show? To keep in your cubicle for a distraction? To win a science fair or engineering prize? Do you want it to be strong? In that case, you'll have to think about which type would work best for the purpose.
- Understand what the different types of catapults are. Remember that a catapult may be considered the generally larger machine based off of the ancient creation that militants would use to hurl weapons such as rocks or fire at enemies; simple slingshots may also be considered catapults. Keep this in mind as you search for instructions.
- Be sure that you have the right kind of materials. For larger models especially, stopping short of appropriate supplies may lead to the catapult breaking or malfunctioning, which may be very unsafe.
- Speaking of unsafe, catapults can be dangerous, whether it breaks or the counterweight hits them or they end up being thrown by it. Use it in a safe, open area with nothing too heavy, hard, or sharp (at least when you start out).
With that said, we can start going into the steps on how to build your own catapult.
How to Build a Trebuchet Catapult
How to Build a Small Catapult
We can start small, say with a little catapult that will fit on a table and that will be powered by rubber bands (almost like a mousetrap!). Please read these steps carefully, keeping the above tips in mind and referencing accompanying photos for additional help. The below instructions are of a sort of mix of the two models shown to the right, using the foundation of the top and the functionality of the bottom.
- 2 larger blocks of wood of similar size to serve as the foundation
- 9 smaller, thinner pieces of wood (sticks or dowels, for instance) of similar size to hold the foundation together
- A larger, thinner piece of wood to serve as the arm of the catapult
- A cup or similar object for the end of the arm, where objects can be placed for hurling
- A metal axle, as from a toy car or a piece of metal from a coat hanger
- 2 small hooks
- Rubber band(s)
- Sander, sandpaper, saw, measuring tape, ruler, hammer, nails (optional)
Make Your Own Catapult Out of PVC Piping
- Find a plan that suits your needs and desires. You can look online for some good ones with dimensions and proportions included so you know how big of a catapult you'll be working toward and what kinds of materials you'll need to build it. Generally, instructions for catapults of a smaller size should be rather similar for the most part. The mangonel type works well for smaller models.
- Acquire the right materials called for in the instructions. You'll need two sturdy blocks of wood set in a square to serve as the base and foundation of the small catapult. You'll also need dowels or sticks of wood for supporting the catapult frame. Fir or oak are solid, strong types of wood, but if you just want to build a smaller catapult, wood strength may not be that important of a factor. You might have to shape the wood, which involves removing awkward pieces of bark and/or sanding the wood. This may require sandpaper or a sander, a small saw, and measuring tape/ruler.
- Cut holes with a drill into the insides of the two blocks for the foundation; four holes along the insides of each so the dowels can be placed inside the holes to hold the two pieces together should be sufficient. Make sure the holes are an appropriate size so the dowels will fit snugly into them, and put some glue on the ends of the dowels before you slide them inside of the holes.
- Cut pretty deep into the tops of the two blocks parallel to each other near the middle of their lengths, large enough for one of the smaller blocks/sticks of wood to fit into to connect the two larger blocks. Glue the smaller block into the cuts in the two larger blocks to connect them. This is where the upright support bar will be built.
- To make the upright support, fit two smaller blocks of wood into the cuts in the tops of the larger blocks of wood, so the smaller pieces stand straight up, then glue them in place. Then connect the two upright pieces by gluing or nailing another piece of wood of the same width across the tops of them. You'll also want to add one smaller piece of wood to each side connecting the upright piece to the foundation, making a triangle with the three. Glue those two pieces to the upright support and the foundation.
- The catapult arm can be as long or thick as you want, so choose a piece of wood for the arm and decide how you want the cup to be; you can build it into the wood by carving into the end so it becomes concaved like a cup, or you can use a paper cup or a small box, then attach it to the arm with nails, thumbtacks, or glue. This might not be the sturdiest option, so you should prepare yourself for some carving and patience in shaping the end of the arm. Be sure there is enough room at the end with the cup so you can pull the arm down without getting in the way of the arm's path when released.
- Drill a hole into the opposite end of the arm from side to side, not top to bottom. This should be wide enough for a metal axle to fit through. (You can get an axle from a toy car, or cut a piece of a metal coat hanger off.) Drill holes of similar sizes through the catapult base's two larger blocks of wood behind the center dowel, then slide the metal axle through all three so the arm is attached to the base with the axle. Remember to add some glue to the axle to try to hold it in place in the wood.
- Find two hooks that can be easily twisted into the wood. Attach one to the outside of the dowel furthest from where the catapult arm is attached to the base. Attach the other to the arm right in front of the cup. Turn the hooks so they curve away from each other. You might want to add some glue to the hooks in the wood as well.
- Get a strong rubber band or similar object to use to propel the catapult arm. Place the rubber band on the hooks, making sure it runs over and not under the upright support of the catapult.
- Find a small object that won't hurt too much if someone or something gets hit with it, like a rubber ball or a sugar packet you didn't add to the coffee swill at work. Place it in the cup, pull the arm back carefully (try not to break the rubber band!), then release it in the desired direction (maybe you set up a tower of cards to aim for).
Additional Assembly Tips
- You can adjust the angle at which the catapult fires by adjusting where the horizontal bar connecting the two upright pieces is. You can remove that horizontal piece of wood and replace it elsewhere along the two upright pieces, making sure it remains perfectly horizontal wherever you place it.
- You can estimate the sizes and widths of the pieces of wood. Just make sure the two larger blocks for the foundation are the same sizes, and that the wooden dowels or sticks that connect them are the same as well, or at least will fit snugly into the holes you drilled for them into the foundation. You don't want the dowels to be loose or the foundation won't be stable enough.
- This model is nice because it's not too difficult to fix; if the rubber band breaks, you can easily add a new one!
- Don't forget that you can decorate the catapult! Spray-paint it, add stickers, or even put a nice lacquer on it!
Building a Catapult by Kit
- How to Build a Catapult
If you don’t know who jimmythejock is, well, he’s a legend on HubPages and a very important contributor to its content. Here’s just one of his Hubs about how to build a catapult… with a link about Vegas.
- How to Build a Catapult | eHow
I know we try to keep away from archive websites, but this set of instructions and tips on eHow is really helpful, with numbered directions and great detail about necessary supplies and more.
- Notes from the Technology Underground: How to Build a Catapult
This guy has written a book about building catapults. He has tips for starting out, information about materials and safety, and a few pictures. He also included some links for books.
- How to build a catapult
This is a great scientific set of instructions on how to build a table-top troll catapult, with instructions and photos included as well as a promise that the process should take only two hours.
- How to Build a Catapult: Instructables—DIY, How To, tech, offbeat
Instructables.com recognizes there are many sets of instructions for building a catapult on the Internet… but claims these trebuchet catapult instructions are for the “low-tech, medieval enthusiasts.”
- How to Build a Catapult
Trebuchetstore.com features abundant information about the best sets of plans and kits to build your own catapult, with descriptions and photos of each of the many shown on the site.
What an interesting page all about catapults, from photos to an animation of a catapult to instructions and links to outside pages about building catapults. You can even build one for your watch!
- Catapult Crazy! Everything About Catapults!
Here’s another stormthecastle.com web page featuring not just instructions on how to make a catapult, but on the different types you can make, the history of catapults, and multiple, helpful links.
Catapultkits.com is the perfect place to start if you don’t want to build a catapult from scratch, but you’re willing to try one from a set. There are a multitude of catapult kits to choose from, so find the one that’s right for you!