0382: "Trebuchet"

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0382: "Trebuchet"

Postby 4=5 » Mon Feb 11, 2008 5:03 am UTC



alt text
it was also fun when those teenagers tried to egg our house and it insta-cooked the eggs in mid-air

I built one of these once, a solid three blocks of range
Last edited by 4=5 on Wed Feb 13, 2008 5:00 am UTC, edited 2 times in total.

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Re: Trebuchet

Postby Azzaman » Mon Feb 11, 2008 5:05 am UTC

I want to build my own trebuchet some day... I wonder if there are laws against them.

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Re: Trebuchet

Postby JorickHorn » Mon Feb 11, 2008 5:08 am UTC

This is awesome! I make Trebuchets myself! They're so cool!

You can see some of mine here: http://www.youtube.com/watch?v=jtcoOKVd1RI

And if you want to learn to make them for the table-top, I made a tutorial: http://www.youtube.com/watch?v=XCiyHBZZPWQ

This made my day, as a trebuchet enthusiast, to see my favourite siege engine in my favourite comic strip.
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Re: Trebuchet

Postby aeiss » Mon Feb 11, 2008 5:14 am UTC

kilowatt lasers...that's not as dangerous as it sounds, is it?

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Re: Trebuchet

Postby UltramaticOrange » Mon Feb 11, 2008 5:17 am UTC

This strip is just BEGGING to have the two items stuck together.

auto-firing kilowatt-laser-sighted trebuchet. Anyone else wanna' take a stab?

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Re: Trebuchet

Postby Kleppner » Mon Feb 11, 2008 5:20 am UTC

UltramaticOrange wrote:This strip is just BEGGING to have the two items stuck together.

auto-firing kilowatt-laser-sighted trebuchet. Anyone else wanna' take a stab?

Listen to this man. We can make it work.
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Re: Trebuchet

Postby Tenth Speed Writer » Mon Feb 11, 2008 5:21 am UTC


I was so about to say the same thing.

And Kleppner, I'll go see if we have some good lumber in the shed. If not, I know a good store just a few minutes from my place.
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Re: Trebuchet

Postby Matthias » Mon Feb 11, 2008 5:22 am UTC

Actually, I think it would be more fun to launch a small black hole with a kilowatt's worth of photons stuck in the middle, so it shatters the stability matrix on impact and blinds your targets.
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Re: Trebuchet

Postby Invisible_Insane » Mon Feb 11, 2008 5:28 am UTC

I discovered trebuchet through Age of Empires II.

Good times.
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Re: Trebuchet

Postby aerojad » Mon Feb 11, 2008 5:38 am UTC

get off her damn lawn

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Re: Trebuchet

Postby 1337geek » Mon Feb 11, 2008 5:39 am UTC

Some kids at my high school made a rather large trebuchet (i.e. taller than me) that was supposed to fling an orange across campus or something. After several months of designing and building it, it completely broke on its test launch. I'd post the video, but I don't want to embarrass them. If only they'd built something useful like a squirrel zapper (which, by the way, would be totally AWESOME).
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Re: Trebuchet

Postby Lyra Ngalia » Mon Feb 11, 2008 5:51 am UTC

I should build another trebuchet one of these days... But oo, lasers!

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Re: Trebuchet

Postby Cheez It » Mon Feb 11, 2008 5:56 am UTC

I built a trebuchet once. Due to some monumentally bad planning it was horrible and only had a range of about 50ft.

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Re: Trebuchet

Postby OneLess » Mon Feb 11, 2008 5:56 am UTC

Argh, this comic has to come out when I don't have the money for either a trebuchet or a kilowatt laser? Curse thee, Mr. Munroe!
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Re: Trebuchet

Postby sninctown » Mon Feb 11, 2008 5:57 am UTC

What is the cheapest kilowatt-plus laser?

I want one. But, I think they cost at least $10K, based on some brief online searching and my guess at the price of this 600mW laser in a lab I used to work at. Well, all the more reason to invent something and/or start a company and make $$$.

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Re: Trebuchet

Postby Teh Russians » Mon Feb 11, 2008 6:00 am UTC

Invisible_Insane wrote:I discovered trebuchet through Age of Empires II.

Good times.

Oh me yarm me too! I used to get like 5 and obliterate my friend's walls as he hopelessly tried to figure out where the hell they were and how they got there. But the best were those catapults that could pwn trees. I used to play on black forest maps and make passages through the forest to the back of the other guy's base. Good times indeed.
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Re: Trebuchet

Postby scarletmanuka » Mon Feb 11, 2008 6:14 am UTC

1. Build trebuchet.
2. Buy kilowatt laser.
3. ???
4. PROFIT!!!

After the recent romantic conflicts and Journal / Journal 2, it's nice to see a geek guy and a geek girl together in xkcd and clearly on the same wavelength. Which would presumably be whatever wavelength the laser is putting out. Is it visible light or not? Invisible beams of destruction FTW!

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Re: Trebuchet

Postby krynd » Mon Feb 11, 2008 6:18 am UTC

Stick Girl From Comic wrote:... But eventually you'll outgrow these toys, and focus your energy on something practical


They are practical. Child psychologists (people I'm sure I'll regret referencing) often say that play is basically practice for later in life. For instance, building something with Legos is supposed to increase your spatial intelligence (probably the wrong phrase. What I mean by it is that playing with Legos will increase your working knowledge of the mechanics behind basic civil engineering and your communication skills, if you work in a group).

So, why wouldn't a trebuchet work under the same principle? At the very least, Stick Guy is learning some nice mechanical engineering skills. At best, he's learning something he'll use in some "real" engineering work he'll do. For instance, he can use it to transport non-critical matter in quick fashion. In other words: throw stuff to people somewhat far away (enough that you don't want to walk, but close enough that a trebuchet can reach) in a cool way. You'd just have to be sure to put everything in a container before you launch it (so it doesn't get overly damaged). Who wouldn't want to throw your boss the latest status report this way?

What does Stick Girl's laser have to do with practicality? Sure, it keeps the squirrels away, but since she's sitting in front of a laptop, I'll venture a guess that her version of practical work probably involves code or web design (note: I'm a developer, so there's probably some (or a lot of) bias there). Unless she'll be running a simulation or writing an AI for a game, I don't see the practical nature there. Otherwise, the only other application I could think of would be as a defense turret, which it sort of is used as already (probably some law preventing an up-scale to use against humans...). Come to think of it, that's an awesome idea. Who wouldn't want an auto-defense turrent? Memories from "classic" games like Goldeneye and Perfect Dark come to mind...

Finally: Trebuchets for the win!
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Re: Trebuchet

Postby Casey » Mon Feb 11, 2008 6:21 am UTC

I'm envisioning a capacitor-fed kilowatt laser warhead hurled by a trebuchet.

Focus the beam on a point 10 cm from the emitter, and run the beam on a watch battery until the projectile is in range.

Then flash-fry the target with the capacitor.


That is all.


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Re: Trebuchet

Postby Embryo » Mon Feb 11, 2008 6:31 am UTC

This totally reminds me of my current relationship, in an awesome and squee way.

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Re: Trebuchet

Postby danpilon54 » Mon Feb 11, 2008 6:38 am UTC

I loved this comic, partly because the physics club at my university is planning to build a trebuchet, and because I work with the most powerful laser at said university. I wonder what he means by kilowatt, however. If its average kilowatt over a whole second then damn run for the hills. The laser I use is 5 watts. If it is a pulse laser with kilowatt pulses, then they better be pretty long pulses, because my other laser has 30 femptosecond pulses with about a millijoule per pulse (about 3 watts averaged over one second). You do the math :P. Lets just say thats about 10^12 watts averaged over the pulse. I guess Ill play it safe and assume the former and never go anywhere near his house.
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Re: Trebuchet

Postby pyroman » Mon Feb 11, 2008 6:45 am UTC

Oh man my friend and built a massive (16ft tall) floating arm trebuchet which we some how conned our school into paying for... anyways it was throwing bowling balls about 300 feet. it was a thing of beauty. Building this thing and the launching was one of the greatest events in my life. There is nothing prettier than seeing a bowling ball fly hundreds of feet in a perfect ballistics arch. and who ever says that you out grow something like this is dead wrong or if you do you are not a true member of the xkcd community.

oh btw heres a picture... http://hs.facebook.com/photo.php?pid=31 ... 2215720300
(sorry i don't have a better link)

sadly my friend still hasn't given me the video so i can upload it onto youtube...
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Re: Trebuchet

Postby bridgeyman » Mon Feb 11, 2008 6:46 am UTC

This has to be the same girl who took black hat man's hat.

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Re: Trebuchet

Postby thechamelion » Mon Feb 11, 2008 6:50 am UTC

Back in the good old days of boyscouts, we would build two 10 foot tall trebuchets that took two kids to launch (and about 8 to build) about 200 feet apart from each other. Then load 'em up with water balloons and let the war begin.

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Re: Trebuchet

Postby iaiaz » Mon Feb 11, 2008 7:03 am UTC

Actually, this makes for an effective solution to the bunnies constantly eating up my garden. My sunflowers, they are like CANDY to them.

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Re: Trebuchet

Postby pyroman » Mon Feb 11, 2008 7:06 am UTC

lol you use the laser to toast em and the trebuchet to get rid of the bodies. very effective system
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Re: Trebuchet

Postby Sprocket » Mon Feb 11, 2008 7:08 am UTC

Auto-Targeting kilowatt laser...I didn't know I had it in me.

...And I DO love eggs.
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Re: Trebuchet

Postby UmbralRaptor » Mon Feb 11, 2008 7:09 am UTC

A kilowatt laser? WANT!!! (But what's the wavelength and beam diameter?(This should give us an idea of dispersion) Where in the kilowatt range is it? What's the duty cycle like? edit: How efficient is it?)

aeiss wrote:kilowatt lasers...that's not as dangerous as it sounds, is it?

Given that Class IV lasers only have to be over ~500 milliwatts, it's probably a lot more dangerous than you think. I would expect that the eggs would be *detonated* in mid air from steam explosions. 8)
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Re: Trebuchet

Postby AltoidAddict » Mon Feb 11, 2008 8:01 am UTC

Somehow I knew before I read the alt text, that it would exponentially increase the comic's awesomeness. Glad I was right.

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Re: Trebuchet

Postby harmless » Mon Feb 11, 2008 8:14 am UTC

My friends and I built a trebuchet together 2 years ago that we still have. The original idea was to build a small one that would essentially just be used to fling tennis balls at people. Fortunately though my one friend discovered the sport of Pumpkin' Chunkin' while researching designs. The tennis ball became a 5 lb. pumpkin and the target became unsuspecting fields of corn. We were fortunate to have a yearly competition that was only a 2 hour drive from us. Between the start of the build and the competition day something interesting happened though... our treb became half trebuchet and half catapult. Needless to say it was fugly. Our best shot at that competition was around 300 I think. The next year our group doubled in size when our other friends realized how cool this was and the trebupult became a full catapult since that was just easier. That year we competed in the same area competition as before and got it to around 500 ft. but we also went to the actual national competition in Delaware. National. It was amazing. The drive kind of sucked but that is only because we live Illinois and Delaware is a 2 day drive when you are hauling a catapult behind you. The experience was slightly harrowing since at first the shots weren't going so well and the distance was only okay. On the third and final shot however we got 853.46 ft. We were in the youth human powered division and we won 1st. place. I can't begin to explain how awesome that was. You can check the official website at http://www.punkinchunkin.com/results2006.htm. Our team name was Failed negotiations. Reading this comic however made me kind of sad since it reminded me that I won't be doing this anymore since we are now all in different colleges. It also reminded me of one of my friends who was the one who came up with the idea, found out about punkin chunkin and inspired us all to put all the effort and money (literally a couple thousand by the end I believe) into the project. He's now at the air force academy and having a rough time knowing that all of his friends are having fun at college while he pretty much has to eat dirt...

But now I'm just getting off topic, sorry.

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Re: Trebuchet

Postby nteon » Mon Feb 11, 2008 8:27 am UTC

i would have been SO much more impressed if it was a picture of a floating arm trebuchet!
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Re: Trebuchet

Postby zenten » Mon Feb 11, 2008 8:27 am UTC

The best part about her laser is it makes for a good source of proten.

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Re: Trebuchet

Postby Nomic » Mon Feb 11, 2008 8:32 am UTC

I once made plans to build a snawball launching catapult (since large snowballs are pretty much only thing around here tat could be feasibly launched from a catapult), but never got to it and now I live in an appartment block so I have no room to build one. I'd still want a fully automated railgun turret that fires solid metal slugs at supersonic speeds.

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Re: Trebuchet

Postby Lord Duffler » Mon Feb 11, 2008 8:34 am UTC

Down in the evil scientist cellar of the physics department where I study, they have a femto-second pulsed laser that will literally tear the electrons from their nucleus, it's peak output is higher than most powerplants (at least of the non-nuclear variety). It looks cooler than you'd think. Anyway, 1KW is about the strength used for laser cutting steel 'n' stuff, so it's not impossible to get a hold of. She really should pulse it though, setting air on fire is nice. Tell ya what, if you bring the laser, I'll pulse it for ya.

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Re: Trebuchet

Postby keozen » Mon Feb 11, 2008 8:47 am UTC

My initial reaction to this comic is:


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Re: Trebuchet

Postby genewitch » Mon Feb 11, 2008 9:05 am UTC

Nomic wrote:I once made plans to build a snawball launching catapult (since large snowballs are pretty much only thing around here tat could be feasibly launched from a catapult), but never got to it and now I live in an appartment block so I have no room to build one. I'd still want a fully automated railgun turret that fires solid metal slugs at supersonic speeds.

Rails get destroyed. Also they're inefficient. Coil weaponry is much cooler, but for some reason no one can figure out how to make them really work well.

trebuchets are cool and all, but it depends on what you are launching. For stuff around a pound, a gas cannon is preferred. For really small stuff (like pellets or marbles) you're better off with a gas piston. catapults are good times, too, for larger objects. but as far as i know, trebuchets are the sort that can launch cars several hundred yards. and that's really good times. Mythbusters made a sort of trebuchet on an episode, it was a crane. it was wicked cool.
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Re: Trebuchet

Postby sstteevvee » Mon Feb 11, 2008 9:25 am UTC

I mentally combined today's xkcd with this comic that I read yesterday... http://www.comet7.com/archive_page.php?id=874, and was waiting for some mention of kittens.

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Re: Trebuchet

Postby Cheez It » Mon Feb 11, 2008 9:54 am UTC

sstteevvee wrote:I mentally combined today's xkcd with this comic that I read yesterday... http://www.comet7.com/archive_page.php?id=874, and was waiting for some mention of kittens.

Don't be silly. Everyone knows you launch kittens with cannons, not trebuchets.

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Re: Trebuchet

Postby synthgene » Mon Feb 11, 2008 9:59 am UTC

Man, I just saw a real live trebuchet today, is XKCD starting to tap into my brain or something?

As for lasers, you can easily get a 1-2 watt for less than $300 on ebay, or a 60 for under $1000 if you really want power. Of course, this is just for the diode without driver circuitry, but you can easily find plans for that online.

And if you really want more bang to the buck, I suggest getting a CO2 laser, which you can find plans for online. http://search.ebay.com/search/search.dll?sofocus=bs&sbrftog=1&dfsp=1&catref=C6&from=R10&_trksid=m37&satitle=Co2+laser&sacat=-1%26catref%3DC6&sargn=-1%26saslc%3D2&sadis=200&fpos=ZIP%2FPostal&sabfmts=1&saobfmts=insif&ftrt=1&ftrv=1&saprclo=&saprchi=&fsop=1%26fsoo%3D1&fgtp=

Another good option is a YAG laser.

You could easily get squirrels off a bird feeder with a fairly low wattage laser(100-200mW should do the trick), as for cooking eggs midflight, well that's gonna take some power.
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Re: Trebuchet

Postby wst » Mon Feb 11, 2008 10:45 am UTC

I swear someone posted here asking for plans for a trebuchet yesterday?!

Awesomeness personified- the laser stick-girl.
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