How To Make A Pumpkin Catapult

To make a pumpkin catapult, you’ll build a small siege machine that uses tension or torsion to fling a pumpkin through the air.
 
It’s a classic fall STEM project, a fun yard game, and honestly one of the most satisfying things you can build with a few pieces of wood and some hardware.
 
Whether you want to launch tiny gourds across the lawn or compete in a pumpkin chunkin’ contest, the basic idea is the same: store energy, release it suddenly, and let physics do the rest.
 
In this post, we’ll walk through how to make a pumpkin catapult step by step, covering the materials you need, the build itself, and the tuning tricks that make your pumpkin catapult actually launch.
 
Let’s get to it.
 

How to Make a Pumpkin Catapult

Learning how to make a pumpkin catapult starts with understanding the three main designs, and here’s what each one offers:

1. The Classic Mangonel (Tension Catapult)

The mangonel is the simplest pumpkin catapult for beginners.
 
It uses a taut rope or spring to pull an arm back, and when you release it, the arm swings up and hurls the pumpkin.
 
This design is forgiving, easy to adjust, and perfect if you’re building a pumpkin catapult with kids.
 
You can scale it from a shoebox-sized version to something that flings a real pumpkin several yards.
 

2. The Trebuchet (Counterweight Catapult)

A trebuchet uses a heavy counterweight instead of tension, and it’s the design used in serious pumpkin chunkin’ competitions.
 
When you make a pumpkin catapult with a pivoting arm and a dropping weight, you get way more power and consistency.
 
The tradeoff is that a trebuchet takes more effort to build and tune, so it’s better as a second project once you’ve mastered the basics.
 

3. The Onager (Torsion Catapult)

The onager twists a skein of rope to store energy, and it’s a middle ground between the two.
 
Building a pumpkin catapult with torsion gives you a compact, punchy launcher, though the twisted rope needs regular attention to stay effective.
 
Most first-time builders skip this one, but it’s worth knowing it exists.
 

Materials You Need to Make a Pumpkin Catapult

Before you make a pumpkin catapult, gather these supplies so you don’t stall halfway through:

1. Lumber and Base

You’ll need a sturdy base (a 2×4 frame or a thick plywood board works well) plus vertical supports and a throwing arm.
 
Scrap wood is fine for a pumpkin catapult, as long as it’s straight and free of cracks.
 

2. The Pivot and Hardware

A bolt through the arm and frame creates your pivot point, and washers keep everything spinning smoothly.
 
Add screws, a hook for your tension rope, and a release mechanism (a simple latch or pin works).
 

3. The Tension Source

Bungee cords, surgical tubing, or a strong rope all work for a tension pumpkin catapult.
 
Pick one that’s strong enough to move your arm but not so stiff you can’t pull it back safely.
 

4. The Pouch and Pumpkin

A small cloth or leather pouch holds the pumpkin, attached to the end of the arm with cord.
 
Start with mini pumpkins or gourds until your pumpkin catapult is dialed in.
 

Steps to Build Your Pumpkin Catapult

Here’s how to make a pumpkin catapult from start to launch:

1. Build the Frame

Lay out your base and attach the vertical supports with screws, forming a sturdy A-frame or box shape.
 
This frame is the backbone of your pumpkin catapult, so make it rigid.
 

2. Mount the Throwing Arm

Drill a hole through the arm and supports, then bolt the arm in place so it swings freely.
 
Test the swing before adding tension, because a sticky pivot ruins any pumpkin catapult.
 

3. Attach the Tension and Pouch

Hook your bungee or tubing to the arm and frame, then tie the pouch to the arm’s tip with cord.
 
Now your pumpkin catapult is ready to load and fire.
 

4. Tune, Test, and Adjust

Fire a few test pumpkins, then adjust tension, arm length, or the release angle.
 
Every tweak teaches you more about how your pumpkin catapult behaves, which is half the fun.
 

So, How Do You Make a Pumpkin Catapult?

You make a pumpkin catapult by building a sturdy frame, mounting a pivoting arm, attaching a tension source and pouch, and tuning the setup until it launches.
 
A tension-powered pumpkin catapult is the easiest place to start, while trebuchet and torsion designs offer more power once you’re ready.
 
Gather your materials, follow the steps above, and keep testing until that pumpkin flies.
 
Hope this post has helped you with learning how to make a pumpkin catapult and getting yours to launch.