Earlier this week I made a lighter arm for my much-rebuilt 4-foot-high trebuchet frame, which has been around in various incarnations since about 2006. So I got out the Flip camera and shot a little footage, or whatever the digital equivalent is called. I stuck a title in front and let Movie Maker paste the clips together, no attempt at editing.

In case anyone's interested, the arm is made from salvaged 1X4 boards fastened together with Gorilla Glue. The long side is 48", and the short side is 13, similar the the pumpkin-throwing arm but half the weight. As it's set up now it's using 2 10-pound weight plates to throw tennis balls. Sling is my unisling design, and trigger is a double trapdoor arrangement adapted from Ron Toms's original floating axle treb. Steep cocking angle gives a longer arm rotation and more counterweight drop for more energy.

Performance is guesstimated, as the balls go over the house, being recovered on the lawn across the street. On the far side of a mini van parked over there. One bounce, I imagine.

Plans are to change CW to 2 25-pounders to throw baseballs or softballs (in the park, too dangerous for at home). I expect around 250 feet.

http://www.youtube.com/watch?v=6C5gK1br0nM

And for Curious Aardvark's edification there are trigger details.

Sweet!Make a video of the whole throw,maybe?

Nice Treb Thom. It would be cool to make miniature castles to destroy with mini trebs. Wonder if anyone does that?  :)

I saw one vid where a lady flung a burning ball of some sort onto a paper castle, setting it ablaze. And one of someone throwing at scacked soda cans. I think SCAdians fling "rocks" at fortifications, but that's not mini. The targets at Fullerton were castles painted on 4X8 plywood.  

Jax, I usually shoot from a tripod and don't try to follow the ball's flight. My main interest is in the arm and sling action. Analyzing how the arm, counterweight and sling interact tells me how well I'll be throwing. Someone once said that a teb is three pendulums going at once, and while I only count two it still can get complex. It's hard to explain, but the angle of the launch is the last thing you really worry about. Distance comes with optimizing multiple factors.

Thom,

 Did you see this one?
http://www.youtube.com/watch?v=H8qS7n0p4Hk

 Brett

Hope you weren't really throwing stuff at people.

No,accidental.Crazy guy that steals things from my yard,and lives in the alley.He went by and apparently did a lap,and there he was.

A safe way to say "don't mess with me" or "don't steal" ...And did you actually hit him...?

You need a big, noisy dog. Vagrants may not respect property rights but do understand self-preservation.