Ancient Engineering
The Atomic Bomb of the Middle Ages
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How to Build a Catapult

Here is a collection of what plans we've been able to collect from around the web. These are compiled from several sources by many people. Some are suitable for physics projects, and some are for more serious hobbyists. You'll have to figure out which ones are right for you.

Most of the rest of us got started with books and encyclopediae. We feel that the research and design of these machines is half the fun. (The other half being building and firing them!), so some of these links are included for information purposes. These resources can help you design and build your own catapults and trebuchets.

Take a look at these links, do some research, and have fun!
Good Luck!

    These first three links include the RLT Kits known as the Warwolf, FAT, Tabletop Trebuchet, PVC Trebuchet, Mangonel, Ballista, Scorpion II, Petraria and a new Rat-Trap catapult.

  • Trebuchet and Catapult Plans and Simulators on CD-ROM
    Includes plans and bonus material for many different types of trebuchets and catapults. The two best trebuchet simulators on the planet are also available here. A fantastic resource!

  • Downloadable Plans for a variety of Trebuchet and Catapult projects!

  • Buy A Kit!
    Complete and easy to assemble kits including everything you need to build a working Trebuchet, Onager, Ballista or other machines. All pieces are pre-cut and pre-drilled for easy construction.

    One of my favorite Chinese proverbs is: "Give a man a fish, he eats for a day. Teach a man to fish, he eats for a lifetime." This philosophy applies to engineering and physical sciences too. You can buy a kit or a set of plans for a single trebuchet, or use these resources below to learn the fundamentals of engineering and mechanical design, a skill that will be useful for a lifetime!

  • Catapult Design, Construction and Competition with
    The Projectile Throwing Engines of the Ancients, and
    Forward by Ron L. Toms. (8-1/4" x 11" Printed Book)

    If you've ever wondered how to build a catapult or trebuchet, or wondered what you'd do with it once you've built one, then this book can help. Filled with anecdotes, plans, photographs, drawings and detailed descriptions of the workings and history of all the major types of catapults, these pages will help you get started in this fascinating hobby. You too will feel the joy of harnessing the power and energy of simple and ancient machines!

  • Catapult Design, Construction and Competition
    (Downloadable PDF E-Book).

    by Dr. Bernard F. Barcio
    Published in 1978. This book talks about the nation-wide catapult competitions in the 1960s and 70s, and the machines that won it. The records, types of machines, schematics of the winning machines, rules and guidelines for competition, and lots of pictures and diagrams included in this 111 page work. It's a must-have if you have any interest in the sport of hurling!

  • The Projectile Throwing Engines of the Ancients
    (Downloadable PDF E-Book).

    by Ralph Payne-Gallwey
    Published in 1907. This English Nobleman researched and developed fully functional catapult and trebuchet recreations at the end of the 19th century, then wrote a book about it. It's a great way to learn how these machines were made. Lots of pictures and diagrams.

  • Get the Trebuchet Simulator!
    This is by far the easiest and fastest way to test your trebuchet designs!
    "It's what I use!" -- Ron L. Toms

  • Get the FAT/F2K Trebuchet Simulator!
    A simulator for the more advanced types of trebuchets.
    "Used to design T-Wrecks, the most powerful trebuchet ever!" -- Ron L. Toms

  • Ripcord's Trebuchet Stuff
    By far the best place to get started and learn the basics of trebuchets, including slings, pouches, and release pins. Tons of great info and pictures!
    Now including detailed PLANS!

  • A Darn Good Looking (and functional!) Paper Card-Stock Trebuched
    A working card-stock model (PDF) that you can print out and make. From Sheila's Paper Models.

  • Dan Becker's GOOD PLANS
    A great resource for building a tabletop model from scratch. Lots of detail photos.

  • INGENIUM medium trebuchet
    Very nice printable plans, and don't forget the smaller version here .

  • The Grey Company Trebuchet Page
    A tremendous source of research, photos, drawings and other info. This is a fabulous place to start.

  • Knight's Armoury
    The best site around for blueprints of real medieval weaponry! Great research material!

  • Onager Online
    Team Carbo's award winning onager. Click on the "upgrades, plans, and construction details" on the left side-bar.

  • The Algorithmic Beauty of the Trebuchet
    WinTrebStar - A fabulous software simulator for trebuchets. Versions for both Mac and Windows. Information about onager behavior and materials strengths is available too!

  • Projectile Motion
    A page with the basic physics formulae for ballistic projectiles:

There are many other great sites as well. If you run across one that should be included on this page, be sure to let me know!

Tell your friends!


Interesting Notes

Some Trebuchet History:

From the 13th century writing: "Itinerarium Peregrinorum et Gesta Regis Ricardi"

In June and July of 1191, Richard the Lionheart (the Duke of Normandy) laid siege to the city of Acre as part of the medieval Crusades.

The Duke concentrated on constructing siege machines and placing trebuchets [petrariae - literally, stone hurler] in suitable places. He arranged for these to shoot continually day and night. He had one excellent one which he called "Bad Neighbor" [Malvoisine]. Its continual bombardment partly destroyed the main city wall and shattered the Cursed Tower. On one side the Templars' trebuchet wreaked impressive devastation, while the Hospitallers trebuchet also never ceased hurling, to the terror of the Turks.

Besides these, there was a trebuchet that had been constructed at general expense, which they called "God's Stone-Thrower". A priest, a man of great probity, always stood next to it preaching and collecting money for its continual repair and for hiring people to gather the stones for its ammunition. This machine at last demolished the wall next to the Cursed Tower for around two perches' Length [11 yards or 10 meters].

The count of Flanders had had a choice trebuchet, which King Richard had after his death, as well as another trebuchet which was not so good. These two constantly bombarded the tower next to a gate which the Turks frequently used, until the tower was half-demolished. Besides these, King Richard had two new ones made with remarkable workmanship and material which would hit the intended target no matter how far off it was. . . . He also had two mangonels [traction trebuchets] prepared. One of these was so swift and violent that its shots reached the inner streets of the city meat market.

King Richard's trebuchets hurled constantly by day and night. It can be firmly stated that one of them killed twelve men with a single stone. That stone was sent for Saladin to see, with messengers who said that the diabolical king of England had brought from Messina, a city he had captured, sea flint and the smoothest stones to punish the Saracens. Nothing could withstand their blows; everything was crushed or reduced to dust.