NEW! Atreb now has an optimization module! Not sure how long to make the sling? The axle placement or arm ratio? Let ATreb figure it out for you. Download the Optimization addendum(pdf) from the manual for more info!

"Atreb estimated that I would throw an 8 lb pumkpin 943 feet - I actually hit 927 during competition, but that was into a slight headwind. I'd say it's pretty accurate."
     -- Chris Gerow, Winner of the 2000, 2001, 2002 and 2003 World Championship Punkin Chunk, Trebuchet division.

Q: What's the best way to learn about trebuchets?

A: Build a lot of them!

What's the easiest, cheapest and safest way to test your theories about trebuchet mechanics? Use a trebuchet simulator!

What is ATreb? "A" stands for accurate, and "Treb" is short for Trebuchet. This is by far the most accurate trebuchet computer simulation you can get!

Engineered and programmed by Les Scholz, this simulator goes beyond just lengths and weights! You can add the effects of air drag, friction, do stress analysis on your arm, sling, pin, axle... and work out all the finer details of your trebuchet design before you even buy a single piece of lumber. It also includes a metric conversion calculator, release pin optimizer, and you can save hundreds of design parameters and simply load them from disk to work on different projects at the click of a button.

BUY NOW!     Only $19.95. Or get the demo version: $FREE *** Also available on CD-Rom with Trebuchet Kit Plans! *** Download the PDF user manual here. Download the Optimization addendum here. In basic mode, just plug in the lengths for your arm, frame, sling, etc. until you're happy with the performance you get. Then click into advanced mode to fine tune things like the shape and taper of your arm, the thickness of your axle, how much (or not) to prop your counterweight and how to prop it! How long and what angle should your pin be? What are the stresses? With over 16 graphs of data, you'll know exactly what your treb should be able to do. Graphs include counterweigh velocity, pivot load, trajectory, projectile acceleration, sling tension/time, finger load, arm stresses, and lots more! Then watch an animation of your design in action. Either smooth motion or strobe mode reveals the timing of your release point and counterweight position. You'll actually be able to see your stall point and how the counterweight reacts. Does propping the CW advance your stall point? Now you'll know!