Portable Treb
Posted: Thu Mar 20, 2014 9:52 pm
When I got into this hobby about 4 years ago, I dove right into the deep end with a unique non traditional design of my own. Later I felt I needed to build something simpler to be able to demonstrate to beginners the basics of the traditional trebuchet design. One night before neighborhood trash day, my neighbor had put to the curb an old exercise walker. One man's junk is another man's treasure. I acquired the walker, because I could envision a portable trebuchet that could be folded for transport in the back of my car. I wanted to keep it simple and basic. I had a feed bucket in my garage that I used as the HCW (hanging counterweight). It makes it very easy to change CW by simply placing loose barbell plates in the bucket. You could also use bricks, stones, sand, or practically anything you have available. I used a 2 x 4 for the arm and cut some taper on the long end, utilizing a basic 4:1 TA (throwing arm) ratio. I did have to do some metal fabricating and welding with my TA holder and axle, the hook to hold the bucket, a reinforcing bar for the bucket handle, and the release pin. The sling is a very simple and custom made from nylon reinforced packing tape, super strong and very handy for repairing and/or reinforcing wood parts also. The whole project turned out very nice and portable. It can hold up to 100 lbs of CW, and I've used it to hurl oranges, baseballs, and softballs about 200 feet. I have an assortment of practice softballs that I purchased of different weights from 6 oz. to 12 oz. These came in handy when I loaned the whole rig to a friend's middle school daughter for a science fair project demonstrating the effect of different CW and different projectile wt.