There are lots of people out there making some terrific cataputls and I received this email and pictures from somebody who is having a ot of cub scout catapult fun! His name is James and my thanks to him and his cub scout group for the picture and for letting me know about their spectacular big catapult!

Here is what James has to say:

Hey There

Thanks for your awesome site - we got some great ideas from it.  I am a den leader for a Maryland cub scout group (3 rd and 4 th graders).  In the book is a marshmallow catapault made with plastic spoons that everybody thought looked neat.  I convinced them it was small and puny looking so we pulled up a bunch of stuff on line.  They loved the idea of your wyvern so we based ours on what you had built - scaled up 2.5 times with added bracing for stability.   Last night we unveiled it to the pack as a pumpkin thrower until we broke the pry bar winding it and snapped one of the ropes. 

Here is a picture -   If you are interested in more pics or the video I can talk to the pack and see if they are okay with that. 

Final dimensions

• Length - 96 inches
• Width - 43 inches
• Throwing arm - 8 ft long, with 10 wraps of 3/8 inch rope (rated to 100 pounds).
• Original bracing - 23 inch long 4X4s which snapped like a twig the first time we wound it up.
• Final bracing - 23 inch long 4X6s with 4 ½ inch lag bolts to add stability.

 

How the Catapult is Powered

The catapault is torsion based and we followed your video on wrapping the rope.  We had a 3/8 inch rope with 5 loops over and 5 loops under, wound up with steel bars.  We probably had about 15 twists in the rope and were tightening it another half turn when it snapped.  One of the improvements for next year is going to be stronger ropes and possibly steel bracing on the side (we also broke the original 4X4 braces that the rope passed through).

 

Thanks for the site and the inspiration - the kids loved it and the parents loved it more.

-James

 

The Art of the Catapult: Build Greek Ballistae, Roman Onagers, English Trebuchets, and More Ancient Artillery - Nice book that shows you how to build ten different catapult projects, moderate wood working and pvc piping kind of stuff. Good book with complete instructions and materials lists.

Buy from Amazon.com: The Art of the Catapult: Build Greek Ballistae, Roman Onagers, English Trebuchets, and More Ancient Artillery

Backyard Ballistics: Build Potato Cannons, Paper Match Rockets, Cincinnati Fire Kites, Tennis Ball Mortars, and More Dynamite Devices Want to get a little more creative? This book is off the hook!

Buy From Amazon.com Backyard Ballistics: Build Potato Cannons, Paper Match Rockets, Cincinnati Fire Kites, Tennis Ball Mortars, and More Dynamite Devices

 

Catapult Kit Lay Siege To The Doghouse! Right after you build your own working medieval catapult. All you'll need is glue, scissors and a steady hand to construct this wooden, Canadian-made siege engine kit. The finished catapult stands 6" tall x 5" wide x 10" long and will toss assorted stuff (meatballs?) 15 feet or further, depending upon the stuff. Comes with detailed instructions.