Building a trebuchet (+ images)

[LaCroix]

Remember this thread?

Well, earlier this spring I got bored again... This time, it had nothing to do with the song contest...


With the proud owner... (camera wedged into a tree...)


It is 5 feet tall at pivoting point and stands at ~12 feet at the arm tip.
The sling and the other stuff are not installed in this picture, as I only mount them when using it. (The wind and sun would seriously age the ropes within a few weeks, so they keep in storage.)

Currently, it has a counterweight of ~60 lbs, and is calibrated to throw 1lb foam targets, which I use for archery skeet...
As these targets are foam and light, and we have steady wind always from north, I have aimed the treb' into the wind.
So, the targets raise to about 30 feet altitude, a good dozen or two feet out, 'hang' there for about a second, and then come down, usually with a few arrows embedded from the crowd at the archery tournament I organize. (I'll post some pics of that later.)

I used an 1.5 lbs stone and a slightly different configuration once for testing, and the stone ended up at ~120 feet distance - leaving a one foot deep hole in the mostly clay ground (wet clay - if it is dry, you need a jackhammer to plant something in my area).

In theory, I could increase the weight up to a good 300lbs, but am satisfied - as long as I don't have to oppress the neighbors.
Again.

Signing off,
Thomas
HAB - Medieval Siege Engine Dept.

[ShadowDragon8685]

Oh man...

I think you should crank that baby up to full counterweight and do some tests to see what kind of stone (in terms of mass and composition) gives you the best distance/penetration.

And oppress the neighbors, of course. If anyone has any houses or other structures slated for demolition, it might not be a bad idea to see if they'll volunteer their digs as test targets.

[LaCroix]

You are aware of the fact that 'AIMING' with that thing is more of a concept and an art form? And orders are given in terms like "I want you to either hit the city or the wall around it, preferably the wall!"

While we have more than one shack in need of demolition, I am much more likely to hit some other house I haven't aimed for.
Also 'demolition' in Hungary means that either the owner, (or the rest of the town) gather around, and the whole building is dismantled, stone for stone, tile for tile and wire for wire, until nothing suggests that there ever was a building there, and the stuff ends up stacked in the various gardens, for "someone might need it" reasons.

Not to mention that I am already pretty scared of the thing - if I increase basket weight, I either have to tie it down and use a much longer release rope, or put it on wheels to stop it from jumping (which would also add 50% efficiency).

[Alyrium Denryle]

Currently, it has a counterweight of ~60 lbs, and is calibrated to throw 1lb foam targets, which I use for archery skeet...

You realize that this statement puts you on my list of awesome people right?

Using a trebuchet for archery skeet...

[madd0ct0r]

Wheels.

looking at the bolt, you're not limiting yourself to 14century construction, so some nice big wheels on bearings, brick weights for stability and a couple of planks.

means you can move it in future too.

[LadyTevar]

I wish I had the acreage to pull off the things you do.

[Kanastrous]

Utter coolness.

A while back we were planning on building/imaging a large trebuchet for a tv show - got axed when the producers saw the price tag but I got to have some fun doing up a few concepts first...of course had we progressed to construction documents there would have been some corrections for the sake of functionality...

[Crossroads Inc.]

The swinging bucket counter weight is absolutely the way to go. No other system gives the added amount of momentum as a swinging counterweight... Except if you added wheels.

The motion of a Trebuchet on wheels adds significantly to a throw as the momentum carries it forward on the wheels. However I can't recall seeing a Trebuchet with wheels AND a hanging counterweight.

Anyone better at physics then I know if the motion form a swinging counterweight AND wheels would mess things up? Or actually further increase the energy produced?

[Simon_Jester]

I seem to recall judging a science fair project where someone went and tried it, and it worked. They got an extra 5% range or so by adding wheels. But then, it might not have been a swinging counterweight design, so I'm not entirely sure.

[LaCroix]

Wheels always add between 30 and 50% energy to the shot. It works on every type: trebuchet and blige (hanging bucket)
If he had modified the sling release, too, he would have gotten even more range after adding the wheels. A trebuchet needs to be fine-tuned for a setup.

Btw: the vertical drop trebuchet in the Game-show plans (the latest design) would have needed wheels for the axle where the arm pivots. The way its drawn, the whole arm would skid along the rails and probably be ripped off...

And now, for Alyrium Denryle, the archery skeet:

There was much wind from ahead and left, so the disks were pushed away too much. Although they flew much faster than the dices and about 60 feet up and out. Only these four heros actually attempted to hit the flying targets.


The dice flew much better...

I wish I had the acreage to pull off the things you do.

I'm not sure whether the next project will be a cast bronze gun or a 60 foot galeon...

[LadyTevar]

The galleon would only work if you have a pond to float it in.

I have to say the "Archery Skeet Shoot" would be a great idea for Pennsic or Estelle wars. I'd not feel safe firing off arrows anywhere else but a site with a LOT of room for those arrows to come down safely.

[Thanas]

You are aware of the fact that 'AIMING' with that thing is more of a concept and an art form? And orders are given in terms like "I want you to either hit the city or the wall around it, preferably the wall!"

Not true, nations that had standing siege units (Byzantines, Arabs and some Italian states) managed to have great hit rates due to using the same siege weapons and carefully selected projectiles.

Of course, random medieval Lord X did not have the money for that, so in his case it was more of a concept.

[LaCroix]

@ The Lady
I plan to have it moved to the Mediteranian Sea (only a few hours drive away) after it has reached the stage where it can safely float, and then it'll be my holiday vessel. But it is more of a long-term pet project. (But I do have a 40 m long pond...)

@Thanas
I know, but at this small size all possible errors weight much more - a few grams projectile weight difference translate to a few feet range difference. Even with the same stone, I measured 20% variation in range between shots, and +/- 15 degrees axial error. Perfectly round stones would be perfect, but I lack the motivation...

[PaperJack]

have you made a floating arm trebuchet ?

[Superman]

That's a mighty fine looking trebuchet. Just remember to protect it from spearmen and swordsmen... Oh wait, that was Civilization 3.

[LaCroix]

have you made a floating arm trebuchet ?

Obviously, no.

@Superman
I have archers and swordmen to guard it. The town is mine...

[PaperJack]

have you made a floating arm trebuchet ?

Obviously, no.

@Superman
I have archers and swordmen to guard it. The town is mine...

I have worded it wrong, I meant "Why haven't you built a floating arm trebuchet instead of a regular one?" Did you want to be more medievalish ?

[LaCroix]

have you made a floating arm trebuchet ?

Obviously, no.

@Superman
I have archers and swordmen to guard it. The town is mine...

I have worded it wrong, I meant "Why haven't you built a floating arm trebuchet instead of a regular one?" Did you want to be more medievalish ?

As I am reenacting and stuff, I wanted a real trebuchet, and not one of those ugly floaters - with a floater, you have to explain to everyone what the thing is, they see a real trebuchet, and know immediately...

[tim31]

Austrians just know where they're at with weapons. Thanks for the Steyr, by the way!

[madd0ct0r]

As I am reenacting and stuff, I wanted a real trebuchet.

Isn't that threaded steel bar at the pivot though?

Or is this one of those cases where a reenacter comes up against health and safety? (like the thickness of the sheep wool padding needed under a suit of armour)

[JointStrikeFighter]

Austrians just know where they're at with weapons. Thanks for the Steyr, by the way!

Australia owns the rights to the Steyr now

[LaCroix]

As I am reenacting and stuff, I wanted a real trebuchet.

Isn't that threaded steel bar at the pivot though?

Or is this one of those cases where a reenacter comes up against health and safety? (like the thickness of the sheep wool padding needed under a suit of armour)

Well. Safety. Getting crushed by your own war machine takes the fun out of it, doesn't it? And everyone wearing armor without a Gambeson underneath isn't "A". Nobody wore plate on plain clothes or skin.

[tim31]

Australia owns the rights to the Steyr now

Smartarse! And the A2 is better than the referenced image

[Kanastrous]

Well...no offense to Australia but I'm glad I have the Austrian-mfgd version...