Trebuchet design for Dr. Seuss

by Eric Ludlam

Dedicated to my new son Trevor born Oct 16th, 1999

Eric
Have you ever wondered why,
 boulders never cross the sky?

You can heave with all your might,
 boulders never will take flight.

but here's a trick that you can do,
 to chunk a rock to Timbucktu.

`A Catapult' as some might say,
 but be correct, it's `treb-u-chet.'


Trevor
I will not build this `treb-u-chet'
 I will not, shall not waste my day

I shall not build it out of wood,
 I shall not build it, it's no good.


Eric
How can you think that it's no good?
 the trebuchet's misunderstood!
  
You can fling a rock real far
 you can even fling a car.

You can fling it through the woods
 thus I say that it is good.


Trevor
This trebuchet that's built of wood
 which you claim's misunderstood,

Who would build it, please do say
 who would build this `treb-u-chet'?

From Gray Co. Trebuchet Page
Stone Carving of a traction trebuchet throwing a carcass.
Eric
The `trebuchet' from ancient years
 were built by Roman engineers.

They could build them out of wood
 Near them castles fell, not stood.

They could fling a giant rock,
 They could fling it in a sock.

With them empires they did build
 and conquered towns where they willed

They could build a `treb-u-chet',
 They could build it, so I say.


Trevor
This `trebuchet' has me vexed
 for it seems to me complex.

With gyres and gimbles long and short
 and rocks a flying with retort

Flying rocks did ricochet
 who else built a `treb-u-chet?'


Monty Python & The Holy Grail: "You stoo-pid Ka-Niggits!"
Eric
Medieval Frenchmen taunting kings
 They sure knew what to fling.

Cats and dogs, pig and sow
 They would even fling a cow

Knights in fear did "Run Away!"
 When frenchmen used the `treb-u-chet.'


Trevor
Medieval Frenchman fling a cow?
 For this purpose tell me how.
 
Cow flinging may sound cliché
 how do you build a `treb-u-chet?'


Eric
To fling a cow, so it's said,
 you must find one that is dead.

Dead cows are so much less crass
 Living cows would kick your ass.


Trevor
Dead or living I do not care
 I want to fling one fair and square.

Let us build this `treb-u-chet'
 Let us build it now I say

Juggernaut 2 is laid out for assembly.
Eric
To build this structure we need tools
 drill and hammer, wrench and spool.

Roger packs Juggernaut 2 into his truck.

For lots of lumber we must go
 make a trip to Home Depot.

Gyres and gimbles, bolts and beams
 fulcrums, triggers, and big dreams


Trevor
With all these things there is no way
 that you could build a `treb-u-chet'.

What is this bolt marked F-2
 what on earth could this thing do?

Eric
Every piece's job is set
 no more pieces need we get.

F-2 is important true,
 but so are all these screws and glue. 
 
To build a frame that is quite tall,
 to fling a cow across a wall,

Geometry will tell us how
 to make a frame, and throw a cow.


Trevor
Geometry! My fate is sealed,
 classroom wounds have not yet healed.

Triangles are bent obtuse
 strangled by hi-pot-a-noose.

I cannot build the numbered way
 I cannot build this `treb-u-chet'


Eric
Numbers Shmumbers it's O.K.
 You can build this `treb-u-chet'

Please remember this simple rule
 Geometry is just a tool

On Site Assembly of the System.
A strong foundation you do need
 it's most important so take heed.

A frame is first, I don't care how
 it must be tall and hold your cow.

Triangles here without delay,
 We do not want to swing and sway.

Nuts and bolts, make sure they're tight
 we need to keep these posts upright.


Trevor
Now I've built it tall and strong,
 but I profess; it does seem wrong.

Looking here I can't see how
 It can be used to throw a cow.

All this lumber could betray
 I do not trust this `treb-u-chet'.


Eric
Woah there fella, do not fret
 Your trebuchet is not done yet!

Grab that pipe there named F-1
 That will be a great fulcrum


Roger Carries the arm.
And let us use this mighty tree,
 Label it L-1, 2 and 3.

The lengths here are quite a mix
 a ratio of 1 to 6.

In L-1 cut a hole like this
 A fulcrum pivot cannot miss.

No not there!  Right here will do
 right between L-3 and 2.


Trevor
Your ratio drives me to distress
 I do not get it, I confess!

Looking here I can't see how
 It can be used to throw a cow.

Killing trees leads to dismay
 I cannot build this `treb-u-chet'.


Eric
Hang on buddy, you're almost done
 and will be flinging just for fun.

Next we need a counterweight
 and to hold it, a giant crate.

How much it weighs, let me see
 You're cow here weighs 3-0-3

A ratio of 600 to 1
 Oh my goodness, it's 90 ton!


Trevor
90 ton does not seem good
 this large frame is made of wood.

Looking here I can't see how
 It can be used to throw a cow.

Our Weight Crate with 600lbs in it.
Giant boulders that are gray
 will now crush this `treb-u-chet'.

Eric
Well now, let us readjust,
 a new ratio is a must.

If now I say 60 to 1
 our new mass is but 9 ton.

There's no need to be exact
 lets see how this treb reacts.

Loading in counterweight.
Now L-2 is too short
 Lengthen it to gain support.

The weight must hang a length L-4
 with fulcrum F-2 at its core.

Now the arm points straight up,
 there's one more thing to hookup.

Trevor
The cow, the cow, throw it's core
 before it decomposes more
 

Eric
Patience friend, the cow is last
 At this time we must haul our mast.

For heave you may, and heave you might
 the Arm has gained far too much height.

Pulling weight into the air
 requires some tough hard-a-ware.

A pulley labeled 1 to 8,
 Surely it can loft that crate.

Roger winches back the arm.

The sliding draw down mechanism.
And hook it to a sliding thing
 We'll do it with this burly ring.

Finish with the mighty winch
 to haul up rocks it is a cinch.


Trevor
Just a minute, stop right there
 hauling rocks into the air.

These poor rocks are scared of heights
 you have given them quite a fright.
 
I must call the S.P.C.A
 I shall not build this `treb-u-chet'.


Eric
Well now, be that as it may,
 We will finish our trebuchet.

Look real close now at this figure,
 that is how you build a trigger.


Our toothy wheel trigger mechanism.

Sling to arm ratio example.
Add a lever and wheel with teeth
 loop some rope down just beneath.

Now detach our draw down line
 and hope our trigger is benign.


Trevor
Your trebuchet does seem weak
 bolts are bending, pivots squeak.

I do fear some foul play
 I shall not use this `treb-u-chet'.


Eric
First let's tie a mighty sling
 Here a bowlin, there a ring

We'll measure it against the tree
 our length this time will match L-3

The length is special beam to sling
 then back again to our ring.

Tie it on right near the end
 and now we need a hook my friend.


Trevor
This sling-ring-thing is so strange
 will it throw our cow down range?

Should our cow fall to decay
 I cannot use this `treb-u-chet'


Eric 
Do not fear your rotting friend,
 now our project is near its end

Crank the lever arm down low
 not so fast, it is quite slow.

Click...

Click...

Click...

Click...

Click...

The ring and hook.
Bolt this hook upon the arm
 and to you will come no harm.

Place this ring upon the hook
 the cow is nestled in it's nook.

Now the event for which you waited;
 release the arm and be elated.


Trevor
I cannot, shall not throw this cow,
 I must profess I don't know how.

Your gyres and gimbles do confuse
 Your ratios do cows abuse

I cannot launch your `treb-u-chet'
 I cannot, will not go astray.

Ready to throw a gallon of water.
Eric
But this trebuchet, it is complete
 In castle siege, we can defeat

Our weight is lofted, bolts did fix
 the cow is ready to deep six

You must launch without delay
 you must launch this `treb-u-chet'


Trevor
Ok, maybe just this one time
 I'll push here to launch some slime.
Launching a gallon of water.
Oh my goodness, watch it go
 over rooftops, into Stow*.

I think I like it, so I say
 I think I like this `treb-u-chet'


Credits:

Footnotes:

Details:

Our trebuchet is 8' tall, and uses a 550lb counterweight.
Our weight ratio is about 60 to 1
Our best throw to date is 299 feet at the World Championship Punkin' Chunk with a 9 lbs pumpkin.

We never bothered calculating what L2, L3, & L4 are.


Copyright (C) November 1999, 2000, 2001 Eric M. Ludlam. All rights reserved.
Unauthorized duplication and distribution of this page is strictly prohibited.
Twas' brillig, and the slithy toves did gyre and gimble in the wabe.