This is a catapult built by a web visitor (John L. and his son, of Oklahoma) They used my plans for the Ogre catapult but made some nice modifications. John himself did the drilling and pre-cutting but his son did all the assembly work. And they built it at a 75% scale of mine so it is a little smaller and a little more compact. This change in size was easy for them. All they did was take 75% of each measurement and used that. Here is a description of what they did and what improvements they made:

First off we only built it at 75% of original size (had size limitations, max 19", from the science teacher).  With building it at 75% we used 1"x2" instead of the 2"x3", they worked out great.  We also used a 3/8" x 8" bolt for the pivot instead of the broom stick or dowel.  We drilled ½" holes, inserted plastic sleeves to make it .385" so the 3/8" bolt slides freely.  And we used eyelets instead of hooks for the bungee cords and I also added a hook at the back so we could lock it down in the drawn position.

This method of using plastic sleeves to get a nice tolerance and a very free slide is an excellent improvement. It makes the catapult much more efficient.

My thanks to John and his son! And thanks for submitting the pictures. A lot of people ask about making the Ogre a little bit smaller and this is perfect.

Quick guide to my catapult making tutorials

Table top catapult: The Troll
Rubber band powered

Mouse Trap Catapult -
fast to make

Table Top Torsion Catapult
(Also known as a Mangonel )

-Backyard Ogre -
3 foot Band powered catapult

The Popsicle Stick catapult

- The Wyvern -
3 foot Torsion Catapult

- Goblin catapult-
Rubber band powered and adjustable

- The Multipult -
5 shot machine gun catapult

The DaVinci Catapult