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As far as readings go, DO start with Sir R.P. Galloway's book.

For those who are interested, I understand that copies are available

through :
Albert Saifer Publisher

BOX 7125

Watchung, NJ

It can also be obtained (in Canada through U. of T. and Ottawa.

My good lord with the sling problem: Try a simple sling of canvas

or, failing that, burlap! My Trebuchet worked OK. It measures

6' at the base and 8' (ish) on the arm with a ratio of 6:1. Try that.
To any and all mundane engineers and physics types... Can YOU work out

the mathematical / mechanical formulae?

For ballista type amusement, try to find _Harry and I Build a Catapult_

They used truck leaf springs and I beams.

My final word is this: Any information, no matter how trivial

about Seige weaponry would be greatly appreciated. This would

include the Car and Driver issue and page number with the Trebuchet info

, Please!

Maybe we'll just e-chat.
Sebastien Roland fils de MArek

"Never challenge a guy who owns a catapult to a snowball fight" - Hagar

amlsmith at

Trebuchet Blues (getting better)

18 May 92

From: 00MJSTUM at leo.bsuvc.bsu.EDU


Organization: The Internet

Unto the good gentles of the Rialto I send Greetings!
I deeply thank each of you who responded so quickly to my request

for help with trebuchet sling construction.

As I posted previously, I attempted to use a "net" type sling as I had

seen in almost all sketches of trebuchets. However, changing the sling

to a "hand-held" design which involved a mere "patch" of leather or

canvas attached with rope gave me the results I was looking for.

Now, given that my prototype construction was very hastily done and

a lot of power was lost due to movement, I was able to cast a tennis-

ball a mere 24 yds with a 4ft/1ft throwing arm with approx. 40 lbs.

of counterweight (the weight a _very_ loose guestimate... the structure

could have held much more but I had no way of attaching any more weight).
To those of you who have built or seen such engines, what are the vital

statistics of your machines? (We can take this to E-mail and summarize

Missile Weight:


Arm Length/Counter-Length:


I'm curious if there's an optimum arm length/counter-length ratio as

well as a maximum counterweight for a given arm length (for some

reason I can envision _too_ fast of an arm movement). My objective is

to construct an engine that will place a ~2lb object 100+ yds. What

kind of scale are we talking about here? My first thought is to build

an engine capable of holding ~6 cement blocks as counterweight with

a 6' to 8' arm. However, my instinct tells me that this is still too

Gratefully yours,

Gwydion ap Myrddin


Trebuchet Blues (getting better)

18 May 92

From: tip at (Tom Perigrin)


Organization: A.I. Chem Lab, University of Arizona
Unto Gwydion ap Myrddin, doth Thomas Ignatius Perigrinus send his greetings,
My Lord,
My largest beast can send a grapefruit about 150 yards. The arm is

a goodly 8' long, and is pivoted about 1 part towards the counterweight, and

6 parts towards the sling. This distance was decided after 5 trials with

different arms. An the arm be to much one way, then the cast is too slow,

an it be to much the other way, the weight be not ponderous enough to swing it

The weight doth seem to be critical, for that I find two hundredweight is

near unto being too little, whilst three hunderdredweight doth serve well.

My counterweight is a mix of bronze and lead weights, suspended by chains

and ropes,

From julian at Fri May 29 00:52:28 1992

Date: Fri, 29 May 92 00:52:20 PDT

From: julian at (Julian Carlisle)

To: allaway, cat

Subject: Seige Engine

_A Scud It's Not, But the Trebuchet Hurls a Mean Piano_
Giant Medieval War Machine Is Wowing British Farmers And Scaring the Sheep
By Glynn Mapes, Staff Reporter of the Wall Street Journal (25 Sept 91)

ACTON ROUND, England--With surprising grace, the grand piano sails through

the sky a hundred feet above a pasture here, finally returning to earth in

a fortissimo explosion of wood chunks, ivory keys and piano wire.

Nor is the piano the strangest thing to startle the grazing sheep this

Sunday morning. A few minutes later, a car soars by - a 1975 blue

two-door Hillman, to be exact - following the same flight path and meeting

the same loud fate. Pigs fly here, too. In recent months, many dead

500-pound sows (two of them wearing parachutes) have passed overhead, as

has the occasional dead horse.

It's the work of Hew Kennedy's medieval siege engine, a four story tall,

30 ton behemoth that's the talk of bucolic Shropshire, 140 miles northwest

of London. In ancient times, such war machines were dreaded instruments

of destruction, flinging huge missiles, including plague-ridden horses,

over the walls of besieged castles. Only one full-sized one exists today,

designed and built by Mr. Kennedy, a wealthy landowner, inventor, military

historian and - need it be said? - full-blown eccentric.
A Pagoda, Too
At Acton, Round Hall, Mr. Kennedy's handsome Georgian manor house here,

one enters the bizarre world of a P. G. Wodehouse novel. A stuffed baboon

hangs from the dining room chandelier (``Shot it in Africa. Nowhere else

to put it,'' Mr. Kennedy explains). Lining the walls are dozens of

halberds and suits of armor. A full suit of Indian elephant armor,

rebuilt by Mr. Kennedy, shimmers resplendently on an elephant-sized frame.

In the garden outside stands a 50-foot-high Chinese pagoda.
Capping this scene, atop a hill on the other side of the 620-acre Kennedy

estate, is the siege engine, punctuating the skyline like an oil derrick.

Known by its 14th-century French name, trebuchet (pronounced

tray-boo-shay), it's not to be confused with a catapult, a much smaller

device that throws rocks with a spoon-like arm propelled by twisted ropes

or animal gut.

Mr. Kennedy, a burly, energetic 52-year-old, and Richard Barr, his

46-year-old neighbor and partner, have spent a year and #10,000 ($17,000)

assembling the trebuchet. They have worked from ancient texts, some in

Latin, and crude wood-block engravings of siege weaponry.

The big question is why?
Mr. Kennedy looks puzzled, as if the thought hadn't occurred to him

before. ``Well why not? It's bloody good fun!'' he finally exclaims.

When pressed, he adds that for several hundred years, military technicians

have been trying fruitlessly to reconstruct a working trebuchet. Cortez

built one for the siege of Mexico City. On its first shot, it flung a

huge boulder straight up - and then straight down, demolishing the

machine. In 1851, Napoleon III had a go at it, as an academic exercise.

His trebuchet was poorly balanced and barely managed to hurl the missiles

- backward. ``Ours works a hell of a lot better than the Frogs', which is

a satisfaction,'' Mr. Kennedy says with relish.

How it works seems simple enough. The heart of the siege engine is a

three-ton, 60-foot tapered beam made from laminated wood. It's pivoted

near the heavy end, to which is attached a weight box filled with 5= tons

of steel bar. Two huge A-frames made from lashed-together tree trunks

support a steel axle, around which the beam pivots. When the machine is

at rest, the beam is vertical, slender end at the top and weight box just

clearing the ground.
When launch time comes, a farm tractor cocks the trebuchet, slowly hauling

the slender end of the beam down and the weighted end up. Several dozen

nervous sheep, hearing the tractor and knowing what comes next, make a

break for the far side of the pasture. A crowd of 60 friends and

neighbors buzzes with anticipation as a 30-foot, steel-cable sling is

attached - one end to the slender end of the beam and the other to the

projectile, in this case a grand piano (purchased by the truckload from a

junk dealer).

``If you see the missile coming toward you, simply step aside,'' Mr.

Kennedy shouts to the onlookers.

Then, with a great groaning, the beam is let go. As the counterweight

plummets, the piano in its sling whips through an enormous arc, up and

over the top of the trebuchet and down the pasture, a flight of 125 yards.

The record for pianos is 151 yards (an upright model, with less wind

resistance). A 112 pound iron weight made it 235 yards. Dead hogs go for

about 175 yards, and horses 100 yards; the field is cratered with the

graves of the beasts, buried by a backhoe where they landed.
Mr. Kennedy has been studying and writing about ancient engines of war

since his days at Sandhurst, Britain's military academy, some 30 years

ago. But what spurred him to build one was, as he puts it, ``my nutter

cousin'' in Northumberland, who put together a pint-sized trebuchet for a

county fair. The device hurled porcelain toilets soaked in gasoline and

set afire. A local paper described the event under the headline ``Those

Magnificent Men and Their Flaming Latrines.''
Building a full-sized siege engine is a more daunting task. Mr. Kennedy

believes that dead horses are the key. That's because engravings usually

depict the trebuchet hurling boulders, and there is no way to determine

what the rocks weigh, or the counterweight necessary to fling them. But a

few drawings show dead horses being loaded onto trebuchets, putrid animals

being an early form of biological warfare. Since horses weigh now what

they did in the 1300s, the engineering calculations followed easily.
One thing has frustrated Mr. Kennedy and his partner: They haven't found

any commercial value to the trebuchet. Says a neighbor helping to carry

the piano to the trebuchet, ``Too bad Hew can't make the transition

between building this marvelous machine and making any money out of it.''

It's not for lack of trying. Last year Mr. Kennedy walked onto the

English set of the Kevin Costner Robin Hood movie, volunteering his

trebuchet for the scene where Robin and his sidekick are catapulted over a

wall. ``The directors insisted on something made out of plastic and

cardboard,'' he recalls with distaste. ``Nobody cares about correctness

these days.''

More recently, he has been approached by an entrepreneur who wants to bus

tourists up from London to see cars and pigs fly through the air. So far,

that's come to naught.
Mr. Kennedy looks to the U.S. as his best chance of getting part of his

investment back: A theme park could commission him to build an even bigger

trebuchet that could throw U.S.-sized cars into the sky. ``Its an

amusement in America to smash up motor cars, isn't it?'' he inquires

Finally, there's the prospect of flinging a man into space - a living man,

that is. This isn't a new idea, Mr. Kennedy points out: Trebuchets were

often used to fling ambassadors and prisoners of war back over castle

walls, a sure way to demoralize the opposition.

Some English sports parachutists think they can throw a man in the air

*and* bring him down alive. In a series of experiments on Mr. Kennedy's

machine, they've thrown several man-sized logs and two quarter-ton dead

pigs into the air; one of the pigs parachuted gently back to earth, the

other landed rather more forcefully.
Trouble is, an accelerometer carried inside the logs recorded a

centrifugal force during the launch of as much as 20 Gs (the actual

acceleration was zero to 90 miles per hour in 1.5 seconds). Scientists are

divided over whether a man can stand that many Gs for more that a second

or two before his blood vessels burst.
The parachutists are nonetheless enthusiastic. But Mr. Kennedy thinks the

idea may only be pie in the sky.

``It would be splendid to throw a bloke, really splendid,'' he says

wistfully. ``He'd float down fine. But he'd float down dead.''

From: haslock at (Nigel Haslock)


Subject: Re: portable seige weapons: rope

Date: 12 Mar 1993 19:14:11 GMT

Organization: Digital Equipment Corporation - DECwest Engineering
The twists in a rope can be measured in twists per inch. The twisting of a

torsion spring bundle might amount to one twist per foot. Yes, there will

be a slight difference in the energy stored on either side of the throwing

arm. The questions are 1) does it affect the accuracy of the engine 2) is it

a self correcting problem.
I would suggest that it is self correcting and so does not affect the engine.

It is self correcting because the throwing arm is free to center itself in

the bundle. As the bundle is would up to tension, the throwing arm will move

so as to equalize the tension on both sides. In an engine in which there are

independent winding mechanisms for each half of the bundle, it is easy to

create an unbalanced bundle. In such an engine, I would expect the shock or

releaseing the arm to cause the bundle to equalise. In such an engine, I

would expect uneven winding to far outweigh the effects of untwisting the

ropes in the bundle.

Aquaterra, AnTir

From: jlagrave at (John Lagrave)

Subject: Our Seige Engine--A Trebuchet

Organization: University of California, Irvine

Date: Fri, 25 Jun 1993 07:14:29 GMT

Greetings M'Lords and M'Ladies
My college, the College of Fenwood Knoll, has completed the construction

of a trebuchet. I wrote to this rialto sometime last year and asked for

suggestions on where to go for sources and help. Lords Aryk Nusbacher, Tibor,

Gille MacDomnuill, Jim Edwards-Hewitt, Hrothgar, Gwydion ap Myrddin

Tarver (W. Ted Szwejkowski), and Sir Michael of York all get a most heart-

felt thanks from myself. (If I have neglected anyone my humblest apologies,

and of course my thanks). What follows is the story of the contruction of a

working seige engine, from design to firing, with a couple of questions that

I hope will be answered. I hope that you enjoy this story, and tolerate this

bit of self aggrandizement. (Insert humble bow here.)

The best source for the construction of a trebuchet is from a journal called

the Viator, (VIATOR 4:99-114 (1973)) by Donald Hill title Trebuchets.

The most entertaining source about trebuchet's is by Sir Paine-Gallwey titled

The crossbow, mediaeval and modern, military and sporting; its

construction, history & management. With a treatise on the balista and

catapult of the ancients, and an appendix on the catapult, balista & the

Turkish bow ( New York, Bramhall House [c1958]). Many a story might be spun

by the clever bard upon reading this delightful, but innaccurate text.

Without further ado, then, my story.
Three intrepid lads, myself include, thinking themselves capable of putting

saw to wood, discussed the possiblity of constructing a seige engine. After

a bit of thought, no small feat for these lads, the possiblity of constructing

a trebuchet reached critical mass and the lads were quite taken by the idea.

Several obstacles lay in their path, however. One being the problem of

transporting the bloody thing, for these lads planned to build something quite

large, larger than, say, the cows they hoped to lauch from the thing, and

not having large mechanisms with which to transport the device seemed a

problem. Well they came upon the idea that no piece of wood would be larger

than five feet. This, of course, led to a new problem, just how the hell were

they going to join the pieces? None of their fathers having been carpenters,

and none of the lads having had a useful education, such as taking a wood shop

class, they created their own joint, which in hindsight could have been much

The specifations of the trebuchet were worked out and the design of the

machine was drawn oh so carefully. It was to measure a full ten feet in

length, spanning some four feet in width, and projecting towards the heavens at

the impressive height of seven and one half feet. This medium is hardly

proper to convey its dimensions, but allow me a simple drawing,

Side View Bird's E View

/o| + + + +

/ | 7 1/2' 4' + + + +

/ | + + + +

/ | + + + +

/ | +--+-----+-------+

+--+------+-------+ 10'

back front

where the + are cross members. The throwing arm was to measure some twelve

feet in length, but be capable of being extended to fifteen feet by some

clever engineering. The counterweight arm was fixed at two feet. The ratio of

throwing arm to counterweight arm was 6:1 (for those lacking the schooling in

mathematics), but be capable of being increased. A sling was to fit onto this

arm to even further increase the ratio--those of you who are wise already

see the problem. The weight for hurtling the objects (we had rejected the

notion of using a traction type trebuchet, do to the tremendous lack of

ability to organize our college for any endeavor) was to be made from

lead and steel encased in concrete.

We proceeded to build our trebuchet, and in sporadic bursts the engine was

completed. All uprights were split in two, along with the ten foot long base

beams. All beams were four by four inches and all joints were joined by one

by four inch boards with one half inch by ten inch bolts running through them.

Corners of the base were joined together with metal braces after the original

lag bolts were determined to be to weak. The pivot beam was joined to the

upright by lag bolts and metal braces bolted to the sides of the beams to

provided further support. The pivoting beam was constructed of a metal pipe

and the throwing arm was made of some plumbing fittings. A four-way connector

had two inch pipes which pivoted about the metal pipe which was in turn

anchored to the uprights. (confused yet?) The throwing arm and counterweight

arm were in turn connected to the four-way connector. The weight was

connected to the counterweight arm by a t-type fitting with a rod placed

though it and a series of links. When all this was finished a winch was fitted on

the side to allow us to pull down the throwing arm. A sling trough consisting

of a flat piece of board was placed between the uprights. The throwing arm

consisted of a wooden dowel one and one half inches thick, twelve feet long.

It fit inside a metal pipe fitted to the four-way connector, and was secured

by bolts. We surveyed our work and felt satisfied. It seemed quite secure.

Only one thing left to do, see if it worked.

So on a fine day, the first of summer, the lads and I set out onto a field and

set up our machine. The sun was hot and we worked up quite a sweat assembling

our engine. We loaded a counterweight (some 150 pounds) thinking it best to try

our engine with one weight lest we break the bloody thing and fall about in

fits of crying. We rigged out sling, and fired the engine. WOOSH! The

weight fell. Up went the throwing arm. Flop went the sling. Our stones

(consisting of hard plastic balls covered with foam and then wrapped with duct

tape) fell about us. DAMN! (Please excuse the language gentle folk but we were

sorely mad.) Well we put our heads together and thought a good thought.

Perhaps the sling was too long. We shortened it and fired again WOOSH! went

the weight. CRACK! went the throwing arm. Wood fell about us as the arm

broke into pieces. DOUBLE DAMN! (Again apologies to all.) Time to buy a new

dowel, and, we reasoned, some reinforcement for said dowel. Off we trekked to

the nearby supply store where we purchased some pvc pipe as a sleeve for the

throwing arm.
With a new throwing arm mounted on the trebuchet, we again tried the

engine, but the sling did not open up completely. The sling is made of canvas

and it is some two feet wide by three feet long. The sling ropes were

shortened considerably and the sling began to extend more than before, until

finally the sling was being fully extended in flight. But the bloody canvas

was staying closed. We tried again and again to no avail, and we managed to

break another wooden dowel in the process. We decide to go with a pvc pipe

throwing arm with an inner wooden rod for support, with a reinforcing outer

pvc sleeve. Well it weighed a lot, but we were darn confident that it would

not break.

Well, we decided to go with an earlier period trebuchet design and we placed

a large basket at the end of our newly constructed arm. It worked splendidly.

The foam balls flew out of the basket, arcing ever so gracefully toward the

heavens, before being reminded that they were not birds. Ah, twas a glorious

sight for these eyes. With one counterweight, the farthest a three-quarter

kilogram ball went was 31 paces before striking the earth, and it was moving

pretty fast went it hit the ground. With four balls placed in the basket,

the range was about 22 paces with a grouping of four by four paces.

We attempted to place a second counterweight on our engine, but the weight

was too much. The release mechanism is also the mechanism we use to pull

down the throwing arm and it bent straight from the weight.
So, you see our predicament. We need to redesign our sling and our release

mechanism. We already have an idea about separating the release mechanism

from the spanning rope, but we need help with the sling design. Any

suggestions? We suspect that the wind resistance of the sling is creating

problems, but how do we overcome them without sacrificing delivery load? The

lack of a sufficient counterweight may also be part of the problem, but that

will (hopefully) be rectified by the modifications to the release mechanism,

which will allow the second counterweight.

I have taken enough, nay far too much of your time, but I thank you all for

your patience. The seige engine will be on display and firing at the

Gyldenholt anniversary this weekend. Those of you in Caid that can make it to

Mile Square Park in Gyldenholt are invited to gaze upon its beauty.

Yours in service,

(gotta quit working on the seige engines and work on that persona thing...:)


jlagrave at

From: kuijt at (David Kuijt)


Subject: Re: Trebuchet/China

Date: 21 Jul 93 15:00:01 GMT

Organization: UMIACS, University of Maryland, College Park, MD 20742
Regarding Trebuchets, Tadhg writes:
>>[....] I know of no evidence that the

>>trebuchet was invented by the Chinese. The earliest citation in the OED is

>>from 1224 (in Latin), [....]
to which Thorvald/James responds:
>Perhaps the trebuchet was not invented by the Chinese, but they

>appear to have used it at least as early as 759. Joseph Needham

>in _Science and Civilisation in China_ quotes from a text of

>that date. [...]


>"Tower-ships; these ships have three decks equipped with bulwarks

>for the fighting-lines.... There are ports and openings for

>crossbows and lances...while (on the topmost deck) there are

>trebuchets for hurling stones...."
Siege engine nomenclature was never standardized, and therein

lies the problem. The word Trebuchet is commonly used by modern

military historians to refer to the huge (HUGE) counterweighted

arm design of siege engine developed around the time of the

crusades, and used (for example) in the siege of Acre by Richard

the Lionhearted and his buddies. This is likely the engine that

Tadhg is referring to.
This is also clearly NOT what Needham's quote refers to--the

counterweight-arm design weighed much more than many ships, and

could never have been placed, much less used, on the third deck

of any medieval ship. It would have turned turtle immediately.

Needham is also choosing an english word to translate a Chinese

word. The fact that Needham called it a "Trebuchet" should not

be used as evidence that this is the same engine as any other

device called by that name unless Needham can provide a basis

for his choice of that word over any of the other common words

used for stone-hurling siege engines, such as Catapult, Onager,

Scorpion, and even Ballista. All of these names have been used

to denote a variety of dissimilar siege engines, and confused

with each other. Some words (e.g. Arbalest) are used by one

author to refer to a hand-held device (a big crossbow), and

by another to refer to an immobile siege engine similar to a


As for Needham's device, it may well have been similar to the

Roman and Greek Ballista, or the Roman Onager. The first is a

giant crossbow with twisted-skein arms, the second is a rigid

arm throwing engine also powered by twisted-skein methods.

Both the Romans and the Greeks used Ballistae on ships; there

is some question as to whether the Onager was used that way,

as the ships of the time were not heavily built, and the Onager

"kicks" when it fires, which could quickly damage the warships

of the time. Both the Ballista and the Onager were used to

throw stones; the Ballista also shot large spears.

Dafydd ap Gwystl David Kuijt

Barony of Storvik kuijt at

Kingdom of Atlantia (MD,DC,VA,NC,SC)

From: doconnor at (Dennis O'Connor)


Subject: Re: Trebuchet/China

Date: 21 Jul 93 08:54:46

Organization: Intel i960(tm) Architecture

kuijt at (David Kuijt) writes:

] >>[....] I know of no evidence that the

] >>trebuchet was invented by the Chinese. The earliest citation in the OED is

] >>from 1224 (in Latin), [....]


] to which Thorvald/James responds:


] >Perhaps the trebuchet was not invented by the Chinese, but they

] >appear to have used it at least as early as 759. Joseph Needham

] >in _Science and Civilisation in China_ quotes from a text of

] >that date. [...]

] >

] >"Tower-ships; these ships have three decks equipped with bulwarks

] >for the fighting-lines.... There are ports and openings for

] >crossbows and lances...while (on the topmost deck) there are

] >trebuchets for hurling stones...."


] The word Trebuchet is commonly used by modern military historians

] to refer to the huge (HUGE) counterweighted arm design [...]


] This is also clearly NOT what Needham's quote refers to--the

] counterweight-arm design weighed much more than many ships, and

] could never have been placed, much less used, on the third deck

] of any medieval ship. It would have turned turtle immediately.
Though you may "commonly" think of a trebuchet as having a "massive"

counter-weight (however much that weighs), this is not reason enough

to dismiss Needham. Obviously you can build different size trebuchets,

and if your intent is to smash wooden boats instead of fortifications,

you probably build a smaller one that throws smaller rocks.
Chinese trebuchets often used men as the counterweight (e.g. 20-30 guys

holding ropes who sit/fall down on command ). This is about 3-4 thousand

pounds of counterweight. Obviously you can put 20-30 men on the deck of

a ship. Also obviously if you can put 3000 pounds of men on the deck you

can put 3000 pounds of rock there instead. If you even need that much.
So unless you have better reasons to fault Needham, I don't think you

have presented enough evidence that he has made a mistake.

Of course, if you are arguing that the Chinese didn't have trebuchets at

all before 1200 ( I hope you are not ) then I definately don't accept it.

There's a lot of pictorial evidence that they did ( tho I have to admit

I'm unable to give exact references right now ).


Dennis O'Connor doconnor at

Intel i960(R) Microprocessor Division Solely responsible for what I do.

From: Charly.The.Bastard at (Charly The Bastard)


Subject: Shield Walls

Date: Tue, 09 Nov 1993 18:29:12 -0500
WA>The question is how do you defeat a shield wall.
The answer is a word, and the word is Catapults. Mobile siege engines that hurl

huge rocks great distances. I designed one some time back that would throw a

bowling ball 100 yards. It would fit in the back of a pickup, so it could be

considered, with wheels and a team, towed artillary.

From: johnric at (RICHARD ALLAN JOHNSON)


Subject: Re: Trebuchets again!

Date: Mon, 28 Mar 1994 17:06:27 GMT

Organization: Walla Walla College
In article <2n1uim$alb at> tvalesky at (Tom Valesky) writes:

>From: tvalesky at (Tom Valesky)

>Subject: Trebuchets again!

>Date: 26 Mar 1994 18:23:18 GMT

>In this Sunday's column, Dave Berry describes a couple of guys who are

>attempting to build a trebuchet sufficient to launch a Buick for a

>distance of 200 yards. This made me curious as to what sort of

>dimensions such a trebuchet would require -- the counterweight would

>have to be enormous, and the strength of the arm prodigious to fling

>such a missile.


>So... I was wondering about the mathematics of trebuchet design. Are

>there any rules of thumb that are followed in building a trebuchet

>(ratio of counterweight to missile weight, length of throwing arm) or

>predicting the distance that the missile will be flung (a function, I

>suppose, of missile weight, counterweight weight, throwing arm length,

>and so forth)?


>Perhaps it would be fun to work up a computer simulation of a trebuchet

>according to these design parameters and see what the effect of

>modification of these parameters is.


>Tom Valesky


Already been done. Read a copy of Mechanical Engineer a couple of

months back and you will see a mechanics class at some military school

completely based around a trebuchet design.


From: Suze Hammond (6/28/94)

To: markh at sphinx

RE>BJECT:Re: Blackpowder, y

>I'd love to see more seige engines, but a full-scale trebuchet is just as

>likely to kill an inexperienced crew member as a target... Wonderful

>engines, but very very nasty... As one of our local experimenters recently

>said "Now we know why you never camp -behind- the trebuchet!"

Uu> Hmm. I can imagine what happened, but before you mentioned it, it

Uu> wouldn't have occured to me. So, what happened?? How big was the

Uu> trebuchet and the projectile?


Uu> Stefan li Rous

Uu> Barony of Bryn Gwlad

Uu> Ansteorra
Unfortunately I wasn't there at the time, and they took it down, rather

than leave it for the neighborhood kids to kill someone with. (Rural site.)

As I understand, they were only throwing "SCA-legal rocks", ie huge lumps

of closed-cell foam wrapped in duct tape. Quite a few it threw straight

up, some it threw to either side, some went up and then somewhat to the

rear, and some flew wonderfully, after they made adjustments to the sling

Evidently the design and release of the sling element is quite critical!
I understood that the fact they weren't using real rocks was something

they were often quite thankful for. (And there are lots of largish rocks

in easy "picking" range, which is why it had to be dismantled.)
The descriptions I got made it sound like about 6 feet tall, with a ten

foot arm (?) and I have no idea how heavy a duct-tape rock larger than

your head might be. (I do know other An Tirians have built small ones to

deliver water balloons in combat, but that was long ago... ):

... Moreach | Suze.Hammond at -IGNORE OTHER ADDRESS!

From: shininga at (ShiningA)


Subject: Re: Cannon anyone?

Date: 8 Jul 1995 17:14:06 -0400

Organization: America Online, Inc. (1-800-827-6364)

If canon are not permissable in the SCA, consider the trebuchet, the

successor to the catapult and used throughout the SCA timeframe. An

excellent article on these siege devices is in the July 1995 issue of

Scientific American. These things were quite advanced for their day, in

terms of engineering, and could fling a load of rock or, occasionly,

Plague ridden bodies, quite a distance. The reconstructed modern day

trebuchet detailed in the Sc. Amer. article is some 60 feet high and

tossed 1200 pound objects around the English countryside, including a

small car sans engine block. Range for smaller recreated trebuchets is

reported at some 550 feet. Will this device be demonstrated at the next

Renaissance Festival?

Sir Luke de Seubert

Knight in Shining Armor

From: morganh at (Morgan Hall)


Subject: Trebuchet Field Trials

Date: 3 Oct 1995 10:37:10 -0700

Organization: Teleport - Portland's Public Access (503) 220-1016

Unto the good gentles assembled, Morgan de Comyn sends greetings.
Upon the thirtyth day of September of this most memorable year we tested the

concept of a traction trebuchet upon the field of combat during Acorn War

here in sunny An Tir. For the furtherance of those who practice or study

the arts of military engineering do I submit this report.

An evening discussion of the principles of the trebuchet, fueled by the

famous article about the gentleman in England who has thrown pianos, a video

clip of one in action in Texas, the infamous Northern Exposure sequence, the

July Scientific American article, and memory of wood cuts showing hand powered

(traction) trebuchets deployed upon towers, culminated in the decision to

build and test such an engine. The two main participants in this

discussion, Edward of Left Field and myself, determined that such an engine

must be small and light enough to be transported, and capable of throwing

something usable in An Tir light combat. As we required the ammunition to

be inexpensive, safe, and reliable we settled upon the ubiquitous tennis

ball. Thus, with the basic parameters established, we began.
As we would be limited in size and weight, we constructed a traction

trebuchet, powered by the pull of two persons. Edward had recently

constructed a forge that needed a test -- thus we combined the initial

firing of his forge to heat the metal that would become the metal portions

of our engine. For the basic construction we cut a number of hazel poles

from the abundance that grow on my property. Lashed together, they formed a

sort of truncated pyramid approximately 3 feet high as the base. The

throwing arm was a (relatively) straight pole approximately 9 feet long,

about 4 inches thick at the base and 3 inches thick at the business end.

They were cut green and left to dry for about a week while other business

was conducted. Motive power would be supplied by attaching two pulleys to

a plank below the powered end of the arm, the pivot point being set at

approximately 18 inches from the point where the ropes would attach. The

traction crew would pull in opposite directions, equalizing side forces on

the engine while the pulleys would change the horizontal forces into

vertical forces pulling down on the short arm of the throwing beam.

We decided that the actual bearings of this arm should be constructed from

iron in order that we not break a wooden pivot by over-enthusiastic yanking

on the ropes. Looking about my forge, we decided that 1/2 inch round mild

steel would be of sufficient strength for the axle and the 1 3/4 inch bar

would be excessive.
Our first inclination was to mount a short axle to the working arm and let

it ride on bearings on the support structure. A quick trial showed that our

bracing was insufficient to allow free motion of the axle, side forces would

distort the framework of light wood and cause the arm to bind. We

re-thought the system and interchanged the pivot and bearing structures such

that the arm carried the bearing and the axle could be bent in a "wishbone"

shape to add rigidity to the frame while the bearing would travel with the

working arm. We fabricated a bearing from a short length of flat iron

approximately 1 inch wide by 3/8 inch thick. It was hot punched to allow

attachment to the arm by screws, flattened on one end and spread out to

nearly two inches, then formed over the 1/2 inch diameter axle rod. Spacers

were then applied to keep the bearing centered on the axle portion of the

wishbone. The whole assembly was screwed and lashed together, using screws

to locate the various portions and tight lashings of cord to provide

strength to the assembly.
The release mechanism was provided by setting a short length of 3/8 inch

iron rod into the long end of the throwing arm (the arm was tightly bound

with cord to help prevent splitting). This was bent cold to what we assumed

would be a useable angle. A sling pouch was fabricated from scrap leather,

sling ropes from baler twine, pulleys and ropes attached, we worked it

through by hand, found a tennis ball and were ready for the first test.

Testing and Tuning the Trebuchet:
The first test of the trebuchet was to pull it through without ammunition.

The sling seemed to release properly so we inserted a tennis ball and pulled

through with a rather easy motion. Our test site was in my back yard (rural

area with neighbors about 1/2 mile away) with a 4 foot board fence about 35

feet from the assembly area. The tennis ball left the trebuchet with a

downward motion, striking the fence with a sharp "crack" similar to a mild

tennis serve. We considered the first "live firing" a sucess.
Tuning was accomplished by altering the angle of the release pin. One of

the old bearings (from the initial conception) was the right size and shape

to be pressed into service as our "trebuchet wrench." We bent the release

pin back to allow for earlier release and tried a second shot. The second

shot sailed up at about a 20 degree angle and landed in my back field. A

bit more tuning and we found that our maximum distance seemed to be

approximately 200 feet at about 40 degrees. Wind resistance seemed to be

the largest factor in the distance we could achieve -- a 45 degree angle

seemed to slow down so fast it fell shorter than a lower angle.
Fearing that continual cold bending of the release pin would eventually

weaken it to the point of failure, we then fabricated two auxillary release

pins and bent one to a low angle release and one to a very high angle

release. Finally, to test the power of a heavier projectile, we placed a

windfall apple in the sling and let 'er fly. The apple seemed to be still

rising as it left my property, crossed a road behind it, and disappeared

somewhere in my neighbor's alfafa field. No range for this shot was


Field Trials:
Intellectually we knew that there was a real difference from experimenting

in the back yard and using an engine of this sort in armor. Knowing this,

we began the great search for light armour to fabricate, borrow, or

improvise. Our heartfelt thanks must go to all who helped in this

endeavour, as only this made the field trials possible. As the morning of

Acorn War dawned, we were making final adjustments, lashings, and fitting

the collection of armour pieces to make ourselves field legal with a strange

combination of light and heavy armor. At armor inspection, we passed.

His excellency Baron Invari of Three Mountains asked us to support his

forces, with Sir Blackhand commanding the other side supported by his

infamous ballista mounted upon a machine gun tripod. We were ready for

A few shots demonstrated -- we had the range on him! At this point, we made

the error of moving the trebuchet back a bit. This put it on rougher ground

which had the unfortunate effect of altering the sling travel and release

point. We lost range. We moved again, near our original setup point, with

shaken confidence. Ed and I lasted through the first battle scenario and

halfway through the second when fatigue took its toll. We were too tired to

continue after that point.

The engine performed quite well. The effect of field conditions had

unanticipated effects when grass clumps affected the swing of the sling and

the release point and range of the engine. In no way could we have

predicted the effects of adrenaline and fatigue upon our performance. Our

judgement definitely was affected, and we didn't notice fatigue until it was

quite severe. Mobility and dexterity became nearly non-existant. Attempts

to power the trebuchet with untrained folks (building the thing seemed to

train Ed and myself to work together) were less than sucessful. The triple

release mechanism was VERY valuable!
We have a number of changes to impliment on the next model. The Mark 1

trebuchet was a qualified success, but the Mark 2 will have some

improvements. Mark 1 will probably take the field agin with some minor

modifications, including a trained relief traction crew. I need to give

some serious thought to improving light armor.
In service, I remain
Morgan de Comyn

(Morgan Hall)

Blacksmith and Piper to Clan Hubert, siege engineer in training


morganh at teleport.COM

From: david.razler at (DAVID RAZLER)


Subject: Re: Suburban Trebuchets?

Date: Mon, 18 Mar 96 21:41:00 -0400

Organization: Compu-Data BBS -=- Turnersville, NJ -=- 609-232-1245

J>Might anyone out there know the title or author of a book that was

J>published a year or two ago about a man and neighbour who built a

J>trebuchet in suburban Anytown, USA? Thanks!

They did NOT build a trebuchet, it was a leaf-spring siege engine:

The book, short on plans is Catapult - Harry and I build a Siege Weapon,

(c) 1981 by Jim Paul, no ISBN, Lib of Congress 623.4'41'097946-dc20

90-50664 Scientific American published a letter about and a picture of

a backyard trebuchet earlier this year.

Aleksandr the Traveller

From: pat at lalaw.lib.CA.US (Pat Lammerts)


Subject: siege weapons

Date: 7 Aug 1996 21:27:47 -0400
I don't know of any comprehensive book on siege weapons, but

I think you will find these two books very interesting.

1) Marsden, Eric William.

Greek and Roman artillery; historical development [by] E. W.

Marsden. Oxford, Clarendon Press, 1969.

ix, 218 p. illus. (part col.) plates. 24 cm.

2) Marsden, Eric William.

Greek and Roman artillery; technical treatises [by] E. W.

Marsden. Oxford, Clarendon P., 1971.

xviii, 278 p. 19 plates, illus. (some col.) 24 cm.

ISBN 0198142692
#2 is the best, in that it gives the original text on one page

and the English translation on the opposite page. It also

gives very detailed plans that show how to make every ballista

and catapault shown.

For a light-hearted view of arms and armaments that touches

on siege weapons, you should read:

Halbritter, Kurt.

Halbritter's Arms through the ages : an introduction to the secret

weapons of history. New York : Viking Press, 1979, c1978.

158 p. : chiefly ill. ; 22 cm.

ISBN 0670359084
It is a real hoot.

(pat at


From: Mark Schneider

Subject: Re: Advice needed- Building a period catapult

Organization: CTLnet - Compu Tech Labs, Inc.

Date: Wed, 22 Jan 1997 16:07:27 GMT
Lord Whoever wrote:

> mrlne95 at (MRLNE95) wrote:

> >I am building a catapult for recreational use, and possibly for use in

> >upcoming wars. Any advice would be welcomed. I am wondering if any

> >Marshalls out there would be able to tell me how, if at all, it could be

> >employed in a war. I am also interested in tension, torsion, and

> >counterweight to make them, advantages, and disadvantages.


> If you are going to use a counterweight system I recommend using water

> for the weight so you can drain it for transportation, adjust the

> power easily, etc. A trebuchet would probably be the most spectacular

> siege weapon due to the large motion of the arm. Just my opinion

> anyway...

There is a Catapult Message Board, at

There are a number of people who have built all scale of Trebuchet. I

imagine someone might be able to help with plans etc.


From: "William Herrera"

Subject: Re: Advice needed- Building a period catapult


Date: 29 Jan 97 05:20:11 GMT
Robert Lightfoot wrote in article

<5cmgq0$7t at>...

> Barnes and Noble has reprinted THE CROSSBOW by Sir Ralph Payne-Gallwey

> which conatins dimensions, materials, and working drawings for trebuchet,
> ballista, catapult, etc. _The_ book on the subject for the home

> handyman.


> Ld. Ernst von Nurenberg

While The Payne-Gallwey Book does have excellent material on CrossBows, and

way cool illustrations there are some caveats. More recent study seems to

point toward a great many innaccurcies and assumptions concerning Siege

Equipment on his part. It seems that he,(Like many of us may have done),

relied on secondary sources mostly Rennaisance interpretations of Medieval

texts, as opposed to the medieval Text itself. Many of his devices require

full machine shop to produce the complex gears, rachets and Pawls, in order

to work. Whilst medieval, and rennaisance craftsmen did produce beautiful,

intricate machinery, It is hard to assume such facilities would be easy to

accquire during Every Siege. Ditto With Viollet-le-Duc (a Renaissance

Scholar). For Further Info on this see- The Traction Trebuchet: A

Reconstruction of an Early Medieval Siege Engine by W.T.S. Tarver

Journal of the Society for the History of Technology.

Other Sources:

Bellifortis -Konrad Kyser ca-1405 Gottingen, Universitas-bibliothek,

Cod.phil.63, Edited by G. Quarg, (Dusseldorf 1967) Possibly available in

paperback at Chivalry sports(?)

Di Rei Militaria-Flavius Vegtius pre-1300- Edited Charles R Shrader (New

York 1976) I've seen in reprint but I can't remember Where.

Medieval Military Technology -Kelly DeVries(Peterborough, Ont, 1992)

But Wait There's more:

Check Out: The Grey Company Trebuchet

Page- For Some Great Practicle

how to stuff!!! Highly recommended .

Also Email me if you'd like to see photos of our Shire's full scale

traction Trebuchet.

An Lastly, Gulf Wars 6 this March in Meridies, will most likely have a wide

variety of practical and not so practical SCAdian Siege Equipment, as we

use a Stockade style wooden Fortress w/ Archer Towers and Platforms. Much

Medieval Mayhem.

Yours in Service,

Ld William De Cordoba


From: "William Herrera"

Subject: Re: Advice needed- Building a period catapult


Date: 30 Jan 97 06:38:37 GMT
Christa Fulton wrote in article

> We have a period (scaled down) catapult. If one assume wood working was

> on site. It would not be to hard to carry the few metal peaces only.
This is very true. However when I wrote: (partial >intricate machinery, It

is hard to assume such facilities would be easy to accquire during Every

I was speaking more from a logistical POV. For Example: (Bear in mind there

are MAJOR differences in the way we fight vs the "Actual" Medievals but

there are some premises which seem to make sense no matter which century.)

When we use seige equipment in a conflict the first thing the enemy

commanders usually try to do is neutralize, eliminate, insert euphemism of

choice, those pieces. Usually by using Archers to take out the crew, or

counter battery fire from a ballista or nag. Back-in-the-day they would

have undoubtably used incendiaries of some sort or smashed them to pieces.

This makes for alot of EXPENSIVE machine work to be salvaged if possible.

We are not talking about one or two but 20 or 30 of the smaller

torsion-Type catapult and in some sieges up 6 or 8 large Trebuchets

operating day and night, with some sieges lasting over year. My main

objection w/ P-G is that they are overengineered for what they are. Simpler

mechanisms would suffice just as well as the "MouseTrap!" maze of gears and

pulley's he depicts in his Torsion-Skein catapult. The medievals needed

sturdy, simple, devastating and cheap weapons of Mass Destruction.

Which leads me to your next statement:

> How ever if you want power do not build a catapult, a Trabushet has more

> power and is not as hard on its own structure.

> there are now sudden Stops.

Absolutely!!!! And it illustrates my point exactly. A Trebuchet is a

basically simple device with few moving parts. Its powered by gravity and

rocks (plenty-o-that and free too), relatively quiet, got great range, and

can be built with basic hand tools, logs and a bunch a peasants you've got

under your boot.

And They 're great fun too, once you get the sling length and pin angle

figured out that is...

From: dietmarrvs at (DietmarRvS)


Subject: Re: Advice needed- Building a period catapult

Date: 31 Jan 1997 04:02:12 GMT
Greetings Siege Engineers,
mrlne95 at wrote:
>I am building a catapult for recreational use, and possibly for use in

>upcoming wars. Any advice would be welcomed.

There are two excellent articles of note in past issues of Scientific


1) Soedel, Werner and Foley, Vernard "Ancient Catapults", (Scientific

American Mar. 79), pp. 150-60.

2) Chevedden, Paul E. et al., "The Trebuchet", (Scientific American Jul.

95), pp. 66-71.

The first article deals with all manner of siege engines in Ancient Greece

and Rome. It includes both tension and piston driven ballista, and

detailed info on torsion bundle driven catapults.
Interestingly enough, the authors of the first article are co-authors of

the second. The second article only talks about trebuchets. There are

some mind-numbing photos of a 60 ft. tall trebuchet in England launching

pianos. (I have a video of this monster in action that I taped off of "A

Current Affair", of all places!)
Both articles contain the usual excellent technical drawings. After

reading the two, I would recommend the trebuchet. The recoil on a

catapult tends to make the entire engine buck violently...or tear it apart

trying, effecting its accuracy. I also think that building the torsion

bundles would be more trouble than it's worth. The best method would seem

to be the hinged and propped counterweight.

I tried to search the message boards mentioned in a previous post, but I

could not get them to come up. I have found a great source for you

though. There is a website for The Grey Company at:

This is a group of guys whose main emphasis is building and testing siege

engines. They also have links to other catapult websites (which I haven't

tried yet).
I haven't built a siege engine yet, but I am an engineering major, and

intend to put all this knowledge to good use when I get out of school. I

do have some questions of my own for those of you who might be able to

help. What are you using as bearings at the pivot point? I'm picturing

some form of ball bearing and axle design.
I hope this is of some help to you all, and would appreciate any

information that you could pass back in my direction. At your service,

Dietmar Reinhart von Straubing

(DietmarRvS at

From: jjmacc at (JJMacC)


Subject: Re: Advice needed- Building a period catapult

Date: 16 Feb 1997 22:16:30 GMT

There is an easier way folks to build an effective, period styled

catapult. While living in the (ever) Incipient Shire of (insert name

here, currently) Northmarch, in the MidRealm, a friend of mine (yes I do

have friends), built a working 1/12th scale model catapult. It was based

on an Ottoman siege catapult from around the 1200's.
The "cat" used rope as the tension device. Simple, all-purpose, heavy

fiber rope. The weapon was about 2' long, with a 30" (approximate) long

throwing arm secured to round, rotating tension bar. It had a range of

about 70 yards with a tennis ball, and slightly less with a 1 lb ball

John James MacCrimmon


From: "Eddy Hamacek"

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