http://tennisko.com/how-do-i-make-a-catapult-to-shoot-a-tennis-ball/4582 Thu, 11 Mar 2010 16:43:19 +0000 http://wordpress.org/?v=2.7.1 hourly 1 http://tennisko.com/how-do-i-make-a-catapult-to-shoot-a-tennis-ball/4582/comment-page-1#comment-6519 jay13178 Wed, 24 Jun 2009 02:26:29 +0000 http://tennisko.com/how-do-i-make-a-catapult-to-shoot-a-tennis-ball/4582#comment-6519 Well, a trebuchet and a catapult are two different things. Your teacher probably won't care, but a trebuchet uses gravitational energy to launch things, and a catapult uses mechanical energy stored in springs to launch things. Anyway, I think metal springs are an excellent idea. What you'll want to do is use torsional springs with an arm you can pull back to launch the tennis ball. That's what I would do anyway. I've linked to a pic showing my idea in "sources". The way you attach the arm to the spring is critical, and will depend on what type of spring you get. If you don' t have someone with a welding rig, you could try lashing the arms to the spring, but you'll just have to experiment until you get something adequately stiff. Also, just so you know, the stiffer the springs and the longer the catapult arms, the farther the tennis ball will go. Another option is to just get a flexible tree branch and put a sling at the end of it. Fix it at one end, pull back and release. The problem though is you'll need a pretty long arm to launch the ball 30 feet and may be over the size limit. You can experiment with other materials like steel or aluminum. This would be a simpler method than the spring catapult, but would be less awesome. ;) However, it definitely would fall under the definition of catapult as you're using the wood/metal as a spring. A trebuchet, on the other hand, may or may not be acceptable, and is at least as complicated as the mechanism I described above. (Also, I'm not sure a trebuchet of such a small size would launch something 30 feet anyway, but maybe). Well, a trebuchet and a catapult are two different things. Your teacher probably won’t care, but a trebuchet uses gravitational energy to launch things, and a catapult uses mechanical energy stored in springs to launch things.
Anyway, I think metal springs are an excellent idea. What you’ll want to do is use torsional springs with an arm you can pull back to launch the tennis ball. That’s what I would do anyway. I’ve linked to a pic showing my idea in “sources”. The way you attach the arm to the spring is critical, and will depend on what type of spring you get. If you don’ t have someone with a welding rig, you could try lashing the arms to the spring, but you’ll just have to experiment until you get something adequately stiff.
Also, just so you know, the stiffer the springs and the longer the catapult arms, the farther the tennis ball will go.
Another option is to just get a flexible tree branch and put a sling at the end of it. Fix it at one end, pull back and release. The problem though is you’ll need a pretty long arm to launch the ball 30 feet and may be over the size limit. You can experiment with other materials like steel or aluminum. This would be a simpler method than the spring catapult, but would be less awesome. However, it definitely would fall under the definition of catapult as you’re using the wood/metal as a spring. A trebuchet, on the other hand, may or may not be acceptable, and is at least as complicated as the mechanism I described above. (Also, I’m not sure a trebuchet of such a small size would launch something 30 feet anyway, but maybe).

]]> http://tennisko.com/how-do-i-make-a-catapult-to-shoot-a-tennis-ball/4582/comment-page-1#comment-6518 LEO Wed, 24 Jun 2009 00:18:42 +0000 http://tennisko.com/how-do-i-make-a-catapult-to-shoot-a-tennis-ball/4582#comment-6518 http://ca.images.search.yahoo.com/images... Try this website http://ca.images.search.yahoo.com/images...
Try this website

]]> http://tennisko.com/how-do-i-make-a-catapult-to-shoot-a-tennis-ball/4582/comment-page-1#comment-6517 phatphil Tue, 23 Jun 2009 23:06:13 +0000 http://tennisko.com/how-do-i-make-a-catapult-to-shoot-a-tennis-ball/4582#comment-6517 Do a trebuchet. This site has complete plans:http://www.tasigh.org/ingenium/medium.ht... Do a trebuchet.
This site has complete plans:http://www.tasigh.org/ingenium/medium.ht…

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