This Nova study is a great link for understanding how a typical trebuchet was constructed and some of the engineering involved.  Enjoy.

 

--David :sheildsmile:

The cleave and I watched this thing - rented it on video - it was good.              

 

I had a specific question for anyone who has an answer:

 

Anyone have engineering-type specs for the mechanics involved in the trebuchet?

Clarifying this question would be:  Any ratios or formulas that are needed?  Anyone already figure this out so that I dont have to re-invent the wheel?   :O

I think there was an old link in Castle Quest that had some good info on a web site, it's been a long while since it was posted so give me some time and I'll try to find it.

 

As an experiment I'm currently working on the throwing mechanism for a modern Ballista.

A heavy truck leaf spring is good and has a flat trajectory for a longer range then expected but I'm thinking of using light weight 2 stage coil springs instead.

The US navy and some fishing fleets use something like this to throw buoys out.

Right on.  Ill look forward to anything you can dig up for me.

You know, I can see this sort of thing getting out of hand and then down the line there being challenges to sack oneanothers castles...  large scale "capture the flag". :D   Cleave and i were discussing the huge scale "entire'neighborhood snowball fight" that we could host with catapults, and all that.  Sort of an assualt the keep re-creation thing.  ####, Id buy a ticket to that thing!

Ya! After watching the Nova program, I was so into trebuchets that I built a trebuchet out of a Star Wars Lego set...(minus the sling and missile, mind you, but it DID have an operator, which by the way, I sent flying into a bowl af apples by pushing down the counterweight...hey, it was his fault for holding onto the throwing arm!)  

Scott drinks moat*#@er and I are determined to build one big enough to sling canteloupes at least 60 yards so we can have fun with target practice.

sorry for the length of time in getting back to this topic

heres the search on CQ for

 

Treb's

 

far more then I could make quotes of and there are really some good ideas too and heres the link from the

 

Timber Framers Guild

that built the first three in modern times with in a dead line no less

Thanks for this kind of data. it really is valuable.  Either cleave and/or myself will definately be chasing this up.  At least for right now I wanted to acknowledge your work - although delayed (you dirty dog) its nice.

Thanks.

Ill be sending you a 200lb thank you note through your window some day.

Scott drinks moat*#@er

takes bow.....  yeah it took me long enough.

 

about your note, just how thick did you say your walls will be?

mines over 8 feet, best bring lots of help.    but what would be better is a water melon attack, their cheaper and much better tasting and does no lasting damage. We might have watermelon plants coming up in the yard for ever :D   but thats allright too. sell what we don't eat or throw every year  

First, the answer: My walls should be approx. 4' thick at ground floor and then maybe 1 foot thick above that (12" cmu plus ashlar so.. 15" maybe)

 

Now for the fun: You totaly said it all with the watermelons.  Ive asked my girlfriend (she's hemming and hawing on becoming more than my girlfriend) about growing watermelon in bountiful ammounts soas to have a surplus arsenal for castle duncan.  This is in the works.  Ok, maybe not for yours per say but.. the idea is one of the things that drive me to keep going.  Cleave and I have thought about it much and talked about it much and we know that there will come a day when we pull the lever/trigger/firing pin and away she hurls!

 I plan on having at least two treb's.  Onelarger one positioned Im not sure where.  The other (smaller) atop the keep or another tower - conveniently positioned soas to be able to fire into the court yards and outside grounds.  Im wondering how powerful a 8' tall treb would be and how effective it would be at hurling watermelon - watermelon not being that heavy Im sure you could have a slightly heavier weight and a shorter arm that would generate some killer torque.

 

Sometime soon Illcatch up with you guys in the chat room.

maybe tues. (Im off.  Well, Im always off - just Tues I dont work. ::

What i meant by asking about your walls was I've been working on the plans for several different types of projectile throwing devices too.

One of my lesser goals is to some day have the Roman Ballista that could throw a god size modern telephone pole just under a half a mile with a semi flat trajectory, you know like an arrow, nothing TO big after all. LOL  

Some of them were mobile back then and of course todays would have to be drawn with horse's also, or with a pickup truck, or a semi tractor, what ever depending on the size of the thing.  :D

 

I agree about the smaller missile (melon) throwing devices too, some of them very strategically placed on the flat roofs of several of the towers of the outer walls just so you can't get into range with the melons of course.    

About the Ballista, the Romans had different types both large and small, some that we now a days would associate with machine gun nests capable of rapid fire and very good accuracy.

These could be spread around the walls and with ripe cantaloupes or squash would make things very interesting for door to door salesmen. (just kidding about the salesman!  

yeah that will teach you to trespass then use the door knocker!! HA!   )

hmm i wonder about grape shot??? we're growing grapes and the little green not ripe ones are harder then heck!  

 

Is your girl friend holding back because you asked her to grow thousands of melons or other reasons, like you hang around other nut cases here in this site?

Mayhaps is there congratulations in order soon?