# Re: Junk Yard Trebucet: Day 2

Hi Silvan, I have never built a trebuchet but have seen several being built. I would like to point out that the ones that were most effective were built on a design used by Edward "Longshanks" of England against the Scots. It had a swinging counterweight box that you could put rocks, dirt, sand, or other material into to whatever mass you wanted. King Longshanks couldn't have told you why, but the design he used imparted more force to the projectile and was more accurate than a counterweight fixed to the throwing arm. It has been a long time since my classes in school, but here's the way I think it works. It has been theorized since the Rennaissance that gravity accelerates all things constantly at the same velocity. This was proven on the moon when one of the astronauts dropped a hammer and a feather at the same time and both hit the surface at the same time. On earth that figure is 32 feet per second per second or 32 feet per second squared. By using a swinging counterweight you, in effect, lengthen the time that the counterweight is in free fall, thereby imparting a greater velocity to imparted to it. This allows more force to be exerted on the object being propelled because force equals mass times velocity squared. Anyway, King Longshanks used his trebuchet to bring down castle walls in Scotland. There was an excellent Nova Special on this sometime ago. It was highly interesting. I am looking forward to reading about your baseball chunker. However, I would advise caution. Always be aware of what is down range, and use a tapering jig next time you cut tapers. Have fun. Later, Beej

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Beej-in-GA wrote:

I think I'm in trouble with my ancestors if I copy a design used by Longshanks to bring down walls in Scotland...
The weight swings, BTW, but after that testomonial, maybe I should pin it? :)
--
Michael McIntyre ---- Silvan < snipped-for-privacy@users.sourceforge.net>
Linux fanatic, and certified Geek; registered Linux user #243621
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