What is the easiest and most effiecient way to construct a trebuchet?

Question

i have to make one for my physics project. it has to throw a tennis ball like 15-20 feet.

Answer 1

I am the creator of the http://mysite.verizon.net/shteinb . If you have any questions about anything on the site let me know. Do keep in mind that alot of the design principles I mention are for large machines. There is no need for you to have wheels, and your arm ratio may be a bit different. You may want to look at the sling though, its quite effective, as well as the general frame, and the method i use to attach counterweight. It is FAR easier to attach counterweight by my method rather than some others.
Finally don't forget to mess around with your firing pin, for your size trebuchet you may want to use a piece from a metal coat hanger(malleable and easily accessible). The angle of the pin can make the difference between a 20 foot throw backwards, and a 40 foot throw forward. I am not sure if you are doing this for science olympiad(which i was a state medalist in), but good luck either way, and don't hesitate to ask me any questions regarding the site.
http://mysite.verizon.net/shteinb

Answer 2

Do what that other guy said about the weight and all. The sling should have one end tethered on the the lever with the sling pouch somewhere in the center and the other end of the sling string should be tied to some sort of ring like a key chain ring. On the end of the lever, furthest away from the weight, should have a pin in it that the ring will go around. In mid-motion of the trebuchet, the ring will slide off of the pin and let the tennis ball come out of the sling. The last thing you have to do is trial and error testing in which you will change the angle of the pin to make it release the ring earlier of later.

Edit: everything I just said is in the other guy's link apparently

Answer 3

A trebuchet uses an unequal arm lever, with a heavy weight on the short arm, to whip the long arm. Simple in concept, but with complications in practice. The heavy weight should swing from the end of the short arm, like a basket with weights pulling the short end almost straight down. The long arm should have a sling attached to it, and therein lies the biggest challenge----making that sling "throw" just right, releasing the projectile at exactly the right time. Otherwise it could 1) throw it straight up or backwards, or 2) maybe not release the projectile at all. You'll need to experiment with the sling arrangement until the projectile flies right.

Check link for photos and free plans

Answer 4

http://mysite.verizon.net/shteinb/id4.html

Make a smaller one with wood and ignore the wheels. The design will be useful

Answer 5

Hire an expert to build you one.

Answer 6

clay pigeon thrower for shot gun practice is a possibility?