DUC IN ALTUM

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This guy Cortez was a spaniard, fighting the Aztecs in Mexico. Here, it is said to have been in 1519, but another source says 1521.

Nonetheless, at some point, they’re facing heavy resistance and they want to break into a city. One of Cortez’ soldiers says he can build a weapon that he saw in Italy that would break them down to nothing in no time flat.

Some have said that they were running low on gunpowder and that’s what motivated this big construction, but this site mentions casualties as being the main focus for Cortez.

Here’s what Diaz wrote on the events…

The “Trebuchet”

“…There was a soldier in Cortez’s camp who said he’d been in Italy, in the Great Captain’s company, and was in the affair at Garellano and other great battles. He talked a good deal of war-engines, and said he could make a catapult in Tlatelolco which, if they were to bombard the quarter of the city into which Guatemoc had retreated, would make them sue for peace in two days.

He talked so much about it, for this man was a great talker, that Cortez promptly set to work on the catapult. They brought lime and stone and wood, as the soldier requested, and carpenters and nails and all that was needed for its construction. They made two slings of strong rope and cords, and brought up great stones bigger than demijohn jars, and when the catapult was made and rigged as he desired, the soldier said that it was ready to be discharged.

So they placed a suitable stone in the sling, but all it did was to rise to the height of the catapult and fall back to its original place.

Cortez was very annoyed with the deviser of the catapult and with himself for having believed him. He said that the man had proved that nothing was more prejudical to war than talk, and that the whole matter had been one of talk for talking’s sake; and he at once ordered the catapult to be taken to pieces…”

I gotta tell ya: The bigger I build my trebuchets, the more important this little tidbit of information becomes relevant.With a 12 inch model, doing a “Cortez” is funny. With a 6 foot model, doing a “Cortez” becomes really dangerous. Possibly deadly.

I’m at the point where this concept has become an obsession. I want to build it.

But I want it to work as expected. I believe it will, but let’s double check, shall we?

We’ll consider explosives later. For now, let’s make sure we don’t get it across the head.

^{DISCLAIMER: I’m not considering explosives. This is meant as a joke, since I consider hurling 20 lb missiles a safety risk as it is. However, I’ve seen Youtube videos where folks used some kind of explosives as trebuchet missiles, and I’ve seen the video of one british nut who threw pianos ablaze with his humungous trebuchet. NOTE: I’m not planning any type of explosives so far. Probably never. Not unless the person who would bring the stuff over had legal qualifications to use them. Then that would be AWSOME!!!!}

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Damn, that’s a good idea. Found here.  I could make that with wood, I just know I could. Argh…options….so many options…

I’m seeing some wheel triggers too, but they don’t attract me for some reason.

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I’m not posting pics because A) they’re too big and B) I don’t want to give the impression that it’s my project.  It’s not.

This was made in 2005.

They posted a series of pics here.

And on this page, they mention…

In the limited amount of time we had, we managed to throw a basketball 175 feet. Maybe not the greatest displacement possible, but with 240 pounds in the counterweight box the ball went very high. I am guessing it must have gone 300 feet high because it was going much higher than its total displacement. Of course the ball would bounce roll to about 300 feet but 175 was where it would land. We may try to experiment more with different weights and launch pin angles to try to get a larger displacement. We may even try to launch some melons and try to get some explosions on impact. Anyway, the trebuchet project was unanimously agreed upon as a success. It even looked impressive!

No shit, Sherlock!  ROFL!

240 lbs of counterweight is more than I’m planning.

16 feet would be two feet more than I’m planning.  Repeat Offender would be six feet high and the arm would stick eight feet higher than that (at 14 feet).

I’m planning a break.  I’m planning the launch pin angle at 10 degrees.  300 feet is my objective.

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ADDED:  This is called a “Trap Door Trigger”.  You can find it here.  And if you’re in the mood, you can find a ton of ideas on triggers here.  Enjoy.  I know I am!

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I saw an animation just like this when I was doing research on trebs. I couldn’t retrace it, so I recreated it.

This is the triggering mechanism. Although, it’s upside-down, since the throwing arm will launch upwards.

Strong points about this: Double layers carry the weight evenly if they’re flat on each other, so the actual weight on the hook is at a minimum. If the hook has only part of the total weight, it’s easy to pull away. If I had a single layer, the hook would hold the entire weight.

One last thing: I figured out what my counterweight should be. If you are able to look away from the animation and you’re actually reading this, here it is: Cat Litter. I have a 40 lb bag of cat litter at home. That’s the idea. Bags, as many as needed, hooked up to the arm. No need to have a 200 lb one-block counterweight.

Since my frame is already too high, I have plenty of room for sand bags. Yeah, at 6 feet high, my arm rests at 42 degrees of angle, which is a tad too much. But it clears space underfoot.

Perhaps I’ll transform old pairs of Levi’s jeans into sandbags. We’ll see.

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I’ve been drawing a lot over the last few weeks. I’m dreaming about this huge trebuchet I want to build, the one I will christen “Repeat Offender”.

With a planned counterweight of 200lbs, an 11 foot long throwing arm and wheels, I expect this trebuchet to throw pumpkins (20lbs or less) beyond 300 feet.

My miniature model, with a throwing arm of 12 inches throws metal screws 27 to 30 feet away. If I compare the scale to the big guy, that means 297 to 330 feet or range. But since Repeat will have wheels, the range should be more than that.

The initial position isn’t 45 degrees either, it’s 42 degrees. This means more speed. I will have to test the angle of the launching pin just so it doesn’t launch too soon.

My smaller model has a pin with a 10 degree angle, but it might not be enough. I found that angle through trial and error, since the hall in my appartment is only so high and so long. If I had no ceiling, I could have gotten more range by shooting higher. I’m not sure, but I think so.

Anyway, the triggering mechanism has been mapped out, dimensions have be measured.  This will be a double arm holding down the launching arm, not a hook holding back the payload.

I can’t wait to build this (and to find a launch site).

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I’m sorry.  There is one little detail that I censored from this picture.

If you’ve ever done serious research to find solutions on how to build your trebuchet, and you looked at pictures, you were frustrated as I was.  Very few historical depictions of ancient trebs revealed just how the trigger worked.

Well, I’m guessing somebody loved their machine as much as I love mine.  Innovations, discoveries or just solving the problems on my own is half the fun here people.

If I ever build this baby, it’s gonna be awsome.

Decisions already made:

• triggering mechanism (type and placement)
• some parts will involve sculpting (the extent of it is unknown)
• front wheels decided, back wheels unclear
• most of the throwing arm is settled, although it’s not really finished.

One question that remains in my mind is inertia.  That arm can’t weigh a ton.  The inertia of it requires a lot of energy.  Granted, once in movement, it’s gonna move, but I count on the counterweight to create the movement.  I really want that arm to be lightweight so it starts moving as soon as possible.

Does that make sense?  I’m not sure.  I guess the question will be answered by the strength of the material used.

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This is my scale model of Repeat Offender, the trebuchet that will someday come to be.

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Well guys, I’m still thinking about my next trebuchet.

I had insomnia the other day, got up, sat down and drew the trigger mechanism.

Ideas rejected so far:

• seat, capable of holding a 200 lb human, used as counterweight…
• 3 wheeled pulley to hoist the counterweight…
• FAT
• using lenghts of 1×3 inch maple…

This thing will be eight feet wide, nine feet long and the axle will stand at 6 feet.

It will have wheels, it will have an odd structure.

This will be a test of endurance for the all mighty Two By Four.

 This drawing had it at 5 feet tall (without that arm).  It will now stand at 6 feet.  I had no choice.  Since I don’t know what I’ll be using as a counterweight, I’m glad to have the extra space to make it bigger.

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